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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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Overview
Comment:Split the OP_Integer opcode into OP_Integer and OP_Int64. This allows comments to be added to OP_Integer. Cleanup in the optimizer. Allow terms of the FROM clause to be reordered automatically. (CVS 2556)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: e2f822ac82d0a5a59de0b63cce65d4fd6c178ff1
User & Date: drh 2005-07-21 18:23:20
Context
2005-07-22
00:31
Begin adding code to support multiple IN constraints on the same index. (CVS 2557) check-in: 103f8ccb user: drh tags: trunk
2005-07-21
18:23
Split the OP_Integer opcode into OP_Integer and OP_Int64. This allows comments to be added to OP_Integer. Cleanup in the optimizer. Allow terms of the FROM clause to be reordered automatically. (CVS 2556) check-in: e2f822ac user: drh tags: trunk
03:48
Add comments to test cases. Improvements to the query plan test variable. (CVS 2555) check-in: ef3a157f user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/build.c.

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**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.331 2005/07/21 03:15:00 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, tnum, pIndex->iDb);
  }
  sqlite3VdbeAddOp(v, OP_Integer, pIndex->iDb, 0);
  sqlite3VdbeOp3(v, OP_OpenWrite, iIdx, tnum,
                    (char*)&pIndex->keyInfo, P3_KEYINFO);
  sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
  sqlite3VdbeAddOp(v, OP_OpenRead, iTab, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, iTab, pTab->nCol);
  addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
  sqlite3GenerateIndexKey(v, pIndex, iTab);
  if( pIndex->onError!=OE_None ){
    int curaddr = sqlite3VdbeCurrentAddr(v);
    int addr2 = curaddr+4;
    sqlite3VdbeChangeP2(v, curaddr-1, addr2);
    sqlite3VdbeAddOp(v, OP_Rowid, iTab, 0);
................................................................................
    sqliteFree(pItem->zDatabase);
    sqliteFree(pItem->zName);
    sqliteFree(pItem->zAlias);
    sqlite3DeleteTable(0, pItem->pTab);
    sqlite3SelectDelete(pItem->pSelect);
    sqlite3ExprDelete(pItem->pOn);
    sqlite3IdListDelete(pItem->pUsing);
    sqlite3WhereIdxListDelete(pItem->pWIdx);
  }
  sqliteFree(pList);
}

/*
** Begin a transaction
*/







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**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.332 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
  }else{
    tnum = pIndex->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, tnum, pIndex->iDb);
  }
  sqlite3VdbeAddOp(v, OP_Integer, pIndex->iDb, 0);
  sqlite3VdbeOp3(v, OP_OpenWrite, iIdx, tnum,
                    (char*)&pIndex->keyInfo, P3_KEYINFO);
  sqlite3OpenTableForReading(v, iTab, pTab);


  addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iTab, 0);
  sqlite3GenerateIndexKey(v, pIndex, iTab);
  if( pIndex->onError!=OE_None ){
    int curaddr = sqlite3VdbeCurrentAddr(v);
    int addr2 = curaddr+4;
    sqlite3VdbeChangeP2(v, curaddr-1, addr2);
    sqlite3VdbeAddOp(v, OP_Rowid, iTab, 0);
................................................................................
    sqliteFree(pItem->zDatabase);
    sqliteFree(pItem->zName);
    sqliteFree(pItem->zAlias);
    sqlite3DeleteTable(0, pItem->pTab);
    sqlite3SelectDelete(pItem->pSelect);
    sqlite3ExprDelete(pItem->pOn);
    sqlite3IdListDelete(pItem->pUsing);

  }
  sqliteFree(pList);
}

/*
** Begin a transaction
*/

Changes to src/delete.c.

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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 contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.108 2005/07/08 13:08:00 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
*/
void sqlite3OpenTableForReading(
  Vdbe *v,        /* Generate code into this VDBE */
  int iCur,       /* The cursor number of the table */
  Table *pTab     /* The table to be opened */
){
  sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
  sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum);
  VdbeComment((v, "# %s", pTab->zName));

  sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}


/*
** Generate code for a DELETE FROM statement.
**







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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 contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.109 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
*/
void sqlite3OpenTableForReading(
  Vdbe *v,        /* Generate code into this VDBE */
  int iCur,       /* The cursor number of the table */
  Table *pTab     /* The table to be opened */
){
  sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);

  VdbeComment((v, "# %s", pTab->zName));
  sqlite3VdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
}


/*
** Generate code for a DELETE FROM statement.
**

Changes to src/expr.c.

