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Overview
Comment:The optimizer now uses only the index and ignores the table if it can get away with doing so, thus saving a single BTree search per row of result. This could potentially double the speed of certain queries. The code passes all regression tests but new tests to exercise the new functionality are yet to be added. (CVS 2170)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: e5aa489453bf31126da6473ef93c89ec27935cde
User & Date: drh 2004-12-19 00:11:35
Context
2004-12-20
19:01
Add PRAGMA 'temp_store_directory'. Added os_*.c function sqlite3OsIsDirWritable(), split pragma.c changeTempStorage() function into invalidateTempStorage(). (CVS 2171) check-in: 772e22cb user: tpoindex tags: trunk
2004-12-19
00:11
The optimizer now uses only the index and ignores the table if it can get away with doing so, thus saving a single BTree search per row of result. This could potentially double the speed of certain queries. The code passes all regression tests but new tests to exercise the new functionality are yet to be added. (CVS 2170) check-in: e5aa4894 user: drh tags: trunk
2004-12-18
18:40
Improvements to the query optimizer. This is a work in progress. (CVS 2169) check-in: 9b86993f user: drh tags: trunk
Changes
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Changes to src/sqliteInt.h.

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**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.347 2004/12/18 18:40:27 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
................................................................................
typedef struct Db Db;
typedef struct AuthContext AuthContext;
typedef struct KeyClass KeyClass;
typedef struct CollSeq CollSeq;
typedef struct KeyInfo KeyInfo;
typedef struct SqlCursor SqlCursor;
typedef struct Fetch Fetch;


/*
** Each database file to be accessed by the system is an instance
** of the following structure.  There are normally two of these structures
** in the sqlite.aDb[] array.  aDb[0] is the main database file and
** aDb[1] is the database file used to hold temporary tables.  Additional
** databases may be attached.
................................................................................
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
*/
struct WhereLevel {
  int iMem;            /* Memory cell used by this level */
  Index *pIdx;         /* Index used */
  int iCur;            /* Cursor number used for this index */

  int score;           /* How well this indexed scored */
  int brk;             /* Jump here to break out of the loop */
  int cont;            /* Jump here to continue with the next loop cycle */
  int op, p1, p2;      /* Opcode used to terminate the loop */
  int iLeftJoin;       /* Memory cell used to implement LEFT OUTER JOIN */
  int top;             /* First instruction of interior of the loop */
  int inOp, inP1, inP2;/* Opcode used to implement an IN operator */
................................................................................
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/
struct WhereInfo {
  Parse *pParse;
  SrcList *pTabList;   /* List of tables in the join */

  int iContinue;       /* Jump here to continue with next record */
  int iBreak;          /* Jump here to break out of the loop */
  int nLevel;          /* Number of nested loop */
  WhereLevel a[1];     /* Information about each nest loop in the WHERE */
};

/*
................................................................................
  Token sLastToken;    /* The last token parsed */
  const char *zSql;    /* All SQL text */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  TriggerStack *trigStack;  /* Trigger actions being coded */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
  
};

/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {







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**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.348 2004/12/19 00:11:35 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
................................................................................
typedef struct Db Db;
typedef struct AuthContext AuthContext;
typedef struct KeyClass KeyClass;
typedef struct CollSeq CollSeq;
typedef struct KeyInfo KeyInfo;
typedef struct SqlCursor SqlCursor;
typedef struct Fetch Fetch;
typedef struct CursorSubst CursorSubst;

/*
** Each database file to be accessed by the system is an instance
** of the following structure.  There are normally two of these structures
** in the sqlite.aDb[] array.  aDb[0] is the main database file and
** aDb[1] is the database file used to hold temporary tables.  Additional
** databases may be attached.
................................................................................
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
*/
struct WhereLevel {
  int iMem;            /* Memory cell used by this level */
  Index *pIdx;         /* Index used.  NULL if no index */
  int iTabCur;         /* The VDBE cursor used to access the table */
  int iIdxCur;         /* The VDBE cursor used to acesss pIdx */
  int score;           /* How well this indexed scored */
  int brk;             /* Jump here to break out of the loop */
  int cont;            /* Jump here to continue with the next loop cycle */
  int op, p1, p2;      /* Opcode used to terminate the loop */
  int iLeftJoin;       /* Memory cell used to implement LEFT OUTER JOIN */
  int top;             /* First instruction of interior of the loop */
  int inOp, inP1, inP2;/* Opcode used to implement an IN operator */
................................................................................
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/
struct WhereInfo {
  Parse *pParse;
  SrcList *pTabList;   /* List of tables in the join */
  int iTop;            /* The very beginning of the WHERE loop */
  int iContinue;       /* Jump here to continue with next record */
  int iBreak;          /* Jump here to break out of the loop */
  int nLevel;          /* Number of nested loop */
  WhereLevel a[1];     /* Information about each nest loop in the WHERE */
};

/*
................................................................................
  Token sLastToken;    /* The last token parsed */
  const char *zSql;    /* All SQL text */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  TriggerStack *trigStack;  /* Trigger actions being coded */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */

};

/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {

Changes to src/vdbe.c.

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**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.433 2004/12/07 14:06:13 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
case OP_SetNumColumns: {
  assert( (pOp->p1)<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  p->apCsr[pOp->p1]->nField = pOp->p2;
  break;
}

/* Opcode: IdxColumn P1 * *
**
** P1 is a cursor opened on an index. Push the first field from the
** current index key onto the stack.
*/
/* Opcode: Column P1 P2 *
**
** Interpret the data that cursor P1 points to as a structure built using
** the MakeRecord instruction.  (See the MakeRecord opcode for additional
** information about the format of the data.) Push onto the stack the value
** of the P2-th column contained in the data.
**
................................................................................
** If P1 is negative, then the record is stored on the stack rather than in
** a table.  For P1==-1, the top of the stack is used.  For P1==-2, the
** next on the stack is used.  And so forth.  The value pushed is always
** just a pointer into the record which is stored further down on the
** stack.  The column value is not copied. The number of columns in the
** record is stored on the stack just above the record itself.
*/
case OP_IdxColumn:
case OP_Column: {
  u32 payloadSize;   /* Number of bytes in the record */
  int p1 = pOp->p1;  /* P1 value of the opcode */
  int p2 = pOp->p2;  /* column number to retrieve */
  Cursor *pC = 0;    /* The VDBE cursor */
  char *zRec;        /* Pointer to complete record-data */
  BtCursor *pCrsr;   /* The BTree cursor */
................................................................................
  pTos--;
  break;
}

/* Opcode: IdxRecno P1 * *
**
** Push onto the stack an integer which is the varint located at the
** end of the index key pointed to by cursor P1.  These integer should be
** the record number of the table entry to which this index entry points.
**
** See also: Recno, MakeIdxKey.
*/
case OP_IdxRecno: {
  int i = pOp->p1;
  BtCursor *pCrsr;







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**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.434 2004/12/19 00:11:35 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
case OP_SetNumColumns: {
  assert( (pOp->p1)<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  p->apCsr[pOp->p1]->nField = pOp->p2;
  break;
}






