SQLite

  $(TOP)/ext/fts3/fts3_test.c  \
  $(TOP)/ext/session/test_session.c \
  $(TOP)/ext/rbu/test_rbu.c 

# Statically linked extensions
#
TESTSRC += \
  $(TOP)/ext/expert/sqlite3expert.c \
  $(TOP)/ext/expert/test_expert.c \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/csv.c \
  $(TOP)/ext/misc/eval.c \
  $(TOP)/ext/misc/fileio.c \
  $(TOP)/ext/misc/fuzzer.c \

sqlite3_analyzer.c: sqlite3.c $(TOP)/src/tclsqlite.c $(TOP)/tool/spaceanal.tcl $(TOP)/tool/mkccode.tcl $(TOP)/tool/sqlite3_analyzer.c.in
	$(TCLSH_CMD) $(TOP)/tool/mkccode.tcl $(TOP)/tool/sqlite3_analyzer.c.in >sqlite3_analyzer.c

sqlite3_analyzer$(TEXE): sqlite3_analyzer.c
	$(LTLINK) sqlite3_analyzer.c -o $@ $(LIBTCL) $(TLIBS)

sqlite3_expert$(TEXE): $(TOP)/ext/expert/sqlite3expert.h $(TOP)/ext/expert/sqlite3expert.c $(TOP)/ext/expert/expert.c sqlite3.c
	$(LTLINK)	$(TOP)/ext/expert/sqlite3expert.h $(TOP)/ext/expert/sqlite3expert.c $(TOP)/ext/expert/expert.c sqlite3.c -o sqlite3_expert $(TLIBS)

CHECKER_DEPS =\
  $(TOP)/tool/mkccode.tcl \
  sqlite3.c \
  $(TOP)/src/tclsqlite.c \
  $(TOP)/ext/repair/sqlite3_checker.tcl \
  $(TOP)/ext/repair/checkindex.c \
  $(TOP)/ext/repair/checkfreelist.c \

  $(TOP)\ext\fts3\fts3_test.c \
  $(TOP)\ext\rbu\test_rbu.c \
  $(TOP)\ext\session\test_session.c

# Statically linked extensions.
#
TESTEXT = \
  $(TOP)\ext\expert\sqlite3expert.c \
  $(TOP)\ext\expert\test_expert.c \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\carray.c \
  $(TOP)\ext\misc\closure.c \
  $(TOP)\ext\misc\csv.c \
  $(TOP)\ext\misc\eval.c \
  $(TOP)\ext\misc\fileio.c \
  $(TOP)\ext\misc\fuzzer.c \

sqlite3_analyzer.c:	$(SQLITE3C) $(SQLITE3H) $(TOP)\src\tclsqlite.c $(TOP)\tool\spaceanal.tcl $(TOP)\tool\mkccode.tcl $(TOP)\tool\sqlite3_analyzer.c.in $(SQLITE_TCL_DEP)
	$(TCLSH_CMD) $(TOP)\tool\mkccode.tcl $(TOP)\tool\sqlite3_analyzer.c.in > $@

sqlite3_analyzer.exe:	sqlite3_analyzer.c $(LIBRESOBJS)
	$(LTLINK) $(NO_WARN) -DBUILD_sqlite -I$(TCLINCDIR) sqlite3_analyzer.c \
		/link $(LDFLAGS) $(LTLINKOPTS) $(LTLIBPATHS) $(LIBRESOBJS) $(LTLIBS) $(TLIBS)

sqlite3_expert.exe: $(SQLITE3C) $(TOP)\ext\expert\sqlite3expert.h $(TOP)\ext\expert\sqlite3expert.c $(TOP)\ext\expert\expert.c
	$(LTLINK) $(NO_WARN)	$(TOP)\ext\expert\sqlite3expert.c $(TOP)\ext\expert\expert.c $(SQLITE3C) $(TLIBS)

CHECKER_DEPS =\
  $(TOP)/tool/mkccode.tcl \
  sqlite3.c \
  $(TOP)/src/tclsqlite.c \
  $(TOP)/ext/repair/sqlite3_checker.tcl \
  $(TOP)/ext/repair/checkindex.c \

## SQLite Expert Extension

This folder contains code for a simple system to propose useful indexes
given a database and a set of SQL queries. It works as follows:

  1. The user database schema is copied to a temporary database.

  1. All SQL queries are prepared against the temporary database.
     Information regarding the WHERE and ORDER BY clauses, and other query
     features that affect index selection are recorded.

  1. The information gathered in step 2 is used to create candidate 
     indexes - indexes that the planner might have made use of in the previous
     step, had they been available.

  1. A subset of the data in the user database is used to generate statistics
     for all existing indexes and the candidate indexes generated in step 3
     above.

  1. The SQL queries are prepared a second time. If the planner uses any
     of the indexes created in step 3, they are recommended to the user.

# C API

The SQLite expert C API is defined in sqlite3expert.h. Most uses will proceed
as follows:

  1. An sqlite3expert object is created by calling **sqlite3\_expert\_new()**.
     A database handle opened by the user is passed as an argument.

  1. The sqlite3expert object is configured with one or more SQL statements
     by making one or more calls to **sqlite3\_expert\_sql()**. Each call may
     specify a single SQL statement, or multiple statements separated by
     semi-colons.
  
  1. Optionally, the **sqlite3\_expert\_config()** API may be used to 
     configure the size of the data subset used to generate index statistics.
     Using a smaller subset of the data can speed up the analysis.

  1. **sqlite3\_expert\_analyze()** is called to run the analysis.

  1. One or more calls are made to **sqlite3\_expert\_report()** to extract
     components of the results of the analysis.

  1. **sqlite3\_expert\_destroy()** is called to free all resources.

Refer to comments in sqlite3expert.h for further details.

# sqlite3_expert application

The file "expert.c" contains the code for a command line application that
uses the API described above. It can be compiled with (for example):

<pre>
  gcc -O2 sqlite3.c expert.c sqlite3expert.c -o sqlite3_expert
</pre>

Assuming the database is named "test.db", it can then be run to analyze a
single query:

<pre>
  ./sqlite3_expert -sql &lt;sql-query&gt; test.db
</pre>

Or an entire text file worth of queries with:

<pre>
  ./sqlite3_expert -file &lt;text-file&gt; test.db
</pre>

By default, sqlite3\_expert generates index statistics using all the data in
the user database. For a large database, this may be prohibitively time
consuming. The "-sample" option may be used to configure sqlite3\_expert to
generate statistics based on an integer percentage of the user database as
follows:

<pre>
  # Generate statistics based on 25% of the user database rows:
  ./sqlite3_expert -sample 25 -sql &lt;sql-query&gt; test.db

  # Do not generate any statistics at all:
  ./sqlite3_expert -sample 0 -sql &lt;sql-query&gt; test.db
</pre>

/*
** 2017 April 07
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/


#include <sqlite3.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "sqlite3expert.h"


static void option_requires_argument(const char *zOpt){
  fprintf(stderr, "Option requires an argument: %s\n", zOpt);
  exit(-3);
}

static int option_integer_arg(const char *zVal){
  return atoi(zVal);
}

static void usage(char **argv){
  fprintf(stderr, "\n");
  fprintf(stderr, "Usage %s ?OPTIONS? DATABASE\n", argv[0]);
  fprintf(stderr, "\n");
  fprintf(stderr, "Options are:\n");
  fprintf(stderr, "  -sql SQL   (analyze SQL statements passed as argument)\n");
  fprintf(stderr, "  -file FILE (read SQL statements from file FILE)\n");
  fprintf(stderr, "  -verbose LEVEL (integer verbosity level. default 1)\n");
  fprintf(stderr, "  -sample PERCENT (percent of db to sample. default 100)\n");
  exit(-1);
}

static int readSqlFromFile(sqlite3expert *p, const char *zFile, char **pzErr){
  FILE *in = fopen(zFile, "rb");
  long nIn;
  size_t nRead;
  char *pBuf;
  int rc;
  if( in==0 ){
    *pzErr = sqlite3_mprintf("failed to open file %s\n", zFile);
    return SQLITE_ERROR;
  }
  fseek(in, 0, SEEK_END);
  nIn = ftell(in);
  rewind(in);
  pBuf = sqlite3_malloc64( nIn+1 );
  nRead = fread(pBuf, nIn, 1, in);
  fclose(in);
  if( nRead!=1 ){
    sqlite3_free(pBuf);
    *pzErr = sqlite3_mprintf("failed to read file %s\n", zFile);
    return SQLITE_ERROR;
  }
  pBuf[nIn] = 0;
  rc = sqlite3_expert_sql(p, pBuf, pzErr);
  sqlite3_free(pBuf);
  return rc;
}

int main(int argc, char **argv){
  const char *zDb;
  int rc = 0;
  char *zErr = 0;
  int i;
  int iVerbose = 1;               /* -verbose option */

  sqlite3 *db = 0;
  sqlite3expert *p = 0;

  if( argc<2 ) usage(argv);
  zDb = argv[argc-1];
  if( zDb[0]=='-' ) usage(argv);
  rc = sqlite3_open(zDb, &db);
  if( rc!=SQLITE_OK ){
    fprintf(stderr, "Cannot open db file: %s - %s\n", zDb, sqlite3_errmsg(db));
    exit(-2);
  }

  p = sqlite3_expert_new(db, &zErr);
  if( p==0 ){
    fprintf(stderr, "Cannot run analysis: %s\n", zErr);
    rc = 1;
  }else{
    for(i=1; i<(argc-1); i++){
      char *zArg = argv[i];
      if( zArg[0]=='-' && zArg[1]=='-' && zArg[2]!=0 ) zArg++;
      int nArg = (int)strlen(zArg);
      if( nArg>=2 && 0==sqlite3_strnicmp(zArg, "-file", nArg) ){
        if( ++i==(argc-1) ) option_requires_argument("-file");
        rc = readSqlFromFile(p, argv[i], &zErr);
      }

      else if( nArg>=3 && 0==sqlite3_strnicmp(zArg, "-sql", nArg) ){
        if( ++i==(argc-1) ) option_requires_argument("-sql");
        rc = sqlite3_expert_sql(p, argv[i], &zErr);
      }

      else if( nArg>=3 && 0==sqlite3_strnicmp(zArg, "-sample", nArg) ){
        int iSample;
        if( ++i==(argc-1) ) option_requires_argument("-sample");
        iSample = option_integer_arg(argv[i]);
        sqlite3_expert_config(p, EXPERT_CONFIG_SAMPLE, iSample);
      }

      else if( nArg>=2 && 0==sqlite3_strnicmp(zArg, "-verbose", nArg) ){
        if( ++i==(argc-1) ) option_requires_argument("-verbose");
        iVerbose = option_integer_arg(argv[i]);
      }

      else{
        usage(argv);
      }
    }
  }

  if( rc==SQLITE_OK ){
    rc = sqlite3_expert_analyze(p, &zErr);
  }

  if( rc==SQLITE_OK ){
    int nQuery = sqlite3_expert_count(p);
    if( iVerbose>0 ){
      const char *zCand = sqlite3_expert_report(p,0,EXPERT_REPORT_CANDIDATES);
      fprintf(stdout, "-- Candidates -------------------------------\n");
      fprintf(stdout, "%s\n", zCand);
    }
    for(i=0; i<nQuery; i++){
      const char *zSql = sqlite3_expert_report(p, i, EXPERT_REPORT_SQL);
      const char *zIdx = sqlite3_expert_report(p, i, EXPERT_REPORT_INDEXES);
      const char *zEQP = sqlite3_expert_report(p, i, EXPERT_REPORT_PLAN);
      if( zIdx==0 ) zIdx = "(no new indexes)\n";
      if( iVerbose>0 ){
        fprintf(stdout, "-- Query %d ----------------------------------\n",i+1);
        fprintf(stdout, "%s\n\n", zSql);
      }
      fprintf(stdout, "%s\n%s\n", zIdx, zEQP);
    }
  }else{
    fprintf(stderr, "Error: %s\n", zErr ? zErr : "?");
  }

  sqlite3_expert_destroy(p);
  sqlite3_free(zErr);
  return rc;
}

# 2009 Nov 11
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# The focus of this file is testing the CLI shell tool. Specifically,
# the ".recommend" command.
#
#

# Test plan:
#
#
if {![info exists testdir]} {
  set testdir [file join [file dirname [info script]] .. .. test]
}
source $testdir/tester.tcl
set testprefix expert1

set CLI [test_binary_name sqlite3]
set CMD [test_binary_name sqlite3_expert]

proc squish {txt} {
  regsub -all {[[:space:]]+} $txt { }
}

proc do_setup_rec_test {tn setup sql res} {
  reset_db
  db eval $setup
  uplevel [list do_rec_test $tn $sql $res]
}

foreach {tn setup} {
  1 {
    if {![file executable $CMD]} { continue }

    proc do_rec_test {tn sql res} {
      set res [squish [string trim $res]]
      set tst [subst -nocommands { 
        squish [string trim [exec $::CMD -verbose 0 -sql {$sql;} test.db]]
      }]
      uplevel [list do_test $tn $tst $res]
    }
  }
  2 {
    if {[info commands sqlite3_expert_new]==""} { continue }

    proc do_rec_test {tn sql res} {
      set expert [sqlite3_expert_new db]
      $expert sql $sql
      $expert analyze

      set result [list]
      for {set i 0} {$i < [$expert count]} {incr i} {
        set idx [string trim [$expert report $i indexes]]
        if {$idx==""} {set idx "(no new indexes)"}
        lappend result $idx
        lappend result [string trim [$expert report $i plan]]
      }

      $expert destroy

      set tst [subst -nocommands {set {} [squish [join {$result}]]}]
      uplevel [list do_test $tn $tst [string trim [squish $res]]]
    }
  }
  3 {
    if {![file executable $CLI]} { continue }

    proc do_rec_test {tn sql res} {
      set res [squish [string trim $res]]
      set tst [subst -nocommands { 
        squish [string trim [exec $::CLI test.db ".expert" {$sql;}]]
      }]
      uplevel [list do_test $tn $tst $res]
    }
  }
} {

  eval $setup


do_setup_rec_test $tn.1 { CREATE TABLE t1(a, b, c) } {
  SELECT * FROM t1
} {
  (no new indexes)
  0|0|0|SCAN TABLE t1
}

do_setup_rec_test $tn.2 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT * FROM t1 WHERE b>?;
} {
  CREATE INDEX t1_idx_00000062 ON t1(b);
  0|0|0|SEARCH TABLE t1 USING INDEX t1_idx_00000062 (b>?)
}

do_setup_rec_test $tn.3 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT * FROM t1 WHERE b COLLATE nocase BETWEEN ? AND ?
} {
  CREATE INDEX t1_idx_3e094c27 ON t1(b COLLATE NOCASE);
  0|0|0|SEARCH TABLE t1 USING INDEX t1_idx_3e094c27 (b>? AND b<?)
}

do_setup_rec_test $tn.4 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT a FROM t1 ORDER BY b;
} {
  CREATE INDEX t1_idx_00000062 ON t1(b);
  0|0|0|SCAN TABLE t1 USING INDEX t1_idx_00000062
}

do_setup_rec_test $tn.5 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT a FROM t1 WHERE a=? ORDER BY b;
} {
  CREATE INDEX t1_idx_000123a7 ON t1(a, b);
  0|0|0|SEARCH TABLE t1 USING COVERING INDEX t1_idx_000123a7 (a=?)
}

do_setup_rec_test $tn.6 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT min(a) FROM t1
} {
  CREATE INDEX t1_idx_00000061 ON t1(a);
  0|0|0|SEARCH TABLE t1 USING COVERING INDEX t1_idx_00000061
}

do_setup_rec_test $tn.7 {
  CREATE TABLE t1(a, b, c);
} {
  SELECT * FROM t1 ORDER BY a, b, c;
} {
  CREATE INDEX t1_idx_033e95fe ON t1(a, b, c);
  0|0|0|SCAN TABLE t1 USING COVERING INDEX t1_idx_033e95fe
}

#do_setup_rec_test $tn.1.8 {
#  CREATE TABLE t1(a, b, c);
#} {
#  SELECT * FROM t1 ORDER BY a ASC, b COLLATE nocase DESC, c ASC;
#} {
#  CREATE INDEX t1_idx_5be6e222 ON t1(a, b COLLATE NOCASE DESC, c);
#  0|0|0|SCAN TABLE t1 USING COVERING INDEX t1_idx_5be6e222
#}

do_setup_rec_test $tn.8.1 {
  CREATE TABLE t1(a COLLATE NOCase, b, c);
} {
  SELECT * FROM t1 WHERE a=?
} {
  CREATE INDEX t1_idx_00000061 ON t1(a);
  0|0|0|SEARCH TABLE t1 USING INDEX t1_idx_00000061 (a=?)
}
do_setup_rec_test $tn.8.2 {
  CREATE TABLE t1(a, b COLLATE nocase, c);
} {
  SELECT * FROM t1 ORDER BY a ASC, b DESC, c ASC;
} {
  CREATE INDEX t1_idx_5cb97285 ON t1(a, b DESC, c);
  0|0|0|SCAN TABLE t1 USING COVERING INDEX t1_idx_5cb97285
}


# Tables with names that require quotes.
#
do_setup_rec_test $tn.9.1 {
  CREATE TABLE "t t"(a, b, c);
} {
  SELECT * FROM "t t" WHERE a=?
} {
  CREATE INDEX 't t_idx_00000061' ON 't t'(a);
  0|0|0|SEARCH TABLE t t USING INDEX t t_idx_00000061 (a=?) 
}

do_setup_rec_test $tn.9.2 {
  CREATE TABLE "t t"(a, b, c);
} {
  SELECT * FROM "t t" WHERE b BETWEEN ? AND ?
} {
  CREATE INDEX 't t_idx_00000062' ON 't t'(b);
  0|0|0|SEARCH TABLE t t USING INDEX t t_idx_00000062 (b>? AND b<?)
}

# Columns with names that require quotes.
#
do_setup_rec_test $tn.10.1 {
  CREATE TABLE t3(a, "b b", c);
} {
  SELECT * FROM t3 WHERE "b b" = ?
} {
  CREATE INDEX t3_idx_00050c52 ON t3('b b');
  0|0|0|SEARCH TABLE t3 USING INDEX t3_idx_00050c52 (b b=?)
}

do_setup_rec_test $tn.10.2 {
  CREATE TABLE t3(a, "b b", c);
} {
  SELECT * FROM t3 ORDER BY "b b"
} {
  CREATE INDEX t3_idx_00050c52 ON t3('b b');
  0|0|0|SCAN TABLE t3 USING INDEX t3_idx_00050c52
}

# Transitive constraints
#
do_setup_rec_test $tn.11.1 {
  CREATE TABLE t5(a, b);
  CREATE TABLE t6(c, d);
} {
  SELECT * FROM t5, t6 WHERE a=? AND b=c AND c=?
} {
  CREATE INDEX t5_idx_000123a7 ON t5(a, b);
  CREATE INDEX t6_idx_00000063 ON t6(c);
  0|0|1|SEARCH TABLE t6 USING INDEX t6_idx_00000063 (c=?) 
  0|1|0|SEARCH TABLE t5 USING COVERING INDEX t5_idx_000123a7 (a=? AND b=?)
}

# OR terms.
#
do_setup_rec_test $tn.12.1 {
  CREATE TABLE t7(a, b);
} {
  SELECT * FROM t7 WHERE a=? OR b=?
} {
  CREATE INDEX t7_idx_00000062 ON t7(b);
  CREATE INDEX t7_idx_00000061 ON t7(a);
  0|0|0|SEARCH TABLE t7 USING INDEX t7_idx_00000061 (a=?) 
  0|0|0|SEARCH TABLE t7 USING INDEX t7_idx_00000062 (b=?)
}

# rowid terms.
#
do_setup_rec_test $tn.13.1 {
  CREATE TABLE t8(a, b);
} {
  SELECT * FROM t8 WHERE rowid=?
} {
  (no new indexes)
  0|0|0|SEARCH TABLE t8 USING INTEGER PRIMARY KEY (rowid=?)
}
do_setup_rec_test $tn.13.2 {
  CREATE TABLE t8(a, b);
} {
  SELECT * FROM t8 ORDER BY rowid
} {
  (no new indexes)
  0|0|0|SCAN TABLE t8
}
do_setup_rec_test $tn.13.3 {
  CREATE TABLE t8(a, b);
} {
  SELECT * FROM t8 WHERE a=? ORDER BY rowid
} {
  CREATE INDEX t8_idx_00000061 ON t8(a); 
  0|0|0|SEARCH TABLE t8 USING INDEX t8_idx_00000061 (a=?)
}

# Triggers
#
do_setup_rec_test $tn.14 {
  CREATE TABLE t9(a, b, c);
  CREATE TABLE t10(a, b, c);
  CREATE TRIGGER t9t AFTER INSERT ON t9 BEGIN
    UPDATE t10 SET a=new.a WHERE b = new.b;
  END;
} {
  INSERT INTO t9 VALUES(?, ?, ?);
} {
  CREATE INDEX t10_idx_00000062 ON t10(b); 
  0|0|0|SEARCH TABLE t10 USING INDEX t10_idx_00000062 (b=?)
}

do_setup_rec_test $tn.15 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(c, d);

  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<100)
  INSERT INTO t1 SELECT (i-1)/50, (i-1)/20 FROM s;

  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<100)
  INSERT INTO t2 SELECT (i-1)/20, (i-1)/5 FROM s;
} {
  SELECT * FROM t2, t1 WHERE b=? AND d=? AND t2.rowid=t1.rowid
} {
  CREATE INDEX t2_idx_00000064 ON t2(d);
  0|0|0|SEARCH TABLE t2 USING INDEX t2_idx_00000064 (d=?) 
  0|1|1|SEARCH TABLE t1 USING INTEGER PRIMARY KEY (rowid=?)
}

do_setup_rec_test $tn.16 {
  CREATE TABLE t1(a, b);
} {
  SELECT * FROM t1 WHERE b IS NOT NULL;
} {
  (no new indexes)
  0|0|0|SCAN TABLE t1
}