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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 contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.212 2005/07/21 03:15:00 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    pTab = pNewItem->pTab = pOldItem->pTab;
    if( pTab ){
      pTab->nRef++;
    }
    pNewItem->pSelect = sqlite3SelectDup(pOldItem->pSelect);
    pNewItem->pOn = sqlite3ExprDup(pOldItem->pOn);
    pNewItem->pUsing = sqlite3IdListDup(pOldItem->pUsing);
    pNewItem->pWIdx = 0;
    pNewItem->colUsed = pOldItem->colUsed;
  }
  return pNew;
}
IdList *sqlite3IdListDup(IdList *p){
  IdList *pNew;
  int i;
................................................................................
** text z[0..n-1] on the stack.
*/
static void codeInteger(Vdbe *v, const char *z, int n){
  int i;
  if( sqlite3GetInt32(z, &i) ){
    sqlite3VdbeAddOp(v, OP_Integer, i, 0);
  }else if( sqlite3FitsIn64Bits(z) ){
    sqlite3VdbeOp3(v, OP_Integer, 0, 0, z, n);
  }else{
    sqlite3VdbeOp3(v, OP_Real, 0, 0, z, n);
  }
}

/*
** Generate code into the current Vdbe to evaluate the given







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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 contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.213 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    pTab = pNewItem->pTab = pOldItem->pTab;
    if( pTab ){
      pTab->nRef++;
    }
    pNewItem->pSelect = sqlite3SelectDup(pOldItem->pSelect);
    pNewItem->pOn = sqlite3ExprDup(pOldItem->pOn);
    pNewItem->pUsing = sqlite3IdListDup(pOldItem->pUsing);

    pNewItem->colUsed = pOldItem->colUsed;
  }
  return pNew;
}
IdList *sqlite3IdListDup(IdList *p){
  IdList *pNew;
  int i;
................................................................................
** text z[0..n-1] on the stack.
*/
static void codeInteger(Vdbe *v, const char *z, int n){
  int i;
  if( sqlite3GetInt32(z, &i) ){
    sqlite3VdbeAddOp(v, OP_Integer, i, 0);
  }else if( sqlite3FitsIn64Bits(z) ){
    sqlite3VdbeOp3(v, OP_Int64, 0, 0, z, n);
  }else{
    sqlite3VdbeOp3(v, OP_Real, 0, 0, z, n);
  }
}

/*
** Generate code into the current Vdbe to evaluate the given

Changes to src/insert.c.

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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 contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.141 2005/07/08 17:13:47 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  Index *pIdx;
  Vdbe *v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
  sqlite3VdbeAddOp(v, op, base, pTab->tnum);
  VdbeComment((v, "# %s", pTab->zName));

  sqlite3VdbeAddOp(v, OP_SetNumColumns, base, pTab->nCol);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0);

    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}







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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 contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.142 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  Index *pIdx;
  Vdbe *v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);

  VdbeComment((v, "# %s", pTab->zName));
  sqlite3VdbeAddOp(v, op, base, pTab->tnum);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, base, pTab->nCol);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}

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 1.395 2005/07/21 03:15:00 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 Select Select;
typedef struct SrcList SrcList;
typedef struct Table Table;
typedef struct Token Token;
typedef struct TriggerStack TriggerStack;
typedef struct TriggerStep TriggerStep;
typedef struct Trigger Trigger;
typedef struct WhereIdx WhereIdx;
typedef struct WhereInfo WhereInfo;
typedef struct WhereLevel WhereLevel;

/*
** 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
................................................................................
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    u8 jointype;      /* Type of join between this table and the next */
    i16 iCursor;      /* The VDBE cursor number used to access this table */
    Expr *pOn;        /* The ON clause of a join */
    IdList *pUsing;   /* The USING clause of a join */
    WhereIdx *pWIdx;  /* List of structures used by the optimizer */
    Bitmask colUsed;  /* Bit N (1<<N) set if column N or pTab is used */
  } a[1];             /* One entry for each identifier on the list */
};

/*
** Permitted values of the SrcList.a.jointype field
*/
................................................................................
/*
** 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 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 */
  int flags;           /* Flags associated with this level */
};

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
................................................................................
void sqlite3AlterFinishAddColumn(Parse *, Token *);
void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
const char *sqlite3TestErrorName(int);
CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);
char sqlite3AffinityType(const Token*);
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);
void sqlite3WhereIdxListDelete(WhereIdx*);

#ifdef SQLITE_SSE
#include "sseInt.h"
#endif

#endif







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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 1.396 2005/07/21 18:23:20 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 Select Select;
typedef struct SrcList SrcList;
typedef struct Table Table;
typedef struct Token Token;
typedef struct TriggerStack TriggerStack;
typedef struct TriggerStep TriggerStep;
typedef struct Trigger Trigger;

typedef struct WhereInfo WhereInfo;
typedef struct WhereLevel WhereLevel;

/*
** 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
................................................................................
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    u8 jointype;      /* Type of join between this table and the next */
    i16 iCursor;      /* The VDBE cursor number used to access this table */
    Expr *pOn;        /* The ON clause of a join */
    IdList *pUsing;   /* The USING clause of a join */

    Bitmask colUsed;  /* Bit N (1<<N) set if column N or pTab is used */
  } a[1];             /* One entry for each identifier on the list */
};

/*
** Permitted values of the SrcList.a.jointype field
*/
................................................................................
/*
** 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 iFrom;            /* Which entry in the FROM clause */
  int flags;            /* Flags associated with this level */
  int iMem;             /* Memory cell used by this level */
  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
  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 brk;              /* Jump here to break out of the loop */
  int cont;             /* Jump here to continue with the next loop cycle */


  int top;              /* First instruction of interior of the loop */
  int op, p1, p2;       /* Opcode used to terminate the loop */
  int inOp, inP1, inP2; /* Opcode used to implement an IN operator */

};

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
................................................................................
void sqlite3AlterFinishAddColumn(Parse *, Token *);
void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
const char *sqlite3TestErrorName(int);
CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);
char sqlite3AffinityType(const Token*);
void sqlite3Analyze(Parse*, Token*, Token*);
int sqlite3InvokeBusyHandler(BusyHandler*);


#ifdef SQLITE_SSE
#include "sseInt.h"
#endif

#endif

Changes to src/update.c.