/* Opcode: Column P1 P2 *
**
** Interpret the data that cursor P1 points to as a structure built using
** the MakeRecord instruction.  (See the MakeRecord opcode for additional
** information about the format of the data.) Push onto the stack the value
** of the P2-th column contained in the data.
**
................................................................................
** If P1 is negative, then the record is stored on the stack rather than in
** a table.  For P1==-1, the top of the stack is used.  For P1==-2, the
** next on the stack is used.  And so forth.  The value pushed is always
** just a pointer into the record which is stored further down on the
** stack.  The column value is not copied. The number of columns in the
** record is stored on the stack just above the record itself.
*/

case OP_Column: {
  u32 payloadSize;   /* Number of bytes in the record */
  int p1 = pOp->p1;  /* P1 value of the opcode */
  int p2 = pOp->p2;  /* column number to retrieve */
  Cursor *pC = 0;    /* The VDBE cursor */
  char *zRec;        /* Pointer to complete record-data */
  BtCursor *pCrsr;   /* The BTree cursor */
................................................................................
  pTos--;
  break;
}

/* Opcode: IdxRecno P1 * *
**
** Push onto the stack an integer which is the varint located at the
** end of the index key pointed to by cursor P1.  This integer should be
** the record number of the table entry to which this index entry points.
**
** See also: Recno, MakeIdxKey.
*/
case OP_IdxRecno: {
  int i = pOp->p1;
  BtCursor *pCrsr;

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** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** 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".
**
** $Id: where.c,v 1.122 2004/12/18 18:40:27 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.
................................................................................
      SWAP(unsigned, pInfo->prereqLeft, pInfo->prereqRight);
      SWAP(short int, pInfo->idxLeft, pInfo->idxRight);
    }
  }      

}

/*
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
** the table has a cursor number of "base".
**
** This routine attempts to find an index for pTab that generates the
** correct record sequence for the given ORDER BY clause.  The return value
** is a pointer to an index that does the job.  NULL is returned if the
** table has no index that will generate the correct sort order.
**
** If there are two or more indices that generate the correct sort order
** and pPreferredIdx is one of those indices, then return pPreferredIdx.
**
** nEqCol is the number of columns of pPreferredIdx that are used as
** equality constraints.  Any index returned must have exactly this same
** set of columns.  The ORDER BY clause only matches index columns beyond the
** the first nEqCol columns.
**
** All terms of the ORDER BY clause must be either ASC or DESC.  The
** *pbRev value is set to 1 if the ORDER BY clause is all DESC and it is
** set to 0 if the ORDER BY clause is all ASC.
**
** TODO:  If earlier terms of an ORDER BY clause match all terms of a
** UNIQUE index, then subsequent terms of the ORDER BY can be ignored.
** This optimization needs to be implemented.
*/
static Index *findSortingIndex(
  Parse *pParse,          /* Parsing context */
  Table *pTab,            /* The table to be sorted */
  int base,               /* Cursor number for pTab */
  ExprList *pOrderBy,     /* The ORDER BY clause */
  Index *pPreferredIdx,   /* Use this index, if possible and not NULL */
  int nEqCol,             /* Number of index columns used with == constraints */
  int *pbRev              /* Set to 1 if ORDER BY is DESC */
){
  int i, j;                    /* Loop counters */
  Index *pMatch;               /* Best matching index so far */
  Index *pIdx;                 /* Current index */
  int sortOrder;               /* Which direction we are sorting */
  sqlite3 *db = pParse->db;

  assert( pOrderBy!=0 );
  assert( pOrderBy->nExpr>0 );
  assert( pPreferredIdx!=0 || nEqCol==0 );
  sortOrder = pOrderBy->a[0].sortOrder;
  for(i=0; i<pOrderBy->nExpr; i++){
    Expr *p;
    if( pOrderBy->a[i].sortOrder!=sortOrder ){
      /* Indices can only be used if all ORDER BY terms are either
      ** DESC or ASC.  Indices cannot be used on a mixture. */
      return 0;
    }
    p = pOrderBy->a[i].pExpr;
    if( p->op!=TK_COLUMN || p->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }
  }

  /* If we get this far, it means the ORDER BY clause consists of columns
  ** that are all either ascending or descending and which refer only to
  ** the left-most table of the FROM clause.  Find the index that is best
  ** used for sorting.
  */
  pMatch = 0;
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    int nExpr = pOrderBy->nExpr;
    if( pIdx->nColumn < nEqCol || pIdx->nColumn < nExpr ) continue;
    for(i=j=0; i<nEqCol; i++){
      CollSeq *pColl = sqlite3ExprCollSeq(pParse, pOrderBy->a[j].pExpr);
      if( !pColl ) pColl = db->pDfltColl;
      if( pPreferredIdx->aiColumn[i]!=pIdx->aiColumn[i] ) break;
      if( pPreferredIdx->keyInfo.aColl[i]!=pIdx->keyInfo.aColl[i] ) break;
      if( j<nExpr && 
          pOrderBy->a[j].pExpr->iColumn==pIdx->aiColumn[i] &&
          pColl==pIdx->keyInfo.aColl[i]
      ){ 
        j++; 
      }
    }
    if( i<nEqCol ) continue;
    for(i=0; i+j<nExpr; i++){
      CollSeq *pColl = sqlite3ExprCollSeq(pParse, pOrderBy->a[i+j].pExpr);
      if( !pColl ) pColl = db->pDfltColl;
      if( pOrderBy->a[i+j].pExpr->iColumn!=pIdx->aiColumn[i+nEqCol] ||
          pColl!=pIdx->keyInfo.aColl[i+nEqCol] ) break;
    }
    if( i+j>=nExpr ){
      pMatch = pIdx;
      if( pIdx==pPreferredIdx ) break;
    }
  }
  *pbRev = sortOrder==SQLITE_SO_DESC;
  return pMatch;
}

/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
................................................................................
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }
    pColl = sqlite3ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( pExpr->iColumn!=pIdx->aiColumn[i] && pColl!=pIdx->keyInfo.aColl[i] ){

      if( i<=nEqCol ){
        /* If an index column that is constrained by == fails to match an
        ** ORDER BY term, that is OK.  Just ignore that column of the index
        */
        continue;
      }else{
        /* If an index column fails to match and is not constrained by ==
        ** then the index cannot satisfy the ORDER BY constraint.
................................................................................
    assert( pX->op==TK_EQ );
    sqlite3ExprCode(pParse, pX->pRight);
  }else{
    int iTab = pX->iTable;
    Vdbe *v = pParse->pVdbe;
    sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk);
    sqlite3VdbeAddOp(v, OP_KeyAsData, iTab, 1);
    pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, iTab, 0);
    pLevel->inOp = OP_Next;
    pLevel->inP1 = iTab;
  }
  disableTerm(pLevel, &pTerm->p);
}

/*
................................................................................
){
  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont = 0;         /* Addresses used during code generation */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  Bitmask loopMask;    /* One bit set for each outer loop */
  int haveKey = 0;     /* True if KEY is on the stack */
  ExprInfo *pTerm;     /* A single term in the WHERE clause; ptr to aExpr[] */
  ExprMaskSet maskSet; /* The expression mask set */
  int iDirectEq[BMS];  /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[BMS];  /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[BMS];  /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[101]; /* The WHERE clause is divided into these terms */