}

proc do_candidates_test {tn sql res} {
  set res [squish [string trim $res]]

  set expert [sqlite3_expert_new db]
  $expert sql $sql
  $expert analyze

  set candidates [squish [string trim [$expert report 0 candidates]]]
  $expert destroy

  uplevel [list do_test $tn [list set {} $candidates] $res]
}


reset_db
do_execsql_test 3.0 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(c, d);

  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<100)
  INSERT INTO t1 SELECT (i-1)/50, (i-1)/20 FROM s;

  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<100)
  INSERT INTO t2 SELECT (i-1)/20, (i-1)/5 FROM s;
}
do_candidates_test 3.1 {
  SELECT * FROM t1,t2 WHERE (b=? OR a=?) AND (c=? OR d=?)
} {
  CREATE INDEX t1_idx_00000062 ON t1(b); -- stat1: 100 20 
  CREATE INDEX t1_idx_00000061 ON t1(a); -- stat1: 100 50 
  CREATE INDEX t2_idx_00000063 ON t2(c); -- stat1: 100 20 
  CREATE INDEX t2_idx_00000064 ON t2(d); -- stat1: 100 5
}

do_candidates_test 3.2 {
  SELECT * FROM t1,t2 WHERE a=? AND b=? AND c=? AND d=?
} {
  CREATE INDEX t1_idx_000123a7 ON t1(a, b); -- stat1: 100 50 17
  CREATE INDEX t2_idx_0001295b ON t2(c, d); -- stat1: 100 20 5
}

do_execsql_test 3.2 {
  CREATE INDEX t1_idx_00000061 ON t1(a); -- stat1: 100 50 
  CREATE INDEX t1_idx_00000062 ON t1(b); -- stat1: 100 20 
  CREATE INDEX t1_idx_000123a7 ON t1(a, b); -- stat1: 100 50 16

  CREATE INDEX t2_idx_00000063 ON t2(c); -- stat1: 100 20 
  CREATE INDEX t2_idx_00000064 ON t2(d); -- stat1: 100 5
  CREATE INDEX t2_idx_0001295b ON t2(c, d); -- stat1: 100 20 5

  ANALYZE;
  SELECT * FROM sqlite_stat1 ORDER BY 1, 2;
} {
  t1 t1_idx_00000061 {100 50} 
  t1 t1_idx_00000062 {100 20}
  t1 t1_idx_000123a7 {100 50 17}
  t2 t2_idx_00000063 {100 20} 
  t2 t2_idx_00000064 {100 5} 
  t2 t2_idx_0001295b {100 20 5}
}


finish_test

/*
** 2017 April 09
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/
#include "sqlite3expert.h"
#include <assert.h>
#include <string.h>
#include <stdio.h>

typedef sqlite3_int64 i64;
typedef sqlite3_uint64 u64;

typedef struct IdxColumn IdxColumn;
typedef struct IdxConstraint IdxConstraint;
typedef struct IdxScan IdxScan;
typedef struct IdxStatement IdxStatement;
typedef struct IdxTable IdxTable;
typedef struct IdxWrite IdxWrite;

#define STRLEN  (int)strlen

/*
** A temp table name that we assume no user database will actually use.
** If this assumption proves incorrect triggers on the table with the
** conflicting name will be ignored.
*/
#define UNIQUE_TABLE_NAME "t592690916721053953805701627921227776"

/*
** A single constraint. Equivalent to either "col = ?" or "col < ?" (or
** any other type of single-ended range constraint on a column).
**
** pLink:
**   Used to temporarily link IdxConstraint objects into lists while
**   creating candidate indexes.
*/
struct IdxConstraint {
  char *zColl;                    /* Collation sequence */
  int bRange;                     /* True for range, false for eq */
  int iCol;                       /* Constrained table column */
  int bFlag;                      /* Used by idxFindCompatible() */
  int bDesc;                      /* True if ORDER BY <expr> DESC */
  IdxConstraint *pNext;           /* Next constraint in pEq or pRange list */
  IdxConstraint *pLink;           /* See above */
};

/*
** A single scan of a single table.
*/
struct IdxScan {
  IdxTable *pTab;                 /* Associated table object */
  int iDb;                        /* Database containing table zTable */
  i64 covering;                   /* Mask of columns required for cov. index */
  IdxConstraint *pOrder;          /* ORDER BY columns */
  IdxConstraint *pEq;             /* List of == constraints */
  IdxConstraint *pRange;          /* List of < constraints */
  IdxScan *pNextScan;             /* Next IdxScan object for same analysis */
};

/*
** Information regarding a single database table. Extracted from 
** "PRAGMA table_info" by function idxGetTableInfo().
*/
struct IdxColumn {
  char *zName;
  char *zColl;
  int iPk;
};
struct IdxTable {
  int nCol;
  char *zName;                    /* Table name */
  IdxColumn *aCol;
  IdxTable *pNext;                /* Next table in linked list of all tables */
};

/*
** An object of the following type is created for each unique table/write-op
** seen. The objects are stored in a singly-linked list beginning at
** sqlite3expert.pWrite.
*/
struct IdxWrite {
  IdxTable *pTab;
  int eOp;                        /* SQLITE_UPDATE, DELETE or INSERT */
  IdxWrite *pNext;
};

/*
** Each statement being analyzed is represented by an instance of this
** structure.
*/
struct IdxStatement {
  int iId;                        /* Statement number */
  char *zSql;                     /* SQL statement */
  char *zIdx;                     /* Indexes */
  char *zEQP;                     /* Plan */
  IdxStatement *pNext;
};


/*
** A hash table for storing strings. With space for a payload string
** with each entry. Methods are:
**
**   idxHashInit()
**   idxHashClear()
**   idxHashAdd()
**   idxHashSearch()
*/
#define IDX_HASH_SIZE 1023
typedef struct IdxHashEntry IdxHashEntry;
typedef struct IdxHash IdxHash;
struct IdxHashEntry {
  char *zKey;                     /* nul-terminated key */
  char *zVal;                     /* nul-terminated value string */
  char *zVal2;                    /* nul-terminated value string 2 */
  IdxHashEntry *pHashNext;        /* Next entry in same hash bucket */
  IdxHashEntry *pNext;            /* Next entry in hash */
};
struct IdxHash {
  IdxHashEntry *pFirst;
  IdxHashEntry *aHash[IDX_HASH_SIZE];
};

/*
** sqlite3expert object.
*/
struct sqlite3expert {
  int iSample;                    /* Percentage of tables to sample for stat1 */
  sqlite3 *db;                    /* User database */
  sqlite3 *dbm;                   /* In-memory db for this analysis */
  sqlite3 *dbv;                   /* Vtab schema for this analysis */
  IdxTable *pTable;               /* List of all IdxTable objects */
  IdxScan *pScan;                 /* List of scan objects */
  IdxWrite *pWrite;               /* List of write objects */
  IdxStatement *pStatement;       /* List of IdxStatement objects */
  int bRun;                       /* True once analysis has run */
  char **pzErrmsg;
  int rc;                         /* Error code from whereinfo hook */
  IdxHash hIdx;                   /* Hash containing all candidate indexes */
  char *zCandidates;              /* For EXPERT_REPORT_CANDIDATES */
};


/*
** Allocate and return nByte bytes of zeroed memory using sqlite3_malloc(). 
** If the allocation fails, set *pRc to SQLITE_NOMEM and return NULL.
*/
static void *idxMalloc(int *pRc, int nByte){
  void *pRet;
  assert( *pRc==SQLITE_OK );
  assert( nByte>0 );
  pRet = sqlite3_malloc(nByte);
  if( pRet ){
    memset(pRet, 0, nByte);
  }else{
    *pRc = SQLITE_NOMEM;
  }
  return pRet;
}

/*
** Initialize an IdxHash hash table.
*/
static void idxHashInit(IdxHash *pHash){
  memset(pHash, 0, sizeof(IdxHash));
}

/*
** Reset an IdxHash hash table.
*/
static void idxHashClear(IdxHash *pHash){
  int i;
  for(i=0; i<IDX_HASH_SIZE; i++){
    IdxHashEntry *pEntry;
    IdxHashEntry *pNext;
    for(pEntry=pHash->aHash[i]; pEntry; pEntry=pNext){
      pNext = pEntry->pHashNext;
      sqlite3_free(pEntry->zVal2);
      sqlite3_free(pEntry);
    }
  }
  memset(pHash, 0, sizeof(IdxHash));
}

/*
** Return the index of the hash bucket that the string specified by the
** arguments to this function belongs.
*/
static int idxHashString(const char *z, int n){
  unsigned int ret = 0;
  int i;
  for(i=0; i<n; i++){
    ret += (ret<<3) + (unsigned char)(z[i]);
  }
  return (int)(ret % IDX_HASH_SIZE);
}

/*
** If zKey is already present in the hash table, return non-zero and do
** nothing. Otherwise, add an entry with key zKey and payload string zVal to
** the hash table passed as the second argument. 
*/
static int idxHashAdd(
  int *pRc, 
  IdxHash *pHash, 
  const char *zKey,
  const char *zVal
){
  int nKey = STRLEN(zKey);
  int iHash = idxHashString(zKey, nKey);
  int nVal = (zVal ? STRLEN(zVal) : 0);
  IdxHashEntry *pEntry;
  assert( iHash>=0 );
  for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
    if( STRLEN(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
      return 1;
    }
  }
  pEntry = idxMalloc(pRc, sizeof(IdxHashEntry) + nKey+1 + nVal+1);
  if( pEntry ){
    pEntry->zKey = (char*)&pEntry[1];
    memcpy(pEntry->zKey, zKey, nKey);
    if( zVal ){
      pEntry->zVal = &pEntry->zKey[nKey+1];
      memcpy(pEntry->zVal, zVal, nVal);
    }
    pEntry->pHashNext = pHash->aHash[iHash];
    pHash->aHash[iHash] = pEntry;

    pEntry->pNext = pHash->pFirst;
    pHash->pFirst = pEntry;
  }
  return 0;
}

/*
** If zKey/nKey is present in the hash table, return a pointer to the 
** hash-entry object.
*/
static IdxHashEntry *idxHashFind(IdxHash *pHash, const char *zKey, int nKey){
  int iHash;
  IdxHashEntry *pEntry;
  if( nKey<0 ) nKey = STRLEN(zKey);
  iHash = idxHashString(zKey, nKey);
  assert( iHash>=0 );
  for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
    if( STRLEN(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
      return pEntry;
    }
  }
  return 0;
}

/*
** If the hash table contains an entry with a key equal to the string
** passed as the final two arguments to this function, return a pointer
** to the payload string. Otherwise, if zKey/nKey is not present in the
** hash table, return NULL.
*/
static const char *idxHashSearch(IdxHash *pHash, const char *zKey, int nKey){
  IdxHashEntry *pEntry = idxHashFind(pHash, zKey, nKey);
  if( pEntry ) return pEntry->zVal;
  return 0;
}

/*
** Allocate and return a new IdxConstraint object. Set the IdxConstraint.zColl
** variable to point to a copy of nul-terminated string zColl.
*/
static IdxConstraint *idxNewConstraint(int *pRc, const char *zColl){
  IdxConstraint *pNew;
  int nColl = STRLEN(zColl);

  assert( *pRc==SQLITE_OK );
  pNew = (IdxConstraint*)idxMalloc(pRc, sizeof(IdxConstraint) * nColl + 1);
  if( pNew ){
    pNew->zColl = (char*)&pNew[1];
    memcpy(pNew->zColl, zColl, nColl+1);
  }
  return pNew;
}

/*
** An error associated with database handle db has just occurred. Pass
** the error message to callback function xOut.
*/
static void idxDatabaseError(
  sqlite3 *db,                    /* Database handle */
  char **pzErrmsg                 /* Write error here */
){
  *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
}

/*
** Prepare an SQL statement.
*/
static int idxPrepareStmt(
  sqlite3 *db,                    /* Database handle to compile against */
  sqlite3_stmt **ppStmt,          /* OUT: Compiled SQL statement */
  char **pzErrmsg,                /* OUT: sqlite3_malloc()ed error message */
  const char *zSql                /* SQL statement to compile */
){
  int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
  if( rc!=SQLITE_OK ){
    *ppStmt = 0;
    idxDatabaseError(db, pzErrmsg);
  }
  return rc;
}

/*
** Prepare an SQL statement using the results of a printf() formatting.
*/
static int idxPrintfPrepareStmt(
  sqlite3 *db,                    /* Database handle to compile against */
  sqlite3_stmt **ppStmt,          /* OUT: Compiled SQL statement */
  char **pzErrmsg,                /* OUT: sqlite3_malloc()ed error message */
  const char *zFmt,               /* printf() format of SQL statement */
  ...                             /* Trailing printf() arguments */
){
  va_list ap;
  int rc;
  char *zSql;
  va_start(ap, zFmt);
  zSql = sqlite3_vmprintf(zFmt, ap);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = idxPrepareStmt(db, ppStmt, pzErrmsg, zSql);
    sqlite3_free(zSql);
  }
  va_end(ap);
  return rc;
}


/*************************************************************************
** Beginning of virtual table implementation.
*/
typedef struct ExpertVtab ExpertVtab;
struct ExpertVtab {
  sqlite3_vtab base;
  IdxTable *pTab;
  sqlite3expert *pExpert;
};

typedef struct ExpertCsr ExpertCsr;
struct ExpertCsr {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pData;
};

static char *expertDequote(const char *zIn){
  int n = STRLEN(zIn);
  char *zRet = sqlite3_malloc(n);

  assert( zIn[0]=='\'' );
  assert( zIn[n-1]=='\'' );

  if( zRet ){
    int iOut = 0;
    int iIn = 0;
    for(iIn=1; iIn<(n-1); iIn++){
      if( zIn[iIn]=='\'' ){
        assert( zIn[iIn+1]=='\'' );
        iIn++;
      }
      zRet[iOut++] = zIn[iIn];
    }
    zRet[iOut] = '\0';
  }

  return zRet;
}

/* 
** This function is the implementation of both the xConnect and xCreate
** methods of the r-tree virtual table.
**
**   argv[0]   -> module name
**   argv[1]   -> database name
**   argv[2]   -> table name
**   argv[...] -> column names...
*/
static int expertConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3expert *pExpert = (sqlite3expert*)pAux;
  ExpertVtab *p = 0;
  int rc;

  if( argc!=4 ){
    *pzErr = sqlite3_mprintf("internal error!");
    rc = SQLITE_ERROR;
  }else{
    char *zCreateTable = expertDequote(argv[3]);
    if( zCreateTable ){
      rc = sqlite3_declare_vtab(db, zCreateTable);
      if( rc==SQLITE_OK ){
        p = idxMalloc(&rc, sizeof(ExpertVtab));
      }
      if( rc==SQLITE_OK ){
        p->pExpert = pExpert;
        p->pTab = pExpert->pTable;
        assert( sqlite3_stricmp(p->pTab->zName, argv[2])==0 );
      }
      sqlite3_free(zCreateTable);
    }else{
      rc = SQLITE_NOMEM;
    }
  }

  *ppVtab = (sqlite3_vtab*)p;
  return rc;
}

static int expertDisconnect(sqlite3_vtab *pVtab){
  ExpertVtab *p = (ExpertVtab*)pVtab;
  sqlite3_free(p);
  return SQLITE_OK;
}

static int expertBestIndex(sqlite3_vtab *pVtab, sqlite3_index_info *pIdxInfo){
  ExpertVtab *p = (ExpertVtab*)pVtab;
  int rc = SQLITE_OK;
  int n = 0;
  IdxScan *pScan;
  const int opmask = 
    SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_GT |
    SQLITE_INDEX_CONSTRAINT_LT | SQLITE_INDEX_CONSTRAINT_GE |
    SQLITE_INDEX_CONSTRAINT_LE;

  pScan = idxMalloc(&rc, sizeof(IdxScan));
  if( pScan ){
    int i;

    /* Link the new scan object into the list */
    pScan->pTab = p->pTab;
    pScan->pNextScan = p->pExpert->pScan;
    p->pExpert->pScan = pScan;

    /* Add the constraints to the IdxScan object */
    for(i=0; i<pIdxInfo->nConstraint; i++){
      struct sqlite3_index_constraint *pCons = &pIdxInfo->aConstraint[i];
      if( pCons->usable 
       && pCons->iColumn>=0 
       && p->pTab->aCol[pCons->iColumn].iPk==0
       && (pCons->op & opmask) 
      ){
        IdxConstraint *pNew;
        const char *zColl = sqlite3_vtab_collation(pIdxInfo, i);
        pNew = idxNewConstraint(&rc, zColl);
        if( pNew ){
          pNew->iCol = pCons->iColumn;
          if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ ){
            pNew->pNext = pScan->pEq;
            pScan->pEq = pNew;
          }else{
            pNew->bRange = 1;
            pNew->pNext = pScan->pRange;
            pScan->pRange = pNew;
          }
        }
        n++;
        pIdxInfo->aConstraintUsage[i].argvIndex = n;
      }
    }

    /* Add the ORDER BY to the IdxScan object */
    for(i=pIdxInfo->nOrderBy-1; i>=0; i--){
      int iCol = pIdxInfo->aOrderBy[i].iColumn;
      if( iCol>=0 ){
        IdxConstraint *pNew = idxNewConstraint(&rc, p->pTab->aCol[iCol].zColl);
        if( pNew ){
          pNew->iCol = iCol;
          pNew->bDesc = pIdxInfo->aOrderBy[i].desc;
          pNew->pNext = pScan->pOrder;
          pNew->pLink = pScan->pOrder;
          pScan->pOrder = pNew;
          n++;
        }
      }
    }
  }

  pIdxInfo->estimatedCost = 1000000.0 / n;
  return rc;
}

static int expertUpdate(
  sqlite3_vtab *pVtab, 
  int nData, 
  sqlite3_value **azData, 
  sqlite_int64 *pRowid
){
  return SQLITE_OK;
}

/* 
** Virtual table module xOpen method.
*/
static int expertOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  int rc = SQLITE_OK;
  ExpertCsr *pCsr;
  pCsr = idxMalloc(&rc, sizeof(ExpertCsr));
  *ppCursor = (sqlite3_vtab_cursor*)pCsr;
  return rc;
}

/* 
** Virtual table module xClose method.
*/
static int expertClose(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  sqlite3_finalize(pCsr->pData);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Virtual table module xEof method.
**
** Return non-zero if the cursor does not currently point to a valid 
** record (i.e if the scan has finished), or zero otherwise.
*/
static int expertEof(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  return pCsr->pData==0;
}

/* 
** Virtual table module xNext method.
*/
static int expertNext(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  int rc = SQLITE_OK;

  assert( pCsr->pData );
  rc = sqlite3_step(pCsr->pData);
  if( rc!=SQLITE_ROW ){
    rc = sqlite3_finalize(pCsr->pData);
    pCsr->pData = 0;
  }else{
    rc = SQLITE_OK;
  }

  return rc;
}

/* 
** Virtual table module xRowid method.
*/
static int expertRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  *pRowid = 0;
  return SQLITE_OK;
}

/* 
** Virtual table module xColumn method.
*/
static int expertColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  sqlite3_value *pVal;
  pVal = sqlite3_column_value(pCsr->pData, i);
  if( pVal ){
    sqlite3_result_value(ctx, pVal);
  }
  return SQLITE_OK;
}

/* 
** Virtual table module xFilter method.
*/
static int expertFilter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  ExpertVtab *pVtab = (ExpertVtab*)(cur->pVtab);
  sqlite3expert *pExpert = pVtab->pExpert;
  int rc;

  rc = sqlite3_finalize(pCsr->pData);
  pCsr->pData = 0;
  if( rc==SQLITE_OK ){
    rc = idxPrintfPrepareStmt(pExpert->db, &pCsr->pData, &pVtab->base.zErrMsg,
        "SELECT * FROM main.%Q WHERE sample()", pVtab->pTab->zName
    );
  }

  if( rc==SQLITE_OK ){
    rc = expertNext(cur);
  }
  return rc;
}

static int idxRegisterVtab(sqlite3expert *p){
  static sqlite3_module expertModule = {
    2,                            /* iVersion */
    expertConnect,                /* xCreate - create a table */
    expertConnect,                /* xConnect - connect to an existing table */
    expertBestIndex,              /* xBestIndex - Determine search strategy */
    expertDisconnect,             /* xDisconnect - Disconnect from a table */
    expertDisconnect,             /* xDestroy - Drop a table */
    expertOpen,                   /* xOpen - open a cursor */
    expertClose,                  /* xClose - close a cursor */
    expertFilter,                 /* xFilter - configure scan constraints */
    expertNext,                   /* xNext - advance a cursor */
    expertEof,                    /* xEof */
    expertColumn,                 /* xColumn - read data */
    expertRowid,                  /* xRowid - read data */
    expertUpdate,                 /* xUpdate - write data */
    0,                            /* xBegin - begin transaction */
    0,                            /* xSync - sync transaction */
    0,                            /* xCommit - commit transaction */
    0,                            /* xRollback - rollback transaction */
    0,                            /* xFindFunction - function overloading */
    0,                            /* xRename - rename the table */
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
  };

  return sqlite3_create_module(p->dbv, "expert", &expertModule, (void*)p);
}
/*
** End of virtual table implementation.
*************************************************************************/
/*
** Finalize SQL statement pStmt. If (*pRc) is SQLITE_OK when this function
** is called, set it to the return value of sqlite3_finalize() before
** returning. Otherwise, discard the sqlite3_finalize() return value.
*/
static void idxFinalize(int *pRc, sqlite3_stmt *pStmt){
  int rc = sqlite3_finalize(pStmt);
  if( *pRc==SQLITE_OK ) *pRc = rc;
}