8
9
10
11
12
13
14
15
16
17
18
19
20
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22
..
43
44
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47
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50



51
52
53
54
55
56
57
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.109 2005/07/08 13:08:00 drh Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve column
** 'i' of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
  if( pTab && !pTab->pSelect ){
    sqlite3_value *pValue;
    u8 enc = sqlite3VdbeDb(v)->enc;
    Column *pCol = &pTab->aCol[i];
    sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);

    sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);



  }
}

/*
** Process an UPDATE statement.
**
**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;







|







 







>
|
>
>
>







8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
..
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.110 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** The most recently coded instruction was an OP_Column to retrieve column
** 'i' of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
................................................................................
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
  if( pTab && !pTab->pSelect ){
    sqlite3_value *pValue;
    u8 enc = sqlite3VdbeDb(v)->enc;
    Column *pCol = &pTab->aCol[i];
    sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);
    if( pValue ){
      sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
    }else{
      VdbeComment((v, "# %s.%s", pTab->zName, pCol->zName));
    }
  }
}

/*
** Process an UPDATE statement.
**
**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;

Changes to src/vdbe.c.

39
40
41
42
43
44
45
46
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48
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50
51
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53
...
666
667
668
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686






687




688
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....
1824
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1831
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....
2024
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2031

2032
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....
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
**
** 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 1.475 2005/07/09 02:16:03 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  if( rc==SQLITE_BUSY ){
    p->rc = SQLITE_BUSY;
    return SQLITE_BUSY;
  }
  return p->rc ? SQLITE_ERROR : SQLITE_DONE;
}

/* Opcode: Integer P1 * P3
**
** The integer value P1 is pushed onto the stack.  If P3 is not zero
** then it is assumed to be a string representation of the same integer.
** If P1 is zero and P3 is not zero, then the value is derived from P3.
**
** If the value cannot be represented as a 32-bits then its value
** will be in P3.
*/
case OP_Integer: {
  pTos++;
  if( pOp->p3==0 ){
    pTos->flags = MEM_Int;
    pTos->i = pOp->p1;






  }else{




    pTos->flags = MEM_Str|MEM_Static|MEM_Term;
    pTos->z = pOp->p3;
    pTos->n = strlen(pTos->z);
    pTos->enc = SQLITE_UTF8;
    pTos->i = sqlite3VdbeIntValue(pTos);
    pTos->flags |= MEM_Int;
  }
  break;
}

/* Opcode: Real * * P3
**
** The string value P3 is converted to a real and pushed on to the stack.
*/
................................................................................
**
** 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 */
................................................................................
      pC->cacheValid = 1;
    }
  }

  /* Get the column information. If aOffset[p2] is non-zero, then 
  ** deserialize the value from the record. If aOffset[p2] is zero,
  ** then there are not enough fields in the record to satisfy the
  ** request. The value is NULL in this case.

  */
  if( aOffset[p2] ){
    assert( rc==SQLITE_OK );
    if( zRec ){
      zData = &zRec[aOffset[p2]];
    }else{
      len = sqlite3VdbeSerialTypeLen(aType[p2]);
................................................................................
        goto op_column_out;
      }
      zData = sMem.z;
    }
    sqlite3VdbeSerialGet(zData, aType[p2], pTos);
    pTos->enc = db->enc;
  }else{
    if( pOp->p3 ){
      sqlite3VdbeMemShallowCopy(pTos, (Mem *)(pOp->p3), MEM_Static);
    }else{
      pTos->flags = MEM_Null;
    }
  }

  /* If we dynamically allocated space to hold the data (in the







|







 







|

|
<
<
<
<
<



<
|
|
>
>
>
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>
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>
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|
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|
<







 







>
>
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>
>
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>







 







|
>







 







|







39
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53
...
666
667
668
669
670
671
672
673
674
675





676
677
678

679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697

698
699
700
701
702
703
704
....
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
....
2034
2035
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2037
2038
2039
2040
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2043
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2045
2046
2047
2048
2049
....
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
**
** 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 1.476 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  if( rc==SQLITE_BUSY ){
    p->rc = SQLITE_BUSY;
    return SQLITE_BUSY;
  }
  return p->rc ? SQLITE_ERROR : SQLITE_DONE;
}

/* Opcode: Integer P1 * *
**
** The 32-bit integer value P1 is pushed onto the stack.