  /* pushKey is only allowed if there is a single table (as in an INSERT or
  ** UPDATE statement)
  */
  assert( pushKey==0 || pTabList->nSrc==1 );

  /* Split the WHERE clause into separate subexpressions where each
................................................................................
  ** doing a second read of the actual database table.
  **
  ** Actually, if there are more than 32 tables in the join, only the
  ** first 32 tables are candidates for indices.  This is (again) due
  ** to the limit of 32 bits in an integer bitmask.
  */
  loopMask = 0;


  for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++){
    int j;
    WhereLevel *pLevel = &pWInfo->a[i];
    int iCur = pTabList->a[i].iCursor;       /* The cursor for this table */
    Bitmask mask = getMask(&maskSet, iCur);  /* Cursor mask for this table */
    Table *pTab = pTabList->a[i].pTab;
    Index *pIdx;
    Index *pBestIdx = 0;
    int bestScore = 0;
    int bestRev = 0;

    /* Check to see if there is an expression that uses only the
    ** ROWID field of this table.  For terms of the form ROWID==expr
    ** set iDirectEq[i] to the index of the term.  For terms of the
    ** form ROWID<expr or ROWID<=expr set iDirectLt[i] to the term index.
    ** For terms like ROWID>expr or ROWID>=expr set iDirectGt[i].
    **
    ** (Added:) Treat ROWID IN expr like ROWID=expr.
    */
    pLevel->iCur = -1;
    iDirectEq[i] = -1;
    iDirectLt[i] = -1;
    iDirectGt[i] = -1;
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      Expr *pX = pTerm->p;
      if( pTerm->idxLeft==iCur && pX->pLeft->iColumn<0
            && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
................................................................................
      m = ((Bitmask)1)<<nEq;
      if( m & ltMask ) score+=4;    /* Increase score for a < constraint */
      if( m & gtMask ) score+=8;    /* Increase score for a > constraint */
      if( score==0 && inMask ) score = 16; /* Default score for IN constraint */

      /* Give bonus points if this index can be used for sorting
      */
      if( i==0 && score>0 && ppOrderBy && *ppOrderBy ){
        int base = pTabList->a[0].iCursor;
        if( isSortingIndex(pParse, pIdx, pTab, base, *ppOrderBy, nEq, &bRev) ){
          score += 2;
        }
      }

















      /* If the score for this index is the best we have seen so far, then
      ** save it
      */
      if( score>bestScore ){
        pBestIdx = pIdx;
        bestScore = score;
................................................................................
      }
    }
    pLevel->pIdx = pBestIdx;
    pLevel->score = bestScore;
    pLevel->bRev = bestRev;
    loopMask |= mask;
    if( pBestIdx ){
      pLevel->iCur = pParse->nTab++;
    }
  }

  /* Check to see if the ORDER BY clause is or can be satisfied by the
  ** use of an index on the first table.
  */
  if( ppOrderBy && *ppOrderBy && pTabList->nSrc>0 ){
     Index *pSortIdx = 0;     /* Index that satisfies the ORDER BY clause */
     Index *pIdx;             /* Index derived from the WHERE clause */
     Table *pTab;             /* Left-most table in the FROM clause */
     int bRev = 0;            /* True to reverse the output order */
     int iCur;                /* Btree-cursor that will be used by pTab */
     WhereLevel *pLevel0 = &pWInfo->a[0];

     pTab = pTabList->a[0].pTab;
................................................................................
       ** So, pretend that no suitable index is found.
       */
     }else if( iDirectEq[0]>=0 || iDirectLt[0]>=0 || iDirectGt[0]>=0 ){
       /* If the left-most column is accessed using its ROWID, then do
       ** not try to sort by index.  But do delete the ORDER BY clause
       ** if it is redundant.
       */
     }else{
       int nEqCol = (pLevel0->score+16)/32;

       pSortIdx = findSortingIndex(pParse, pTab, iCur, 
                                   *ppOrderBy, pIdx, nEqCol, &bRev);
     }
     if( pSortIdx && (pIdx==0 || pIdx==pSortIdx) ){
       if( pIdx==0 ){
         pLevel0->pIdx = pSortIdx;
         pLevel0->iCur = pParse->nTab++;
       }
       pLevel0->bRev = bRev;
       *ppOrderBy = 0;
     }
  }

  /* Open all tables in the pTabList and all indices used by those tables.

  */
  sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */

  for(i=0; i<pTabList->nSrc; i++){
    Table *pTab;
    Index *pIx;


    pTab = pTabList->a[i].pTab;
    if( pTab->isTransient || pTab->pSelect ) continue;

    sqlite3OpenTableForReading(v, pTabList->a[i].iCursor, pTab);
    sqlite3CodeVerifySchema(pParse, pTab->iDb);


    if( (pIx = pWInfo->a[i].pIdx)!=0 ){
      sqlite3VdbeAddOp(v, OP_Integer, pIx->iDb, 0);
      sqlite3VdbeOp3(v, OP_OpenRead, pWInfo->a[i].iCur, pIx->tnum,
                     (char*)&pIx->keyInfo, P3_KEYINFO);
    }



  }




  /* Generate the code to do the search
  */
  loopMask = 0;


  for(i=0; i<pTabList->nSrc; i++){
    int j, k;
    int iCur = pTabList->a[i].iCursor;

    Index *pIdx;
    WhereLevel *pLevel = &pWInfo->a[i];












    /* If this is the right table of a LEFT OUTER JOIN, allocate and
    ** initialize a memory cell that records if this table matches any
    ** row of the left table of the join.
    */
    if( i>0 && (pTabList->a[i-1].jointype & JT_LEFT)!=0 ){
      if( !pParse->nMem ) pParse->nMem++;
      pLevel->iLeftJoin = pParse->nMem++;
      sqlite3VdbeAddOp(v, OP_String8, 0, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# init LEFT JOIN no-match flag"));
    }

    pIdx = pLevel->pIdx;
    pLevel->inOp = OP_Noop;
    if( i<ARRAYSIZE(iDirectEq) && (k = iDirectEq[i])>=0 ){
      /* Case 1:  We can directly reference a single row using an
      **          equality comparison against the ROWID field.  Or
      **          we reference multiple rows using a "rowid IN (...)"
      **          construct.
      */
      assert( k<nExpr );
      pTerm = &aExpr[k];
      assert( pTerm->p!=0 );
      assert( pTerm->idxLeft==iCur );

      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      codeEqualityTerm(pParse, pTerm, brk, pLevel);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);
      haveKey = 0;
      sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);

      pLevel->op = OP_Noop;
    }else if( pIdx!=0 && pLevel->score>0 && (pLevel->score&0x0c)==0 ){
      /* Case 2:  There is an index and all terms of the WHERE clause that
      **          refer to the index using the "==" or "IN" operators.
      */
      int start;
      int nColumn = (pLevel->score+16)/32;
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