/*
** Attempt to allocate an IdxTable structure corresponding to table zTab
** in the main database of connection db. If successful, set (*ppOut) to
** point to the new object and return SQLITE_OK. Otherwise, return an
** SQLite error code and set (*ppOut) to NULL. In this case *pzErrmsg may be
** set to point to an error string.
**
** It is the responsibility of the caller to eventually free either the
** IdxTable object or error message using sqlite3_free().
*/
static int idxGetTableInfo(
  sqlite3 *db,                    /* Database connection to read details from */
  const char *zTab,               /* Table name */
  IdxTable **ppOut,               /* OUT: New object (if successful) */
  char **pzErrmsg                 /* OUT: Error message (if not) */
){
  sqlite3_stmt *p1 = 0;
  int nCol = 0;
  int nTab = STRLEN(zTab);
  int nByte = sizeof(IdxTable) + nTab + 1;
  IdxTable *pNew = 0;
  int rc, rc2;
  char *pCsr = 0;

  rc = idxPrintfPrepareStmt(db, &p1, pzErrmsg, "PRAGMA table_info=%Q", zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    nByte += 1 + STRLEN(zCol);
    rc = sqlite3_table_column_metadata(
        db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
    );
    nByte += 1 + STRLEN(zCol);
    nCol++;
  }
  rc2 = sqlite3_reset(p1);
  if( rc==SQLITE_OK ) rc = rc2;

  nByte += sizeof(IdxColumn) * nCol;
  if( rc==SQLITE_OK ){
    pNew = idxMalloc(&rc, nByte);
  }
  if( rc==SQLITE_OK ){
    pNew->aCol = (IdxColumn*)&pNew[1];
    pNew->nCol = nCol;
    pCsr = (char*)&pNew->aCol[nCol];
  }

  nCol = 0;
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    int nCopy = STRLEN(zCol) + 1;
    pNew->aCol[nCol].zName = pCsr;
    pNew->aCol[nCol].iPk = sqlite3_column_int(p1, 5);
    memcpy(pCsr, zCol, nCopy);
    pCsr += nCopy;

    rc = sqlite3_table_column_metadata(
        db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
    );
    if( rc==SQLITE_OK ){
      nCopy = STRLEN(zCol) + 1;
      pNew->aCol[nCol].zColl = pCsr;
      memcpy(pCsr, zCol, nCopy);
      pCsr += nCopy;
    }

    nCol++;
  }
  idxFinalize(&rc, p1);

  if( rc!=SQLITE_OK ){
    sqlite3_free(pNew);
    pNew = 0;
  }else{
    pNew->zName = pCsr;
    memcpy(pNew->zName, zTab, nTab+1);
  }

  *ppOut = pNew;
  return rc;
}

/*
** This function is a no-op if *pRc is set to anything other than 
** SQLITE_OK when it is called.
**
** If *pRc is initially set to SQLITE_OK, then the text specified by
** the printf() style arguments is appended to zIn and the result returned
** in a buffer allocated by sqlite3_malloc(). sqlite3_free() is called on
** zIn before returning.
*/
static char *idxAppendText(int *pRc, char *zIn, const char *zFmt, ...){
  va_list ap;
  char *zAppend = 0;
  char *zRet = 0;
  int nIn = zIn ? STRLEN(zIn) : 0;
  int nAppend = 0;
  va_start(ap, zFmt);
  if( *pRc==SQLITE_OK ){
    zAppend = sqlite3_vmprintf(zFmt, ap);
    if( zAppend ){
      nAppend = STRLEN(zAppend);
      zRet = (char*)sqlite3_malloc(nIn + nAppend + 1);
    }
    if( zAppend && zRet ){
      memcpy(zRet, zIn, nIn);
      memcpy(&zRet[nIn], zAppend, nAppend+1);
    }else{
      sqlite3_free(zRet);
      zRet = 0;
      *pRc = SQLITE_NOMEM;
    }
    sqlite3_free(zAppend);
    sqlite3_free(zIn);
  }
  va_end(ap);
  return zRet;
}

/*
** Return true if zId must be quoted in order to use it as an SQL
** identifier, or false otherwise.
*/
static int idxIdentifierRequiresQuotes(const char *zId){
  int i;
  for(i=0; zId[i]; i++){
    if( !(zId[i]=='_')
     && !(zId[i]>='0' && zId[i]<='9')
     && !(zId[i]>='a' && zId[i]<='z')
     && !(zId[i]>='A' && zId[i]<='Z')
    ){
      return 1;
    }
  }
  return 0;
}

/*
** This function appends an index column definition suitable for constraint
** pCons to the string passed as zIn and returns the result.
*/
static char *idxAppendColDefn(
  int *pRc,                       /* IN/OUT: Error code */
  char *zIn,                      /* Column defn accumulated so far */
  IdxTable *pTab,                 /* Table index will be created on */
  IdxConstraint *pCons
){
  char *zRet = zIn;
  IdxColumn *p = &pTab->aCol[pCons->iCol];
  if( zRet ) zRet = idxAppendText(pRc, zRet, ", ");

  if( idxIdentifierRequiresQuotes(p->zName) ){
    zRet = idxAppendText(pRc, zRet, "%Q", p->zName);
  }else{
    zRet = idxAppendText(pRc, zRet, "%s", p->zName);
  }

  if( sqlite3_stricmp(p->zColl, pCons->zColl) ){
    if( idxIdentifierRequiresQuotes(pCons->zColl) ){
      zRet = idxAppendText(pRc, zRet, " COLLATE %Q", pCons->zColl);
    }else{
      zRet = idxAppendText(pRc, zRet, " COLLATE %s", pCons->zColl);
    }
  }

  if( pCons->bDesc ){
    zRet = idxAppendText(pRc, zRet, " DESC");
  }
  return zRet;
}

/*
** Search database dbm for an index compatible with the one idxCreateFromCons()
** would create from arguments pScan, pEq and pTail. If no error occurs and 
** such an index is found, return non-zero. Or, if no such index is found,
** return zero.
**
** If an error occurs, set *pRc to an SQLite error code and return zero.
*/
static int idxFindCompatible(
  int *pRc,                       /* OUT: Error code */
  sqlite3* dbm,                   /* Database to search */
  IdxScan *pScan,                 /* Scan for table to search for index on */
  IdxConstraint *pEq,             /* List of == constraints */
  IdxConstraint *pTail            /* List of range constraints */
){
  const char *zTbl = pScan->pTab->zName;
  sqlite3_stmt *pIdxList = 0;
  IdxConstraint *pIter;
  int nEq = 0;                    /* Number of elements in pEq */
  int rc;

  /* Count the elements in list pEq */
  for(pIter=pEq; pIter; pIter=pIter->pLink) nEq++;

  rc = idxPrintfPrepareStmt(dbm, &pIdxList, 0, "PRAGMA index_list=%Q", zTbl);
  while( rc==SQLITE_OK && sqlite3_step(pIdxList)==SQLITE_ROW ){
    int bMatch = 1;
    IdxConstraint *pT = pTail;
    sqlite3_stmt *pInfo = 0;
    const char *zIdx = (const char*)sqlite3_column_text(pIdxList, 1);

    /* Zero the IdxConstraint.bFlag values in the pEq list */
    for(pIter=pEq; pIter; pIter=pIter->pLink) pIter->bFlag = 0;

    rc = idxPrintfPrepareStmt(dbm, &pInfo, 0, "PRAGMA index_xInfo=%Q", zIdx);
    while( rc==SQLITE_OK && sqlite3_step(pInfo)==SQLITE_ROW ){
      int iIdx = sqlite3_column_int(pInfo, 0);
      int iCol = sqlite3_column_int(pInfo, 1);
      const char *zColl = (const char*)sqlite3_column_text(pInfo, 4);

      if( iIdx<nEq ){
        for(pIter=pEq; pIter; pIter=pIter->pLink){
          if( pIter->bFlag ) continue;
          if( pIter->iCol!=iCol ) continue;
          if( sqlite3_stricmp(pIter->zColl, zColl) ) continue;
          pIter->bFlag = 1;
          break;
        }
        if( pIter==0 ){
          bMatch = 0;
          break;
        }
      }else{
        if( pT ){
          if( pT->iCol!=iCol || sqlite3_stricmp(pT->zColl, zColl) ){
            bMatch = 0;
            break;
          }
          pT = pT->pLink;
        }
      }
    }
    idxFinalize(&rc, pInfo);

    if( rc==SQLITE_OK && bMatch ){
      sqlite3_finalize(pIdxList);
      return 1;
    }
  }
  idxFinalize(&rc, pIdxList);

  *pRc = rc;
  return 0;
}

static int idxCreateFromCons(
  sqlite3expert *p,
  IdxScan *pScan,
  IdxConstraint *pEq, 
  IdxConstraint *pTail
){
  sqlite3 *dbm = p->dbm;
  int rc = SQLITE_OK;
  if( (pEq || pTail) && 0==idxFindCompatible(&rc, dbm, pScan, pEq, pTail) ){
    IdxTable *pTab = pScan->pTab;
    char *zCols = 0;
    char *zIdx = 0;
    IdxConstraint *pCons;
    int h = 0;
    const char *zFmt;

    for(pCons=pEq; pCons; pCons=pCons->pLink){
      zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
    }
    for(pCons=pTail; pCons; pCons=pCons->pLink){
      zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
    }

    if( rc==SQLITE_OK ){
      /* Hash the list of columns to come up with a name for the index */
      const char *zTable = pScan->pTab->zName;
      char *zName;                /* Index name */
      int i;
      for(i=0; zCols[i]; i++){
        h += ((h<<3) + zCols[i]);
      }
      zName = sqlite3_mprintf("%s_idx_%08x", zTable, h);
      if( zName==0 ){ 
        rc = SQLITE_NOMEM;
      }else{
        if( idxIdentifierRequiresQuotes(zTable) ){
          zFmt = "CREATE INDEX '%q' ON %Q(%s)";
        }else{
          zFmt = "CREATE INDEX %s ON %s(%s)";
        }
        zIdx = sqlite3_mprintf(zFmt, zName, zTable, zCols);
        if( !zIdx ){
          rc = SQLITE_NOMEM;
        }else{
          rc = sqlite3_exec(dbm, zIdx, 0, 0, p->pzErrmsg);
          idxHashAdd(&rc, &p->hIdx, zName, zIdx);
        }
        sqlite3_free(zName);
        sqlite3_free(zIdx);
      }
    }

    sqlite3_free(zCols);
  }
  return rc;
}

/*
** Return true if list pList (linked by IdxConstraint.pLink) contains
** a constraint compatible with *p. Otherwise return false.
*/
static int idxFindConstraint(IdxConstraint *pList, IdxConstraint *p){
  IdxConstraint *pCmp;
  for(pCmp=pList; pCmp; pCmp=pCmp->pLink){
    if( p->iCol==pCmp->iCol ) return 1;
  }
  return 0;
}

static int idxCreateFromWhere(
  sqlite3expert *p, 
  IdxScan *pScan,                 /* Create indexes for this scan */
  IdxConstraint *pTail            /* range/ORDER BY constraints for inclusion */
){
  IdxConstraint *p1 = 0;
  IdxConstraint *pCon;
  int rc;

  /* Gather up all the == constraints. */
  for(pCon=pScan->pEq; pCon; pCon=pCon->pNext){
    if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
      pCon->pLink = p1;
      p1 = pCon;
    }
  }

  /* Create an index using the == constraints collected above. And the
  ** range constraint/ORDER BY terms passed in by the caller, if any. */
  rc = idxCreateFromCons(p, pScan, p1, pTail);

  /* If no range/ORDER BY passed by the caller, create a version of the
  ** index for each range constraint.  */
  if( pTail==0 ){
    for(pCon=pScan->pRange; rc==SQLITE_OK && pCon; pCon=pCon->pNext){
      assert( pCon->pLink==0 );
      if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
        rc = idxCreateFromCons(p, pScan, p1, pCon);
      }
    }
  }

  return rc;
}

/*
** Create candidate indexes in database [dbm] based on the data in 
** linked-list pScan.
*/
static int idxCreateCandidates(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  IdxScan *pIter;

  for(pIter=p->pScan; pIter && rc==SQLITE_OK; pIter=pIter->pNextScan){
    rc = idxCreateFromWhere(p, pIter, 0);
    if( rc==SQLITE_OK && pIter->pOrder ){
      rc = idxCreateFromWhere(p, pIter, pIter->pOrder);
    }
  }

  return rc;
}

/*
** Free all elements of the linked list starting at pConstraint.
*/
static void idxConstraintFree(IdxConstraint *pConstraint){
  IdxConstraint *pNext;
  IdxConstraint *p;

  for(p=pConstraint; p; p=pNext){
    pNext = p->pNext;
    sqlite3_free(p);
  }
}

/*
** Free all elements of the linked list starting from pScan up until pLast
** (pLast is not freed).
*/
static void idxScanFree(IdxScan *pScan, IdxScan *pLast){
  IdxScan *p;
  IdxScan *pNext;
  for(p=pScan; p!=pLast; p=pNext){
    pNext = p->pNextScan;
    idxConstraintFree(p->pOrder);
    idxConstraintFree(p->pEq);
    idxConstraintFree(p->pRange);
    sqlite3_free(p);
  }
}

/*
** Free all elements of the linked list starting from pStatement up 
** until pLast (pLast is not freed).
*/
static void idxStatementFree(IdxStatement *pStatement, IdxStatement *pLast){
  IdxStatement *p;
  IdxStatement *pNext;
  for(p=pStatement; p!=pLast; p=pNext){
    pNext = p->pNext;
    sqlite3_free(p->zEQP);
    sqlite3_free(p->zIdx);
    sqlite3_free(p);
  }
}

/*
** Free the linked list of IdxTable objects starting at pTab.
*/
static void idxTableFree(IdxTable *pTab){
  IdxTable *pIter;
  IdxTable *pNext;
  for(pIter=pTab; pIter; pIter=pNext){
    pNext = pIter->pNext;
    sqlite3_free(pIter);
  }
}

/*
** Free the linked list of IdxWrite objects starting at pTab.
*/
static void idxWriteFree(IdxWrite *pTab){
  IdxWrite *pIter;
  IdxWrite *pNext;
  for(pIter=pTab; pIter; pIter=pNext){
    pNext = pIter->pNext;
    sqlite3_free(pIter);
  }
}



/*
** This function is called after candidate indexes have been created. It
** runs all the queries to see which indexes they prefer, and populates
** IdxStatement.zIdx and IdxStatement.zEQP with the results.
*/
int idxFindIndexes(
  sqlite3expert *p,
  char **pzErr                         /* OUT: Error message (sqlite3_malloc) */
){
  IdxStatement *pStmt;
  sqlite3 *dbm = p->dbm;
  int rc = SQLITE_OK;

  IdxHash hIdx;
  idxHashInit(&hIdx);

  for(pStmt=p->pStatement; rc==SQLITE_OK && pStmt; pStmt=pStmt->pNext){
    IdxHashEntry *pEntry;
    sqlite3_stmt *pExplain = 0;
    idxHashClear(&hIdx);
    rc = idxPrintfPrepareStmt(dbm, &pExplain, pzErr,
        "EXPLAIN QUERY PLAN %s", pStmt->zSql
    );
    while( rc==SQLITE_OK && sqlite3_step(pExplain)==SQLITE_ROW ){
      int iSelectid = sqlite3_column_int(pExplain, 0);
      int iOrder = sqlite3_column_int(pExplain, 1);
      int iFrom = sqlite3_column_int(pExplain, 2);
      const char *zDetail = (const char*)sqlite3_column_text(pExplain, 3);
      int nDetail = STRLEN(zDetail);
      int i;

      for(i=0; i<nDetail; i++){
        const char *zIdx = 0;
        if( memcmp(&zDetail[i], " USING INDEX ", 13)==0 ){
          zIdx = &zDetail[i+13];
        }else if( memcmp(&zDetail[i], " USING COVERING INDEX ", 22)==0 ){
          zIdx = &zDetail[i+22];
        }
        if( zIdx ){
          const char *zSql;
          int nIdx = 0;
          while( zIdx[nIdx]!='\0' && (zIdx[nIdx]!=' ' || zIdx[nIdx+1]!='(') ){
            nIdx++;
          }
          zSql = idxHashSearch(&p->hIdx, zIdx, nIdx);
          if( zSql ){
            idxHashAdd(&rc, &hIdx, zSql, 0);
            if( rc ) goto find_indexes_out;
          }
          break;
        }
      }

      pStmt->zEQP = idxAppendText(&rc, pStmt->zEQP, "%d|%d|%d|%s\n", 
          iSelectid, iOrder, iFrom, zDetail
      );
    }

    for(pEntry=hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
      pStmt->zIdx = idxAppendText(&rc, pStmt->zIdx, "%s;\n", pEntry->zKey);
    }

    idxFinalize(&rc, pExplain);
  }

 find_indexes_out:
  idxHashClear(&hIdx);
  return rc;
}

static int idxAuthCallback(
  void *pCtx,
  int eOp,
  const char *z3,
  const char *z4,
  const char *zDb,
  const char *zTrigger
){
  int rc = SQLITE_OK;
  if( eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE || eOp==SQLITE_DELETE ){
    if( sqlite3_stricmp(zDb, "main")==0 ){
      sqlite3expert *p = (sqlite3expert*)pCtx;
      IdxTable *pTab;
      for(pTab=p->pTable; pTab; pTab=pTab->pNext){
        if( 0==sqlite3_stricmp(z3, pTab->zName) ) break;
      }
      if( pTab ){
        IdxWrite *pWrite;
        for(pWrite=p->pWrite; pWrite; pWrite=pWrite->pNext){
          if( pWrite->pTab==pTab && pWrite->eOp==eOp ) break;
        }
        if( pWrite==0 ){
          pWrite = idxMalloc(&rc, sizeof(IdxWrite));
          if( rc==SQLITE_OK ){
            pWrite->pTab = pTab;
            pWrite->eOp = eOp;
            pWrite->pNext = p->pWrite;
            p->pWrite = pWrite;
          }
        }
      }
    }
  }
  return rc;
}

static int idxProcessOneTrigger(
  sqlite3expert *p, 
  IdxWrite *pWrite, 
  char **pzErr
){
  static const char *zInt = UNIQUE_TABLE_NAME;
  static const char *zDrop = "DROP TABLE " UNIQUE_TABLE_NAME;
  IdxTable *pTab = pWrite->pTab;
  const char *zTab = pTab->zName;
  const char *zSql = 
    "SELECT 'CREATE TEMP' || substr(sql, 7) FROM sqlite_master "
    "WHERE tbl_name = %Q AND type IN ('table', 'trigger') "
    "ORDER BY type;";
  sqlite3_stmt *pSelect = 0;
  int rc = SQLITE_OK;
  char *zWrite = 0;

  /* Create the table and its triggers in the temp schema */
  rc = idxPrintfPrepareStmt(p->db, &pSelect, pzErr, zSql, zTab, zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSelect) ){
    const char *zCreate = (const char*)sqlite3_column_text(pSelect, 0);
    rc = sqlite3_exec(p->dbv, zCreate, 0, 0, pzErr);
  }
  idxFinalize(&rc, pSelect);

  /* Rename the table in the temp schema to zInt */
  if( rc==SQLITE_OK ){
    char *z = sqlite3_mprintf("ALTER TABLE temp.%Q RENAME TO %Q", zTab, zInt);
    if( z==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_exec(p->dbv, z, 0, 0, pzErr);
      sqlite3_free(z);
    }
  }

  switch( pWrite->eOp ){
    case SQLITE_INSERT: {
      int i;
      zWrite = idxAppendText(&rc, zWrite, "INSERT INTO %Q VALUES(", zInt);
      for(i=0; i<pTab->nCol; i++){
        zWrite = idxAppendText(&rc, zWrite, "%s?", i==0 ? "" : ", ");
      }
      zWrite = idxAppendText(&rc, zWrite, ")");
      break;
    }
    case SQLITE_UPDATE: {
      int i;
      zWrite = idxAppendText(&rc, zWrite, "UPDATE %Q SET ", zInt);
      for(i=0; i<pTab->nCol; i++){
        zWrite = idxAppendText(&rc, zWrite, "%s%Q=?", i==0 ? "" : ", ", 
            pTab->aCol[i].zName
        );
      }
      break;
    }
    default: {
      assert( pWrite->eOp==SQLITE_DELETE );
      if( rc==SQLITE_OK ){
        zWrite = sqlite3_mprintf("DELETE FROM %Q", zInt);
        if( zWrite==0 ) rc = SQLITE_NOMEM;
      }
    }
  }

  if( rc==SQLITE_OK ){
    sqlite3_stmt *pX = 0;
    rc = sqlite3_prepare_v2(p->dbv, zWrite, -1, &pX, 0);
    idxFinalize(&rc, pX);
    if( rc!=SQLITE_OK ){
      idxDatabaseError(p->dbv, pzErr);
    }
  }
  sqlite3_free(zWrite);

  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(p->dbv, zDrop, 0, 0, pzErr);
  }

  return rc;
}

static int idxProcessTriggers(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  IdxWrite *pEnd = 0;
  IdxWrite *pFirst = p->pWrite;

  while( rc==SQLITE_OK && pFirst!=pEnd ){
    IdxWrite *pIter;
    for(pIter=pFirst; rc==SQLITE_OK && pIter!=pEnd; pIter=pIter->pNext){
      rc = idxProcessOneTrigger(p, pIter, pzErr);
    }
    pEnd = pFirst;
    pFirst = p->pWrite;
  }

  return rc;
}


static int idxCreateVtabSchema(sqlite3expert *p, char **pzErrmsg){
  int rc = idxRegisterVtab(p);
  sqlite3_stmt *pSchema = 0;

