SQLite

    int i;          /* Bytes of space required */
    tRowcnt *pSpace;

    zIndex = (char *)sqlite3_column_text(pStmt, 0);
    if( zIndex==0 ) continue;
    nSample = sqlite3_column_int(pStmt, 1);
    pIdx = sqlite3FindIndex(db, zIndex, zDb);
    assert( pIdx==0 || bStat3 || pIdx->nSample==0 );
    /* Index.nSample is non-zero at this point if data has already been
    ** loaded from the stat4 table. In this case ignore stat3 data.  */
    if( pIdx==0 || pIdx->nSample ) continue;

    if( bStat3==0 ){
      nIdxCol = pIdx->nColumn+1;
      nAvgCol = pIdx->nColumn;
    }
    pIdx->nSample = nSample;
    nByte = sizeof(IndexSample) * nSample;
    nByte += sizeof(tRowcnt) * nIdxCol * 3 * nSample;

    if( pIdx==pPrevIdx ){
      idx++;
    }else{
      pPrevIdx = pIdx;
      idx = 0;
    }
    assert( idx<pIdx->nSample );
    /* This next condition is true if data has already been loaded from 
    ** the sqlite_stat4 table. In this case ignore stat3 data.  */
    if( bStat3 && pIdx->aSample[idx].anEq[0] ) continue;
    pSample = &pIdx->aSample[idx];

    if( bStat3==0 ){
      nCol = pIdx->nColumn+1;
    }
    decodeIntArray((char*)sqlite3_column_text(pStmt,1), nCol, pSample->anEq, 0);
    decodeIntArray((char*)sqlite3_column_text(pStmt,2), nCol, pSample->anLt, 0);

set testprefix analyzeA

ifcapable !stat4&&!stat3 {
  finish_test
  return
}

# Populate the stat3 table according to the current contents of the db
#
proc populate_stat3 {{bDropTable 1}} {
  # Open a second connection on database "test.db" and run ANALYZE. If this
  # is an ENABLE_STAT3 build, this is all that is required to create and
  # populate the sqlite_stat3 table. 
  # 
  sqlite3 db2 test.db
  execsql { ANALYZE }

  # Now, if this is an ENABLE_STAT4 build, create and populate the 
  # sqlite_stat3 table based on the stat4 data gathered by the ANALYZE
  # above. Then drop the sqlite_stat4 table.
  #
  ifcapable stat4 {
    db2 func lindex lindex
    execsql {
      PRAGMA writable_schema = on;
      CREATE TABLE sqlite_stat3(tbl,idx,neq,nlt,ndlt,sample);
      INSERT INTO sqlite_stat3 
      SELECT DISTINCT tbl, idx, 
        lindex(neq,0), lindex(nlt,0), lindex(ndlt,0), test_extract(sample, 0)
      FROM sqlite_stat4;
    } db2
    if {$bDropTable} { execsql {DROP TABLE sqlite_stat4} db2 }
    execsql { PRAGMA writable_schema = off }

  }

  # Modify the database schema cookie to ensure that the other connection
  # reloads the schema.
  #
  execsql {
    CREATE TABLE obscure_tbl_nm(x);
    DROP TABLE obscure_tbl_nm;
  } db2
  db2 close
}

# Populate the stat4 table according to the current contents of the db.
# Leave deceptive data in the stat3 table. This data should be ignored
# in favour of that from the stat4 table.
#
proc populate_both {} {
  populate_stat3 0

  sqlite3 db2 test.db
  execsql {
    PRAGMA writable_schema = on;
    UPDATE sqlite_stat3 SET idx = 
      CASE idx WHEN 't1b' THEN 't1c' ELSE 't1b'
    END;
    PRAGMA writable_schema = off;
    CREATE TABLE obscure_tbl_nm(x);
    DROP TABLE obscure_tbl_nm;
  } db2

  db2 close
}


# Populate the stat4 table according to the current contents of the db
#
proc populate_stat4 {} {
  execsql { ANALYZE }
#  ifcapable stat3 {
#    execsql {
#      PRAGMA writable_schema = on;
#      CREATE TABLE sqlite_stat4(tbl,idx,neq,nlt,ndlt,sample);
#      INSERT INTO sqlite_stat4 SELECT 
#          tbl, idx, nlt, neq, ndlt,
#          test_extract(sample, 1)
#      FROM sqlite_stat4;
#      DROP TABLE sqlite_stat4;
#      PRAGMA writable_schema = off;
#      ANALYZE sqlite_master;
#    }
#  }
}

foreach {tn analyze_cmd} {
  1 populate_stat4 
  2 populate_stat3
  3 populate_both
} {
  reset_db
  do_test 1.$tn.1 {
    execsql { CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c) }
    for {set i 0} {$i < 100} {incr i} {
      set c [expr int(pow(1.1,$i)/100)]
      set b [expr 125 - int(pow(1.1,99-$i))/100]
      execsql {INSERT INTO t1 VALUES($i, $b, $c)}

  do_execsql_test 1.$tn.3.1 { 
    SELECT count(*) FROM t1 WHERE b BETWEEN 0 AND 50
  } {6}
  do_execsql_test 1.$tn.3.2 { 
    SELECT count(*) FROM t1 WHERE c BETWEEN 0 AND 50
  } {90}

  do_execsql_test 1.$tn.3.3 { 
    SELECT count(*) FROM t1 WHERE b BETWEEN 75 AND 125
  } {90}
  do_execsql_test 1.$tn.3.4 { 
    SELECT count(*) FROM t1 WHERE c BETWEEN 75 AND 125
  } {6}