................................................................................
      /* Generate code (1) to move to the first matching element of the table.
      ** Then generate code (2) that jumps to "brk" after the cursor is past
      ** the last matching element of the table.  The code (1) is executed
      ** once to initialize the search, the code (2) is executed before each
      ** iteration of the scan to see if the scan has finished. */
      if( pLevel->bRev ){
        /* Scan in reverse order */
        sqlite3VdbeAddOp(v, OP_MoveLe, pLevel->iCur, brk);
        start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, OP_IdxLT, pLevel->iCur, brk);
        pLevel->op = OP_Prev;
      }else{
        /* Scan in the forward order */
        sqlite3VdbeAddOp(v, OP_MoveGe, pLevel->iCur, brk);
        start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeOp3(v, OP_IdxGE, pLevel->iCur, brk, "+", P3_STATIC);
        pLevel->op = OP_Next;
      }
      sqlite3VdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
      sqlite3VdbeAddOp(v, OP_IdxIsNull, nColumn, cont);
      sqlite3VdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        haveKey = 0;

      }
      pLevel->p1 = pLevel->iCur;
      pLevel->p2 = start;
    }else if( i<ARRAYSIZE(iDirectLt) && (iDirectLt[i]>=0 || iDirectGt[i]>=0) ){
      /* Case 3:  We have an inequality comparison against the ROWID field.
      */
      int testOp = OP_Noop;
      int start;
      int bRev = pLevel->bRev;


      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( bRev ){
        int t = iDirectGt[i];
        iDirectGt[i] = iDirectLt[i];
        iDirectLt[i] = t;
      }
................................................................................
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
        sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, testOp, 0, brk);
      }
      haveKey = 0;
    }else if( pIdx==0 ){
      /* Case 4:  There is no usable index.  We must do a complete
      **          scan of the entire database table.
      */
      int start;
      int opRewind;


      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( pLevel->bRev ){
        opRewind = OP_Last;
        pLevel->op = OP_Prev;
      }else{
        opRewind = OP_Rewind;
        pLevel->op = OP_Next;
      }
      sqlite3VdbeAddOp(v, opRewind, iCur, brk);
      start = sqlite3VdbeCurrentAddr(v);
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      haveKey = 0;
    }else{
      /* Case 5: The WHERE clause term that refers to the right-most
      **         column of the index is an inequality.  For example, if
      **         the index is on (x,y,z) and the WHERE clause is of the
      **         form "x=5 AND y<10" then this case is used.  Only the
      **         right-most column can be an inequality - the rest must
      **         use the "==" operator.
................................................................................
      }
      if( testOp!=OP_Noop ){
        int nCol = nEqColumn + ((score & 4)!=0);
        pLevel->iMem = pParse->nMem++;
        buildIndexProbe(v, nCol, brk, pIdx);
        if( pLevel->bRev ){
          int op = leFlag ? OP_MoveLe : OP_MoveLt;
          sqlite3VdbeAddOp(v, op, pLevel->iCur, brk);
        }else{
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
        }
      }else if( pLevel->bRev ){
        sqlite3VdbeAddOp(v, OP_Last, pLevel->iCur, brk);
      }

      /* Generate the start key.  This is the key that defines the lower
      ** bound on the search.  There is no start key if there are no
      ** equality terms and if there is no "X>..." term.  In
      ** that case, generate a "Rewind" instruction in place of the
      ** start key search.
................................................................................
        buildIndexProbe(v, nCol, brk, pIdx);
        if( pLevel->bRev ){
          pLevel->iMem = pParse->nMem++;
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
          testOp = OP_IdxLT;
        }else{
          int op = geFlag ? OP_MoveGe : OP_MoveGt;
          sqlite3VdbeAddOp(v, op, pLevel->iCur, brk);
        }
      }else if( pLevel->bRev ){
        testOp = OP_Noop;
      }else{
        sqlite3VdbeAddOp(v, OP_Rewind, pLevel->iCur, brk);
      }

      /* Generate the the top of the loop.  If there is a termination
      ** key we have to test for that key and abort at the top of the
      ** loop.
      */
      start = sqlite3VdbeCurrentAddr(v);
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, testOp, pLevel->iCur, brk);
        if( (leFlag && !pLevel->bRev) || (!geFlag && pLevel->bRev) ){
          sqlite3VdbeChangeP3(v, -1, "+", P3_STATIC);
        }
      }
      sqlite3VdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
      sqlite3VdbeAddOp(v, OP_IdxIsNull, nEqColumn + ((score&4)!=0), cont);
      sqlite3VdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
      if( i==pTabList->nSrc-1 && pushKey ){
        haveKey = 1;
      }else{
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        haveKey = 0;

      }

      /* Record the instruction used to terminate the loop.
      */
      pLevel->op = pLevel->bRev ? OP_Prev : OP_Next;
      pLevel->p1 = pLevel->iCur;
      pLevel->p2 = start;
    }
    loopMask |= getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      if( pTerm->p==0 ) continue;
      if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
      if( pLevel->iLeftJoin && !ExprHasProperty(pTerm->p,EP_FromJoin) ){
        continue;
      }
      if( haveKey ){
        haveKey = 0;



        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
      }

      sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
      pTerm->p = 0;
    }
    brk = cont;

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
................................................................................
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# record LEFT JOIN hit"));
      for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
        if( pTerm->p==0 ) continue;
        if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
        if( haveKey ){
          /* Cannot happen.  "haveKey" can only be true if pushKey is true
          ** an pushKey can only be true for DELETE and UPDATE and there are
          ** no outer joins with DELETE and UPDATE.
          */
          haveKey = 0;

          sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        }
        sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
        pTerm->p = 0;
      }
    }
  }









  pWInfo->iContinue = cont;
  if( pushKey && !haveKey ){
    sqlite3VdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
  }
  freeMaskSet(&maskSet);
  return pWInfo;
}

/*
................................................................................
** sqlite3WhereBegin() for additional information.
*/
void sqlite3WhereEnd(WhereInfo *pWInfo){
  Vdbe *v = pWInfo->pParse->pVdbe;
  int i;
  WhereLevel *pLevel;
  SrcList *pTabList = pWInfo->pTabList;




  for(i=pTabList->nSrc-1; i>=0; i--){
    pLevel = &pWInfo->a[i];
    sqlite3VdbeResolveLabel(v, pLevel->cont);
    if( pLevel->op!=OP_Noop ){
      sqlite3VdbeAddOp(v, pLevel->op, pLevel->p1, pLevel->p2);
    }
    sqlite3VdbeResolveLabel(v, pLevel->brk);
    if( pLevel->inOp!=OP_Noop ){
      sqlite3VdbeAddOp(v, pLevel->inOp, pLevel->inP1, pLevel->inP2);
    }
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iLeftJoin, 0);
      sqlite3VdbeAddOp(v, OP_NotNull, 1, addr+4 + (pLevel->iCur>=0));
      sqlite3VdbeAddOp(v, OP_NullRow, pTabList->a[i].iCursor, 0);
      if( pLevel->iCur>=0 ){
        sqlite3VdbeAddOp(v, OP_NullRow, pLevel->iCur, 0);
      }
      sqlite3VdbeAddOp(v, OP_Goto, 0, pLevel->top);
    }
  }




