/ Check-in [7ab0b258]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Omit all use of Expr nodes for TK_AS, as those nodes no longer served a useful purpose and in fact interferred with the query planner.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 7ab0b258eabfcfb7f1b0bd1b12e166d2f267823d
User & Date: drh 2015-09-05 22:36:07
References
2015-11-24
02:08 New ticket [e5c6268d] Assertion fault on DISTINCT query containing a correlated aggregate.. artifact: 0d68ffc0 user: drh
Context
2015-09-06
02:51
Add a memory barrier to the mutex initialization logic, try to work around an issue reported by WebKit. check-in: 11a9a786 user: drh tags: trunk
2015-09-05
22:36
Omit all use of Expr nodes for TK_AS, as those nodes no longer served a useful purpose and in fact interferred with the query planner. check-in: 7ab0b258 user: drh tags: trunk
19:21
Fix an unreachable conditional in the WHERE clause analysis logic. check-in: 24924a58 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Show Whitespace Changes Patch

Changes to src/expr.c.

87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
....
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
  assert( zC!=0 );
  s.z = zC;
  s.n = sqlite3Strlen30(s.z);
  return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
}

/*
** Skip over any TK_COLLATE or TK_AS operators and any unlikely()
** or likelihood() function at the root of an expression.
*/
Expr *sqlite3ExprSkipCollate(Expr *pExpr){
  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
    if( ExprHasProperty(pExpr, EP_Unlikely) ){
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      assert( pExpr->x.pList->nExpr>0 );
      assert( pExpr->op==TK_FUNCTION );
      pExpr = pExpr->x.pList->a[0].pExpr;
    }else{
      assert( pExpr->op==TK_COLLATE || pExpr->op==TK_AS );
      pExpr = pExpr->pLeft;
    }
  }   
  return pExpr;
}

/*
................................................................................
      }
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }
    case TK_AS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      if( inReg!=target ){
        sqlite3VdbeAddOp2(v, OP_SCopy, inReg, target);
        inReg = target;







|










|







 







<
<
<
<







87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
....
2697
2698
2699
2700
2701
2702
2703




2704
2705
2706
2707
2708
2709
2710
  assert( zC!=0 );
  s.z = zC;
  s.n = sqlite3Strlen30(s.z);
  return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
}

/*
** Skip over any TK_COLLATE operators and any unlikely()
** or likelihood() function at the root of an expression.
*/
Expr *sqlite3ExprSkipCollate(Expr *pExpr){
  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
    if( ExprHasProperty(pExpr, EP_Unlikely) ){
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      assert( pExpr->x.pList->nExpr>0 );
      assert( pExpr->op==TK_FUNCTION );
      pExpr = pExpr->x.pList->a[0].pExpr;
    }else{
      assert( pExpr->op==TK_COLLATE );
      pExpr = pExpr->pLeft;
    }
  }   
  return pExpr;
}

/*
................................................................................
      }
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }




#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      if( inReg!=target ){
        sqlite3VdbeAddOp2(v, OP_SCopy, inReg, target);
        inReg = target;

Changes to src/resolve.c.

41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
..
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117

118
119
120
121
122
123
124
...
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
  }
}

/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy.  But for any other kind of expression, this
** routine make a copy of the result set column as the argument to the
** TK_AS operator.  The TK_AS operator causes the expression to be
** evaluated just once and then reused for each alias.
**
** The reason for suppressing the TK_AS term when the expression is a simple
** column reference is so that the column reference will be recognized as
** usable by indices within the WHERE clause processing logic. 
**
** The TK_AS operator is inhibited if zType[0]=='G'.  This means
** that in a GROUP BY clause, the expression is evaluated twice.  Hence:
**
**     SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
**
** Is equivalent to:
**
**     SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set.  On the other hand Standard SQL does
** not allow the GROUP BY clause to contain references to result-set columns.
** So this should never come up in well-formed queries.
**
** If the reference is followed by a COLLATE operator, then make sure
** the COLLATE operator is preserved.  For example:
**
**     SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
**
** Should be transformed into:
**
................................................................................

