/ Check-in [bad4d7a0]
Login
SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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

Overview
Comment:Attempt to optimize the resolveExprStep() routine by mapping Expr opcodes into a subset of opcodes that resolveExprStep() cares about and only calling the routine when those opcodes are encountered. Is slightly faster, but it seems like the very slight performance bump is not worth the added complexity. Saved on a dead-end branch for historical reference.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | dead-end
Files: files | file ages | folders
SHA3-256: bad4d7a0d93f4d8f9a33c3b9960003e7edf99472781252cc914be98ae542e998
User & Date: drh 2018-06-06 00:36:41
Context
2018-06-06
00:36
Attempt to optimize the resolveExprStep() routine by mapping Expr opcodes into a subset of opcodes that resolveExprStep() cares about and only calling the routine when those opcodes are encountered. Is slightly faster, but it seems like the very slight performance bump is not worth the added complexity. Saved on a dead-end branch for historical reference. Closed-Leaf check-in: bad4d7a0 user: drh tags: dead-end
2018-06-05
23:51
Update the version number to 3.25.0 for the next development cycle. check-in: 7598236c user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/resolve.c.

598
599
600
601
602
603
604
605

606
607
608
609
610
611
612
...
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
...
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
...
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
...
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
...
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
...
868
869
870
871
872
873
874






875
876
877
878
879
880
881
** node in the expression tree.  Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names.  The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep(Walker *pWalker, Expr *pExpr){

  NameContext *pNC;
  Parse *pParse;

  pNC = pWalker->u.pNC;
  assert( pNC!=0 );
  pParse = pNC->pParse;
  assert( pParse==pWalker->pParse );
................................................................................
    SrcList *pSrcList = pNC->pSrcList;
    int i;
    for(i=0; i<pNC->pSrcList->nSrc; i++){
      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
    }
  }
#endif
  switch( pExpr->op ){

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
    /* The special operator TK_ROW means use the rowid for the first
    ** column in the FROM clause.  This is used by the LIMIT and ORDER BY
    ** clause processing on UPDATE and DELETE statements.
    */
    case TK_ROW: {
      SrcList *pSrcList = pNC->pSrcList;
      struct SrcList_item *pItem;
      assert( pSrcList && pSrcList->nSrc==1 );
      pItem = pSrcList->a;
      assert( HasRowid(pItem->pTab) && pItem->pTab->pSelect==0 );
      pExpr->op = TK_COLUMN;
      pExpr->pTab = pItem->pTab;
................................................................................
    ** Or table name and column name:    ID.ID
    ** Or a database, table and column:  ID.ID.ID
    **
    ** The TK_ID and TK_OUT cases are combined so that there will only
    ** be one call to lookupName().  Then the compiler will in-line 
    ** lookupName() for a size reduction and performance increase.
    */
    case TK_ID:
    case TK_DOT: {
      const char *zColumn;
      const char *zTable;
      const char *zDb;
      Expr *pRight;

      if( pExpr->op==TK_ID ){
        zDb = 0;
................................................................................
        }
      }
      return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
    }

