SQLite

*/
static void display_scanstats(
  sqlite3 *db,                    /* Database to query */
  ShellState *pArg                /* Pointer to ShellState */
){
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  int i;
  double rEstLoop = 1.0;
  fprintf(pArg->out, "-------- scanstats --------\n");
  for(i=0; 1; i++){
    sqlite3_stmt *p = pArg->pStmt;
    sqlite3_int64 nLoop, nVisit;
    double rEst;
    const char *zExplain;
    if( sqlite3_stmt_scanstatus(p, i, SQLITE_SCANSTAT_NLOOP, (void*)&nLoop) ){
      break;
    }
    sqlite3_stmt_scanstatus(p, i, SQLITE_SCANSTAT_NVISIT, (void*)&nVisit);
    sqlite3_stmt_scanstatus(p, i, SQLITE_SCANSTAT_EST, (void*)&rEst);
    sqlite3_stmt_scanstatus(p, i, SQLITE_SCANSTAT_EXPLAIN, (void*)&zExplain);

    fprintf(pArg->out, "Loop %2d: \"%s\"\n", i, zExplain);
    rEstLoop *= rEst;
    fprintf(pArg->out, "        nLoop=%-8lld nRow=%-8lld estRow=%-8lld estRow/Loop=%-8g\n",
        nLoop, nVisit, (sqlite3_int64)rEstLoop, rEst
    );
  }
#else
  fprintf(pArg->out, "-------- scanstats --------\n");
  fprintf(pArg->out,
      "sqlite3_stmt_scanstatus() unavailable - "
      "rebuild with SQLITE_ENABLE_STMT_SCANSTATUS\n"

** <dl>
** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set to the
** total number of times that the X-th loop has run.</dd>
**
** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set to the
** total number of rows examined by all iterations of the X-th loop.</dd>
**
** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
** <dd>^The "double" variable pointed to by the T parameter will be set to the
** query planner's estimate for the average number of rows output from each
** iteration of the X-th loop.  If the query planner's estimates was accurate,
** then this value will approximate the quotient NVISIT/NLOOP and the
** product of this value for the first N-1 loops will approximate
** the NLOOP value for the N-th loop.
**
** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
** <dd>^The "const char *" variable pointed to by the T parameter will be set to 
** a zero-terminated UTF-8 string containing the name of the index or table used
** for the X-th loop.
**
** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>

  sqlite3_stmt *pStmt;            /* First argument */
  int idx;                        /* Second argument */

  const char *zName;
  const char *zExplain;
  sqlite3_int64 nLoop;
  sqlite3_int64 nVisit;
  double rEst;
  int res;

  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "STMT IDX");
    return TCL_ERROR;
  }
  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &idx) ) return TCL_ERROR;

  res = sqlite3_stmt_scanstatus(pStmt, idx, SQLITE_SCANSTAT_NLOOP, (void*)&nLoop);
  if( res==0 ){
    Tcl_Obj *pRet = Tcl_NewObj();
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj("nLoop", -1));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewWideIntObj(nLoop));
    sqlite3_stmt_scanstatus(pStmt, idx, SQLITE_SCANSTAT_NVISIT, (void*)&nVisit);
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj("nVisit", -1));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewWideIntObj(nVisit));
    sqlite3_stmt_scanstatus(pStmt, idx, SQLITE_SCANSTAT_EST, (void*)&rEst);
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj("nEst", -1));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewDoubleObj(rEst));
    sqlite3_stmt_scanstatus(pStmt, idx, SQLITE_SCANSTAT_NAME, (void*)&zName);
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj("zName", -1));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zName, -1));
    sqlite3_stmt_scanstatus(pStmt, idx, SQLITE_SCANSTAT_EXPLAIN, (void*)&zExplain);
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj("zExplain", -1));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zExplain, -1));
    Tcl_SetObjResult(interp, pRet);

# define VdbeCoverageIf(v,x)
# define VdbeCoverageAlwaysTaken(v)
# define VdbeCoverageNeverTaken(v)
# define VDBE_OFFSET_LINENO(x) 0
#endif