  /* For each table in the main db schema:
  **
  **   1) Add an entry to the p->pTable list, and
  **   2) Create the equivalent virtual table in dbv.
  */
  rc = idxPrepareStmt(p->db, &pSchema, pzErrmsg,
      "SELECT type, name, sql, 1 FROM sqlite_master "
      "WHERE type IN ('table','view') AND name NOT LIKE 'sqlite_%%' "
      " UNION ALL "
      "SELECT type, name, sql, 2 FROM sqlite_master "
      "WHERE type = 'trigger'"
      "  AND tbl_name IN(SELECT name FROM sqlite_master WHERE type = 'view') "
      "ORDER BY 4, 1"
  );
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSchema) ){
    const char *zType = (const char*)sqlite3_column_text(pSchema, 0);
    const char *zName = (const char*)sqlite3_column_text(pSchema, 1);
    const char *zSql = (const char*)sqlite3_column_text(pSchema, 2);

    if( zType[0]=='v' || zType[1]=='r' ){
      rc = sqlite3_exec(p->dbv, zSql, 0, 0, pzErrmsg);
    }else{
      IdxTable *pTab;
      rc = idxGetTableInfo(p->db, zName, &pTab, pzErrmsg);
      if( rc==SQLITE_OK ){
        int i;
        char *zInner = 0;
        char *zOuter = 0;
        pTab->pNext = p->pTable;
        p->pTable = pTab;

        /* The statement the vtab will pass to sqlite3_declare_vtab() */
        zInner = idxAppendText(&rc, 0, "CREATE TABLE x(");
        for(i=0; i<pTab->nCol; i++){
          zInner = idxAppendText(&rc, zInner, "%s%Q COLLATE %s", 
              (i==0 ? "" : ", "), pTab->aCol[i].zName, pTab->aCol[i].zColl
          );
        }
        zInner = idxAppendText(&rc, zInner, ")");

        /* The CVT statement to create the vtab */
        zOuter = idxAppendText(&rc, 0, 
            "CREATE VIRTUAL TABLE %Q USING expert(%Q)", zName, zInner
        );
        if( rc==SQLITE_OK ){
          rc = sqlite3_exec(p->dbv, zOuter, 0, 0, pzErrmsg);
        }
        sqlite3_free(zInner);
        sqlite3_free(zOuter);
      }
    }
  }
  idxFinalize(&rc, pSchema);
  return rc;
}

struct IdxSampleCtx {
  int iTarget;
  double target;                  /* Target nRet/nRow value */
  double nRow;                    /* Number of rows seen */
  double nRet;                    /* Number of rows returned */
};

static void idxSampleFunc(
  sqlite3_context *pCtx,
  int argc,
  sqlite3_value **argv
){
  struct IdxSampleCtx *p = (struct IdxSampleCtx*)sqlite3_user_data(pCtx);
  int bRet;

  assert( argc==0 );
  if( p->nRow==0.0 ){
    bRet = 1;
  }else{
    bRet = (p->nRet / p->nRow) <= p->target;
    if( bRet==0 ){
      unsigned short rnd;
      sqlite3_randomness(2, (void*)&rnd);
      bRet = ((int)rnd % 100) <= p->iTarget;
    }
  }

  sqlite3_result_int(pCtx, bRet);
  p->nRow += 1.0;
  p->nRet += (double)bRet;
}

struct IdxRemCtx {
  int nSlot;
  struct IdxRemSlot {
    int eType;                    /* SQLITE_NULL, INTEGER, REAL, TEXT, BLOB */
    i64 iVal;                     /* SQLITE_INTEGER value */
    double rVal;                  /* SQLITE_FLOAT value */
    int nByte;                    /* Bytes of space allocated at z */
    int n;                        /* Size of buffer z */
    char *z;                      /* SQLITE_TEXT/BLOB value */
  } aSlot[1];
};

/*
** Implementation of scalar function rem().
*/
static void idxRemFunc(
  sqlite3_context *pCtx,
  int argc,
  sqlite3_value **argv
){
  struct IdxRemCtx *p = (struct IdxRemCtx*)sqlite3_user_data(pCtx);
  struct IdxRemSlot *pSlot;
  int iSlot;
  assert( argc==2 );

  iSlot = sqlite3_value_int(argv[0]);
  assert( iSlot<=p->nSlot );
  pSlot = &p->aSlot[iSlot];

  switch( pSlot->eType ){
    case SQLITE_NULL:
      /* no-op */
      break;

    case SQLITE_INTEGER:
      sqlite3_result_int64(pCtx, pSlot->iVal);
      break;

    case SQLITE_FLOAT:
      sqlite3_result_double(pCtx, pSlot->rVal);
      break;

    case SQLITE_BLOB:
      sqlite3_result_blob(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
      break;

    case SQLITE_TEXT:
      sqlite3_result_text(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
      break;
  }

  pSlot->eType = sqlite3_value_type(argv[1]);
  switch( pSlot->eType ){
    case SQLITE_NULL:
      /* no-op */
      break;

    case SQLITE_INTEGER:
      pSlot->iVal = sqlite3_value_int64(argv[1]);
      break;

    case SQLITE_FLOAT:
      pSlot->rVal = sqlite3_value_double(argv[1]);
      break;

    case SQLITE_BLOB:
    case SQLITE_TEXT: {
      int nByte = sqlite3_value_bytes(argv[1]);
      if( nByte>pSlot->nByte ){
        char *zNew = (char*)sqlite3_realloc(pSlot->z, nByte*2);
        if( zNew==0 ){
          sqlite3_result_error_nomem(pCtx);
          return;
        }
        pSlot->nByte = nByte*2;
        pSlot->z = zNew;
      }
      pSlot->n = nByte;
      if( pSlot->eType==SQLITE_BLOB ){
        memcpy(pSlot->z, sqlite3_value_blob(argv[1]), nByte);
      }else{
        memcpy(pSlot->z, sqlite3_value_text(argv[1]), nByte);
      }
      break;
    }
  }
}

static int idxLargestIndex(sqlite3 *db, int *pnMax, char **pzErr){
  int rc = SQLITE_OK;
  const char *zMax = 
    "SELECT max(i.seqno) FROM "
    "  sqlite_master AS s, "
    "  pragma_index_list(s.name) AS l, "
    "  pragma_index_info(l.name) AS i "
    "WHERE s.type = 'table'";
  sqlite3_stmt *pMax = 0;

  *pnMax = 0;
  rc = idxPrepareStmt(db, &pMax, pzErr, zMax);
  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
    *pnMax = sqlite3_column_int(pMax, 0) + 1;
  }
  idxFinalize(&rc, pMax);

  return rc;
}

static int idxPopulateOneStat1(
  sqlite3expert *p,
  sqlite3_stmt *pIndexXInfo,
  sqlite3_stmt *pWriteStat,
  const char *zTab,
  const char *zIdx,
  char **pzErr
){
  char *zCols = 0;
  char *zOrder = 0;
  char *zQuery = 0;
  int nCol = 0;
  int i;
  sqlite3_stmt *pQuery = 0;
  int *aStat = 0;
  int rc = SQLITE_OK;

  assert( p->iSample>0 );

  /* Formulate the query text */
  sqlite3_bind_text(pIndexXInfo, 1, zIdx, -1, SQLITE_STATIC);
  while( SQLITE_OK==rc && SQLITE_ROW==sqlite3_step(pIndexXInfo) ){
    const char *zComma = zCols==0 ? "" : ", ";
    const char *zName = (const char*)sqlite3_column_text(pIndexXInfo, 0);
    const char *zColl = (const char*)sqlite3_column_text(pIndexXInfo, 1);
    zCols = idxAppendText(&rc, zCols, 
        "%sx.%Q IS rem(%d, x.%Q) COLLATE %s", zComma, zName, nCol, zName, zColl
    );
    zOrder = idxAppendText(&rc, zOrder, "%s%d", zComma, ++nCol);
  }
  if( rc==SQLITE_OK ){
    if( p->iSample==100 ){
      zQuery = sqlite3_mprintf(
          "SELECT %s FROM %Q x ORDER BY %s", zCols, zTab, zOrder
      );
    }else{
      zQuery = sqlite3_mprintf(
          "SELECT %s FROM temp."UNIQUE_TABLE_NAME" x ORDER BY %s", zCols, zOrder
      );
    }
  }
  sqlite3_free(zCols);
  sqlite3_free(zOrder);

  /* Formulate the query text */
  if( rc==SQLITE_OK ){
    sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
    rc = idxPrepareStmt(dbrem, &pQuery, pzErr, zQuery);
  }
  sqlite3_free(zQuery);

  if( rc==SQLITE_OK ){
    aStat = (int*)idxMalloc(&rc, sizeof(int)*(nCol+1));
  }
  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
    IdxHashEntry *pEntry;
    char *zStat = 0;
    for(i=0; i<=nCol; i++) aStat[i] = 1;
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
      aStat[0]++;
      for(i=0; i<nCol; i++){
        if( sqlite3_column_int(pQuery, i)==0 ) break;
      }
      for(/*no-op*/; i<nCol; i++){
        aStat[i+1]++;
      }
    }

    if( rc==SQLITE_OK ){
      int s0 = aStat[0];
      zStat = sqlite3_mprintf("%d", s0);
      if( zStat==0 ) rc = SQLITE_NOMEM;
      for(i=1; rc==SQLITE_OK && i<=nCol; i++){
        zStat = idxAppendText(&rc, zStat, " %d", (s0+aStat[i]/2) / aStat[i]);
      }
    }

    if( rc==SQLITE_OK ){
      sqlite3_bind_text(pWriteStat, 1, zTab, -1, SQLITE_STATIC);
      sqlite3_bind_text(pWriteStat, 2, zIdx, -1, SQLITE_STATIC);
      sqlite3_bind_text(pWriteStat, 3, zStat, -1, SQLITE_STATIC);
      sqlite3_step(pWriteStat);
      rc = sqlite3_reset(pWriteStat);
    }

    pEntry = idxHashFind(&p->hIdx, zIdx, STRLEN(zIdx));
    if( pEntry ){
      assert( pEntry->zVal2==0 );
      pEntry->zVal2 = zStat;
    }else{
      sqlite3_free(zStat);
    }
  }
  sqlite3_free(aStat);
  idxFinalize(&rc, pQuery);

  return rc;
}

static int idxBuildSampleTable(sqlite3expert *p, const char *zTab){
  int rc;
  char *zSql;

  rc = sqlite3_exec(p->dbv,"DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
  if( rc!=SQLITE_OK ) return rc;

  zSql = sqlite3_mprintf(
      "CREATE TABLE temp." UNIQUE_TABLE_NAME " AS SELECT * FROM %Q", zTab
  );
  if( zSql==0 ) return SQLITE_NOMEM;
  rc = sqlite3_exec(p->dbv, zSql, 0, 0, 0);
  sqlite3_free(zSql);

  return rc;
}

/*
** This function is called as part of sqlite3_expert_analyze(). Candidate
** indexes have already been created in database sqlite3expert.dbm, this
** function populates sqlite_stat1 table in the same database.
**
** The stat1 data is generated by querying the 
*/
static int idxPopulateStat1(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  int nMax =0;
  struct IdxRemCtx *pCtx = 0;
  struct IdxSampleCtx samplectx; 
  int i;
  i64 iPrev = -100000;
  sqlite3_stmt *pAllIndex = 0;
  sqlite3_stmt *pIndexXInfo = 0;
  sqlite3_stmt *pWrite = 0;

  const char *zAllIndex =
    "SELECT s.rowid, s.name, l.name FROM "
    "  sqlite_master AS s, "
    "  pragma_index_list(s.name) AS l "
    "WHERE s.type = 'table'";
  const char *zIndexXInfo = 
    "SELECT name, coll FROM pragma_index_xinfo(?) WHERE key";
  const char *zWrite = "INSERT INTO sqlite_stat1 VALUES(?, ?, ?)";

  /* If iSample==0, no sqlite_stat1 data is required. */
  if( p->iSample==0 ) return SQLITE_OK;

  rc = idxLargestIndex(p->dbm, &nMax, pzErr);
  if( nMax<=0 || rc!=SQLITE_OK ) return rc;

  rc = sqlite3_exec(p->dbm, "ANALYZE; PRAGMA writable_schema=1", 0, 0, 0);

  if( rc==SQLITE_OK ){
    int nByte = sizeof(struct IdxRemCtx) + (sizeof(struct IdxRemSlot) * nMax);
    pCtx = (struct IdxRemCtx*)idxMalloc(&rc, nByte);
  }

  if( rc==SQLITE_OK ){
    sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
    rc = sqlite3_create_function(
        dbrem, "rem", 2, SQLITE_UTF8, (void*)pCtx, idxRemFunc, 0, 0
    );
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(
        p->db, "sample", 0, SQLITE_UTF8, (void*)&samplectx, idxSampleFunc, 0, 0
    );
  }

  if( rc==SQLITE_OK ){
    pCtx->nSlot = nMax+1;
    rc = idxPrepareStmt(p->dbm, &pAllIndex, pzErr, zAllIndex);
  }
  if( rc==SQLITE_OK ){
    rc = idxPrepareStmt(p->dbm, &pIndexXInfo, pzErr, zIndexXInfo);
  }
  if( rc==SQLITE_OK ){
    rc = idxPrepareStmt(p->dbm, &pWrite, pzErr, zWrite);
  }

  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pAllIndex) ){
    i64 iRowid = sqlite3_column_int64(pAllIndex, 0);
    const char *zTab = (const char*)sqlite3_column_text(pAllIndex, 1);
    const char *zIdx = (const char*)sqlite3_column_text(pAllIndex, 2);
    if( p->iSample<100 && iPrev!=iRowid ){
      samplectx.target = (double)p->iSample / 100.0;
      samplectx.iTarget = p->iSample;
      samplectx.nRow = 0.0;
      samplectx.nRet = 0.0;
      rc = idxBuildSampleTable(p, zTab);
      if( rc!=SQLITE_OK ) break;
    }
    rc = idxPopulateOneStat1(p, pIndexXInfo, pWrite, zTab, zIdx, pzErr);
    iPrev = iRowid;
  }
  if( rc==SQLITE_OK && p->iSample<100 ){
    rc = sqlite3_exec(p->dbv, 
        "DROP TABLE IF EXISTS temp." UNIQUE_TABLE_NAME, 0,0,0
    );
  }

  idxFinalize(&rc, pAllIndex);
  idxFinalize(&rc, pIndexXInfo);
  idxFinalize(&rc, pWrite);

  for(i=0; i<pCtx->nSlot; i++){
    sqlite3_free(pCtx->aSlot[i].z);
  }
  sqlite3_free(pCtx);

  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(p->dbm, "ANALYZE sqlite_master", 0, 0, 0);
  }

  sqlite3_exec(p->db, "DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
  return rc;
}

/*
** Allocate a new sqlite3expert object.
*/
sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErrmsg){
  int rc = SQLITE_OK;
  sqlite3expert *pNew;

  pNew = (sqlite3expert*)idxMalloc(&rc, sizeof(sqlite3expert));

  /* Open two in-memory databases to work with. The "vtab database" (dbv)
  ** will contain a virtual table corresponding to each real table in
  ** the user database schema, and a copy of each view. It is used to
  ** collect information regarding the WHERE, ORDER BY and other clauses
  ** of the user's query.
  */
  if( rc==SQLITE_OK ){
    pNew->db = db;
    pNew->iSample = 100;
    rc = sqlite3_open(":memory:", &pNew->dbv);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_open(":memory:", &pNew->dbm);
    if( rc==SQLITE_OK ){
      sqlite3_db_config(pNew->dbm, SQLITE_DBCONFIG_TRIGGER_EQP, 1, (int*)0);
    }
  }
  

  /* Copy the entire schema of database [db] into [dbm]. */
  if( rc==SQLITE_OK ){
    sqlite3_stmt *pSql;
    rc = idxPrintfPrepareStmt(pNew->db, &pSql, pzErrmsg, 
        "SELECT sql FROM sqlite_master WHERE name NOT LIKE 'sqlite_%%'"
        " AND sql NOT LIKE 'CREATE VIRTUAL %%'"
    );
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
      const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
      rc = sqlite3_exec(pNew->dbm, zSql, 0, 0, pzErrmsg);
    }
    idxFinalize(&rc, pSql);
  }

  /* Create the vtab schema */
  if( rc==SQLITE_OK ){
    rc = idxCreateVtabSchema(pNew, pzErrmsg);
  }

  /* Register the auth callback with dbv */
  if( rc==SQLITE_OK ){
    sqlite3_set_authorizer(pNew->dbv, idxAuthCallback, (void*)pNew);
  }

  /* If an error has occurred, free the new object and reutrn NULL. Otherwise,
  ** return the new sqlite3expert handle.  */
  if( rc!=SQLITE_OK ){
    sqlite3_expert_destroy(pNew);
    pNew = 0;
  }
  return pNew;
}

/*
** Configure an sqlite3expert object.
*/
int sqlite3_expert_config(sqlite3expert *p, int op, ...){
  int rc = SQLITE_OK;
  va_list ap;
  va_start(ap, op);
  switch( op ){
    case EXPERT_CONFIG_SAMPLE: {
      int iVal = va_arg(ap, int);
      if( iVal<0 ) iVal = 0;
      if( iVal>100 ) iVal = 100;
      p->iSample = iVal;
      break;
    }
    default:
      rc = SQLITE_NOTFOUND;
      break;
  }

  va_end(ap);
  return rc;
}

/*
** Add an SQL statement to the analysis.
*/
int sqlite3_expert_sql(
  sqlite3expert *p,               /* From sqlite3_expert_new() */
  const char *zSql,               /* SQL statement to add */
  char **pzErr                    /* OUT: Error message (if any) */
){
  IdxScan *pScanOrig = p->pScan;
  IdxStatement *pStmtOrig = p->pStatement;
  int rc = SQLITE_OK;
  const char *zStmt = zSql;

  if( p->bRun ) return SQLITE_MISUSE;

  while( rc==SQLITE_OK && zStmt && zStmt[0] ){
    sqlite3_stmt *pStmt = 0;
    rc = sqlite3_prepare_v2(p->dbv, zStmt, -1, &pStmt, &zStmt);
    if( rc==SQLITE_OK ){
      if( pStmt ){
        IdxStatement *pNew;
        const char *z = sqlite3_sql(pStmt);
        int n = STRLEN(z);
        pNew = (IdxStatement*)idxMalloc(&rc, sizeof(IdxStatement) + n+1);
        if( rc==SQLITE_OK ){
          pNew->zSql = (char*)&pNew[1];
          memcpy(pNew->zSql, z, n+1);
          pNew->pNext = p->pStatement;
          if( p->pStatement ) pNew->iId = p->pStatement->iId+1;
          p->pStatement = pNew;
        }
        sqlite3_finalize(pStmt);
      }
    }else{
      idxDatabaseError(p->dbv, pzErr);
    }
  }

  if( rc!=SQLITE_OK ){
    idxScanFree(p->pScan, pScanOrig);
    idxStatementFree(p->pStatement, pStmtOrig);
    p->pScan = pScanOrig;
    p->pStatement = pStmtOrig;
  }

  return rc;
}

int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr){
  int rc;
  IdxHashEntry *pEntry;

  /* Do trigger processing to collect any extra IdxScan structures */
  rc = idxProcessTriggers(p, pzErr);

  /* Create candidate indexes within the in-memory database file */
  if( rc==SQLITE_OK ){
    rc = idxCreateCandidates(p, pzErr);
  }

  /* Generate the stat1 data */
  if( rc==SQLITE_OK ){
    rc = idxPopulateStat1(p, pzErr);
  }

  /* Formulate the EXPERT_REPORT_CANDIDATES text */
  for(pEntry=p->hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
    p->zCandidates = idxAppendText(&rc, p->zCandidates, 
        "%s;%s%s\n", pEntry->zVal, 
        pEntry->zVal2 ? " -- stat1: " : "", pEntry->zVal2
    );
  }

  /* Figure out which of the candidate indexes are preferred by the query
  ** planner and report the results to the user.  */
  if( rc==SQLITE_OK ){
    rc = idxFindIndexes(p, pzErr);
  }

  if( rc==SQLITE_OK ){
    p->bRun = 1;
  }
  return rc;
}

/*
** Return the total number of statements that have been added to this
** sqlite3expert using sqlite3_expert_sql().
*/
int sqlite3_expert_count(sqlite3expert *p){
  int nRet = 0;
  if( p->pStatement ) nRet = p->pStatement->iId+1;
  return nRet;
}

/*
** Return a component of the report.
*/
const char *sqlite3_expert_report(sqlite3expert *p, int iStmt, int eReport){
  const char *zRet = 0;
  IdxStatement *pStmt;

  if( p->bRun==0 ) return 0;
  for(pStmt=p->pStatement; pStmt && pStmt->iId!=iStmt; pStmt=pStmt->pNext);
  switch( eReport ){
    case EXPERT_REPORT_SQL:
      if( pStmt ) zRet = pStmt->zSql;
      break;
    case EXPERT_REPORT_INDEXES:
      if( pStmt ) zRet = pStmt->zIdx;
      break;
    case EXPERT_REPORT_PLAN:
      if( pStmt ) zRet = pStmt->zEQP;
      break;
    case EXPERT_REPORT_CANDIDATES:
      zRet = p->zCandidates;
      break;
  }
  return zRet;
}

/*
** Free an sqlite3expert object.
*/
void sqlite3_expert_destroy(sqlite3expert *p){
  if( p ){
    sqlite3_close(p->dbm);
    sqlite3_close(p->dbv);
    idxScanFree(p->pScan, 0);
    idxStatementFree(p->pStatement, 0);
    idxTableFree(p->pTable);
    idxWriteFree(p->pWrite);
    idxHashClear(&p->hIdx);
    sqlite3_free(p->zCandidates);
    sqlite3_free(p);
  }
}

/*
** 2017 April 07
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/


#include "sqlite3.h"

typedef struct sqlite3expert sqlite3expert;

/*
** Create a new sqlite3expert object.
**
** If successful, a pointer to the new object is returned and (*pzErr) set
** to NULL. Or, if an error occurs, NULL is returned and (*pzErr) set to
** an English-language error message. In this case it is the responsibility
** of the caller to eventually free the error message buffer using
** sqlite3_free().
*/
sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErr);