  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);





  for(i=0; i<pTabList->nSrc; i++){
    Table *pTab = pTabList->a[i].pTab;
    assert( pTab!=0 );
    if( pTab->isTransient || pTab->pSelect ) continue;
    pLevel = &pWInfo->a[i];

    sqlite3VdbeAddOp(v, OP_Close, pTabList->a[i].iCursor, 0);

    if( pLevel->pIdx!=0 ){
      sqlite3VdbeAddOp(v, OP_Close, pLevel->iCur, 0);
    }
  }





































  sqliteFree(pWInfo);
  return;
}







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** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** 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".
**
** $Id: where.c,v 1.123 2004/12/19 00:11:35 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.
................................................................................
      SWAP(unsigned, pInfo->prereqLeft, pInfo->prereqRight);
      SWAP(short int, pInfo->idxLeft, pInfo->idxRight);
    }
  }      

}


































































































/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
................................................................................
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      return 0;
    }
    pColl = sqlite3ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( pExpr->iColumn!=pIdx->aiColumn[i] || pColl!=pIdx->keyInfo.aColl[i] ){
      /* Term j of the ORDER BY clause does not match column i of the index */
      if( i<nEqCol ){
        /* If an index column that is constrained by == fails to match an
        ** ORDER BY term, that is OK.  Just ignore that column of the index
        */
        continue;
      }else{
        /* If an index column fails to match and is not constrained by ==
        ** then the index cannot satisfy the ORDER BY constraint.
................................................................................
    assert( pX->op==TK_EQ );
    sqlite3ExprCode(pParse, pX->pRight);
  }else{
    int iTab = pX->iTable;
    Vdbe *v = pParse->pVdbe;
    sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk);
    sqlite3VdbeAddOp(v, OP_KeyAsData, iTab, 1);
    pLevel->inP2 = sqlite3VdbeAddOp(v, OP_Column, iTab, 0);
    pLevel->inOp = OP_Next;
    pLevel->inP1 = iTab;
  }
  disableTerm(pLevel, &pTerm->p);
}

/*
................................................................................
){
  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont = 0;         /* Addresses used during code generation */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  Bitmask loopMask;    /* One bit set for each outer loop */
  int haveRowid = 0;   /* True if the ROWID is on the stack */
  ExprInfo *pTerm;     /* A single term in the WHERE clause; ptr to aExpr[] */
  ExprMaskSet maskSet; /* The expression mask set */
  int iDirectEq[BMS];  /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[BMS];  /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[BMS];  /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[101]; /* The WHERE clause is divided into these terms */
  struct SrcList_item *pTabItem;  /* A single entry from pTabList */
  WhereLevel *pLevel;             /* A single level in the pWInfo list */

  /* pushKey is only allowed if there is a single table (as in an INSERT or
  ** UPDATE statement)
  */
  assert( pushKey==0 || pTabList->nSrc==1 );

  /* Split the WHERE clause into separate subexpressions where each
................................................................................
  ** doing a second read of the actual database table.
  **
  ** Actually, if there are more than 32 tables in the join, only the
  ** first 32 tables are candidates for indices.  This is (again) due
  ** to the limit of 32 bits in an integer bitmask.
  */
  loopMask = 0;
  pTabItem = pTabList->a;
  pLevel = pWInfo->a;
  for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++,pTabItem++,pLevel++){
    int j;

    int iCur = pTabItem->iCursor;            /* The cursor for this table */
    Bitmask mask = getMask(&maskSet, iCur);  /* Cursor mask for this table */
    Table *pTab = pTabItem->pTab;
    Index *pIdx;
    Index *pBestIdx = 0;
    int bestScore = 0;
    int bestRev = 0;

    /* Check to see if there is an expression that uses only the
    ** ROWID field of this table.  For terms of the form ROWID==expr
    ** set iDirectEq[i] to the index of the term.  For terms of the
    ** form ROWID<expr or ROWID<=expr set iDirectLt[i] to the term index.
    ** For terms like ROWID>expr or ROWID>=expr set iDirectGt[i].
    **
    ** (Added:) Treat ROWID IN expr like ROWID=expr.
    */
    pLevel->iIdxCur = -1;
    iDirectEq[i] = -1;
    iDirectLt[i] = -1;
    iDirectGt[i] = -1;
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      Expr *pX = pTerm->p;
      if( pTerm->idxLeft==iCur && pX->pLeft->iColumn<0
            && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
................................................................................
      m = ((Bitmask)1)<<nEq;
      if( m & ltMask ) score+=4;    /* Increase score for a < constraint */
      if( m & gtMask ) score+=8;    /* Increase score for a > constraint */
      if( score==0 && inMask ) score = 16; /* Default score for IN constraint */

      /* Give bonus points if this index can be used for sorting
      */
      if( i==0 && score!=16 && ppOrderBy && *ppOrderBy ){
        int base = pTabList->a[0].iCursor;
        if( isSortingIndex(pParse, pIdx, pTab, base, *ppOrderBy, nEq, &bRev) ){
          score += 2;
        }
      }

      /* Check to see if we can get away with using just the index without
      ** ever reading the table.  If that is the case, then add one bonus
      ** point to the score.
      */
      if( score && pTabItem->colUsed < (((Bitmask)1)<<(BMS-1)) ){
        for(m=0, j=0; j<pIdx->nColumn; j++){
          int x = pIdx->aiColumn[j];
          if( x<BMS-1 ){
            m |= ((Bitmask)1)<<x;
          }
        }
        if( (pTabItem->colUsed & m)==pTabItem->colUsed ){
          score++;
        }
      }

      /* If the score for this index is the best we have seen so far, then
      ** save it
      */
      if( score>bestScore ){
        pBestIdx = pIdx;
        bestScore = score;
................................................................................
      }
    }
    pLevel->pIdx = pBestIdx;
    pLevel->score = bestScore;
    pLevel->bRev = bestRev;
    loopMask |= mask;
    if( pBestIdx ){
      pLevel->iIdxCur = pParse->nTab++;
    }
  }

  /* Check to see if the ORDER BY clause is or can be satisfied by the
  ** use of an index on the first table.
  */
  if( ppOrderBy && *ppOrderBy && pTabList->nSrc>0 ){

    Index *pIdx;             /* Index derived from the WHERE clause */
    Table *pTab;             /* Left-most table in the FROM clause */
    int bRev = 0;            /* True to reverse the output order */
    int iCur;                /* Btree-cursor that will be used by pTab */
    WhereLevel *pLevel0 = &pWInfo->a[0];

    pTab = pTabList->a[0].pTab;
................................................................................
      ** So, pretend that no suitable index is found.
      */
    }else if( iDirectEq[0]>=0 || iDirectLt[0]>=0 || iDirectGt[0]>=0 ){
      /* If the left-most column is accessed using its ROWID, then do
      ** not try to sort by index.  But do delete the ORDER BY clause
      ** if it is redundant.
      */

    }else if( (pLevel0->score&2)!=0 ){
      /* The index that was selected for searching will cause rows to
      ** appear in sorted order.
      */