*/
case OP_Integer: {
  pTos++;

  pTos->flags = MEM_Int;
  pTos->i = pOp->p1;
  break;
}

/* Opcode: Int64 * * P3
**
** P3 is a string representation of an integer.  Convert that integer
** to a 64-bit value and push it onto the stack.
*/
case OP_Int64: {
  pTos++;
  assert( pOp->p3!=0 );
  pTos->flags = MEM_Str|MEM_Static|MEM_Term;
  pTos->z = pOp->p3;
  pTos->n = strlen(pTos->z);
  pTos->enc = SQLITE_UTF8;
  pTos->i = sqlite3VdbeIntValue(pTos);
  pTos->flags |= MEM_Int;

  break;
}

/* Opcode: Real * * P3
**
** The string value P3 is converted to a real and pushed on to the stack.
*/
................................................................................
**
** 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.
**
** If the column contains fewer than P2 fields, then push a NULL.  Or
** if P3 is of type P3_MEM, then push the P3 value.  The P3 value will
** be default value for a column that has been added using the ALTER TABLE
** ADD COLUMN command.  If P3 is an ordinary string, just push a NULL.
** When P3 is a string it is really just a comment describing the value
** to be pushed, not a default value.
*/
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 */
................................................................................
      pC->cacheValid = 1;
    }
  }

  /* Get the column information. If aOffset[p2] is non-zero, then 
  ** deserialize the value from the record. If aOffset[p2] is zero,
  ** then there are not enough fields in the record to satisfy the
  ** request.  In this case, set the value NULL or to P3 if P3 is
  ** a pointer to a Mem object.
  */
  if( aOffset[p2] ){
    assert( rc==SQLITE_OK );
    if( zRec ){
      zData = &zRec[aOffset[p2]];
    }else{
      len = sqlite3VdbeSerialTypeLen(aType[p2]);
................................................................................
        goto op_column_out;
      }
      zData = sMem.z;
    }
    sqlite3VdbeSerialGet(zData, aType[p2], pTos);
    pTos->enc = db->enc;
  }else{
    if( pOp->p3type==P3_MEM ){
      sqlite3VdbeMemShallowCopy(pTos, (Mem *)(pOp->p3), MEM_Static);
    }else{
      pTos->flags = MEM_Null;
    }
  }

  /* If we dynamically allocated space to hold the data (in the

Changes to src/where.c.

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...
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...
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995
....
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1025
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1066
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1116
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1118
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1120
1121


1122
1123
1124
1125
1126
1127
1128
1129
1130
1131

1132


1133
1134
1135


1136
1137
1138




1139
1140


1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
....
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
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1177
1178
1179
1180
1181
1182
1183
1184
1185
....
1190
1191
1192
1193
1194
1195
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1198
1199
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1201
1202
1203
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1209
1210
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1212
1213
....
1226
1227
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1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
....
1304
1305
1306
1307
1308
1309
1310
1311
1312
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1314
1315
1316
1317
1318
....
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
....
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
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1446
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1448
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1450
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1455
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1457

1458
1459
1460
1461
1462
1463
1464
....
1469
1470
1471
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1474
1475
1476
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1480
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1482
1483
....
1499
1500
1501
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1503
1504
1505
1506
1507

1508
1509
1510
1511
1512
1513
1514
....
1536
1537
1538
1539
1540
1541
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1543


1544
1545
1546
1547
1548
1549
1550
....
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
....
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
....
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
** 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 1.149 2005/07/21 03:48:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8-1)

/*
** Determine the number of elements in an array.
*/
#define ARRAYSIZE(X)  (sizeof(X)/sizeof(X[0]))

/* Forward reference
*/
typedef struct WhereClause WhereClause;

/*
** An instance of the following structure holds information about how well
** a particular index helps in a search.  A list of such structures is
** attached to each SrcList_item of a SrcList.
*/
struct WhereIdx {
  Index *pIdx;      /* The index under consideration */
  Bitmask prereq;   /* Prerequesite FROM clause elements for using this index */
  int nEqTerm;      /* Number of Idx column constrainted by == or IN */
  int nTerm;        /* Total number of Index Columns used */
  int flags;        /* Flags.  See below */
  double rRowEst;   /* Estimated number of rows selected */
  double rScore;    /* Score of this index */
  WhereIdx *pNext;  /* Next WhereIdx on the same FROM clause element */
};

/*
** 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.
**
** All WhereTerms are collected into a single WhereClause structure.  
** The following identity holds:
................................................................................
**      foreach row1 in t1 do       \    Code generated
**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
**          foreach row3 in t3 do   /
**            ...
**          end                     \    Code generated
**        end                        |-- by sqlite3WhereEnd()
**      end                         /




**
** There are Btree cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite3WhereEnd() generates the code to close them.
**
** The code that sqlite3WhereBegin() generates leaves the cursors named
................................................................................
  int brk, cont = 0;         /* Addresses used during code generation */
  Bitmask notReady;          /* Cursors that are not yet positioned */
  WhereTerm *pTerm;          /* A single term in the WHERE clause */
  ExprMaskSet maskSet;       /* The expression mask set */
  WhereClause wc;            /* 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 */


  /* The number of terms in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  if( pTabList->nSrc>sizeof(Bitmask)*8 ){
    sqlite3ErrorMsg(pParse, "at most %d tables in a join",
       sizeof(Bitmask)*8);
    return 0;
  }

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.  If the wc.a[]
  ** array fills up, the last entry might point to an expression which
  ** contains additional unfactored AND operators.
  */
  initMaskSet(&maskSet);
  whereClauseInit(&wc, pParse);
  whereSplit(&wc, pWhere);
    
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
................................................................................
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstant(pWhere)) ){
    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.