    /* Resolve function names
    */
    case TK_FUNCTION: {
      ExprList *pList = pExpr->x.pList;    /* The argument list */
      int n = pList ? pList->nExpr : 0;    /* Number of arguments */
      int no_such_func = 0;       /* True if no such function exists */
      int wrong_num_args = 0;     /* True if wrong number of arguments */
      int is_agg = 0;             /* True if is an aggregate function */
      int nId;                    /* Number of characters in function name */
      const char *zId;            /* The function name. */
................................................................................
      }
      /* FIX ME:  Compute pExpr->affinity based on the expected return
      ** type of the function 
      */
      return WRC_Prune;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT:
    case TK_EXISTS:  testcase( pExpr->op==TK_EXISTS );
#endif
    case TK_IN: {
      testcase( pExpr->op==TK_IN );
      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        int nRef = pNC->nRef;
        notValid(pParse, pNC, "subqueries", NC_IsCheck|NC_PartIdx|NC_IdxExpr);
        sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
        assert( pNC->nRef>=nRef );
        if( nRef!=pNC->nRef ){
          ExprSetProperty(pExpr, EP_VarSelect);
          pNC->ncFlags |= NC_VarSelect;
        }
      }
      break;
    }
    case TK_VARIABLE: {
      notValid(pParse, pNC, "parameters", NC_IsCheck|NC_PartIdx|NC_IdxExpr);
      break;
    }
    case TK_IS:
    case TK_ISNOT: {
      Expr *pRight;
      assert( !ExprHasProperty(pExpr, EP_Reduced) );
      /* Handle special cases of "x IS TRUE", "x IS FALSE", "x IS NOT TRUE",
      ** and "x IS NOT FALSE". */
      if( (pRight = pExpr->pRight)->op==TK_ID ){
        int rc = resolveExprStep(pWalker, pRight);
        if( rc==WRC_Abort ) return WRC_Abort;
................................................................................
          pExpr->op2 = pExpr->op;
          pExpr->op = TK_TRUTH;
          return WRC_Continue;
        }
      }
      /* Fall thru */
    }
    case TK_BETWEEN:
    case TK_EQ:
    case TK_NE:
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE: {
      int nLeft, nRight;
      if( pParse->db->mallocFailed ) break;
      assert( pExpr->pLeft!=0 );
      nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
      if( pExpr->op==TK_BETWEEN ){
        nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[0].pExpr);
        if( nRight==nLeft ){
................................................................................
        sqlite3ErrorMsg(pParse, "row value misused");
      }
      break; 
    }
  }
  return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
}







/*
** pEList is a list of expressions which are really the result set of the
** a SELECT statement.  pE is a term in an ORDER BY or GROUP BY clause.
** This routine checks to see if pE is a simple identifier which corresponds
** to the AS-name of one of the terms of the expression list.  If it is,
** this routine return an integer between 1 and N where N is the number of







|
>







 







|






|







 







|
|







 







|







 







|
|

|













|



|
|







 







|
|
|
|
|
|
|







 







>
>
>
>
>
>







598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
...
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
...
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
...
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
...
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
...
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
...
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
** node in the expression tree.  Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names.  The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep(Walker *pWalker, Expr *pExpr);
static SQLITE_NOINLINE int resolveExprStepEx(Walker *pWalker,Expr *pExpr,u8 op){
  NameContext *pNC;
  Parse *pParse;

  pNC = pWalker->u.pNC;
  assert( pNC!=0 );
  pParse = pNC->pParse;
  assert( pParse==pWalker->pParse );
................................................................................
    SrcList *pSrcList = pNC->pSrcList;
    int i;
    for(i=0; i<pNC->pSrcList->nSrc; i++){
      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
    }
  }
#endif
  switch( op ){

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
    /* The special operator TK_ROW means use the rowid for the first
    ** column in the FROM clause.  This is used by the LIMIT and ORDER BY
    ** clause processing on UPDATE and DELETE statements.
    */
    case RESOLVE_ROW: {
      SrcList *pSrcList = pNC->pSrcList;
      struct SrcList_item *pItem;
      assert( pSrcList && pSrcList->nSrc==1 );
      pItem = pSrcList->a;
      assert( HasRowid(pItem->pTab) && pItem->pTab->pSelect==0 );
      pExpr->op = TK_COLUMN;
      pExpr->pTab = pItem->pTab;
................................................................................
    ** Or table name and column name:    ID.ID
    ** Or a database, table and column:  ID.ID.ID
    **
    ** The TK_ID and TK_OUT cases are combined so that there will only
    ** be one call to lookupName().  Then the compiler will in-line 
    ** lookupName() for a size reduction and performance increase.
    */
    case RESOLVE_ID:
    case RESOLVE_DOT: {
      const char *zColumn;
      const char *zTable;
      const char *zDb;
      Expr *pRight;

      if( pExpr->op==TK_ID ){
        zDb = 0;
................................................................................
        }
      }
      return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
    }