      *ppOrderBy = 0;
    }
  }

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */
  sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
  pLevel = pWInfo->a;
  for(i=0, pTabItem=pTabList->a; i<pTabList->nSrc; i++, pTabItem++, pLevel++){
    Table *pTab;
    Index *pIx;
    int iIdxCur = pLevel->iIdxCur;

    pTab = pTabItem->pTab;
    if( pTab->isTransient || pTab->pSelect ) continue;
    if( (pLevel->score & 1)==0 ){
      sqlite3OpenTableForReading(v, pTabItem->iCursor, pTab);

    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){
      sqlite3VdbeAddOp(v, OP_Integer, pIx->iDb, 0);
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)&pIx->keyInfo, P3_KEYINFO);
    }
    if( (pLevel->score & 1)!=0 ){
      sqlite3VdbeAddOp(v, OP_KeyAsData, iIdxCur, 1);
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, pTab->iDb);
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);

  /* Generate the code to do the search
  */
  loopMask = 0;
  pLevel = pWInfo->a;
  pTabItem = pTabList->a;
  for(i=0; i<pTabList->nSrc; i++, pTabItem++, pLevel++){
    int j, k;

    int iCur = pTabItem->iCursor;  /* The VDBE cursor for the table */
    Index *pIdx;       /* The index we will be using */

    int iIdxCur;       /* The VDBE cursor for the index */
    int omitTable;     /* True if we use the index only */

    pIdx = pLevel->pIdx;
    iIdxCur = pLevel->iIdxCur;
    pLevel->inOp = OP_Noop;

    /* Check to see if it is appropriate to omit the use of the table
    ** here and use its index instead.
    */
    omitTable = (pLevel->score&1)!=0;

    /* If this is the right table of a LEFT OUTER JOIN, allocate and
    ** initialize a memory cell that records if this table matches any
    ** row of the left table of the join.
    */
    if( i>0 && (pTabList->a[i-1].jointype & JT_LEFT)!=0 ){
      if( !pParse->nMem ) pParse->nMem++;
      pLevel->iLeftJoin = pParse->nMem++;
      sqlite3VdbeAddOp(v, OP_String8, 0, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# init LEFT JOIN no-match flag"));
    }



    if( i<ARRAYSIZE(iDirectEq) && (k = iDirectEq[i])>=0 ){
      /* Case 1:  We can directly reference a single row using an
      **          equality comparison against the ROWID field.  Or
      **          we reference multiple rows using a "rowid IN (...)"
      **          construct.
      */
      assert( k<nExpr );
      pTerm = &aExpr[k];
      assert( pTerm->p!=0 );
      assert( pTerm->idxLeft==iCur );
      assert( omitTable==0 );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      codeEqualityTerm(pParse, pTerm, brk, pLevel);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);

      sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);
      haveRowid = 0;
      pLevel->op = OP_Noop;
    }else if( pIdx!=0 && pLevel->score>3 && (pLevel->score&0x0c)==0 ){
      /* Case 2:  There is an index and all terms of the WHERE clause that
      **          refer to the index using the "==" or "IN" operators.
      */
      int start;
      int nColumn = (pLevel->score+16)/32;
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

................................................................................
      /* Generate code (1) to move to the first matching element of the table.
      ** Then generate code (2) that jumps to "brk" after the cursor is past
      ** the last matching element of the table.  The code (1) is executed
      ** once to initialize the search, the code (2) is executed before each
      ** iteration of the scan to see if the scan has finished. */
      if( pLevel->bRev ){
        /* Scan in reverse order */
        sqlite3VdbeAddOp(v, OP_MoveLe, iIdxCur, brk);
        start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, OP_IdxLT, iIdxCur, brk);
        pLevel->op = OP_Prev;
      }else{
        /* Scan in the forward order */
        sqlite3VdbeAddOp(v, OP_MoveGe, iIdxCur, brk);
        start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeOp3(v, OP_IdxGE, iIdxCur, brk, "+", P3_STATIC);
        pLevel->op = OP_Next;
      }
      sqlite3VdbeAddOp(v, OP_RowKey, iIdxCur, 0);
      sqlite3VdbeAddOp(v, OP_IdxIsNull, nColumn, cont);
      if( omitTable ){
        haveRowid = 0;

      }else{
        sqlite3VdbeAddOp(v, OP_IdxRecno, iIdxCur, 0);

        haveRowid = 1;
      }
      pLevel->p1 = iIdxCur;
      pLevel->p2 = start;
    }else if( i<ARRAYSIZE(iDirectLt) && (iDirectLt[i]>=0 || iDirectGt[i]>=0) ){
      /* Case 3:  We have an inequality comparison against the ROWID field.
      */
      int testOp = OP_Noop;
      int start;
      int bRev = pLevel->bRev;

      assert( omitTable==0 );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( bRev ){
        int t = iDirectGt[i];
        iDirectGt[i] = iDirectLt[i];
        iDirectLt[i] = t;
      }
................................................................................
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
        sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, testOp, 0, brk);
      }
      haveRowid = 0;
    }else if( pIdx==0 ){
      /* Case 4:  There is no usable index.  We must do a complete
      **          scan of the entire database table.
      */
      int start;
      int opRewind;

      assert( omitTable==0 );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( pLevel->bRev ){
        opRewind = OP_Last;
        pLevel->op = OP_Prev;
      }else{
        opRewind = OP_Rewind;
        pLevel->op = OP_Next;
      }
      sqlite3VdbeAddOp(v, opRewind, iCur, brk);
      start = sqlite3VdbeCurrentAddr(v);
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      haveRowid = 0;
    }else{
      /* Case 5: The WHERE clause term that refers to the right-most
      **         column of the index is an inequality.  For example, if
      **         the index is on (x,y,z) and the WHERE clause is of the
      **         form "x=5 AND y<10" then this case is used.  Only the
      **         right-most column can be an inequality - the rest must
      **         use the "==" operator.
................................................................................
      }
      if( testOp!=OP_Noop ){
        int nCol = nEqColumn + ((score & 4)!=0);
        pLevel->iMem = pParse->nMem++;
        buildIndexProbe(v, nCol, brk, pIdx);
        if( pLevel->bRev ){
          int op = leFlag ? OP_MoveLe : OP_MoveLt;
          sqlite3VdbeAddOp(v, op, iIdxCur, brk);
        }else{
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
        }
      }else if( pLevel->bRev ){
        sqlite3VdbeAddOp(v, OP_Last, iIdxCur, brk);
      }

      /* Generate the start key.  This is the key that defines the lower
      ** bound on the search.  There is no start key if there are no
      ** equality terms and if there is no "X>..." term.  In
      ** that case, generate a "Rewind" instruction in place of the
      ** start key search.
................................................................................
        buildIndexProbe(v, nCol, brk, pIdx);
        if( pLevel->bRev ){
          pLevel->iMem = pParse->nMem++;
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
          testOp = OP_IdxLT;
        }else{
          int op = geFlag ? OP_MoveGe : OP_MoveGt;
          sqlite3VdbeAddOp(v, op, iIdxCur, brk);
        }
      }else if( pLevel->bRev ){
        testOp = OP_Noop;
      }else{
        sqlite3VdbeAddOp(v, OP_Rewind, iIdxCur, brk);
      }