  assert( iCol>=0 && iCol<pEList->nExpr );
  pOrig = pEList->a[iCol].pExpr;
  assert( pOrig!=0 );
  db = pParse->db;
  pDup = sqlite3ExprDup(db, pOrig, 0);
  if( pDup==0 ) return;
  if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
    incrAggFunctionDepth(pDup, nSubquery);
    pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
    if( pDup==0 ) return;
    ExprSetProperty(pDup, EP_Skip);
    if( pEList->a[iCol].u.x.iAlias==0 ){
      pEList->a[iCol].u.x.iAlias = (u16)(++pParse->nAlias);
    }
    pDup->iTable = pEList->a[iCol].u.x.iAlias;
  }
  if( pExpr->op==TK_COLLATE ){
    pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
  }


  /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This 
  ** prevents ExprDelete() from deleting the Expr structure itself,
  ** allowing it to be repopulated by the memcpy() on the following line.
  ** The pExpr->u.zToken might point into memory that will be freed by the
  ** sqlite3DbFree(db, pDup) on the last line of this block, so be sure to
  ** make a copy of the token before doing the sqlite3DbFree().
................................................................................
  pExpr->pLeft = 0;
  sqlite3ExprDelete(db, pExpr->pRight);
  pExpr->pRight = 0;
  pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
lookupname_end:
  if( cnt==1 ){
    assert( pNC!=0 );
    if( pExpr->op!=TK_AS ){
      sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
    }
    /* Increment the nRef value on all name contexts from TopNC up to
    ** the point where the name matched. */
    for(;;){
      assert( pTopNC!=0 );
      pTopNC->nRef++;







<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







<
|
<
<
<
<
<
<
<
<



>







 







|







41
42
43
44
45
46
47
























48
49
50
51
52
53
54
..
74
75
76
77
78
79
80

81








82
83
84
85
86
87
88
89
90
91
92
...
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
  }
}

/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
























** If the reference is followed by a COLLATE operator, then make sure
** the COLLATE operator is preserved.  For example:
**
**     SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
**
** Should be transformed into:
**
................................................................................

  assert( iCol>=0 && iCol<pEList->nExpr );
  pOrig = pEList->a[iCol].pExpr;
  assert( pOrig!=0 );
  db = pParse->db;
  pDup = sqlite3ExprDup(db, pOrig, 0);
  if( pDup==0 ) return;

  if( zType[0]!='G' ) incrAggFunctionDepth(pDup, nSubquery);








  if( pExpr->op==TK_COLLATE ){
    pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
  }
  ExprSetProperty(pDup, EP_Alias);

  /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This 
  ** prevents ExprDelete() from deleting the Expr structure itself,
  ** allowing it to be repopulated by the memcpy() on the following line.
  ** The pExpr->u.zToken might point into memory that will be freed by the
  ** sqlite3DbFree(db, pDup) on the last line of this block, so be sure to
  ** make a copy of the token before doing the sqlite3DbFree().
................................................................................
  pExpr->pLeft = 0;
  sqlite3ExprDelete(db, pExpr->pRight);
  pExpr->pRight = 0;
  pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
lookupname_end:
  if( cnt==1 ){
    assert( pNC!=0 );
    if( !ExprHasProperty(pExpr, EP_Alias) ){
      sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
    }
    /* Increment the nRef value on all name contexts from TopNC up to
    ** the point where the name matched. */
    for(;;){
      assert( pTopNC!=0 );
      pTopNC->nRef++;

Changes to src/sqliteInt.h.