/*
** Configure an sqlite3expert object.
**
** EXPERT_CONFIG_SAMPLE:
**   By default, sqlite3_expert_analyze() generates sqlite_stat1 data for
**   each candidate index. This involves scanning and sorting the entire
**   contents of each user database table once for each candidate index
**   associated with the table. For large databases, this can be 
**   prohibitively slow. This option allows the sqlite3expert object to
**   be configured so that sqlite_stat1 data is instead generated based on a
**   subset of each table, or so that no sqlite_stat1 data is used at all.
**
**   A single integer argument is passed to this option. If the value is less
**   than or equal to zero, then no sqlite_stat1 data is generated or used by
**   the analysis - indexes are recommended based on the database schema only.
**   Or, if the value is 100 or greater, complete sqlite_stat1 data is
**   generated for each candidate index (this is the default). Finally, if the
**   value falls between 0 and 100, then it represents the percentage of user
**   table rows that should be considered when generating sqlite_stat1 data.
**
**   Examples:
**
**     // Do not generate any sqlite_stat1 data
**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 0);
**
**     // Generate sqlite_stat1 data based on 10% of the rows in each table.
**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 10);
*/
int sqlite3_expert_config(sqlite3expert *p, int op, ...);

#define EXPERT_CONFIG_SAMPLE 1    /* int */

/*
** Specify zero or more SQL statements to be included in the analysis.
**
** Buffer zSql must contain zero or more complete SQL statements. This
** function parses all statements contained in the buffer and adds them
** to the internal list of statements to analyze. If successful, SQLITE_OK
** is returned and (*pzErr) set to NULL. Or, if an error occurs - for example
** due to a error in the SQL - an SQLite error code is returned and (*pzErr)
** may be set to point to an English language error message. In this case
** the caller is responsible for eventually freeing the error message buffer
** using sqlite3_free().
**
** If an error does occur while processing one of the statements in the
** buffer passed as the second argument, none of the statements in the
** buffer are added to the analysis.
**
** This function must be called before sqlite3_expert_analyze(). If a call
** to this function is made on an sqlite3expert object that has already
** been passed to sqlite3_expert_analyze() SQLITE_MISUSE is returned
** immediately and no statements are added to the analysis.
*/
int sqlite3_expert_sql(
  sqlite3expert *p,               /* From a successful sqlite3_expert_new() */
  const char *zSql,               /* SQL statement(s) to add */
  char **pzErr                    /* OUT: Error message (if any) */
);


/*
** This function is called after the sqlite3expert object has been configured
** with all SQL statements using sqlite3_expert_sql() to actually perform
** the analysis. Once this function has been called, it is not possible to
** add further SQL statements to the analysis.
**
** If successful, SQLITE_OK is returned and (*pzErr) is set to NULL. Or, if
** an error occurs, an SQLite error code is returned and (*pzErr) set to 
** point to a buffer containing an English language error message. In this
** case it is the responsibility of the caller to eventually free the buffer
** using sqlite3_free().
**
** If an error does occur within this function, the sqlite3expert object
** is no longer useful for any purpose. At that point it is no longer
** possible to add further SQL statements to the object or to re-attempt
** the analysis. The sqlite3expert object must still be freed using a call
** sqlite3_expert_destroy().
*/
int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr);

/*
** Return the total number of statements loaded using sqlite3_expert_sql().
** The total number of SQL statements may be different from the total number
** to calls to sqlite3_expert_sql().
*/
int sqlite3_expert_count(sqlite3expert*);

/*
** Return a component of the report.
**
** This function is called after sqlite3_expert_analyze() to extract the
** results of the analysis. Each call to this function returns either a
** NULL pointer or a pointer to a buffer containing a nul-terminated string.
** The value passed as the third argument must be one of the EXPERT_REPORT_*
** #define constants defined below.
**
** For some EXPERT_REPORT_* parameters, the buffer returned contains 
** information relating to a specific SQL statement. In these cases that
** SQL statement is identified by the value passed as the second argument.
** SQL statements are numbered from 0 in the order in which they are parsed.
** If an out-of-range value (less than zero or equal to or greater than the
** value returned by sqlite3_expert_count()) is passed as the second argument
** along with such an EXPERT_REPORT_* parameter, NULL is always returned.
**
** EXPERT_REPORT_SQL:
**   Return the text of SQL statement iStmt.
**
** EXPERT_REPORT_INDEXES:
**   Return a buffer containing the CREATE INDEX statements for all recommended
**   indexes for statement iStmt. If there are no new recommeded indexes, NULL 
**   is returned.
**
** EXPERT_REPORT_PLAN:
**   Return a buffer containing the EXPLAIN QUERY PLAN output for SQL query
**   iStmt after the proposed indexes have been added to the database schema.
**
** EXPERT_REPORT_CANDIDATES:
**   Return a pointer to a buffer containing the CREATE INDEX statements 
**   for all indexes that were tested (for all SQL statements). The iStmt
**   parameter is ignored for EXPERT_REPORT_CANDIDATES calls.
*/
const char *sqlite3_expert_report(sqlite3expert*, int iStmt, int eReport);

/*
** Values for the third argument passed to sqlite3_expert_report().
*/
#define EXPERT_REPORT_SQL        1
#define EXPERT_REPORT_INDEXES    2
#define EXPERT_REPORT_PLAN       3
#define EXPERT_REPORT_CANDIDATES 4

/*
** Free an (sqlite3expert*) handle and all associated resources. There 
** should be one call to this function for each successful call to 
** sqlite3-expert_new().
*/
void sqlite3_expert_destroy(sqlite3expert*);

/*
** 2017 April 07
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/

#if defined(SQLITE_TEST)

#include "sqlite3expert.h"
#include <assert.h>
#include <string.h>

#if defined(INCLUDE_SQLITE_TCL_H)
#  include "sqlite_tcl.h"
#else
#  include "tcl.h"
#  ifndef SQLITE_TCLAPI
#    define SQLITE_TCLAPI
#  endif
#endif

/*
** Extract an sqlite3* db handle from the object passed as the second
** argument. If successful, set *pDb to point to the db handle and return
** TCL_OK. Otherwise, return TCL_ERROR.
*/
static int dbHandleFromObj(Tcl_Interp *interp, Tcl_Obj *pObj, sqlite3 **pDb){
  Tcl_CmdInfo info;
  if( 0==Tcl_GetCommandInfo(interp, Tcl_GetString(pObj), &info) ){
    Tcl_AppendResult(interp, "no such handle: ", Tcl_GetString(pObj), 0);
    return TCL_ERROR;
  }

  *pDb = *(sqlite3 **)info.objClientData;
  return TCL_OK;
}


/*
** Tclcmd:  $expert sql SQL
**          $expert analyze
**          $expert count
**          $expert report STMT EREPORT
**          $expert destroy
*/
static int SQLITE_TCLAPI testExpertCmd(
  void *clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3expert *pExpert = (sqlite3expert*)clientData;
  struct Subcmd {
    const char *zSub;
    int nArg;
    const char *zMsg;
  } aSub[] = {
    { "sql",       1, "TABLE",        }, /* 0 */
    { "analyze",   0, "",             }, /* 1 */
    { "count",     0, "",             }, /* 2 */
    { "report",    2, "STMT EREPORT", }, /* 3 */
    { "destroy",   0, "",             }, /* 4 */
    { 0 }
  };
  int iSub;
  int rc = TCL_OK;
  char *zErr = 0;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;
  }
  rc = Tcl_GetIndexFromObjStruct(interp, 
      objv[1], aSub, sizeof(aSub[0]), "sub-command", 0, &iSub
  );
  if( rc!=TCL_OK ) return rc;
  if( objc!=2+aSub[iSub].nArg ){
    Tcl_WrongNumArgs(interp, 2, objv, aSub[iSub].zMsg);
    return TCL_ERROR;
  }

  switch( iSub ){
    case 0: {      /* sql */
      char *zArg = Tcl_GetString(objv[2]);
      rc = sqlite3_expert_sql(pExpert, zArg, &zErr);
      break;
    }

    case 1: {      /* analyze */
      rc = sqlite3_expert_analyze(pExpert, &zErr);
      break;
    }

    case 2: {      /* count */
      int n = sqlite3_expert_count(pExpert);
      Tcl_SetObjResult(interp, Tcl_NewIntObj(n));
      break;
    }

    case 3: {      /* report */
      const char *aEnum[] = {
        "sql", "indexes", "plan", "candidates", 0
      };
      int iEnum;
      int iStmt;
      const char *zReport;

      if( Tcl_GetIntFromObj(interp, objv[2], &iStmt) 
       || Tcl_GetIndexFromObj(interp, objv[3], aEnum, "report", 0, &iEnum)
      ){
        return TCL_ERROR;
      }

      assert( EXPERT_REPORT_SQL==1 );
      assert( EXPERT_REPORT_INDEXES==2 );
      assert( EXPERT_REPORT_PLAN==3 );
      assert( EXPERT_REPORT_CANDIDATES==4 );
      zReport = sqlite3_expert_report(pExpert, iStmt, 1+iEnum);
      Tcl_SetObjResult(interp, Tcl_NewStringObj(zReport, -1));
      break;
    }

    default:       /* destroy */
      assert( iSub==4 );     
      Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
      break;
  }

  if( rc!=TCL_OK ){
    if( zErr ){
      Tcl_SetObjResult(interp, Tcl_NewStringObj(zErr, -1));
    }else{
      extern const char *sqlite3ErrName(int);
      Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
    }
  }
  sqlite3_free(zErr);
  return rc;
}

static void SQLITE_TCLAPI testExpertDel(void *clientData){
  sqlite3expert *pExpert = (sqlite3expert*)clientData;
  sqlite3_expert_destroy(pExpert);
}

/*
** sqlite3_expert_new DB
*/
static int SQLITE_TCLAPI test_sqlite3_expert_new(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  static int iCmd = 0;
  sqlite3 *db;
  char *zCmd = 0;
  char *zErr = 0;
  sqlite3expert *pExpert;
  int rc = TCL_OK;

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( dbHandleFromObj(interp, objv[1], &db) ){
    return TCL_ERROR;
  }

  zCmd = sqlite3_mprintf("sqlite3expert%d", ++iCmd);
  if( zCmd==0 ){
    Tcl_AppendResult(interp, "out of memory", (char*)0);
    return TCL_ERROR;
  }

  pExpert = sqlite3_expert_new(db, &zErr);
  if( pExpert==0 ){
    Tcl_AppendResult(interp, zErr, (char*)0);
    rc = TCL_ERROR;
  }else{
    void *p = (void*)pExpert;
    Tcl_CreateObjCommand(interp, zCmd, testExpertCmd, p, testExpertDel);
    Tcl_SetObjResult(interp, Tcl_NewStringObj(zCmd, -1));
  }

  sqlite3_free(zCmd);
  sqlite3_free(zErr);
  return rc;
}

int TestExpert_Init(Tcl_Interp *interp){
  struct Cmd {
    const char *zCmd;
    Tcl_ObjCmdProc *xProc;
  } aCmd[] = {
    { "sqlite3_expert_new", test_sqlite3_expert_new },
  };
  int i;

  for(i=0; i<sizeof(aCmd)/sizeof(struct Cmd); i++){
    struct Cmd *p = &aCmd[i];
    Tcl_CreateObjCommand(interp, p->zCmd, p->xProc, 0, 0);
  }

  return TCL_OK;
}

#endif

};

/*
** A single step of the Keccak mixing function for a 1600-bit state
*/
static void KeccakF1600Step(SHA3Context *p){
  int i;
  u64 b0, b1, b2, b3, b4;
  u64 c0, c1, c2, c3, c4;
  u64 d0, d1, d2, d3, d4;
  static const u64 RC[] = {
    0x0000000000000001ULL,  0x0000000000008082ULL,
    0x800000000000808aULL,  0x8000000080008000ULL,
    0x000000000000808bULL,  0x0000000080000001ULL,
    0x8000000080008081ULL,  0x8000000000008009ULL,
    0x000000000000008aULL,  0x0000000000000088ULL,
    0x0000000080008009ULL,  0x000000008000000aULL,
    0x000000008000808bULL,  0x800000000000008bULL,
    0x8000000000008089ULL,  0x8000000000008003ULL,
    0x8000000000008002ULL,  0x8000000000000080ULL,
    0x000000000000800aULL,  0x800000008000000aULL,
    0x8000000080008081ULL,  0x8000000000008080ULL,
    0x0000000080000001ULL,  0x8000000080008008ULL
  };
# define a00 (p->u.s[0])
# define a01 (p->u.s[1])
# define a02 (p->u.s[2])
# define a03 (p->u.s[3])
# define a04 (p->u.s[4])
# define a10 (p->u.s[5])
# define a11 (p->u.s[6])
# define a12 (p->u.s[7])
# define a13 (p->u.s[8])
# define a14 (p->u.s[9])
# define a20 (p->u.s[10])
# define a21 (p->u.s[11])
# define a22 (p->u.s[12])
# define a23 (p->u.s[13])
# define a24 (p->u.s[14])
# define a30 (p->u.s[15])
# define a31 (p->u.s[16])
# define a32 (p->u.s[17])
# define a33 (p->u.s[18])
# define a34 (p->u.s[19])
# define a40 (p->u.s[20])
# define a41 (p->u.s[21])
# define a42 (p->u.s[22])
# define a43 (p->u.s[23])
# define a44 (p->u.s[24])
# define ROL64(a,x) ((a<<x)|(a>>(64-x)))

  for(i=0; i<24; i+=4){
    c0 = a00^a10^a20^a30^a40;
    c1 = a01^a11^a21^a31^a41;
    c2 = a02^a12^a22^a32^a42;
    c3 = a03^a13^a23^a33^a43;
    c4 = a04^a14^a24^a34^a44;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a11^d1), 44);
    b2 = ROL64((a22^d2), 43);
    b3 = ROL64((a33^d3), 21);
    b4 = ROL64((a44^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i];
    a11 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a20^d0), 3);
    b3 = ROL64((a31^d1), 45);
    b4 = ROL64((a42^d2), 61);
    b0 = ROL64((a03^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a20 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a40^d0), 18);
    b0 = ROL64((a01^d1), 1);
    b1 = ROL64((a12^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a34^d4), 8);
    a40 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a10^d0), 36);
    b2 = ROL64((a21^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a43^d3), 56);
    b0 = ROL64((a04^d4), 27);
    a10 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a30^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a02^d2), 62);
    b1 = ROL64((a13^d3), 55);
    b2 = ROL64((a24^d4), 39);
    a30 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    c0 = a00^a20^a40^a10^a30;
    c1 = a11^a31^a01^a21^a41;
    c2 = a22^a42^a12^a32^a02;
    c3 = a33^a03^a23^a43^a13;
    c4 = a44^a14^a34^a04^a24;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a31^d1), 44);
    b2 = ROL64((a12^d2), 43);
    b3 = ROL64((a43^d3), 21);
    b4 = ROL64((a24^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+1];
    a31 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a40^d0), 3);
    b3 = ROL64((a21^d1), 45);
    b4 = ROL64((a02^d2), 61);
    b0 = ROL64((a33^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a40 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a30^d0), 18);
    b0 = ROL64((a11^d1), 1);
    b1 = ROL64((a42^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a04^d4), 8);
    a30 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a20^d0), 36);
    b2 = ROL64((a01^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a13^d3), 56);
    b0 = ROL64((a44^d4), 27);
    a20 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a10^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a22^d2), 62);
    b1 = ROL64((a03^d3), 55);
    b2 = ROL64((a34^d4), 39);
    a10 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    c0 = a00^a40^a30^a20^a10;
    c1 = a31^a21^a11^a01^a41;
    c2 = a12^a02^a42^a32^a22;
    c3 = a43^a33^a23^a13^a03;
    c4 = a24^a14^a04^a44^a34;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a21^d1), 44);
    b2 = ROL64((a42^d2), 43);
    b3 = ROL64((a13^d3), 21);
    b4 = ROL64((a34^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+2];
    a21 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a30^d0), 3);
    b3 = ROL64((a01^d1), 45);
    b4 = ROL64((a22^d2), 61);
    b0 = ROL64((a43^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a30 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a10^d0), 18);
    b0 = ROL64((a31^d1), 1);
    b1 = ROL64((a02^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a44^d4), 8);
    a10 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a40^d0), 36);
    b2 = ROL64((a11^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a03^d3), 56);
    b0 = ROL64((a24^d4), 27);
    a40 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a20^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a12^d2), 62);
    b1 = ROL64((a33^d3), 55);
    b2 = ROL64((a04^d4), 39);
    a20 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    c0 = a00^a30^a10^a40^a20;
    c1 = a21^a01^a31^a11^a41;
    c2 = a42^a22^a02^a32^a12;
    c3 = a13^a43^a23^a03^a33;
    c4 = a34^a14^a44^a24^a04;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a01^d1), 44);
    b2 = ROL64((a02^d2), 43);
    b3 = ROL64((a03^d3), 21);
    b4 = ROL64((a04^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+3];
    a01 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a10^d0), 3);
    b3 = ROL64((a11^d1), 45);
    b4 = ROL64((a12^d2), 61);
    b0 = ROL64((a13^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a10 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a20^d0), 18);
    b0 = ROL64((a21^d1), 1);
    b1 = ROL64((a22^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a24^d4), 8);
    a20 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a30^d0), 36);
    b2 = ROL64((a31^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a33^d3), 56);
    b0 = ROL64((a34^d4), 27);
    a30 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a40^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a42^d2), 62);
    b1 = ROL64((a43^d3), 55);
    b2 = ROL64((a44^d4), 39);
    a40 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );
  }
}

/*
** Initialize a new hash.  iSize determines the size of the hash
** in bits and should be one of 224, 256, 384, or 512.  Or iSize
** can be zero to use the default hash size of 256 bits.

**     3. The smallest rowid in the range of rowids that may be stored in the
**        database table (an integer).
**
**     4. The largest rowid in the range of rowids that may be stored in the
**        database table (an integer).
**
** SWARMVTAB
**
**  LEGACY SYNTAX:
**
**   A "swarmvtab" virtual table is created similarly to a unionvtab table:
**
**     CREATE VIRTUAL TABLE <name>
**      USING swarmvtab(<sql-statement>, <callback>);
**
**   The difference is that for a swarmvtab table, the first column returned
**   by the <sql statement> must return a path or URI that can be used to open
**   the database file containing the source table.  The <callback> option
**   is optional.  If included, it is the name of an application-defined
**   SQL function that is invoked with the URI of the file, if the file
**   does not already exist on disk when required by swarmvtab.
**
**  NEW SYNTAX:
**
**   Using the new syntax, a swarmvtab table is created with:
**
**      CREATE VIRTUAL TABLE <name> USING swarmvtab(
**        <sql-statement> [, <options>]
**      );
**
**   where valid <options> are:
**
**      missing=<udf-function-name>
**      openclose=<udf-function-name>
**      maxopen=<integer>
**      <sql-parameter>=<text-value>
**
**   The <sql-statement> must return the same 4 columns as for a swarmvtab
**   table in legacy mode. However, it may also return a 5th column - the
**   "context" column. The text value returned in this column is not used
**   at all by the swarmvtab implementation, except that it is passed as
**   an additional argument to the two UDF functions that may be invoked
**   (see below).
**
**   The "missing" option, if present, specifies the name of an SQL UDF
**   function to be invoked if a database file is not already present on
**   disk when required by swarmvtab. If the <sql-statement> did not provide
**   a context column, it is invoked as:
**
**     SELECT <missing-udf>(<database filename/uri>);
**
**   Or, if there was a context column:
**
**     SELECT <missing-udf>(<database filename/uri>, <context>);
**
**   The "openclose" option may also specify a UDF function. This function
**   is invoked right before swarmvtab opens a database, and right after
**   it closes one. The first argument - or first two arguments, if
**   <sql-statement> supplied the context column - is the same as for
**   the "missing" UDF. Following this, the UDF is passed integer value
**   0 before a db is opened, and 1 right after it is closed. If both
**   a missing and openclose UDF is supplied, the application should expect
**   the following sequence of calls (for a single database):
**
**      SELECT <openclose-udf>(<db filename>, <context>, 0);
**      if( db not already on disk ){
**          SELECT <missing-udf>(<db filename>, <context>);
**      }
**      ... swarmvtab uses database ...
**      SELECT <openclose-udf>(<db filename>, <context>, 1);
**
**   The "maxopen" option is used to configure the maximum number of
**   database files swarmvtab will hold open simultaneously (default 9).
**
**   If an option name begins with a ":" character, then it is assumed
**   to be an SQL parameter. In this case, the specified text value is
**   bound to the same variable of the <sql-statement> before it is 
**   executed. It is an error of the named SQL parameter does not exist.
**   For example:
**
**     CREATE VIRTUAL TABLE swarm USING swarmvtab(
**       'SELECT :path || localfile, tbl, min, max FROM swarmdir',
**       :path='/home/user/databases/'
**       missing='missing_func'
**     );
*/

#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>
#include <stdlib.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE

/*
** Largest and smallest possible 64-bit signed integers. These macros
** copied from sqliteInt.h.
*/

  char *zDb;                      /* Database containing source table */
  char *zTab;                     /* Source table name */
  sqlite3_int64 iMin;             /* Minimum rowid */
  sqlite3_int64 iMax;             /* Maximum rowid */

  /* Fields used by swarmvtab only */
  char *zFile;                    /* Database file containing table zTab */
  char *zContext;                 /* Context string, if any */
  int nUser;                      /* Current number of users */
  sqlite3 *db;                    /* Database handle */
  UnionSrc *pNextClosable;        /* Next in list of closable sources */
};

/*
** Virtual table  type for union vtab.
*/
struct UnionTab {
  sqlite3_vtab base;              /* Base class - must be first */
  sqlite3 *db;                    /* Database handle */
  int bSwarm;                     /* 1 for "swarmvtab", 0 for "unionvtab" */
  int iPK;                        /* INTEGER PRIMARY KEY column, or -1 */
  int nSrc;                       /* Number of elements in the aSrc[] array */
  UnionSrc *aSrc;                 /* Array of source tables, sorted by rowid */