#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
void sqlite3VdbeScanStatus(Vdbe*, int, int, int, LogEst, const char*);
#else
# define sqlite3VdbeScanStatus(a,b,c,d,e)
#endif

#endif

typedef unsigned bft;  /* Bit Field Type */

typedef struct ScanStatus ScanStatus;
struct ScanStatus {
  int addrExplain;                /* OP_Explain for loop */
  int addrLoop;                   /* Address of "loops" counter */
  int addrVisit;                  /* Address of "rows visited" counter */
  LogEst nEst;                    /* Estimated output rows per loop */
  char *zName;                    /* Name of table or index */
};

/*
** An instance of the virtual machine.  This structure contains the complete
** state of the virtual machine.
**

      break;
    }
    case SQLITE_SCANSTAT_NVISIT: {
      *(sqlite3_int64*)pOut = p->anExec[pScan->addrVisit];
      break;
    }
    case SQLITE_SCANSTAT_EST: {
      double r = 1.0;
      LogEst x = pScan->nEst;
      while( x<100 ){
        x += 10;
        r *= 0.5;
      }
      *(double*)pOut = r*sqlite3LogEstToInt(x);
      break;
    }
    case SQLITE_SCANSTAT_NAME: {
      *(const char**)pOut = pScan->zName;
      break;
    }
    case SQLITE_SCANSTAT_EXPLAIN: {

** Add an entry to the array of counters managed by sqlite3_stmt_scanstatus().
*/
void sqlite3VdbeScanStatus(
  Vdbe *p,                        /* VM to add scanstatus() to */
  int addrExplain,                /* Address of OP_Explain (or 0) */
  int addrLoop,                   /* Address of loop counter */ 
  int addrVisit,                  /* Address of rows visited counter */
  LogEst nEst,                    /* Estimated number of output rows */
  const char *zName               /* Name of table or index being scanned */
){
  int nByte = (p->nScan+1) * sizeof(ScanStatus);
  ScanStatus *aNew;
  aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
  if( aNew ){
    ScanStatus *pNew = &aNew[p->nScan++];

static void addScanStatus(
  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
  int addrExplain                 /* Address of OP_Explain (or 0) */
){
  const char *zObj = 0;

  WhereLoop *pLoop = pLvl->pWLoop;
  if( (pLoop->wsFlags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){
    zObj = pLoop->u.btree.pIndex->zName;
  }else{
    zObj = pSrclist->a[pLvl->iFrom].zName;
  }



  sqlite3VdbeScanStatus(
      v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj
  );
}
#else
# define addScanStatus(a, b, c, d) ((void)d)
#endif

  }

  uplevel [list do_test $tn [list set {} $ret] [list {*}$res]]
}

do_execsql_test 1.1 { SELECT count(*) FROM t1, t2; } 6
do_scanstatus_test 1.2 {
  nLoop 1 nVisit 2 nEst 1048576.0 zName t1 zExplain {SCAN TABLE t1}
  nLoop 2 nVisit 6 nEst 1048576.0 zName t2 zExplain {SCAN TABLE t2}
}

do_execsql_test 1.3 {
  ANALYZE;
  SELECT count(*) FROM t1, t2;
} 6
do_scanstatus_test 1.4 {
  nLoop 1 nVisit 2 nEst 2.0 zName t1 zExplain {SCAN TABLE t1}
  nLoop 2 nVisit 6 nEst 3.0 zName t2 zExplain {SCAN TABLE t2}
}

do_execsql_test 1.5 { ANALYZE }
do_execsql_test 1.6 {
  SELECT count(*) FROM t1, t2 WHERE t2.rowid>1;
} 4
do_scanstatus_test 1.7 {
  nLoop 1 nVisit 2 nEst 2.0 zName t2 zExplain 
  {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid>?)}
  nLoop 2 nVisit 4 nEst 2.0 zName t1 zExplain {SCAN TABLE t1}
}

do_execsql_test 1.8 {
  SELECT count(*) FROM t1, t2 WHERE t2.rowid>1;
} 4

do_scanstatus_test 1.9 {
  nLoop 2 nVisit 4 nEst 2.0 zName t2 zExplain 
  {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid>?)}
  nLoop 4 nVisit 8 nEst 2.0 zName t1 zExplain {SCAN TABLE t1}
}

do_test 1.9 {
  sqlite3_stmt_scanstatus_reset [db_last_stmt_ptr db]
} {}

do_scanstatus_test 1.10 {
  nLoop 0 nVisit 0 nEst 2.0 zName t2 zExplain 
  {SEARCH TABLE t2 USING INTEGER PRIMARY KEY (rowid>?)}
  nLoop 0 nVisit 0 nEst 2.0 zName t1 zExplain {SCAN TABLE t1}
}