  */
  for(i=0; i<pTabList->nSrc; i++){
    createMask(&maskSet, pTabList->a[i].iCursor);
  }
  for(i=wc.nTerm-1; i>=0; i--){
    exprAnalyze(pTabList, &maskSet, &wc.a[i]);
  }

  /* Chose the best index to use for each table in the FROM clause





  */
  notReady = ~(Bitmask)0;
  pTabItem = pTabList->a;
  pLevel = pWInfo->a;
  for(i=0; i<pTabList->nSrc; i++, pTabItem++, pLevel++){
    Index *pBest;
    int flags;
















    bestIndex(pParse, &wc, pTabItem, notReady,
              (i==0 && ppOrderBy) ? *ppOrderBy : 0,
              &pBest, &flags);












    if( flags & WHERE_ORDERBY ){
      *ppOrderBy = 0;
    }
    pLevel->flags = flags;
    pLevel->pIdx = pBest;
    if( pBest ){
      pLevel->iIdxCur = pParse->nTab++;
    }else{
      pLevel->iIdxCur = -1;
    }
    notReady &= ~getMask(&maskSet, pTabItem->iCursor);

  }

  /* 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->flags & WHERE_IDX_ONLY)==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->flags & WHERE_IDX_ONLY)!=0 ){
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, pTab->iDb);

#ifdef SQLITE_TEST
    /* Record in the query plan information about the current table
    ** and the index used to access it (if any).  If the table itself
    ** is not used, its name is just '{}'.  If no index is used
    ** the index is listed as "{}"
    */
    {
      char *z = pTabItem->zAlias;
      int n;
      if( z==0 ) z = pTab->zName;
      n = strlen(z);
      if( n+nQPlan < sizeof(sqlite3_query_plan)-10 ){
        if( pLevel->flags & WHERE_IDX_ONLY ){
          strcpy(&sqlite3_query_plan[nQPlan], "{}");
          nQPlan += 2;
        }else{
          strcpy(&sqlite3_query_plan[nQPlan], z);
          nQPlan += n;
        }
        sqlite3_query_plan[nQPlan++] = ' ';
      }
      if( pIx==0 ){
        strcpy(&sqlite3_query_plan[nQPlan], " {}");
        nQPlan += 3;
      }else{
        n = strlen(pIx->zName);
        if( n+nQPlan < sizeof(sqlite3_query_plan)-2 ){
          strcpy(&sqlite3_query_plan[nQPlan], pIx->zName);
          nQPlan += n;
          sqlite3_query_plan[nQPlan++] = ' ';
        }
      }
    }
#endif
  }
  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);

#ifdef SQLITE_TEST
  /* Terminate the query plan description
  */
  while( nQPlan>0 && sqlite3_query_plan[nQPlan-1]==' ' ){
    sqlite3_query_plan[--nQPlan] = 0;
  }
  sqlite3_query_plan[nQPlan] = 0;
  nQPlan = 0;
#endif

  /* Generate the code to do the search


  */
  notReady = ~(Bitmask)0;
  pLevel = pWInfo->a;
  pTabItem = pTabList->a;
  for(i=0; i<pTabList->nSrc; i++, pTabItem++, pLevel++){
    int j;
    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->flags & WHERE_IDX_ONLY)!=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_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# init LEFT JOIN no-match flag"));
    }

................................................................................
      **          construct.
      */
      pTerm = findTerm(&wc, iCur, -1, notReady, WO_EQ|WO_IN, 0);
      assert( pTerm!=0 );
      assert( pTerm->pExpr!=0 );
      assert( pTerm->leftCursor==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);
      VdbeComment((v, "pk"));
      pLevel->op = OP_Noop;
    }else if( pLevel->flags & WHERE_COLUMN_EQ ){
      /* 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;
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

      /* For each column of the index, find the term of the WHERE clause that
      ** constraints that column.  If the WHERE clause term is X=expr, then
      ** generate code to evaluate expr and leave the result on the stack */
      for(j=0; 1; j++){
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, WO_EQ|WO_IN, pIdx);
................................................................................
        if( pTerm->operator==WO_IN ){
          j++;
          break;
        }
      }
      nColumn = j;
      pLevel->iMem = pParse->nMem++;
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      buildIndexProbe(v, nColumn, brk, pIdx);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);