      /* Generate the the top of the loop.  If there is a termination
      ** key we have to test for that key and abort at the top of the
      ** loop.
      */
      start = sqlite3VdbeCurrentAddr(v);
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, testOp, iIdxCur, brk);
        if( (leFlag && !pLevel->bRev) || (!geFlag && pLevel->bRev) ){
          sqlite3VdbeChangeP3(v, -1, "+", P3_STATIC);
        }
      }
      sqlite3VdbeAddOp(v, OP_RowKey, iIdxCur, 0);
      sqlite3VdbeAddOp(v, OP_IdxIsNull, nEqColumn + ((score&4)!=0), cont);
      if( omitTable ){
        haveRowid = 0;

      }else{
        sqlite3VdbeAddOp(v, OP_IdxRecno, iIdxCur, 0);

        haveRowid = 1;
      }

      /* Record the instruction used to terminate the loop.
      */
      pLevel->op = pLevel->bRev ? OP_Prev : OP_Next;
      pLevel->p1 = iIdxCur;
      pLevel->p2 = start;
    }
    loopMask |= getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      if( pTerm->p==0 ) continue;
      if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
      if( pLevel->iLeftJoin && !ExprHasProperty(pTerm->p,EP_FromJoin) ){
        continue;
      }
      if( haveRowid ){
        haveRowid = 0;
        if( omitTable ){
          sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
        }else{
          sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        }
      }
      sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
      pTerm->p = 0;
    }
    brk = cont;

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
................................................................................
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# record LEFT JOIN hit"));
      for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
        if( pTerm->p==0 ) continue;
        if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
        if( haveRowid ){
          /* Cannot happen.  "haveRowid" can only be true if pushKey is true
          ** an pushKey can only be true for DELETE and UPDATE and there are
          ** no outer joins with DELETE and UPDATE.
          */
          assert( 0 );
          haveRowid = 0;
          sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        }
        sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
        pTerm->p = 0;
      }
    }

    if( haveRowid && (i<pTabList->nSrc-1 || !pushKey) ){
      haveRowid = 0;
      if( omitTable ){
        sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
      }else{
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
      }
    }    
  }
  pWInfo->iContinue = cont;
  if( pushKey && !haveRowid ){
    sqlite3VdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
  }
  freeMaskSet(&maskSet);
  return pWInfo;
}

/*
................................................................................
** sqlite3WhereBegin() for additional information.
*/
void sqlite3WhereEnd(WhereInfo *pWInfo){
  Vdbe *v = pWInfo->pParse->pVdbe;
  int i;
  WhereLevel *pLevel;
  SrcList *pTabList = pWInfo->pTabList;
  struct SrcList_item *pTabItem;

  /* Generate loop termination code.
  */
  for(i=pTabList->nSrc-1; i>=0; i--){
    pLevel = &pWInfo->a[i];
    sqlite3VdbeResolveLabel(v, pLevel->cont);
    if( pLevel->op!=OP_Noop ){
      sqlite3VdbeAddOp(v, pLevel->op, pLevel->p1, pLevel->p2);
    }
    sqlite3VdbeResolveLabel(v, pLevel->brk);
    if( pLevel->inOp!=OP_Noop ){
      sqlite3VdbeAddOp(v, pLevel->inOp, pLevel->inP1, pLevel->inP2);
    }
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iLeftJoin, 0);
      sqlite3VdbeAddOp(v, OP_NotNull, 1, addr+4 + (pLevel->iIdxCur>=0));
      sqlite3VdbeAddOp(v, OP_NullRow, pTabList->a[i].iCursor, 0);
      if( pLevel->iIdxCur>=0 ){
        sqlite3VdbeAddOp(v, OP_NullRow, pLevel->iIdxCur, 0);
      }
      sqlite3VdbeAddOp(v, OP_Goto, 0, pLevel->top);
    }
  }

  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors
  */
  pLevel = pWInfo->a;
  pTabItem = pTabList->a;
  for(i=0; i<pTabList->nSrc; i++, pTabItem++, pLevel++){
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    if( pTab->isTransient || pTab->pSelect ) continue;

    if( (pLevel->score & 1)==0 ){
      sqlite3VdbeAddOp(v, OP_Close, pTabItem->iCursor, 0);
    }
    if( pLevel->pIdx!=0 ){
      sqlite3VdbeAddOp(v, OP_Close, pLevel->iIdxCur, 0);
    }

    /* Make all cursor substitutions for cases where we want to use
    ** just the index and never reference the table.
    ** 
    ** Calls to the code generator in between sqlite3WhereBegin and
    ** sqlite3WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( pLevel->score & 1 ){
      int i, j, last;
      VdbeOp *pOp;
      Index *pIdx = pLevel->pIdx;

      assert( pIdx!=0 );
      pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
      last = sqlite3VdbeCurrentAddr(v);
      for(i=pWInfo->iTop; i<last; i++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          pOp->p1 = pLevel->iIdxCur;
          for(j=0; j<pIdx->nColumn; j++){
            if( pOp->p2==pIdx->aiColumn[j] ){
              pOp->p2 = j;
              break;
            }
          }
        }else if( pOp->opcode==OP_Recno ){
          pOp->p1 = pLevel->iIdxCur;
          pOp->opcode = OP_IdxRecno;
        }
      }
    }
  }

  /* Final cleanup
  */
  sqliteFree(pWInfo);
  return;
}

Changes to test/collate4.test.

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#    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 script is page cache subsystem.
#
# $Id: collate4.test,v 1.5 2004/11/22 19:12:21 drh Exp $

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

db collate TEXT text_collate
proc text_collate {a b} {
  return [string compare $a $b]
................................................................................
do_test collate4-2.1.2 {
  execsql {
    CREATE INDEX collate4i1 ON collate4t1(a);
  }
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE a = b;
  }
} {A a A A 7}
do_test collate4-2.1.3 {
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE b = a;
  }
} {A A 19}
do_test collate4-2.1.4 {
  execsql {
................................................................................
    SELECT * FROM collate4t2, collate4t1 WHERE a = b;
  }
} {A a A A 19}
do_test collate4-2.1.5 {
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE b = a;
  }
} {A A 5}
do_test collate4-2.1.6 {
  count {
    SELECT a FROM collate4t1 WHERE a IN (SELECT * FROM collate4t2);
  }
} {a A 10}
do_test collate4-2.1.7 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a);
  }
  count {
    SELECT a FROM collate4t1 WHERE a IN (SELECT * FROM collate4t2);
  }
} {a A 8}
do_test collate4-2.1.8 {
  count {
    SELECT a FROM collate4t1 WHERE a IN ('z', 'a');
  }
} {a A 7}
do_test collate4-2.1.9 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE TEXT);
  }
  count {
    SELECT a FROM collate4t1 WHERE a IN ('z', 'a');
................................................................................
  }
} {}
do_test collate4-2.2.1 {
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;
  }
} {0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 63}
do_test collate4-2.2.1 {
  execsql {
    CREATE INDEX collate4i1 ON collate4t1(a, b, c);
  }
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;
  }
} {0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 45}
do_test collate4-2.2.2 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a, b, c COLLATE text);
  }
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;