#-------------------------------------------------------------------------
# Try a few different types of scans.
#
reset_db
do_execsql_test 2.1 {
  CREATE TABLE x1(i INTEGER PRIMARY KEY, j);
  INSERT INTO x1 VALUES(1, 'one');
  INSERT INTO x1 VALUES(2, 'two');
  INSERT INTO x1 VALUES(3, 'three');
  INSERT INTO x1 VALUES(4, 'four');
  CREATE INDEX x1j ON x1(j);

  SELECT * FROM x1 WHERE i=2;
} {2 two}

do_scanstatus_test 2.2 {
  nLoop 1 nVisit 1 nEst 1.0 zName x1 
  zExplain {SEARCH TABLE x1 USING INTEGER PRIMARY KEY (rowid=?)}
}

do_execsql_test 2.3.1 {
  SELECT * FROM x1 WHERE j='two'
} {2 two}
do_scanstatus_test 2.3.2 {
  nLoop 1 nVisit 1 nEst 10.0 zName x1j 
  zExplain {SEARCH TABLE x1 USING COVERING INDEX x1j (j=?)}
}

do_execsql_test 2.4.1 {
  SELECT * FROM x1 WHERE j<'two'
} {4 four 1 one 3 three}
do_scanstatus_test 2.4.2 {
  nLoop 1 nVisit 3 nEst 262144.0 zName x1j 
  zExplain {SEARCH TABLE x1 USING COVERING INDEX x1j (j<?)}
}

do_execsql_test 2.5.1 {
  SELECT * FROM x1 WHERE j>='two'
} {2 two}
do_scanstatus_test 2.5.2 {
  nLoop 1 nVisit 1 nEst 262144.0 zName x1j 
  zExplain {SEARCH TABLE x1 USING COVERING INDEX x1j (j>?)}
}

do_execsql_test 2.6.1 {
  SELECT * FROM x1 WHERE j BETWEEN 'three' AND 'two'
} {3 three 2 two}
do_scanstatus_test 2.6.2 {
  nLoop 1 nVisit 2 nEst 16384.0 zName x1j 
  zExplain {SEARCH TABLE x1 USING COVERING INDEX x1j (j>? AND j<?)}
}

do_execsql_test 2.7.1 {
  CREATE TABLE x2(i INTEGER, j, k);
  INSERT INTO x2 SELECT i, j, i || ' ' || j FROM x1;
  CREATE INDEX x2j ON x2(j);
  CREATE INDEX x2ij ON x2(i, j);
  SELECT * FROM x2 WHERE j BETWEEN 'three' AND 'two'
} {3 three {3 three} 2 two {2 two}}

do_scanstatus_test 2.7.2 {
  nLoop 1 nVisit 2 nEst 16384.0 zName x2j 
  zExplain {SEARCH TABLE x2 USING INDEX x2j (j>? AND j<?)}
}

do_execsql_test 2.8.1 {
  SELECT * FROM x2 WHERE i=1 AND j='two'
}
do_scanstatus_test 2.8.2 {
  nLoop 1 nVisit 0 nEst 8.0 zName x2ij 
  zExplain {SEARCH TABLE x2 USING INDEX x2ij (i=? AND j=?)}
}

do_execsql_test 2.9.1 {
  SELECT * FROM x2 WHERE i=5 AND j='two'
}
do_scanstatus_test 2.9.2 {
  nLoop 1 nVisit 0 nEst 8.0 zName x2ij 
  zExplain {SEARCH TABLE x2 USING INDEX x2ij (i=? AND j=?)}
}

do_execsql_test 2.10.1 {
  SELECT * FROM x2 WHERE i=3 AND j='three'
} {3 three {3 three}}
do_scanstatus_test 2.10.2 {
  nLoop 1 nVisit 1 nEst 8.0 zName x2ij 
  zExplain {SEARCH TABLE x2 USING INDEX x2ij (i=? AND j=?)}
}