    /* Resolve function names
    */
    case RESOLVE_FUNCTION: {
      ExprList *pList = pExpr->x.pList;    /* The argument list */
      int n = pList ? pList->nExpr : 0;    /* Number of arguments */
      int no_such_func = 0;       /* True if no such function exists */
      int wrong_num_args = 0;     /* True if wrong number of arguments */
      int is_agg = 0;             /* True if is an aggregate function */
      int nId;                    /* Number of characters in function name */
      const char *zId;            /* The function name. */
................................................................................
      }
      /* FIX ME:  Compute pExpr->affinity based on the expected return
      ** type of the function 
      */
      return WRC_Prune;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case RESOLVE_SELECT:
    case RESOLVE_EXISTS:  testcase( pExpr->op==TK_EXISTS );
#endif
    case RESOLVE_IN: {
      testcase( pExpr->op==TK_IN );
      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        int nRef = pNC->nRef;
        notValid(pParse, pNC, "subqueries", NC_IsCheck|NC_PartIdx|NC_IdxExpr);
        sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
        assert( pNC->nRef>=nRef );
        if( nRef!=pNC->nRef ){
          ExprSetProperty(pExpr, EP_VarSelect);
          pNC->ncFlags |= NC_VarSelect;
        }
      }
      break;
    }
    case RESOLVE_VARIABLE: {
      notValid(pParse, pNC, "parameters", NC_IsCheck|NC_PartIdx|NC_IdxExpr);
      break;
    }
    case RESOLVE_IS:
    case RESOLVE_ISNOT: {
      Expr *pRight;
      assert( !ExprHasProperty(pExpr, EP_Reduced) );
      /* Handle special cases of "x IS TRUE", "x IS FALSE", "x IS NOT TRUE",
      ** and "x IS NOT FALSE". */
      if( (pRight = pExpr->pRight)->op==TK_ID ){
        int rc = resolveExprStep(pWalker, pRight);
        if( rc==WRC_Abort ) return WRC_Abort;
................................................................................
          pExpr->op2 = pExpr->op;
          pExpr->op = TK_TRUTH;
          return WRC_Continue;
        }
      }
      /* Fall thru */
    }
    case RESOLVE_BETWEEN:
    case RESOLVE_EQ:
    case RESOLVE_NE:
    case RESOLVE_LT:
    case RESOLVE_LE:
    case RESOLVE_GT:
    case RESOLVE_GE: {
      int nLeft, nRight;
      if( pParse->db->mallocFailed ) break;
      assert( pExpr->pLeft!=0 );
      nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
      if( pExpr->op==TK_BETWEEN ){
        nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[0].pExpr);
        if( nRight==nLeft ){
................................................................................
        sqlite3ErrorMsg(pParse, "row value misused");
      }
      break; 
    }
  }
  return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
}
static int resolveExprStep(Walker *pWalker, Expr *pExpr){
  static const u8 resolveMap[] = RESOLVE_MAP;
  u8 op = resolveMap[pExpr->op];
  return op>RESOLVE_Max ? WRC_Continue : resolveExprStepEx(pWalker,pExpr,op);
}


/*
** pEList is a list of expressions which are really the result set of the
** a SELECT statement.  pE is a term in an ORDER BY or GROUP BY clause.
** This routine checks to see if pE is a simple identifier which corresponds
** to the AS-name of one of the terms of the expression list.  If it is,
** this routine return an integer between 1 and N where N is the number of

Changes to tool/addopcodes.tcl.

