SQLite

/*
** This function populates the pRtree->nRowEst variable with an estimate
** of the number of rows in the virtual table. If possible, this is based
** on sqlite_stat1 data. Otherwise, use RTREE_DEFAULT_ROWEST.
*/
static int rtreeQueryStat1(sqlite3 *db, Rtree *pRtree){
  const char *zFmt = "SELECT stat FROM %Q.sqlite_stat1 WHERE tbl = '%q_rowid'";
  char *zSql;
  sqlite3_stmt *p;
  int rc;
  i64 nRow = 0;

  zSql = sqlite3_mprintf(zFmt, pRtree->zDb, pRtree->zName);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = sqlite3_prepare_v2(db, zSql, -1, &p, 0);
    if( rc==SQLITE_OK ){

      if( sqlite3_step(p)==SQLITE_ROW ) nRow = sqlite3_column_int64(p, 0);
      rc = sqlite3_finalize(p);
    }else if( rc!=SQLITE_NOMEM ){
      rc = SQLITE_OK;
    }

    if( rc==SQLITE_OK ){
      if( nRow==0 ){
        pRtree->nRowEst = RTREE_DEFAULT_ROWEST;
      }else{
        pRtree->nRowEst = MAX(nRow, RTREE_MIN_ROWEST);
      }
    }
    sqlite3_free(zSql);
  }

  return rc;
}

static sqlite3_module rtreeModule = {
  0,                          /* iVersion */

do_execsql_test 4.2 {
  SELECT a, b FROM t1 LEFT JOIN t2 ON (+a = +b);
} {1 1 2 {}}

do_execsql_test 4.3 {
  SELECT b, a FROM t2 LEFT JOIN t1 ON (+a = +b);
} {1 1 3 {}}

#--------------------------------------------------------------------
# Test that the sqlite_stat1 data is used correctly.
#
reset_db
do_execsql_test 5.1 {
  CREATE TABLE t1(x PRIMARY KEY, y);
  CREATE VIRTUAL TABLE rt USING rtree(id, x1, x2);

  INSERT INTO t1(x) VALUES(1);
  INSERT INTO t1(x) SELECT x+1 FROM t1;   --   2
  INSERT INTO t1(x) SELECT x+2 FROM t1;   --   4
  INSERT INTO t1(x) SELECT x+4 FROM t1;   --   8
  INSERT INTO t1(x) SELECT x+8 FROM t1;   --  16
  INSERT INTO t1(x) SELECT x+16 FROM t1;  --  32
  INSERT INTO t1(x) SELECT x+32 FROM t1;  --  64
  INSERT INTO t1(x) SELECT x+64 FROM t1;  -- 128
  INSERT INTO t1(x) SELECT x+128 FROM t1; -- 256
  INSERT INTO t1(x) SELECT x+256 FROM t1; -- 512
  INSERT INTO t1(x) SELECT x+512 FROM t1; --1024

  INSERT INTO rt SELECT x, x, x+1 FROM t1 WHERE x<=5;
}

# First test a query with no ANALYZE data at all. The outer loop is
# real table "t1".
#
do_eqp_test 5.2 {
  SELECT * FROM t1, rt WHERE x==id;
} {
  0 0 0 {SCAN TABLE t1} 
  0 1 1 {SCAN TABLE rt VIRTUAL TABLE INDEX 1:}
}

# Now create enough ANALYZE data to tell SQLite that virtual table "rt"
# contains very few rows. This causes it to move "rt" to the outer loop.
#
do_execsql_test 5.3 {
  ANALYZE;
  DELETE FROM sqlite_stat1 WHERE tbl='t1';
}
db close
sqlite3 db test.db
do_eqp_test 5.4 {
  SELECT * FROM t1, rt WHERE x==id;
} {
  0 0 1 {SCAN TABLE rt VIRTUAL TABLE INDEX 2:} 
  0 1 0 {SEARCH TABLE t1 USING INDEX sqlite_autoindex_t1_1 (x=?)}
}

# Delete the ANALYZE data. "t1" should be the outer loop again.
#
do_execsql_test 5.5 { DROP TABLE sqlite_stat1; }
db close
sqlite3 db test.db
do_eqp_test 5.6 {
  SELECT * FROM t1, rt WHERE x==id;
} {
  0 0 0 {SCAN TABLE t1} 
  0 1 1 {SCAN TABLE rt VIRTUAL TABLE INDEX 1:}
}

# This time create and attach a database that contains ANALYZE data for
# tables of the same names as those used internally by virtual table
# "rt". Check that the rtree module is not fooled into using this data.
# Table "t1" should remain the outer loop.
#
do_test 5.7 {
  db backup test.db2
  sqlite3 db2 test.db2
  db2 eval {
    ANALYZE;
    DELETE FROM sqlite_stat1 WHERE tbl='t1';
  }
  db2 close
  db close
  sqlite3 db test.db
  execsql { ATTACH 'test.db2' AS aux; }
} {}
do_eqp_test 5.8 {
  SELECT * FROM t1, rt WHERE x==id;
} {
  0 0 0 {SCAN TABLE t1} 
  0 1 1 {SCAN TABLE rt VIRTUAL TABLE INDEX 1:}
}


finish_test