      /* 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->flags & WHERE_REVERSE ){
        /* 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 */
................................................................................
      pLevel->p2 = start;
    }else if( pLevel->flags & WHERE_ROWID_RANGE ){
      /* Case 3:  We have an inequality comparison against the ROWID field.
      */
      int testOp = OP_Noop;
      int start;
      WhereTerm *pStart, *pEnd;
      int bRev = (pLevel->flags & WHERE_REVERSE)!=0;

      assert( omitTable==0 );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( pLevel->flags & WHERE_BTM_LIMIT ){
        pStart = findTerm(&wc, iCur, -1, notReady, WO_GT|WO_GE, 0);
        assert( pStart!=0 );
      }else{
        pStart = 0;
      }
      if( pLevel->flags & WHERE_TOP_LIMIT ){
................................................................................
      */
      int nEqColumn;
      int start;
      int leFlag=0, geFlag=0;
      int testOp;
      int topLimit = (pLevel->flags & WHERE_TOP_LIMIT)!=0;
      int btmLimit = (pLevel->flags & WHERE_BTM_LIMIT)!=0;
      int bRev = (pLevel->flags & WHERE_REVERSE)!=0;

      /* Evaluate the equality constraints
      */
      for(j=0; 1; j++){
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, WO_EQ, pIdx);
        if( pTerm==0 ) break;
................................................................................
      ** used twice: once to make the termination key and once to make the
      ** start key.
      */
      for(j=0; j<nEqColumn; j++){
        sqlite3VdbeAddOp(v, OP_Dup, nEqColumn-1, 0);
      }

      /* Labels for the beginning and end of the loop
      */
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

      /* Generate the termination key.  This is the key value that
      ** will end the search.  There is no termination key if there
      ** are no equality terms and no "X<..." term.
      **
      ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
      ** key computed here really ends up being the start key.
      */
................................................................................
      pLevel->op = bRev ? OP_Prev : OP_Next;
      pLevel->p1 = iIdxCur;
      pLevel->p2 = start;
    }else{
      /* Case 5:  There is no usable index.  We must do a complete
      **          scan of the entire table.
      */
      int start;
      int opRewind;

      assert( omitTable==0 );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( pLevel->flags & WHERE_REVERSE ){
        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;

    }
    notReady &= ~getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(pTerm=wc.a, j=wc.nTerm; j>0; j--, pTerm++){
................................................................................
      assert( pE!=0 );
      if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
        continue;
      }
      sqlite3ExprIfFalse(pParse, pE, cont, 1);
      pTerm->flags |= TERM_CODED;
    }
    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.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
................................................................................
  ** is not used, its name is just '{}'.  If no index is used
  ** the index is listed as "{}".  If the primary key is used the
  ** index name is '*'.
  */
  for(i=0; i<pTabList->nSrc; i++){
    char *z;
    int n;
    pTabItem = &pTabList->a[i];
    pLevel = &pWInfo->a[i];

    z = pTabItem->zAlias;
    if( z==0 ) z = pTabItem->pTab->zName;
    n = strlen(z);
    if( n+nQPlan < sizeof(sqlite3_query_plan)-10 ){
      if( pLevel->flags & WHERE_IDX_ONLY ){
        strcpy(&sqlite3_query_plan[nQPlan], "{}");
        nQPlan += 2;
................................................................................
  while( nQPlan>0 && sqlite3_query_plan[nQPlan-1]==' ' ){
    sqlite3_query_plan[--nQPlan] = 0;
  }
  sqlite3_query_plan[nQPlan] = 0;
  nQPlan = 0;
#endif /* SQLITE_TEST // Testing and debugging use only */




  pWInfo->iContinue = cont;
  freeMaskSet(&maskSet);
  whereClauseClear(&wc);
  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 ){
................................................................................
  }

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

  /* Close all of the cursors that were opend by sqlite3WhereBegin.
  */
  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->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3VdbeAddOp(v, OP_Close, pTabItem->iCursor, 0);
    }
    if( pLevel->pIdx!=0 ){
................................................................................
  }

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


/*
** Delete a list of WhereIdx structures.
*/
void sqlite3WhereIdxListDelete(WhereIdx *p){
  WhereIdx *pNext;
  while( p ){
    pNext = p->pNext;
    sqliteFree(p);
    p = pNext;
  }
}







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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 1.150 2005/07/21 18:23:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

/*
** Determine the number of elements in an array.
*/
#define ARRAYSIZE(X)  (sizeof(X)/sizeof(X[0]))

/* Forward reference
*/
typedef struct WhereClause WhereClause;

















/*
** 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.
**
** All WhereTerms are collected into a single WhereClause structure.  
** The following identity holds:
................................................................................
**      foreach row1 in t1 do       \    Code generated
**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
**          foreach row3 in t3 do   /
**            ...
**          end                     \    Code generated
**        end                        |-- by sqlite3WhereEnd()
**      end                         /
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.
**
** There are Btree cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite3WhereEnd() generates the code to close them.
**
** The code that sqlite3WhereBegin() generates leaves the cursors named
................................................................................
  int brk, cont = 0;         /* Addresses used during code generation */
  Bitmask notReady;          /* Cursors that are not yet positioned */
  WhereTerm *pTerm;          /* A single term in the WHERE clause */
  ExprMaskSet maskSet;       /* The expression mask set */
  WhereClause wc;            /* 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 */
  int iFrom;                      /* First unused FROM clause element */

  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  if( pTabList->nSrc>BMS ){
    sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);

    return 0;
  }

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.