#-------------------------------------------------------------------------
# Try with queries that use the OR optimization.
#
do_execsql_test 3.1 {
  CREATE TABLE a1(a, b, c, d);
  CREATE INDEX a1a ON a1(a);
  CREATE INDEX a1bc ON a1(b, c);

  WITH d(x) AS (SELECT 1 UNION ALL SELECT x+1 AS n FROM d WHERE n<=100)
  INSERT INTO a1 SELECT x, x, x, x FROM d;
}

do_execsql_test 3.2.1 {
  SELECT d FROM a1 WHERE (a=4 OR b=13)
} {4 13}
do_scanstatus_test 3.2.2 {
  nLoop 1 nVisit 1 nEst 10.0 zName a1a 
  zExplain {SEARCH TABLE a1 USING INDEX a1a (a=?)}
  nLoop 1 nVisit 1 nEst 10.0 zName a1bc 
  zExplain {SEARCH TABLE a1 USING INDEX a1bc (b=?)}
}

do_execsql_test 3.2.1 {
  SELECT count(*) FROM a1 WHERE (a BETWEEN 4 AND 12) OR (b BETWEEN 40 AND 60)
} {30}
do_scanstatus_test 3.2.2 {
  nLoop 1 nVisit 9 nEst 16384.0 zName a1a 
  zExplain {SEARCH TABLE a1 USING INDEX a1a (a>? AND a<?)}
  nLoop 1 nVisit 21 nEst 16384.0 zName a1bc
  zExplain {SEARCH TABLE a1 USING INDEX a1bc (b>? AND b<?)}
}

do_execsql_test 3.3.1 {
  SELECT count(*) FROM a1 AS x, a1 AS y 
  WHERE (x.a BETWEEN 4 AND 12) AND (y.b BETWEEN 1 AND 10)
} {90}
do_scanstatus_test 3.2.2 {
  nLoop 1 nVisit 10 nEst 16384.0 zName a1bc 
  zExplain {SEARCH TABLE a1 AS y USING COVERING INDEX a1bc (b>? AND b<?)}
  nLoop 10 nVisit 90 nEst 16384.0 zName a1a
  zExplain {SEARCH TABLE a1 AS x USING COVERING INDEX a1a (a>? AND a<?)}
}

do_execsql_test 3.4.1 {
  SELECT count(*) FROM a1 WHERE a IN (1, 5, 10, 15);
} {4}
do_scanstatus_test 3.4.2 {
  nLoop 1 nVisit 4 nEst 40.0 zName a1a 
  zExplain {SEARCH TABLE a1 USING COVERING INDEX a1a (a=?)}
}

do_execsql_test 3.4.1 {
  SELECT count(*) FROM a1 WHERE rowid IN (1, 5, 10, 15);
} {4}
do_scanstatus_test 3.4.2 {
  nLoop 1 nVisit 4 nEst 4.0 zName a1
  zExplain {SEARCH TABLE a1 USING INTEGER PRIMARY KEY (rowid=?)}
}

#-------------------------------------------------------------------------
# Test that scanstatus() data is not available for searches performed
# by triggers.
#

  INSERT INTO p1 VALUES(1), (2), (3), (4);
  CREATE TABLE c1(y REFERENCES p1);
  INSERT INTO c1 VALUES(1), (2), (3);
  PRAGMA foreign_keys=on;
}
do_execsql_test    4.2.1 { DELETE FROM p1 WHERE x=4 }
do_scanstatus_test 4.2.2 { 
  nLoop 1 nVisit 1 nEst 1.0 zName sqlite_autoindex_p1_1 
  zExplain {SEARCH TABLE p1 USING INDEX sqlite_autoindex_p1_1 (x=?)}

  nLoop 1 nVisit 3 nEst 524288.0 zName c1 zExplain {SCAN TABLE c1}
}

#-------------------------------------------------------------------------
# Further tests of different scan types.
#
reset_db
proc tochar {i} {