6
7
8
9
10
11
12
13
14
15
16


17
18
19
20
21
22
23
..
45
46
47
48
49
50
51


52
53
54
55
56
57
58
59
60
61
62
63
64




















































# the code generator.
#
#
set in [open [lindex $argv 0] rb]
set max 0
while {![eof $in]} {
  set line [gets $in]
  if {[regexp {^#define TK_} $line]} {
    puts $line
    set x [lindex $line 2]
    if {$x>$max} {set max $x}


  }
}
close $in

# The following are the extra token codes to be added.  SPACE and 
# ILLEGAL *must* be the last two token codes and they must be in that order.
#
................................................................................
if {[lrange $extras end-1 end]!="SPACE ILLEGAL"} {
  error "SPACE and ILLEGAL must be the last two token codes and they\
         must be in that order"
}
foreach x $extras {
  incr max
  puts [format "#define TK_%-29s %4d" $x $max]


}

# Some additional #defines related to token codes.
#
puts "\n/* The token codes above must all fit in 8 bits */"
puts [format "#define %-20s %-6s" TKFLG_MASK 0xff]
puts "\n/* Flags that can be added to a token code when it is not"
puts "** being stored in a u8: */"
foreach {fg val comment} {
  TKFLG_DONTFOLD  0x100  {/* Omit constant folding optimizations */}
} {
  puts [format "#define %-20s %-6s %s" $fg $val $comment]
}



























































|

<

>
>







 







>
>













>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
6
7
8
9
10
11
12
13
14

15
16
17
18
19
20
21
22
23
24
..
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
79
80
81
82
83
84
85
86
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
113
114
115
116
117
118
119
# the code generator.
#
#
set in [open [lindex $argv 0] rb]
set max 0
while {![eof $in]} {
  set line [gets $in]
  if {[regexp {^#define TK_([A-Z_]+) +(\d+)} $line all nm x]} {
    puts $line

    if {$x>$max} {set max $x}
    set tk($nm) $x
    set rtk($x) $nm
  }
}
close $in

# The following are the extra token codes to be added.  SPACE and 
# ILLEGAL *must* be the last two token codes and they must be in that order.
#
................................................................................
if {[lrange $extras end-1 end]!="SPACE ILLEGAL"} {
  error "SPACE and ILLEGAL must be the last two token codes and they\
         must be in that order"
}
foreach x $extras {
  incr max
  puts [format "#define TK_%-29s %4d" $x $max]
  set tk($x) $max
  set rtk($max) $x
}

# Some additional #defines related to token codes.
#
puts "\n/* The token codes above must all fit in 8 bits */"
puts [format "#define %-20s %-6s" TKFLG_MASK 0xff]
puts "\n/* Flags that can be added to a token code when it is not"
puts "** being stored in a u8: */"
foreach {fg val comment} {
  TKFLG_DONTFOLD  0x100  {/* Omit constant folding optimizations */}
} {
  puts [format "#define %-20s %-6s %s" $fg $val $comment]
}

# Opcodes of significance to resolveExprStep()
#
set resolveOps {
  ROW
  ID
  DOT
  FUNCTION
  SELECT
  EXISTS
  VARIABLE
  IS
  ISNOT
  IN
  BETWEEN
  EQ
  NE
  LT
  LE
  GT
  GE
}

puts "\n"
puts {/* Symbols used by resolveExprStep() */}

set i 0
foreach x $resolveOps {
  puts [format "#define %-20s %3d" RESOLVE_$x $i]
  set rmap($x) $i
  incr i
}
set rmax $i
puts [format "#define %-20s %3d" RESOLVE_Max [expr {$rmax-1}]]
puts "#define RESOLVE_MAP \173\\"
set col 0
set sep \173
set rtk(0) noop
for {set i 0} {$i<=$max} {incr i} {
  if {$col>70} {
    puts "\\"
    set col 0
  }
  set nm $rtk($i)
  if {[info exists rmap($nm)]} {
    puts -nonewline " $rmap($nm),"
  } else {
    puts -nonewline " $rmax,"
  }
  incr col 4
}
puts " $rmax \175"