  */
  initMaskSet(&maskSet);
  whereClauseInit(&wc, pParse);
  whereSplit(&wc, pWhere);
    
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
................................................................................
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstant(pWhere)) ){
    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
  ** add new virtual terms onto the end of the WHERE clause.  We do not
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that they added virtual terms are never processed.
  */
  for(i=0; i<pTabList->nSrc; i++){
    createMask(&maskSet, pTabList->a[i].iCursor);
  }
  for(i=wc.nTerm-1; i>=0; i--){
    exprAnalyze(pTabList, &maskSet, &wc.a[i]);
  }

  /* Chose the best index to use for each table in the FROM clause.
  **
  ** This loop fills in the pWInfo->a[].pIdx and pWInfo->a[].flags fields
  ** with information
  ** Reorder tables if necessary in order to choose a good ordering.
  ** However, LEFT JOIN tables cannot be reordered.
  */
  notReady = ~(Bitmask)0;
  pTabItem = pTabList->a;
  pLevel = pWInfo->a;
  for(i=iFrom=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){


    Index *pIdx;                /* Index for FROM table at pTabItem */
    int flags;                  /* Flags asssociated with pIdx */
    double score;               /* The score for pIdx */
    int j;                      /* For looping over FROM tables */
    Index *pBest = 0;           /* The best index seen so far */
    int bestFlags = 0;          /* Flags associated with pBest */
    double bestScore = -1.0;    /* The score of pBest */
    int bestJ;                  /* The value of j */
    Bitmask m;                  /* Bitmask value for j or bestJ */

    for(j=iFrom, pTabItem=&pTabList->a[j]; j<pTabList->nSrc; j++, pTabItem++){
      m = getMask(&maskSet, pTabItem->iCursor);
      if( (m & notReady)==0 ){
        if( j==iFrom ) iFrom++;
        continue;
      }
      score = bestIndex(pParse, &wc, pTabItem, notReady,
                        (j==0 && ppOrderBy) ? *ppOrderBy : 0,
                        &pIdx, &flags);
      if( score>bestScore ){
        bestScore = score;
        pBest = pIdx;
        bestFlags = flags;
        bestJ = j;
      }
      if( (pTabItem->jointype & JT_LEFT)!=0
         || (j>0 && (pTabItem[-1].jointype & JT_LEFT)!=0)
      ){
        break;
      }
    }
    if( bestFlags & WHERE_ORDERBY ){
      *ppOrderBy = 0;
    }
    pLevel->flags = bestFlags;
    pLevel->pIdx = pBest;
    if( pBest ){
      pLevel->iIdxCur = pParse->nTab++;
    }else{
      pLevel->iIdxCur = -1;
    }
    notReady &= ~getMask(&maskSet, pTabList->a[bestJ].iCursor);
    pLevel->iFrom = bestJ;
  }

  /* 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, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
    Table *pTab;
    Index *pIx;
    int iIdxCur = pLevel->iIdxCur;

    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;
    if( pTab->isTransient || pTab->pSelect ) continue;
    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3OpenTableForReading(v, pTabItem->iCursor, pTab);
    }
    pLevel->iTabCur = pTabItem->iCursor;
    if( (pIx = pLevel->pIdx)!=0 ){
      sqlite3VdbeAddOp(v, OP_Integer, pIx->iDb, 0);
      VdbeComment((v, "# %s", pIx->zName));
      sqlite3VdbeOp3(v, OP_OpenRead, iIdxCur, pIx->tnum,
                     (char*)&pIx->keyInfo, P3_KEYINFO);
    }
    if( (pLevel->flags & WHERE_IDX_ONLY)!=0 ){
      sqlite3VdbeAddOp(v, OP_SetNumColumns, iIdxCur, pIx->nColumn+1);
    }
    sqlite3CodeVerifySchema(pParse, pTab->iDb);
  }



































  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);











  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */
  notReady = ~(Bitmask)0;


  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
    int j;
    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 */
    int bRev;          /* True if we need to scan in reverse order */

    pTabItem = &pTabList->a[pLevel->iFrom];
    iCur = pTabItem->iCursor;
    pIdx = pLevel->pIdx;
    iIdxCur = pLevel->iIdxCur;
    pLevel->inOp = OP_Noop;
    bRev = (pLevel->flags & WHERE_REVERSE)!=0;
    omitTable = (pLevel->flags & WHERE_IDX_ONLY)!=0;



    /* Create labels for the "break" and "continue" instructions
    ** for the current loop.  Jump to brk to break out of a loop.
    ** Jump to cont to go immediately to the next iteration of the
    ** loop.
    */

    brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
    cont = pLevel->cont = sqlite3VdbeMakeLabel(v);

    /* 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( pLevel->iFrom>0 && (pTabItem[-1].jointype & JT_LEFT)!=0 ){
      if( !pParse->nMem ) pParse->nMem++;
      pLevel->iLeftJoin = pParse->nMem++;
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      VdbeComment((v, "# init LEFT JOIN no-match flag"));
    }

................................................................................
      **          construct.
      */
      pTerm = findTerm(&wc, iCur, -1, notReady, WO_EQ|WO_IN, 0);
      assert( pTerm!=0 );
      assert( pTerm->pExpr!=0 );
      assert( pTerm->leftCursor==iCur );
      assert( omitTable==0 );

      codeEqualityTerm(pParse, pTerm, brk, pLevel);

      sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);
      sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);
      VdbeComment((v, "pk"));
      pLevel->op = OP_Noop;
    }else if( pLevel->flags & WHERE_COLUMN_EQ ){
      /* 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;