  ANALYZE;
}

do_execsql_test 5.1.1 {
  SELECT count(*) FROM t1 WHERE a IN (SELECT b FROM t1 AS ii)
} {2}
do_scanstatus_test 5.1.2 { 
  nLoop 1 nVisit 10 nEst 10.0 zName t1bc 
  zExplain {SCAN TABLE t1 AS ii USING COVERING INDEX t1bc}
  nLoop 1 nVisit 2 nEst 8.0 zName sqlite_autoindex_t1_1
  zExplain {SEARCH TABLE t1 USING COVERING INDEX sqlite_autoindex_t1_1 (a=?)}
}

do_execsql_test 5.2.1 {
  SELECT count(*) FROM t1 WHERE a IN (0, 1)
} {2}
do_scanstatus_test 5.2.2 { 
  nLoop 1 nVisit 2 nEst 2.0 zName sqlite_autoindex_t1_1
  zExplain {SEARCH TABLE t1 USING COVERING INDEX sqlite_autoindex_t1_1 (a=?)}
}

do_eqp_test 5.3.1 {
  SELECT count(*) FROM t2 WHERE y = 'j';
} {0 0 0 {SEARCH TABLE t2 USING COVERING INDEX t2xy (ANY(x) AND y=?)}}
do_execsql_test 5.3.2 {
  SELECT count(*) FROM t2 WHERE y = 'j';
} {19}
do_scanstatus_test 5.3.3 { 
  nLoop 1 nVisit 19 nEst 56.0 zName t2xy zExplain
  {SEARCH TABLE t2 USING COVERING INDEX t2xy (ANY(x) AND y=?)}
}

do_eqp_test 5.4.1 {
  SELECT count(*) FROM t1, t2 WHERE y = c;
} {
  0 0 0 {SCAN TABLE t1 USING COVERING INDEX t1bc}
  0 1 1 {SEARCH TABLE t2 USING COVERING INDEX t2xy (ANY(x) AND y=?)}
}
do_execsql_test 5.4.2 {
  SELECT count(*) FROM t1, t2 WHERE y = c;
} {200}
do_scanstatus_test 5.4.3 { 
  nLoop 1 nVisit 10 nEst 10.0 zName t1bc 
  zExplain {SCAN TABLE t1 USING COVERING INDEX t1bc}
  nLoop 10 nVisit 200 nEst 56.0 zName t2xy 
  zExplain {SEARCH TABLE t2 USING COVERING INDEX t2xy (ANY(x) AND y=?)}
}

do_eqp_test 5.5.1 {
  SELECT count(*) FROM t1, t3 WHERE y = c;
} {
  0 0 1 {SCAN TABLE t3} 
  0 1 0 {SEARCH TABLE t1 USING AUTOMATIC COVERING INDEX (c=?)}
}
do_execsql_test 5.5.2 {
  SELECT count(*) FROM t1, t3 WHERE y = c;
} {200}
do_scanstatus_test 5.5.3 { 
  nLoop 1 nVisit 501 nEst 480.0 zName t3 zExplain {SCAN TABLE t3}
  nLoop 501 nVisit 200 nEst 20.0 zName auto-index zExplain
  {SEARCH TABLE t1 USING AUTOMATIC COVERING INDEX (c=?)}
}

#-------------------------------------------------------------------------
# Virtual table scans
#
ifcapable fts3 {

    INSERT INTO ft1 VALUES('j e a b j e c b c i');
    INSERT INTO ft1 VALUES('a d e f b j j c g d');
  }
  do_execsql_test 6.1.1 {
    SELECT count(*) FROM ft1 WHERE ft1 MATCH 'd'
  } {6}
  do_scanstatus_test 6.1.2 { 
    nLoop 1 nVisit 6 nEst 24.0 zName ft1 zExplain 
    {SCAN TABLE ft1 VIRTUAL TABLE INDEX 3:}
  }
}


finish_test