  /* Used by swarmvtab only */
  int bHasContext;                /* Has context strings */
  char *zSourceStr;               /* Expected unionSourceToStr() value */
  sqlite3_stmt *pNotFound;        /* UDF to invoke if file not found on open */
  sqlite3_stmt *pOpenClose;       /* UDF to invoke on open and close */

  UnionSrc *pClosable;            /* First in list of closable sources */
  int nOpen;                      /* Current number of open sources */
  int nMaxOpen;                   /* Maximum number of open sources */
};

/*
** Virtual table cursor type for union vtab.

  if( *pRc==SQLITE_OK ){
    *pRc = rc;
    if( rc ){
      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
    }
  }
}

/*
** If an "openclose" UDF was supplied when this virtual table was created,
** invoke it now. The first argument passed is the name of the database
** file for source pSrc. The second is integer value bClose.
**
** If successful, return SQLITE_OK. Otherwise an SQLite error code. In this
** case if argument pzErr is not NULL, also set (*pzErr) to an English
** language error message. The caller is responsible for eventually freeing 
** any error message using sqlite3_free().
*/
static int unionInvokeOpenClose(
  UnionTab *pTab, 
  UnionSrc *pSrc, 
  int bClose,
  char **pzErr
){
  int rc = SQLITE_OK;
  if( pTab->pOpenClose ){
    sqlite3_bind_text(pTab->pOpenClose, 1, pSrc->zFile, -1, SQLITE_STATIC);
    if( pTab->bHasContext ){
      sqlite3_bind_text(pTab->pOpenClose, 2, pSrc->zContext, -1, SQLITE_STATIC);
    }
    sqlite3_bind_int(pTab->pOpenClose, 2+pTab->bHasContext, bClose);
    sqlite3_step(pTab->pOpenClose);
    if( SQLITE_OK!=(rc = sqlite3_reset(pTab->pOpenClose)) ){
      if( pzErr ){
        *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
      }
    }
  }
  return rc;
}

/*
** This function is a no-op for unionvtab. For swarmvtab, it attempts to
** close open database files until at most nMax are open. An SQLite error
** code is returned if an error occurs, or SQLITE_OK otherwise.
*/
static void unionCloseSources(UnionTab *pTab, int nMax){
  while( pTab->pClosable && pTab->nOpen>nMax ){
    UnionSrc *p;
    UnionSrc **pp;
    for(pp=&pTab->pClosable; (*pp)->pNextClosable; pp=&(*pp)->pNextClosable);
    p = *pp;
    assert( p->db );
    sqlite3_close(p->db);
    p->db = 0;
    *pp = 0;
    pTab->nOpen--;
    unionInvokeOpenClose(pTab, p, 1, 0);
  }
}

/*
** xDisconnect method.
*/
static int unionDisconnect(sqlite3_vtab *pVtab){
  if( pVtab ){
    UnionTab *pTab = (UnionTab*)pVtab;
    int i;
    for(i=0; i<pTab->nSrc; i++){
      UnionSrc *pSrc = &pTab->aSrc[i];
      if( pSrc->db ){
        unionInvokeOpenClose(pTab, pSrc, 1, 0);
      }
      sqlite3_free(pSrc->zDb);
      sqlite3_free(pSrc->zTab);
      sqlite3_free(pSrc->zFile);
      sqlite3_free(pSrc->zContext);
      sqlite3_close(pSrc->db);
    }
    sqlite3_finalize(pTab->pNotFound);
    sqlite3_finalize(pTab->pOpenClose);
    sqlite3_free(pTab->zSourceStr);
    sqlite3_free(pTab->aSrc);
    sqlite3_free(pTab);
  }
  return SQLITE_OK;
}

/*

    sqlite3_free(z);
  }
  sqlite3_free(z0);

  return rc;
}


/*
** Try to open the swarmvtab database.  If initially unable, invoke the
** not-found callback UDF and then try again.
*/
static int unionOpenDatabaseInner(UnionTab *pTab, UnionSrc *pSrc, char **pzErr){
  static const int openFlags = SQLITE_OPEN_READONLY | SQLITE_OPEN_URI;
  int rc;

  rc = unionInvokeOpenClose(pTab, pSrc, 0, pzErr);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3_open_v2(pSrc->zFile, &pSrc->db, openFlags, 0);
  if( rc==SQLITE_OK ) return rc;
  if( pTab->pNotFound ){


    sqlite3_close(pSrc->db);
    pSrc->db = 0;
    sqlite3_bind_text(pTab->pNotFound, 1, pSrc->zFile, -1, SQLITE_STATIC);
    if( pTab->bHasContext ){
      sqlite3_bind_text(pTab->pNotFound, 2, pSrc->zContext, -1, SQLITE_STATIC);
    }
    sqlite3_step(pTab->pNotFound);
    if( SQLITE_OK!=(rc = sqlite3_reset(pTab->pNotFound)) ){
      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
      return rc;
    }



    rc = sqlite3_open_v2(pSrc->zFile, &pSrc->db, openFlags, 0);
  }
  if( rc!=SQLITE_OK ){
    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pSrc->db));
  }
  return rc;
}

    if( rc==SQLITE_OK ){
      pSrc->pNextClosable = pTab->pClosable;
      pTab->pClosable = pSrc;
      pTab->nOpen++;
    }else{
      sqlite3_close(pSrc->db);
      pSrc->db = 0;
      unionInvokeOpenClose(pTab, pSrc, 1, 0);
    }
  }

  return rc;
}

        pTab->pClosable = pSrc;
      }
      unionCloseSources(pTab, pTab->nMaxOpen);
    }
  }
  return rc;
}

/* 
** Return true if the argument is a space, tab, CR or LF character.
*/
static int union_isspace(char c){
  return (c==' ' || c=='\n' || c=='\r' || c=='\t');
}

/* 
** Return true if the argument is an alphanumeric character in the 
** ASCII range.
*/
static int union_isidchar(char c){
  return ((c>='a' && c<='z') || (c>='A' && c<'Z') || (c>='0' && c<='9'));
}

/*
** This function is called to handle all arguments following the first 
** (the SQL statement) passed to a swarmvtab (not unionvtab) CREATE 
** VIRTUAL TABLE statement. It may bind parameters to the SQL statement 
** or configure members of the UnionTab object passed as the second
** argument.
**
** Refer to header comments at the top of this file for a description
** of the arguments parsed.
**
** This function is a no-op if *pRc is other than SQLITE_OK when it is
** called. Otherwise, if an error occurs, *pRc is set to an SQLite error
** code. In this case *pzErr may be set to point to a buffer containing
** an English language error message. It is the responsibility of the 
** caller to eventually free the buffer using sqlite3_free().
*/
static void unionConfigureVtab(
  int *pRc,                       /* IN/OUT: Error code */
  UnionTab *pTab,                 /* Table to configure */
  sqlite3_stmt *pStmt,            /* SQL statement to find sources */
  int nArg,                       /* Number of entries in azArg[] array */
  const char * const *azArg,      /* Array of arguments to consider */
  char **pzErr                    /* OUT: Error message */
){
  int rc = *pRc;
  int i;
  if( rc==SQLITE_OK ){
    pTab->bHasContext = (sqlite3_column_count(pStmt)>4);
  }
  for(i=0; rc==SQLITE_OK && i<nArg; i++){
    char *zArg = unionStrdup(&rc, azArg[i]);
    if( zArg ){
      int nOpt = 0;               /* Size of option name in bytes */
      char *zOpt;                 /* Pointer to option name */
      char *zVal;                 /* Pointer to value */

      unionDequote(zArg);
      zOpt = zArg;
      while( union_isspace(*zOpt) ) zOpt++;
      zVal = zOpt;
      if( *zVal==':' ) zVal++;
      while( union_isidchar(*zVal) ) zVal++;
      nOpt = zVal-zOpt;

      while( union_isspace(*zVal) ) zVal++;
      if( *zVal=='=' ){
        zOpt[nOpt] = '\0';
        zVal++;
        while( union_isspace(*zVal) ) zVal++;
        zVal = unionStrdup(&rc, zVal);
        if( zVal ){
          unionDequote(zVal);
          if( zOpt[0]==':' ){
            /* A value to bind to the SQL statement */
            int iParam = sqlite3_bind_parameter_index(pStmt, zOpt);
            if( iParam==0 ){
              *pzErr = sqlite3_mprintf(
                  "swarmvtab: no such SQL parameter: %s", zOpt
              );
              rc = SQLITE_ERROR;
            }else{
              rc = sqlite3_bind_text(pStmt, iParam, zVal, -1, SQLITE_TRANSIENT);
            }
          }else if( nOpt==7 && 0==sqlite3_strnicmp(zOpt, "maxopen", 7) ){
            pTab->nMaxOpen = atoi(zVal);
            if( pTab->nMaxOpen<=0 ){
              *pzErr = sqlite3_mprintf("swarmvtab: illegal maxopen value");
              rc = SQLITE_ERROR;
            }
          }else if( nOpt==7 && 0==sqlite3_strnicmp(zOpt, "missing", 7) ){
            if( pTab->pNotFound ){
              *pzErr = sqlite3_mprintf(
                  "swarmvtab: duplicate \"missing\" option");
              rc = SQLITE_ERROR;
            }else{
              pTab->pNotFound = unionPreparePrintf(&rc, pzErr, pTab->db,
                  "SELECT \"%w\"(?%s)", zVal, pTab->bHasContext ? ",?" : ""
              );
            }
          }else if( nOpt==9 && 0==sqlite3_strnicmp(zOpt, "openclose", 9) ){
            if( pTab->pOpenClose ){
              *pzErr = sqlite3_mprintf(
                  "swarmvtab: duplicate \"openclose\" option");
              rc = SQLITE_ERROR;
            }else{
              pTab->pOpenClose = unionPreparePrintf(&rc, pzErr, pTab->db,
                  "SELECT \"%w\"(?,?%s)", zVal, pTab->bHasContext ? ",?" : ""
              );
            }
          }else{
            *pzErr = sqlite3_mprintf("swarmvtab: unrecognized option: %s",zOpt);
            rc = SQLITE_ERROR;
          }
          sqlite3_free(zVal);
        }
      }else{
        if( i==0 && nArg==1 ){
          pTab->pNotFound = unionPreparePrintf(&rc, pzErr, pTab->db,
              "SELECT \"%w\"(?)", zArg
          );
        }else{
          *pzErr = sqlite3_mprintf( "swarmvtab: parse error: %s", azArg[i]);
          rc = SQLITE_ERROR;
        }
      }
      sqlite3_free(zArg);
    }
  }
  *pRc = rc;
}

/* 
** xConnect/xCreate method.
**
** The argv[] array contains the following:
**
**   argv[0]   -> module name  ("unionvtab" or "swarmvtab")

  int bSwarm = (pAux==0 ? 0 : 1);
  const char *zVtab = (bSwarm ? "swarmvtab" : "unionvtab");

  if( sqlite3_stricmp("temp", argv[1]) ){
    /* unionvtab tables may only be created in the temp schema */
    *pzErr = sqlite3_mprintf("%s tables must be created in TEMP schema", zVtab);
    rc = SQLITE_ERROR;
  }else if( argc<4 || (argc>4 && bSwarm==0) ){
    *pzErr = sqlite3_mprintf("wrong number of arguments for %s", zVtab);
    rc = SQLITE_ERROR;
  }else{
    int nAlloc = 0;               /* Allocated size of pTab->aSrc[] */
    sqlite3_stmt *pStmt = 0;      /* Argument statement */
    char *zArg = unionStrdup(&rc, argv[3]);      /* Copy of argument to CVT */

    /* Prepare the SQL statement. Instead of executing it directly, sort
    ** the results by the "minimum rowid" field. This makes it easier to
    ** check that there are no rowid range overlaps between source tables 
    ** and that the UnionTab.aSrc[] array is always sorted by rowid.  */
    unionDequote(zArg);
    pStmt = unionPreparePrintf(&rc, pzErr, db, 
        "SELECT * FROM (%z) ORDER BY 3", zArg
    );

    /* Allocate the UnionTab structure */
    pTab = unionMalloc(&rc, sizeof(UnionTab));
    if( pTab ){
      assert( rc==SQLITE_OK );
      pTab->db = db;
      pTab->bSwarm = bSwarm;
      pTab->nMaxOpen = SWARMVTAB_MAX_OPEN;
    }

    /* Parse other CVT arguments, if any */
    if( bSwarm ){
      unionConfigureVtab(&rc, pTab, pStmt, argc-4, &argv[4], pzErr);
    }

    /* Iterate through the rows returned by the SQL statement specified
    ** as an argument to the CREATE VIRTUAL TABLE statement. */
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
      const char *zDb = (const char*)sqlite3_column_text(pStmt, 0);
      const char *zTab = (const char*)sqlite3_column_text(pStmt, 1);
      sqlite3_int64 iMin = sqlite3_column_int64(pStmt, 2);

        pSrc->iMin = iMin;
        pSrc->iMax = iMax;
        if( bSwarm ){
          pSrc->zFile = unionStrdup(&rc, zDb);
        }else{
          pSrc->zDb = unionStrdup(&rc, zDb);
        }
        if( pTab->bHasContext ){
          const char *zContext = (const char*)sqlite3_column_text(pStmt, 4);
          pSrc->zContext = unionStrdup(&rc, zContext);
        }
      }
    }
    unionFinalize(&rc, pStmt, pzErr);
    pStmt = 0;







    /* It is an error if the SELECT statement returned zero rows. If only
    ** because there is no way to determine the schema of the virtual 
    ** table in this case.  */
    if( rc==SQLITE_OK && pTab->nSrc==0 ){
      *pzErr = sqlite3_mprintf("no source tables configured");
      rc = SQLITE_ERROR;
    }

    /* For unionvtab, verify that all source tables exist and have 
    ** compatible schemas. For swarmvtab, attach the first database and
    ** check that the first table is a rowid table only.  */
    if( rc==SQLITE_OK ){



      if( bSwarm ){
        rc = unionOpenDatabase(pTab, 0, pzErr);
      }else{
        rc = unionSourceCheck(pTab, pzErr);
      }
    }

  Rtree *pRtree,               /* Rtree table */
  RtreeCell *pCell,            /* Cell to insert into rtree */
  int iHeight,                 /* Height of sub-tree rooted at pCell */
  RtreeNode **ppLeaf           /* OUT: Selected leaf page */
){
  int rc;
  int ii;
  RtreeNode *pNode = 0;
  rc = nodeAcquire(pRtree, 1, 0, &pNode);

  for(ii=0; rc==SQLITE_OK && ii<(pRtree->iDepth-iHeight); ii++){
    int iCell;
    sqlite3_int64 iBest = 0;

    RtreeDValue fMinGrowth = RTREE_ZERO;

  **
  ** This is equivalent to copying the contents of the child into
  ** the root node (the operation that Gutman's paper says to perform 
  ** in this scenario).
  */
  if( rc==SQLITE_OK && pRtree->iDepth>0 && NCELL(pRoot)==1 ){
    int rc2;
    RtreeNode *pChild = 0;
    i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
    rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);
    if( rc==SQLITE_OK ){
      rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
    }
    rc2 = nodeRelease(pRtree, pChild);
    if( rc==SQLITE_OK ) rc = rc2;

  shell.c \
  sqlite3.h


# Source code to the test files.
#
TESTSRC = \
  $(TOP)/ext/expert/sqlite3expert.c \
  $(TOP)/ext/expert/test_expert.c \
  $(TOP)/ext/fts3/fts3_term.c \
  $(TOP)/ext/fts3/fts3_test.c \
  $(TOP)/ext/rbu/test_rbu.c \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c \
  $(TOP)/src/test3.c \
  $(TOP)/src/test4.c \

# Source files that go into making shell.c
SHELL_SRC = \
	$(TOP)/src/shell.c.in \
	$(TOP)/ext/misc/shathree.c \
	$(TOP)/ext/misc/fileio.c \
	$(TOP)/ext/misc/completion.c \
	$(TOP)/ext/misc/sqlar.c \
	$(TOP)/ext/expert/sqlite3expert.c \
	$(TOP)/ext/expert/sqlite3expert.h

shell.c:	$(SHELL_SRC) $(TOP)/tool/mkshellc.tcl
	tclsh $(TOP)/tool/mkshellc.tcl >shell.c



# Rules to build the extension objects.

sqlite3_analyzer.c: sqlite3.c $(TOP)/src/tclsqlite.c $(TOP)/tool/spaceanal.tcl $(TOP)/tool/sqlite3_analyzer.c.in $(TOP)/tool/mkccode.tcl
	tclsh $(TOP)/tool/mkccode.tcl $(TOP)/tool/sqlite3_analyzer.c.in >sqlite3_analyzer.c

sqlite3_analyzer$(EXE): sqlite3_analyzer.c
	$(TCCX) $(TCL_FLAGS) sqlite3_analyzer.c -o $@ $(LIBTCL) $(THREADLIB) 

sqlite3_expert$(EXE): $(TOP)/ext/expert/sqlite3expert.h $(TOP)/ext/expert/sqlite3expert.c $(TOP)/ext/expert/expert.c sqlite3.c
	$(TCCX) -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION $(TOP)/ext/expert/sqlite3expert.c $(TOP)/ext/expert/expert.c sqlite3.c -o sqlite3_expert$(EXE) $(THREADLIB)

CHECKER_DEPS =\
  $(TOP)/tool/mkccode.tcl \
  sqlite3.c \
  $(TOP)/src/tclsqlite.c \
  $(TOP)/ext/repair/sqlite3_checker.tcl \
  $(TOP)/ext/repair/checkindex.c \
  $(TOP)/ext/repair/checkfreelist.c \

	rm -f wordcount wordcount.exe
	rm -f rbu rbu.exe
	rm -f srcck1 srcck1.exe
	rm -f sqlite3.c sqlite3-*.c fts?amal.c tclsqlite3.c
	rm -f sqlite3rc.h
	rm -f shell.c sqlite3ext.h
	rm -f sqlite3_analyzer sqlite3_analyzer.exe sqlite3_analyzer.c
	rm -f sqlite3_expert sqlite3_expert.exe 
	rm -f sqlite-*-output.vsix
	rm -f mptester mptester.exe
	rm -f fuzzershell fuzzershell.exe
	rm -f fuzzcheck fuzzcheck.exe
	rm -f sqldiff sqldiff.exe
	rm -f fts5.* fts5parse.*
	rm -f lsm.h lsm1.c

      assert(pParse->nTab==1);
      sqlite3MayAbort(pParse);
      sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
      sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
      pParse->nTab = 2;
      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);





      pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect);
      if( pSelTab==0 ) return;
      assert( p->aCol==0 );
      p->nCol = pSelTab->nCol;
      p->aCol = pSelTab->aCol;
      pSelTab->nCol = 0;
      pSelTab->aCol = 0;
      sqlite3DeleteTable(db, pSelTab);
      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
      sqlite3Select(pParse, pSelect, &dest);
      sqlite3VdbeEndCoroutine(v, regYield);
      sqlite3VdbeJumpHere(v, addrTop - 1);
      addrInsLoop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
      VdbeCoverage(v);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, dest.iSdst, dest.nSdst, regRec);
      sqlite3TableAffinity(v, p, 0);
      sqlite3VdbeAddOp2(v, OP_NewRowid, 1, regRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, 1, regRec, regRowid);
      sqlite3VdbeGoto(v, addrInsLoop);

  zEntry = zProc ? zProc : "sqlite3_extension_init";

  handle = sqlite3OsDlOpen(pVfs, zFile);
#if SQLITE_OS_UNIX || SQLITE_OS_WIN
  for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
    char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
    int bExists = 0;
    if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
    sqlite3OsAccess(pVfs, zAltFile, SQLITE_ACCESS_EXISTS, &bExists);
    if( bExists )  handle = sqlite3OsDlOpen(pVfs, zAltFile);
    sqlite3_free(zAltFile);
  }
#endif
  if( handle==0 ){
    if( pzErrMsg ){
      *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
      if( zErrmsg ){

      } aFlagOp[] = {
        { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
        { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
        { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
        { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
        { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
        { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
        { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
      };
      unsigned int i;
      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
      for(i=0; i<ArraySize(aFlagOp); i++){
        if( aFlagOp[i].op==op ){
          int onoff = va_arg(ap, int);
          int *pRes = va_arg(ap, int*);

  ** the returned data set are:
  **
  ** cid:        Column id (numbered from left to right, starting at 0)
  ** name:       Column name
  ** type:       Column declaration type.
  ** notnull:    True if 'NOT NULL' is part of column declaration
  ** dflt_value: The default value for the column, if any.
  ** pk:         Non-zero for PK fields.
  */
  case PragTyp_TABLE_INFO: if( zRight ){
    Table *pTab;
    pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
    if( pTab ){
      int i, k;
      int nHidden = 0;

  char const *zOrigDb = 0;
  char const *zOrigTab = 0;
  char const *zOrigCol = 0;
#endif

  assert( pExpr!=0 );
  assert( pNC->pSrcList!=0 );
  assert( pExpr->op!=TK_AGG_COLUMN );  /* This routine runes before aggregates
                                       ** are processed */
  switch( pExpr->op ){

    case TK_COLUMN: {
      /* The expression is a column. Locate the table the column is being
      ** extracted from in NameContext.pSrcList. This table may be real
      ** database table or a subquery.
      */
      Table *pTab = 0;            /* Table structure column is extracted from */
      Select *pS = 0;             /* Select the column is extracted from */
      int iCol = pExpr->iColumn;  /* Index of column in pTab */


      while( pNC && !pTab ){
        SrcList *pTabList = pNC->pSrcList;
        for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
        if( j<pTabList->nSrc ){
          pTab = pTabList->a[j].pTab;
          pS = pTabList->a[j].pSelect;
        }else{

    return;
  }
#endif

  if( pParse->colNamesSet || db->mallocFailed ) return;
  /* Column names are determined by the left-most term of a compound select */
  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
  SELECTTRACE(1,pParse,pSelect,("generating column names\n"));
  pTabList = pSelect->pSrc;
  pEList = pSelect->pEList;
  assert( v!=0 );
  assert( pTabList!=0 );
  pParse->colNamesSet = 1;
  fullName = (db->flags & SQLITE_FullColNames)!=0;
  srcName = (db->flags & SQLITE_ShortColNames)!=0 || fullName;