      /* For each column of the index, find the term of the WHERE clause that
      ** constraints that column.  If the WHERE clause term is X=expr, then
      ** generate code to evaluate expr and leave the result on the stack */
      for(j=0; 1; j++){
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, WO_EQ|WO_IN, pIdx);
................................................................................
        if( pTerm->operator==WO_IN ){
          j++;
          break;
        }
      }
      nColumn = j;
      pLevel->iMem = pParse->nMem++;

      buildIndexProbe(v, nColumn, brk, pIdx);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);

      /* 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( 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 */
................................................................................
      pLevel->p2 = start;
    }else if( pLevel->flags & WHERE_ROWID_RANGE ){
      /* Case 3:  We have an inequality comparison against the ROWID field.
      */
      int testOp = OP_Noop;
      int start;
      WhereTerm *pStart, *pEnd;


      assert( omitTable==0 );


      if( pLevel->flags & WHERE_BTM_LIMIT ){
        pStart = findTerm(&wc, iCur, -1, notReady, WO_GT|WO_GE, 0);
        assert( pStart!=0 );
      }else{
        pStart = 0;
      }
      if( pLevel->flags & WHERE_TOP_LIMIT ){
................................................................................
      */
      int nEqColumn;
      int start;
      int leFlag=0, geFlag=0;
      int testOp;
      int topLimit = (pLevel->flags & WHERE_TOP_LIMIT)!=0;
      int btmLimit = (pLevel->flags & WHERE_BTM_LIMIT)!=0;


      /* Evaluate the equality constraints
      */
      for(j=0; 1; j++){
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, WO_EQ, pIdx);
        if( pTerm==0 ) break;
................................................................................
      ** used twice: once to make the termination key and once to make the
      ** start key.
      */
      for(j=0; j<nEqColumn; j++){
        sqlite3VdbeAddOp(v, OP_Dup, nEqColumn-1, 0);
      }






      /* Generate the termination key.  This is the key value that
      ** will end the search.  There is no termination key if there
      ** are no equality terms and no "X<..." term.
      **
      ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
      ** key computed here really ends up being the start key.
      */
................................................................................
      pLevel->op = bRev ? OP_Prev : OP_Next;
      pLevel->p1 = iIdxCur;
      pLevel->p2 = start;
    }else{
      /* Case 5:  There is no usable index.  We must do a complete
      **          scan of the entire table.
      */

      int opRewind;

      assert( omitTable==0 );
      if( bRev ){


        opRewind = OP_Last;
        pLevel->op = OP_Prev;
      }else{
        opRewind = OP_Rewind;
        pLevel->op = OP_Next;
      }


      pLevel->p1 = iCur;

      pLevel->p2 = 1 + sqlite3VdbeAddOp(v, opRewind, iCur, brk);
    }
    notReady &= ~getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(pTerm=wc.a, j=wc.nTerm; j>0; j--, pTerm++){
................................................................................
      assert( pE!=0 );
      if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
        continue;
      }
      sqlite3ExprIfFalse(pParse, pE, cont, 1);
      pTerm->flags |= TERM_CODED;
    }


    /* 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.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
................................................................................
  ** is not used, its name is just '{}'.  If no index is used
  ** the index is listed as "{}".  If the primary key is used the
  ** index name is '*'.
  */
  for(i=0; i<pTabList->nSrc; i++){
    char *z;
    int n;

    pLevel = &pWInfo->a[i];
    pTabItem = &pTabList->a[pLevel->iFrom];
    z = pTabItem->zAlias;
    if( z==0 ) z = pTabItem->pTab->zName;
    n = strlen(z);
    if( n+nQPlan < sizeof(sqlite3_query_plan)-10 ){
      if( pLevel->flags & WHERE_IDX_ONLY ){
        strcpy(&sqlite3_query_plan[nQPlan], "{}");
        nQPlan += 2;
................................................................................
  while( nQPlan>0 && sqlite3_query_plan[nQPlan-1]==' ' ){
    sqlite3_query_plan[--nQPlan] = 0;
  }
  sqlite3_query_plan[nQPlan] = 0;
  nQPlan = 0;
#endif /* SQLITE_TEST // Testing and debugging use only */

  /* Record the continuation address in the WhereInfo structure.  Then
  ** clean up and return.
  */
  pWInfo->iContinue = cont;
  freeMaskSet(&maskSet);
  whereClauseClear(&wc);
  return pWInfo;
}

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


  /* 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 ){
................................................................................
  }

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

  /* Close all of the cursors that were opened by sqlite3WhereBegin.
  */
  for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
    struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];

    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    if( pTab->isTransient || pTab->pSelect ) continue;
    if( (pLevel->flags & WHERE_IDX_ONLY)==0 ){
      sqlite3VdbeAddOp(v, OP_Close, pTabItem->iCursor, 0);
    }
    if( pLevel->pIdx!=0 ){
................................................................................
  }

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