2131
2132
2133
2134
2135
2136
2137

2138
2139
2140
2141
2142
2143
2144
#define EP_Static    0x008000 /* Held in memory not obtained from malloc() */
#define EP_MemToken  0x010000 /* Need to sqlite3DbFree() Expr.zToken */
#define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
#define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
#define EP_CanBeNull 0x100000 /* Can be null despite NOT NULL constraint */
#define EP_Subquery  0x200000 /* Tree contains a TK_SELECT operator */


/*
** Combinations of two or more EP_* flags
*/
#define EP_Propagate (EP_Collate|EP_Subquery) /* Propagate these bits up tree */

/*







>







2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
#define EP_Static    0x008000 /* Held in memory not obtained from malloc() */
#define EP_MemToken  0x010000 /* Need to sqlite3DbFree() Expr.zToken */
#define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
#define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
#define EP_CanBeNull 0x100000 /* Can be null despite NOT NULL constraint */
#define EP_Subquery  0x200000 /* Tree contains a TK_SELECT operator */
#define EP_Alias     0x400000 /* Is an alias for a result set column */

/*
** Combinations of two or more EP_* flags
*/
#define EP_Propagate (EP_Collate|EP_Subquery) /* Propagate these bits up tree */

/*

Changes to src/treeview.c.

249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
                          pExpr->u.zToken, pExpr->iColumn);
      break;
    }
    case TK_REGISTER: {
      sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
      break;
    }
    case TK_AS: {
      sqlite3TreeViewLine(pView,"AS %Q", pExpr->u.zToken);
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
      break;
    }
    case TK_ID: {
      sqlite3TreeViewLine(pView,"ID \"%w\"", pExpr->u.zToken);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */







<
<
<
<
<







249
250
251
252
253
254
255





256
257
258
259
260
261
262
                          pExpr->u.zToken, pExpr->iColumn);
      break;
    }
    case TK_REGISTER: {
      sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
      break;
    }





    case TK_ID: {
      sqlite3TreeViewLine(pView,"ID \"%w\"", pExpr->u.zToken);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */

Changes to test/indexexpr1.test.

193
194
195
196
197
198
199
200





















201
    SELECT x, printf('ab%04xyz',x), random() FROM c;
  CREATE UNIQUE INDEX t3abc ON t3(CAST(a AS text), b, substr(c,1,3));
  SELECT a FROM t3 WHERE CAST(a AS text)<='10' ORDER BY +a;
} {1 10}
do_catchsql_test indexexpr1-410 {
  INSERT INTO t3 SELECT * FROM t3 WHERE rowid=10;
} {1 {UNIQUE constraint failed: index 't3abc'}}






















finish_test








>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
    SELECT x, printf('ab%04xyz',x), random() FROM c;
  CREATE UNIQUE INDEX t3abc ON t3(CAST(a AS text), b, substr(c,1,3));
  SELECT a FROM t3 WHERE CAST(a AS text)<='10' ORDER BY +a;
} {1 10}
do_catchsql_test indexexpr1-410 {
  INSERT INTO t3 SELECT * FROM t3 WHERE rowid=10;
} {1 {UNIQUE constraint failed: index 't3abc'}}

do_execsql_test indexexpr1-500 {
  CREATE TABLE t5(a);
  CREATE TABLE cnt(x);
  WITH RECURSIVE
    c(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM c WHERE x<5)
  INSERT INTO cnt(x) SELECT x FROM c;
  INSERT INTO t5(a) SELECT printf('abc%03dxyz',x) FROM cnt;
  CREATE INDEX t5ax ON t5( substr(a,4,3) );
} {}
do_execsql_test indexexpr1-510 {
  -- The use of the "k" alias in the WHERE clause is technically
  -- illegal, but SQLite allows it for historical reasons.  In this
  -- test and the next, verify that "k" can be used by the t5ax index
  SELECT substr(a,4,3) AS k FROM cnt, t5 WHERE k=printf('%03d',x);
} {001 002 003 004 005}
do_execsql_test indexexpr1-510eqp {
  EXPLAIN QUERY PLAN
  SELECT substr(a,4,3) AS k FROM cnt, t5 WHERE k=printf('%03d',x);
} {/USING INDEX t5ax/}


finish_test