      /* If the column contains an "AS <name>" phrase, use <name> as the name */
    }else{
      Expr *pColExpr = sqlite3ExprSkipCollate(pEList->a[i].pExpr);
      while( pColExpr->op==TK_DOT ){
        pColExpr = pColExpr->pRight;
        assert( pColExpr!=0 );
      }
      assert( pColExpr->op!=TK_AGG_COLUMN );
      if( pColExpr->op==TK_COLUMN ){

        /* For columns use the column name name */
        int iCol = pColExpr->iColumn;
        Table *pTab = pColExpr->pTab;
        assert( pTab!=0 );
        if( iCol<0 ) iCol = pTab->iPKey;
        zName = iCol>=0 ? pTab->aCol[iCol].zName : "rowid";
      }else if( pColExpr->op==TK_ID ){
        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
        zName = pColExpr->u.zToken;
      }else{
        /* Use the original text of the column expression as its name */

INCLUDE ../ext/misc/shathree.c
INCLUDE ../ext/misc/fileio.c
INCLUDE ../ext/misc/completion.c
#ifdef SQLITE_HAVE_ZLIB
INCLUDE ../ext/misc/sqlar.c
#endif
INCLUDE ../ext/expert/sqlite3expert.h
INCLUDE ../ext/expert/sqlite3expert.c

#if defined(SQLITE_ENABLE_SESSION)
/*
** State information for a single open session
*/
typedef struct OpenSession OpenSession;
struct OpenSession {

typedef struct SavedModeInfo SavedModeInfo;
struct SavedModeInfo {
  int valid;          /* Is there legit data in here? */
  int mode;           /* Mode prior to ".explain on" */
  int showHeader;     /* The ".header" setting prior to ".explain on" */
  int colWidth[100];  /* Column widths prior to ".explain on" */
};

typedef struct ExpertInfo ExpertInfo;
struct ExpertInfo {
  sqlite3expert *pExpert;
  int bVerbose;
};

/*
** State information about the database connection is contained in an
** instance of the following structure.
*/
typedef struct ShellState ShellState;
struct ShellState {

  int *aiIndent;         /* Array of indents used in MODE_Explain */
  int nIndent;           /* Size of array aiIndent[] */
  int iIndent;           /* Index of current op in aiIndent[] */
#if defined(SQLITE_ENABLE_SESSION)
  int nSession;             /* Number of active sessions */
  OpenSession aSession[4];  /* Array of sessions.  [0] is in focus. */
#endif
  ExpertInfo expert;        /* Valid if previous command was ".expert OPT..." */
};

/* Allowed values for ShellState.autoEQP
*/
#define AUTOEQP_off      0
#define AUTOEQP_on       1
#define AUTOEQP_trigger  2
#define AUTOEQP_full     3

/*
** These are the allowed shellFlgs values
*/
#define SHFLG_Pagecache      0x00000001 /* The --pagecache option is used */
#define SHFLG_Lookaside      0x00000002 /* Lookaside memory is used */
#define SHFLG_Backslash      0x00000004 /* The --backslash option is used */

    }else{
      do{
        rc = sqlite3_step(pStmt);
      } while( rc == SQLITE_ROW );
    }
  }
}

/*
** This function is called to process SQL if the previous shell command
** was ".expert". It passes the SQL in the second argument directly to
** the sqlite3expert object.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error
** code. In this case, (*pzErr) may be set to point to a buffer containing
** an English language error message. It is the responsibility of the
** caller to eventually free this buffer using sqlite3_free().
*/
static int expertHandleSQL(
  ShellState *pState, 
  const char *zSql, 
  char **pzErr
){
  assert( pState->expert.pExpert );
  assert( pzErr==0 || *pzErr==0 );
  return sqlite3_expert_sql(pState->expert.pExpert, zSql, pzErr);
}

/*
** This function is called either to silently clean up the object
** created by the ".expert" command (if bCancel==1), or to generate a 
** report from it and then clean it up (if bCancel==0).
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error
** code. In this case, (*pzErr) may be set to point to a buffer containing
** an English language error message. It is the responsibility of the
** caller to eventually free this buffer using sqlite3_free().
*/
static int expertFinish(
  ShellState *pState,
  int bCancel,
  char **pzErr
){
  int rc = SQLITE_OK;
  sqlite3expert *p = pState->expert.pExpert;
  assert( p );
  assert( bCancel || pzErr==0 || *pzErr==0 );
  if( bCancel==0 ){
    FILE *out = pState->out;
    int bVerbose = pState->expert.bVerbose;

    rc = sqlite3_expert_analyze(p, pzErr);
    if( rc==SQLITE_OK ){
      int nQuery = sqlite3_expert_count(p);
      int i;

      if( bVerbose ){
        const char *zCand = sqlite3_expert_report(p,0,EXPERT_REPORT_CANDIDATES);
        raw_printf(out, "-- Candidates -----------------------------\n");
        raw_printf(out, "%s\n", zCand);
      }
      for(i=0; i<nQuery; i++){
        const char *zSql = sqlite3_expert_report(p, i, EXPERT_REPORT_SQL);
        const char *zIdx = sqlite3_expert_report(p, i, EXPERT_REPORT_INDEXES);
        const char *zEQP = sqlite3_expert_report(p, i, EXPERT_REPORT_PLAN);
        if( zIdx==0 ) zIdx = "(no new indexes)\n";
        if( bVerbose ){
          raw_printf(out, "-- Query %d --------------------------------\n",i+1);
          raw_printf(out, "%s\n\n", zSql);
        }
        raw_printf(out, "%s\n", zIdx);
        raw_printf(out, "%s\n", zEQP);
      }
    }
  }
  sqlite3_expert_destroy(p);
  pState->expert.pExpert = 0;
  return rc;
}


/*
** Execute a statement or set of statements.  Print
** any result rows/columns depending on the current mode
** set via the supplied callback.
**
** This is very similar to SQLite's built-in sqlite3_exec()

  int rc = SQLITE_OK;             /* Return Code */
  int rc2;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  if( pArg->expert.pExpert ){
    rc = expertHandleSQL(pArg, zSql, pzErrMsg);
    return expertFinish(pArg, (rc!=SQLITE_OK), pzErrMsg);
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
    static const char *zStmtSql;
    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
    if( SQLITE_OK != rc ){
      if( pzErrMsg ){
        *pzErrMsg = save_err_msg(db);

        utf8_printf(pArg->out, "%s\n", zStmtSql ? zStmtSql : zSql);
      }

      /* Show the EXPLAIN QUERY PLAN if .eqp is on */
      if( pArg && pArg->autoEQP && sqlite3_strlike("EXPLAIN%",zStmtSql,0)!=0 ){
        sqlite3_stmt *pExplain;
        char *zEQP;
        int triggerEQP = 0;
        disable_debug_trace_modes();
        sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, -1, &triggerEQP);
        if( pArg->autoEQP>=AUTOEQP_trigger ){
          sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, 1, 0);
        }
        zEQP = sqlite3_mprintf("EXPLAIN QUERY PLAN %s", zStmtSql);
        rc = sqlite3_prepare_v2(db, zEQP, -1, &pExplain, 0);
        if( rc==SQLITE_OK ){
          while( sqlite3_step(pExplain)==SQLITE_ROW ){
            raw_printf(pArg->out,"--EQP-- %d,",sqlite3_column_int(pExplain, 0));
            raw_printf(pArg->out,"%d,", sqlite3_column_int(pExplain, 1));
            raw_printf(pArg->out,"%d,", sqlite3_column_int(pExplain, 2));
            utf8_printf(pArg->out,"%s\n", sqlite3_column_text(pExplain, 3));
          }
        }
        sqlite3_finalize(pExplain);
        sqlite3_free(zEQP);
        if( pArg->autoEQP>=AUTOEQP_full ){
          /* Also do an EXPLAIN for ".eqp full" mode */
          zEQP = sqlite3_mprintf("EXPLAIN %s", zStmtSql);
          rc = sqlite3_prepare_v2(db, zEQP, -1, &pExplain, 0);
          if( rc==SQLITE_OK ){
            pArg->cMode = MODE_Explain;
            explain_data_prepare(pArg, pExplain);
            exec_prepared_stmt(pArg, pExplain, xCallback);
            explain_data_delete(pArg);
          }
          sqlite3_finalize(pExplain);
          sqlite3_free(zEQP);
        }
        sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, triggerEQP, 0);
        restore_debug_trace_modes();
      }

      if( pArg ){
        pArg->cMode = pArg->mode;
        if( pArg->autoExplain
         && sqlite3_column_count(pStmt)==8

  ".dbinfo ?DB?           Show status information about the database\n"
  ".dump ?TABLE? ...      Dump the database in an SQL text format\n"
  "                         If TABLE specified, only dump tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".echo on|off           Turn command echo on or off\n"
  ".eqp on|off|full       Enable or disable automatic EXPLAIN QUERY PLAN\n"
  ".exit                  Exit this program\n"
  ".expert                EXPERIMENTAL. Suggest indexes for specified queries\n"
/* Because explain mode comes on automatically now, the ".explain" mode
** is removed from the help screen.  It is still supported for legacy, however */
/*".explain ?on|off|auto? Turn EXPLAIN output mode on or off or to automatic\n"*/
  ".fullschema ?--indent? Show schema and the content of sqlite_stat tables\n"
  ".headers on|off        Turn display of headers on or off\n"
  ".help                  Show this message\n"
  ".import FILE TABLE     Import data from FILE into TABLE\n"

      sqlite3_close(db);
    }
  }

  return rc;
}

/*
** Implementation of ".expert" dot command.
*/
static int expertDotCommand(
  ShellState *pState,             /* Current shell tool state */
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg                        /* Number of entries in azArg[] */
){
  int rc = SQLITE_OK;
  char *zErr = 0;
  int i;
  int iSample = 0;

  assert( pState->expert.pExpert==0 );
  memset(&pState->expert, 0, sizeof(ExpertInfo));

  for(i=1; rc==SQLITE_OK && i<nArg; i++){
    char *z = azArg[i];
    int n;
    if( z[0]=='-' && z[1]=='-' ) z++;
    n = strlen(z);
    if( n>=2 && 0==strncmp(z, "-verbose", n) ){
      pState->expert.bVerbose = 1;
    }
    else if( n>=2 && 0==strncmp(z, "-sample", n) ){
      if( i==(nArg-1) ){
        raw_printf(stderr, "option requires an argument: %s\n", z);
        rc = SQLITE_ERROR;
      }else{
        iSample = (int)integerValue(azArg[++i]);
        if( iSample<0 || iSample>100 ){
          raw_printf(stderr, "value out of range: %s\n", azArg[i]);
          rc = SQLITE_ERROR;
        }
      }
    }
    else{
      raw_printf(stderr, "unknown option: %s\n", z);
      rc = SQLITE_ERROR;
    }
  }

  if( rc==SQLITE_OK ){
    pState->expert.pExpert = sqlite3_expert_new(pState->db, &zErr);
    if( pState->expert.pExpert==0 ){
      raw_printf(stderr, "sqlite3_expert_new: %s\n", zErr);
      rc = SQLITE_ERROR;
    }else{
      sqlite3_expert_config(
          pState->expert.pExpert, EXPERT_CONFIG_SAMPLE, iSample
      );
    }
  }

  return rc;
}


/*
** If an input line begins with "." then invoke this routine to
** process that line.
**
** Return 1 on error, 2 to exit, and 0 otherwise.
*/
static int do_meta_command(char *zLine, ShellState *p){
  int h = 1;
  int nArg = 0;
  int n, c;
  int rc = 0;
  char *azArg[50];

  if( p->expert.pExpert ){
    expertFinish(p, 1, 0);
  }

  /* Parse the input line into tokens.
  */
  while( zLine[h] && nArg<ArraySize(azArg) ){
    while( IsSpace(zLine[h]) ){ h++; }
    if( zLine[h]==0 ) break;
    if( zLine[h]=='\'' || zLine[h]=='"' ){

      rc = 1;
    }
  }else

  if( c=='e' && strncmp(azArg[0], "eqp", n)==0 ){
    if( nArg==2 ){
      if( strcmp(azArg[1],"full")==0 ){
        p->autoEQP = AUTOEQP_full;
      }else if( strcmp(azArg[1],"trigger")==0 ){
        p->autoEQP = AUTOEQP_trigger;
      }else{
        p->autoEQP = booleanValue(azArg[1]);
      }
    }else{
      raw_printf(stderr, "Usage: .eqp off|on|trigger|full\n");
      rc = 1;
    }
  }else

  if( c=='e' && strncmp(azArg[0], "exit", n)==0 ){
    if( nArg>1 && (rc = (int)integerValue(azArg[1]))!=0 ) exit(rc);
    rc = 2;

      if( p->mode==MODE_Explain ) p->mode = p->normalMode;
      p->autoExplain = 0;
    }else if( val==99 ){
      if( p->mode==MODE_Explain ) p->mode = p->normalMode;
      p->autoExplain = 1;
    }
  }else

  if( c=='e' && strncmp(azArg[0], "expert", n)==0 ){
    open_db(p, 0);
    expertDotCommand(p, azArg, nArg);
  }else

  if( c=='f' && strncmp(azArg[0], "fullschema", n)==0 ){
    ShellState data;
    char *zErrMsg = 0;
    int doStats = 0;
    memcpy(&data, p, sizeof(data));
    data.showHeader = 0;

    }
    x = system(zCmd);
    sqlite3_free(zCmd);
    if( x ) raw_printf(stderr, "System command returns %d\n", x);
  }else

  if( c=='s' && strncmp(azArg[0], "show", n)==0 ){
    static const char *azBool[] = { "off", "on", "trigger", "full"};
    int i;
    if( nArg!=1 ){
      raw_printf(stderr, "Usage: .show\n");
      rc = 1;
      goto meta_command_exit;
    }
    utf8_printf(p->out, "%12.12s: %s\n","echo",

    }else if( strcmp(z,"-header")==0 ){
      data.showHeader = 1;
    }else if( strcmp(z,"-noheader")==0 ){
      data.showHeader = 0;
    }else if( strcmp(z,"-echo")==0 ){
      ShellSetFlag(&data, SHFLG_Echo);
    }else if( strcmp(z,"-eqp")==0 ){
      data.autoEQP = AUTOEQP_on;
    }else if( strcmp(z,"-eqpfull")==0 ){
      data.autoEQP = AUTOEQP_full;
    }else if( strcmp(z,"-stats")==0 ){
      data.statsOn = 1;
    }else if( strcmp(z,"-scanstats")==0 ){
      data.scanstatsOn = 1;
    }else if( strcmp(z,"-backslash")==0 ){
      /* Undocumented command-line option: -backslash
      ** Causes C-style backslash escapes to be evaluated in SQL statements

** operation before closing the connection. This option may be used to
** override this behaviour. The first parameter passed to this operation
** is an integer - non-zero to disable checkpoints-on-close, or zero (the
** default) to enable them. The second parameter is a pointer to an integer
** into which is written 0 or 1 to indicate whether checkpoints-on-close
** have been disabled - 0 if they are not disabled, 1 if they are.
** </dd>

** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
** a single SQL query statement will always use the same algorithm regardless
** of values of [bound parameters].)^ The QPSG disables some query optimizations
** that look at the values of bound parameters, which can make some queries
** slower.  But the QPSG has the advantage of more predictable behavior.  With
** the QPSG active, SQLite will always use the same query plan in the field as
** was used during testing in the lab.
** </dd>
** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 
** include output for any operations performed by trigger programs. This
** option is used to set or clear (the default) a flag that governs this
** behavior. The first parameter passed to this operation is an integer -
** non-zero to enable output for trigger programs, or zero to disable it.
** The second parameter is a pointer to an integer into which is written 
** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 
** it is not disabled, 1 if it is.  
** </dd>
** </dl>
*/
#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
#define SQLITE_DBCONFIG_MAX                   1008 /* Largest DBCONFIG */

/*
** CAPI3REF: Enable Or Disable Extended Result Codes
** METHOD: sqlite3
**
** ^The sqlite3_extended_result_codes() routine enables or disables the
** [extended result codes] feature of SQLite. ^The extended result

#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
#define SQLITE_TESTCTRL_BYTEORDER               22
#define SQLITE_TESTCTRL_ISINIT                  23
#define SQLITE_TESTCTRL_SORTER_MMAP             24
#define SQLITE_TESTCTRL_IMPOSTER                25
#define SQLITE_TESTCTRL_LAST                    25  /* Largest TESTCTRL */

/*
** CAPI3REF: SQLite Runtime Status
**
** ^These interfaces are used to retrieve runtime status information
** about the performance of SQLite, and optionally to reset various
** highwater marks.  ^The first argument is an integer code for

** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
** of the SQL statement that triggered the call to the [xUpdate] method of the
** [virtual table].
*/
int sqlite3_vtab_on_conflict(sqlite3 *);

/*
** CAPI3REF: Determine The Collation For a Virtual Table Constraint
**
** This function may only be called from within a call to the [xBestIndex]
** method of a [virtual table implementation]. 
**
** The first argument must be the sqlite3_index_info object that is the
** first parameter to the xBestIndex() method. The second argument must be
** an index into the aConstraint[] array belonging to the sqlite3_index_info
** structure passed to xBestIndex. This function returns a pointer to a buffer 
** containing the name of the collation sequence for the corresponding
** constraint.
*/
SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);

/*
** CAPI3REF: Conflict resolution modes
** KEYWORDS: {conflict resolution mode}
**
** These constants are returned by [sqlite3_vtab_on_conflict()] to
** inform a [virtual table] implementation what the [ON CONFLICT] mode
** is for the SQL statement being evaluated.

  unsigned nProgressOps;        /* Number of opcodes for progress callback */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int nVTrans;                  /* Allocated size of aVTrans */
  Hash aModule;                 /* populated by sqlite3_create_module() */
  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
  VTable **aVTrans;             /* Virtual tables with open transactions */
  VTable *pDisconnect;          /* Disconnect these in next sqlite3_prepare() */
#endif
  Hash aFunc;                   /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int busyTimeout;              /* Busy handler timeout, in msec */

#define SQLITE_LoadExtension  0x00010000  /* Enable load_extension */
#define SQLITE_LoadExtFunc    0x00020000  /* Enable load_extension() SQL func */
#define SQLITE_EnableTrigger  0x00040000  /* True to enable triggers */
#define SQLITE_DeferFKs       0x00080000  /* Defer all FK constraints */
#define SQLITE_QueryOnly      0x00100000  /* Disable database changes */
#define SQLITE_CellSizeCk     0x00200000  /* Check btree cell sizes on load */
#define SQLITE_Fts3Tokenizer  0x00400000  /* Enable fts3_tokenizer(2) */
#define SQLITE_EnableQPSG     0x00800000  /* Query Planner Stability Guarantee*/
#define SQLITE_TriggerEQP     0x01000000  /* Show trigger EXPLAIN QUERY PLAN */

/* Flags used only if debugging */
#ifdef SQLITE_DEBUG
#define SQLITE_SqlTrace       0x08000000  /* Debug print SQL as it executes */
#define SQLITE_VdbeListing    0x10000000  /* Debug listings of VDBE programs */
#define SQLITE_VdbeTrace      0x20000000  /* True to trace VDBE execution */
#define SQLITE_VdbeAddopTrace 0x40000000  /* Trace sqlite3VdbeAddOp() calls */
#define SQLITE_VdbeEQP        0x80000000  /* Debug EXPLAIN QUERY PLAN */

  extern int Sqlitetesttcl_Init(Tcl_Interp*);
#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  extern int Sqlitetestfts3_Init(Tcl_Interp *interp);
#endif
#ifdef SQLITE_ENABLE_ZIPVFS
  extern int Zipvfs_Init(Tcl_Interp*);
#endif
  extern int TestExpert_Init(Tcl_Interp*);

  Tcl_CmdInfo cmdInfo;

  /* Since the primary use case for this binary is testing of SQLite,
  ** be sure to generate core files if we crash */
#if defined(unix)
  { struct rlimit x;
    getrlimit(RLIMIT_CORE, &x);

  Fts5tcl_Init(interp);
  SqliteRbu_Init(interp);
  Sqlitetesttcl_Init(interp);

#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  Sqlitetestfts3_Init(interp);
#endif
  TestExpert_Init(interp);

  Tcl_CreateObjCommand(
      interp, "load_testfixture_extensions", load_testfixture_extensions,0,0
  );
  return 0;
}

  if( pList==0 ){
    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
  }else{
    int i;
    sqlite3TreeViewLine(pView, "%s", zLabel);
    for(i=0; i<pList->nExpr; i++){
      int j = pList->a[i].u.x.iOrderByCol;
      char *zName = pList->a[i].zName;
      if( j || zName ){
        sqlite3TreeViewPush(pView, 0);
      }
      if( zName ){
        sqlite3TreeViewLine(pView, "AS %s", zName);
      }
      if( j ){
        sqlite3TreeViewLine(pView, "iOrderByCol=%d", j);
      }
      sqlite3TreeViewExpr(pView, pList->a[i].pExpr, i<pList->nExpr-1);
      if( j || zName ){
        sqlite3TreeViewPop(pView);
      }
    }
  }
}
void sqlite3TreeViewExprList(
  TreeView *pView,
  const ExprList *pList,
  u8 moreToFollow,

  int nSub = 0;                        /* Number of sub-vdbes seen so far */
  SubProgram **apSub = 0;              /* Array of sub-vdbes */
  Mem *pSub = 0;                       /* Memory cell hold array of subprogs */
  sqlite3 *db = p->db;                 /* The database connection */
  int i;                               /* Loop counter */
  int rc = SQLITE_OK;                  /* Return code */
  Mem *pMem = &p->aMem[1];             /* First Mem of result set */
  int bListSubprogs = (p->explain==1 || (db->flags & SQLITE_TriggerEQP)!=0);
  Op *pOp = 0;

  assert( p->explain );
  assert( p->magic==VDBE_MAGIC_RUN );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );

  /* Even though this opcode does not use dynamic strings for
  ** the result, result columns may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  releaseMemArray(pMem, 8);
  p->pResultSet = 0;

  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    sqlite3OomFault(db);
    return SQLITE_ERROR;
  }

  /* When the number of output rows reaches nRow, that means the
  ** listing has finished and sqlite3_step() should return SQLITE_DONE.
  ** nRow is the sum of the number of rows in the main program, plus
  ** the sum of the number of rows in all trigger subprograms encountered
  ** so far.  The nRow value will increase as new trigger subprograms are
  ** encountered, but p->pc will eventually catch up to nRow.
  */
  nRow = p->nOp;
  if( bListSubprogs ){
    /* The first 8 memory cells are used for the result set.  So we will
    ** commandeer the 9th cell to use as storage for an array of pointers
    ** to trigger subprograms.  The VDBE is guaranteed to have at least 9
    ** cells.  */
    assert( p->nMem>9 );
    pSub = &p->aMem[9];
    if( pSub->flags&MEM_Blob ){
      /* On the first call to sqlite3_step(), pSub will hold a NULL.  It is
      ** initialized to a BLOB by the P4_SUBPROGRAM processing logic below */
      nSub = pSub->n/sizeof(Vdbe*);
      apSub = (SubProgram **)pSub->z;
    }
    for(i=0; i<nSub; i++){
      nRow += apSub[i]->nOp;
    }
  }

  do{
    i = p->pc++;

    if( i>=nRow ){
      p->rc = SQLITE_OK;
      rc = SQLITE_DONE;




      break;


    }
    if( i<p->nOp ){
      /* The output line number is small enough that we are still in the
      ** main program. */
      pOp = &p->aOp[i];
    }else{
      /* We are currently listing subprograms.  Figure out which one and
      ** pick up the appropriate opcode. */
      int j;
      i -= p->nOp;
      for(j=0; i>=apSub[j]->nOp; j++){
        i -= apSub[j]->nOp;
      }
      pOp = &apSub[j]->aOp[i];
    }

    /* When an OP_Program opcode is encounter (the only opcode that has
    ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
    ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
    ** has not already been seen.
    */
    if( bListSubprogs && pOp->p4type==P4_SUBPROGRAM ){
      int nByte = (nSub+1)*sizeof(SubProgram*);
      int j;
      for(j=0; j<nSub; j++){
        if( apSub[j]==pOp->p4.pProgram ) break;
      }
      if( j==nSub ){
        p->rc = sqlite3VdbeMemGrow(pSub, nByte, nSub!=0);
        if( p->rc!=SQLITE_OK ){
          rc = SQLITE_ERROR;
          break;
        }
        apSub = (SubProgram **)pSub->z;
        apSub[nSub++] = pOp->p4.pProgram;
        pSub->flags |= MEM_Blob;
        pSub->n = nSub*sizeof(SubProgram*);
        nRow += pOp->p4.pProgram->nOp;
      }
    }
  }while( p->explain==2 && pOp->opcode!=OP_Explain );

  if( rc==SQLITE_OK ){
    if( db->u1.isInterrupted ){
      p->rc = SQLITE_INTERRUPT;
      rc = SQLITE_ERROR;
      sqlite3VdbeError(p, sqlite3ErrStr(p->rc));
    }else{
      char *zP4;
      if( p->explain==1 ){
        pMem->flags = MEM_Int;
        pMem->u.i = i;                                /* Program counter */
        pMem++;
    
        pMem->flags = MEM_Static|MEM_Str|MEM_Term;
        pMem->z = (char*)sqlite3OpcodeName(pOp->opcode); /* Opcode */
        assert( pMem->z!=0 );
        pMem->n = sqlite3Strlen30(pMem->z);
        pMem->enc = SQLITE_UTF8;
        pMem++;



















      }

      pMem->flags = MEM_Int;
      pMem->u.i = pOp->p1;                          /* P1 */
      pMem++;

      pMem->flags = MEM_Int;
      pMem->u.i = pOp->p2;                          /* P2 */
      pMem++;

      pMem->flags = MEM_Int;
      pMem->u.i = pOp->p3;                          /* P3 */
      pMem++;

      if( sqlite3VdbeMemClearAndResize(pMem, 100) ){ /* P4 */
        assert( p->db->mallocFailed );
        return SQLITE_ERROR;
      }
      pMem->flags = MEM_Str|MEM_Term;
      zP4 = displayP4(pOp, pMem->z, pMem->szMalloc);
      if( zP4!=pMem->z ){
        pMem->n = 0;
        sqlite3VdbeMemSetStr(pMem, zP4, -1, SQLITE_UTF8, 0);
      }else{
        assert( pMem->z!=0 );
        pMem->n = sqlite3Strlen30(pMem->z);
        pMem->enc = SQLITE_UTF8;
      }
      pMem++;

      if( p->explain==1 ){
        if( sqlite3VdbeMemClearAndResize(pMem, 4) ){
          assert( p->db->mallocFailed );
          return SQLITE_ERROR;
        }
        pMem->flags = MEM_Str|MEM_Term;
        pMem->n = 2;
        sqlite3_snprintf(3, pMem->z, "%.2x", pOp->p5);   /* P5 */
        pMem->enc = SQLITE_UTF8;
        pMem++;
    
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
        if( sqlite3VdbeMemClearAndResize(pMem, 500) ){
          assert( p->db->mallocFailed );
          return SQLITE_ERROR;
        }
        pMem->flags = MEM_Str|MEM_Term;
        pMem->n = displayComment(pOp, zP4, pMem->z, 500);
        pMem->enc = SQLITE_UTF8;
#else
        pMem->flags = MEM_Null;                       /* Comment */
#endif
      }

      p->nResColumn = 8 - 4*(p->explain-1);
      p->pResultSet = &p->aMem[1];
      p->rc = SQLITE_OK;
      rc = SQLITE_ROW;
    }
  }
  return rc;
}
#endif /* SQLITE_OMIT_EXPLAIN */

#ifdef SQLITE_DEBUG
/*

** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
*/
#include "sqliteInt.h"
#include "whereInt.h"

/*
** Extra information appended to the end of sqlite3_index_info but not
** visible to the xBestIndex function, at least not directly.  The
** sqlite3_vtab_collation() interface knows how to reach it, however.
**
** This object is not an API and can be changed from one release to the
** next.  As long as allocateIndexInfo() and sqlite3_vtab_collation()
** agree on the structure, all will be well.
*/
typedef struct HiddenIndexInfo HiddenIndexInfo;
struct HiddenIndexInfo {
  WhereClause *pWC;   /* The Where clause being analyzed */
  Parse *pParse;      /* The parsing context */
};

/* Forward declaration of methods */
static int whereLoopResize(sqlite3*, WhereLoop*, int);

/* Test variable that can be set to enable WHERE tracing */
#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
/***/ int sqlite3WhereTrace = 0;

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Allocate and populate an sqlite3_index_info structure. It is the 
** responsibility of the caller to eventually release the structure
** by passing the pointer returned by this function to sqlite3_free().
*/
static sqlite3_index_info *allocateIndexInfo(
  Parse *pParse,                  /* The parsing context */
  WhereClause *pWC,               /* The WHERE clause being analyzed */
  Bitmask mUnusable,              /* Ignore terms with these prereqs */
  struct SrcList_item *pSrc,      /* The FROM clause term that is the vtab */
  ExprList *pOrderBy,             /* The ORDER BY clause */
  u16 *pmNoOmit                   /* Mask of terms not to omit */
){
  int i, j;
  int nTerm;
  struct sqlite3_index_constraint *pIdxCons;
  struct sqlite3_index_orderby *pIdxOrderBy;
  struct sqlite3_index_constraint_usage *pUsage;
  struct HiddenIndexInfo *pHidden;
  WhereTerm *pTerm;
  int nOrderBy;
  sqlite3_index_info *pIdxInfo;
  u16 mNoOmit = 0;

  /* Count the number of possible WHERE clause constraints referring
  ** to this virtual table */

    }
  }

  /* Allocate the sqlite3_index_info structure
  */
  pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
                           + sizeof(*pIdxOrderBy)*nOrderBy + sizeof(*pHidden) );
  if( pIdxInfo==0 ){
    sqlite3ErrorMsg(pParse, "out of memory");
    return 0;
  }

  /* Initialize the structure.  The sqlite3_index_info structure contains
  ** many fields that are declared "const" to prevent xBestIndex from
  ** changing them.  We have to do some funky casting in order to
  ** initialize those fields.
  */
  pHidden = (struct HiddenIndexInfo*)&pIdxInfo[1];
  pIdxCons = (struct sqlite3_index_constraint*)&pHidden[1];
  pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
  pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
  *(int*)&pIdxInfo->nConstraint = nTerm;
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
  *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
  *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
  *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
                                                                   pUsage;

  pHidden->pWC = pWC;
  pHidden->pParse = pParse;
  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    u16 op;
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    if( pTerm->prereqRight & mUnusable ) continue;
    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
    testcase( pTerm->eOperator & WO_IN );
    testcase( pTerm->eOperator & WO_IS );

  WHERETRACE(0xffff, ("  bIn=%d prereqIn=%04llx prereqOut=%04llx\n",
                      *pbIn, (sqlite3_uint64)mPrereq,
                      (sqlite3_uint64)(pNew->prereq & ~mPrereq)));

  return rc;
}

/*
** If this function is invoked from within an xBestIndex() callback, it
** returns a pointer to a buffer containing the name of the collation
** sequence associated with element iCons of the sqlite3_index_info.aConstraint
** array. Or, if iCons is out of range or there is no active xBestIndex
** call, return NULL.
*/
const char *sqlite3_vtab_collation(sqlite3_index_info *pIdxInfo, int iCons){
  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
  const char *zRet = 0;
  if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
    CollSeq *pC = 0;
    int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
    Expr *pX = pHidden->pWC->a[iTerm].pExpr;
    if( pX->pLeft ){
      pC = sqlite3BinaryCompareCollSeq(pHidden->pParse, pX->pLeft, pX->pRight);
    }
    zRet = (pC ? pC->zName : "BINARY");
  }
  return zRet;
}

/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
**
** If there are no LEFT or CROSS JOIN joins in the query, both mPrereq and
** mUnusable are set to 0. Otherwise, mPrereq is a mask of all FROM clause

  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  int iLevel,                     /* Value for "level" column of output */
  int iFrom,                      /* Value for "from" column of output */
  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
){
  int ret = 0;
#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS)
  if( sqlite3ParseToplevel(pParse)->explain==2 )
#endif
  {
    struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
    sqlite3 *db = pParse->db;     /* Database handle */
    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
    int isSearch;                 /* True for a SEARCH. False for SCAN. */

} {a 1 n 3}
do_test colname-9.211 {
  execsql2 {SELECT t1.a AS n, v3.a FROM t1 JOIN v3}
} {n 1 a 3}
do_test colname-9.210 {
  execsql2 {SELECT t1.a, v3.a AS n FROM t1 JOIN v3}
} {a 1 n 3}

# 2017-12-23:  Ticket https://www.sqlite.org/src/info/3b4450072511e621
# Inconsistent column names in CREATE TABLE AS
#
# Verify that the names of columns in the created table of a CREATE TABLE AS
# are the same as the names of result columns in the SELECT statement.
#
do_execsql_test colname-9.300 {
  DROP TABLE IF EXISTS t1;
  DROP TABLE IF EXISTS t2;
  CREATE TABLE t1(aaa INT);
  INSERT INTO t1(aaa) VALUES(123);
}
do_test colname-9.310 {
  execsql2 {SELECT BBb FROM (SELECT aaa AS Bbb FROM t1)}
} {Bbb 123}
do_execsql_test colname-9.320 {
  CREATE TABLE t2 AS SELECT BBb FROM (SELECT aaa AS Bbb FROM t1);
  SELECT name FROM pragma_table_info('t2');
} {Bbb}


# Make sure the quotation marks get removed from the column names
# when constructing a new table from an aggregate SELECT.
# Email from Juergen Palm on 2017-07-11.
#
do_execsql_test colname-10.100 {
  DROP TABLE IF EXISTS t1;

# various test scripts:
#
#   $alltests
#   $allquicktests
#
set alltests [list]
foreach f [glob $testdir/*.test] { lappend alltests [file tail $f] }
foreach f [glob -nocomplain            \
    $testdir/../ext/rtree/*.test       \
    $testdir/../ext/fts5/test/*.test   \
    $testdir/../ext/expert/*.test      \
    $testdir/../ext/lsm1/test/*.test   \
] {
  lappend alltests $f 
}
foreach f [glob -nocomplain $testdir/../ext/session/*.test] { 
  lappend alltests $f 
}

do_catchsql_test 3.1 {
  CREATE VIRTUAL TABLE temp.xyz USING swarmvtab(
    'VALUES
        ("test.db1", "t1", 1, 10),
        ("test.db2", "t1", 11, 20)
    ', 'fetch_db_no_such_function'
  );
} {1 {sql error: no such function: fetch_db_no_such_function}}

do_catchsql_test 3.2 {
  CREATE VIRTUAL TABLE temp.xyz USING swarmvtab(
    'VALUES
        ("test.db1", "t1", 1, 10),
        ("test.db2", "t1", 11, 20)
    ', 'fetch_db'

#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is the "swarmvtab" extension
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix swarmvtab2
do_not_use_codec

ifcapable !vtab {
  finish_test
  return
}

# 2017-07-15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is the "swarmvtab" extension
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix swarmvtab3
do_not_use_codec

ifcapable !vtab {
  finish_test
  return
}

load_static_extension db unionvtab

set nFile $sqlite_open_file_count

do_execsql_test 1.0 {
  CREATE TEMP TABLE swarm(id, tbl, minval, maxval);
}

# Set up 100 databases with filenames "remote_test.dbN", where N is between
# 0 and 99.
do_test 1.1 {
  for {set i 0} {$i < 100} {incr i} {
    set file remote_test.db$i
    forcedelete $file
    forcedelete test.db$i
    sqlite3 rrr $file
    rrr eval {
      CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
      INSERT INTO t1 VALUES($i, $i);
    }
    rrr close
    db eval {
      INSERT INTO swarm VALUES($i, 't1', $i, $i);
    }
    set ::dbcache(test.db$i) 0
  }
} {}

proc missing_db {filename} {
  set remote "remote_$filename"
  forcedelete $filename
  file copy $remote $filename
}
db func missing_db missing_db

proc openclose_db {filename bClose} {
  if {$bClose} {
    incr ::dbcache($filename) -1
  } else {
    incr ::dbcache($filename) 1
  }
  if {$::dbcache($filename)==0} {
    forcedelete $filename
  }
}
db func openclose_db openclose_db

proc check_dbcache {} {
  set n 0
  for {set i 0} {$i<100} {incr i} {
    set exists [file exists test.db$i]
    if {$exists!=($::dbcache(test.db$i)!=0)} {
      error "inconsistent ::dbcache and disk"
    }
    incr n $exists
  }
  return $n
}

foreach {tn nMaxOpen cvt} {
  1 5 {
    CREATE VIRTUAL TABLE temp.s USING swarmvtab(
        'SELECT :prefix || id, tbl, minval, minval FROM swarm',
        :prefix='test.db',
        missing=missing_db,
        openclose=openclose_db,
        maxopen=5
    )
  }

  2 3 {
    CREATE VIRTUAL TABLE temp.s USING swarmvtab(
        'SELECT :prefix || id, tbl, minval, minval FROM swarm',
        :prefix='test.db',
        missing =       'missing_db',
        openclose=[openclose_db],
        maxopen = 3
    )
  }

  3 1 {
    CREATE VIRTUAL TABLE temp.s USING swarmvtab(
        'SELECT :prefix||''.''||:suffix||id, tbl, minval, minval FROM swarm',
        :prefix=test, :suffix=db,
        missing =       'missing_db',
        openclose=[openclose_db],
        maxopen = 1
    )
  }

} {
  execsql { DROP TABLE IF EXISTS s }
  
  do_execsql_test 1.$tn.1 $cvt

  do_execsql_test 1.$tn.2 {
    SELECT b FROM s WHERE a<10;
  } {0 1 2 3 4 5 6 7 8 9}

  do_test 1.$tn.3 { check_dbcache } $nMaxOpen

  do_execsql_test 1.$tn.4 {
    SELECT b FROM s WHERE (b%10)=0;
  } {0 10 20 30 40 50 60 70 80 90}

  do_test 1.$tn.5 { check_dbcache } $nMaxOpen
}

execsql { DROP TABLE IF EXISTS s }
for {set i 0} {$i < 100} {incr i} {
  forcedelete remote_test.db$i
}

#----------------------------------------------------------------------------
#
do_execsql_test 2.0 {
  DROP TABLE IF EXISTS swarm;
  CREATE TEMP TABLE swarm(file, tbl, minval, maxval, ctx);
}

catch { array unset ::dbcache }

# Set up 100 databases with filenames "remote_test.dbN", where N is a
# random integer between 0 and 1,000,000
# 0 and 99.
do_test 2.1 {
  for {set i 0} {$i < 100} {incr i} {
    while 1 {
      set ctx [expr abs(int(rand() *1000000))]
      if {[info exists ::dbcache($ctx)]==0} break
    }

    set file test_remote.db$ctx
    forcedelete $file
    forcedelete test.db$i
    sqlite3 rrr $file
    rrr eval {
      CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
      INSERT INTO t1 VALUES($i, $i);
    }
    rrr close
    db eval {
      INSERT INTO swarm VALUES('test.db' || $i, 't1', $i, $i, $file)
    }
    set ::dbcache(test.db$i) 0
  }
} {}

proc missing_db {filename ctx} {
  file copy $ctx $filename
}
db func missing_db missing_db

proc openclose_db {filename ctx bClose} {
  if {$bClose} {
    incr ::dbcache($filename) -1
  } else {
    incr ::dbcache($filename) 1
  }
  if {$::dbcache($filename)==0} {
    forcedelete $filename
  }
}
db func openclose_db openclose_db

proc check_dbcache {} {
  set n 0
  foreach k [array names ::dbcache] {
    set exists [file exists $k]
    if {$exists!=($::dbcache($k)!=0)} {
      error "inconsistent ::dbcache and disk ($k)"
    }
    incr n $exists
  }
  return $n
}

foreach {tn nMaxOpen cvt} {
  2 5 {
    CREATE VIRTUAL TABLE temp.s USING swarmvtab(
        'SELECT file, tbl, minval, minval, ctx FROM swarm',
        missing=missing_db,
        openclose=openclose_db,
        maxopen=5
    )
  }
} {
  execsql { DROP TABLE IF EXISTS s }
  
  do_execsql_test 1.$tn.1 $cvt

  do_execsql_test 1.$tn.2 {
    SELECT b FROM s WHERE a<10;
  } {0 1 2 3 4 5 6 7 8 9}

  do_test 1.$tn.3 { check_dbcache } $nMaxOpen

  do_execsql_test 1.$tn.4 {
    SELECT b FROM s WHERE (b%10)=0;
  } {0 10 20 30 40 50 60 70 80 90}

  do_test 1.$tn.5 { check_dbcache } $nMaxOpen
}

db close
forcedelete {*}[glob test_remote.db*]

finish_test

  eval sqlite3_config_pagecache $::old_pagecache_config
  unset ::old_pagecache_config 
  sqlite3_initialize
  autoinstall_test_functions
  sqlite3 db test.db
}

proc test_binary_name {nm} {
  if {$::tcl_platform(platform)=="windows"} {
    set ret "$nm.exe"
  } else {
    set ret $nm
  }
  file normalize [file join $::cmdlinearg(TESTFIXTURE_HOME) $ret]
}

proc test_find_binary {nm} {
  set ret [test_binary_name $nm]
  if {![file executable $ret]} {
    finish_test
    return ""
  }
  return $ret
}

};

static void yy_accept(yyParser*);  /* Forward Declaration */

/*
** Perform a reduce action and the shift that must immediately
** follow the reduce.
**
** The yyLookahead and yyLookaheadToken parameters provide reduce actions
** access to the lookahead token (if any).  The yyLookahead will be YYNOCODE
** if the lookahead token has already been consumed.  As this procedure is
** only called from one place, optimizing compilers will in-line it, which
** means that the extra parameters have no performance impact.
*/
static void yy_reduce(
  yyParser *yypParser,         /* The parser */
  unsigned int yyruleno,       /* Number of the rule by which to reduce */
  int yyLookahead,             /* Lookahead token, or YYNOCODE if none */
  ParseTOKENTYPE yyLookaheadToken  /* Value of the lookahead token */
){
  int yygoto;                     /* The next state */
  int yyact;                      /* The next action */
  yyStackEntry *yymsp;            /* The top of the parser's stack */
  int yysize;                     /* Amount to pop the stack */
  ParseARG_FETCH;
  yymsp = yypParser->yytos;

    if( yyact <= YY_MAX_SHIFTREDUCE ){
      yy_shift(yypParser,yyact,yymajor,yyminor);
#ifndef YYNOERRORRECOVERY
      yypParser->yyerrcnt--;
#endif
      yymajor = YYNOCODE;
    }else if( yyact <= YY_MAX_REDUCE ){
      yy_reduce(yypParser,yyact-YY_MIN_REDUCE,yymajor,yyminor);
    }else{
      assert( yyact == YY_ERROR_ACTION );
      yyminorunion.yy0 = yyminor;
#ifdef YYERRORSYMBOL
      int yymx;
#endif
#ifndef NDEBUG