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#    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 script is page cache subsystem.
#
# $Id: collate4.test,v 1.6 2004/12/19 00:11:36 drh Exp $

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

db collate TEXT text_collate
proc text_collate {a b} {
  return [string compare $a $b]
................................................................................
do_test collate4-2.1.2 {
  execsql {
    CREATE INDEX collate4i1 ON collate4t1(a);
  }
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE a = b;
  }
} {A a A A 5}
do_test collate4-2.1.3 {
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE b = a;
  }
} {A A 19}
do_test collate4-2.1.4 {
  execsql {
................................................................................
    SELECT * FROM collate4t2, collate4t1 WHERE a = b;
  }
} {A a A A 19}
do_test collate4-2.1.5 {
  count {
    SELECT * FROM collate4t2, collate4t1 WHERE b = a;
  }
} {A A 4}
do_test collate4-2.1.6 {
  count {
    SELECT a FROM collate4t1 WHERE a IN (SELECT * FROM collate4t2);
  }
} {a A 10}
do_test collate4-2.1.7 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a);
  }
  count {
    SELECT a FROM collate4t1 WHERE a IN (SELECT * FROM collate4t2);
  }
} {a A 6}
do_test collate4-2.1.8 {
  count {
    SELECT a FROM collate4t1 WHERE a IN ('z', 'a');
  }
} {a A 5}
do_test collate4-2.1.9 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE TEXT);
  }
  count {
    SELECT a FROM collate4t1 WHERE a IN ('z', 'a');
................................................................................
  }
} {}
do_test collate4-2.2.1 {
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;
  }
} {0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 63}
do_test collate4-2.2.1b {
  execsql {
    CREATE INDEX collate4i1 ON collate4t1(a, b, c);
  }
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;
  }
} {0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 29}
do_test collate4-2.2.2 {
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a, b, c COLLATE text);
  }
  count {
    SELECT * FROM collate4t2 NATURAL JOIN collate4t1;

Changes to test/where.test.

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#    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 testing the use of indices in WHERE clases.
#
# $Id: where.test,v 1.25 2004/12/18 18:40:28 drh Exp $

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

# Build some test data
#
do_test where-1.0 {
................................................................................
do_test where-1.29 {
  count {SELECT w FROM t1 WHERE y==121}
} {10 99}


do_test where-1.30 {
  count {SELECT w FROM t1 WHERE w>97}
} {98 99 100 6}
do_test where-1.31 {
  count {SELECT w FROM t1 WHERE w>=97}
} {97 98 99 100 8}
do_test where-1.33 {
  count {SELECT w FROM t1 WHERE w==97}
} {97 3}
do_test where-1.34 {
  count {SELECT w FROM t1 WHERE w+1==98}
} {97 99}
do_test where-1.35 {
  count {SELECT w FROM t1 WHERE w<3}
} {1 2 4}
do_test where-1.36 {
  count {SELECT w FROM t1 WHERE w<=3}
} {1 2 3 6}
do_test where-1.37 {
  count {SELECT w FROM t1 WHERE w+1<=4 ORDER BY w}
} {1 2 3 199}

do_test where-1.38 {
  count {SELECT (w) FROM t1 WHERE (w)>(97)}
} {98 99 100 6}
do_test where-1.39 {
  count {SELECT (w) FROM t1 WHERE (w)>=(97)}
} {97 98 99 100 8}
do_test where-1.40 {
  count {SELECT (w) FROM t1 WHERE (w)==(97)}
} {97 3}
do_test where-1.41 {
  count {SELECT (w) FROM t1 WHERE ((w)+(1))==(98)}
} {97 99}


# Do the same kind of thing except use a join as the data source.
#
................................................................................
# Lets do a 3-way join.
#
do_test where-3.1 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=11
  }
} {11 90 11 9}
do_test where-3.2 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=12
  }
} {12 89 12 9}
do_test where-3.3 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE A.w=15 AND B.p=C.w AND B.r=10202-A.y
  }
} {15 86 86 9}

# Test to see that the special case of a constant WHERE clause is
# handled.
#
do_test where-4.1 {
  count {
    SELECT * FROM t1 WHERE 0
................................................................................
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}
do_test where-6.8 {
  cksort {
    SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.2 {
  cksort {
................................................................................
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c,a LIMIT 3
  }
} {1 100 4 sort}
do_test where-6.9.8 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a DESC, c ASC LIMIT 3
  }
} {1 100 4 sort}
do_test where-6.9.9 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a ASC, c DESC LIMIT 3
  }
} {1 100 4 sort}
do_test where-6.10 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.11 {
  cksort {







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#    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 testing the use of indices in WHERE clases.
#
# $Id: where.test,v 1.26 2004/12/19 00:11:36 drh Exp $

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

# Build some test data
#
do_test where-1.0 {
................................................................................
do_test where-1.29 {
  count {SELECT w FROM t1 WHERE y==121}
} {10 99}


do_test where-1.30 {
  count {SELECT w FROM t1 WHERE w>97}
} {98 99 100 3}
do_test where-1.31 {
  count {SELECT w FROM t1 WHERE w>=97}
} {97 98 99 100 4}
do_test where-1.33 {
  count {SELECT w FROM t1 WHERE w==97}
} {97 2}
do_test where-1.34 {
  count {SELECT w FROM t1 WHERE w+1==98}
} {97 99}
do_test where-1.35 {
  count {SELECT w FROM t1 WHERE w<3}
} {1 2 2}
do_test where-1.36 {
  count {SELECT w FROM t1 WHERE w<=3}
} {1 2 3 3}
do_test where-1.37 {
  count {SELECT w FROM t1 WHERE w+1<=4 ORDER BY w}
} {1 2 3 99}

do_test where-1.38 {
  count {SELECT (w) FROM t1 WHERE (w)>(97)}
} {98 99 100 3}
do_test where-1.39 {
  count {SELECT (w) FROM t1 WHERE (w)>=(97)}
} {97 98 99 100 4}
do_test where-1.40 {
  count {SELECT (w) FROM t1 WHERE (w)==(97)}
} {97 2}
do_test where-1.41 {
  count {SELECT (w) FROM t1 WHERE ((w)+(1))==(98)}
} {97 99}


# Do the same kind of thing except use a join as the data source.
#
................................................................................
# Lets do a 3-way join.
#
do_test where-3.1 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=11
  }
} {11 90 11 8}
do_test where-3.2 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=12
  }
} {12 89 12 8}
do_test where-3.3 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE A.w=15 AND B.p=C.w AND B.r=10202-A.y
  }
} {15 86 86 8}

# Test to see that the special case of a constant WHERE clause is
# handled.
#
do_test where-4.1 {
  count {
    SELECT * FROM t1 WHERE 0
................................................................................
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}
do_test where-6.8 {
  cksort {
    SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.2 {
  cksort {
................................................................................
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c,a LIMIT 3
  }
} {1 100 4 sort}
do_test where-6.9.8 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a DESC, c ASC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.9 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a ASC, c DESC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.10 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.11 {
  cksort {