Make sure that the use of a double-quoted string literal does not trick

the optimizer into using a correlated subquery when a static
subquery would suffice. (CVS 2477)

FossilOrigin-Name: ef4059e3afa1a61a9e59df00cdfedc57d8df9fec

diff --git a/manifest b/manifest
index a553b39c66b4f49e2ce305310a30adb392bcc127..b3cc33eed5cbc2fef778a6ed495ade323dce25ee 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Retain\sthe\serror\sstring\sif\san\serror\sis\sgenerated\sby\sSSE\sduring\sa\sVACUUM.\s(CVS\s2476)
-D 2005-05-23T13:00:58
+C Make\ssure\sthat\sthe\suse\sof\sa\sdouble-quoted\sstring\sliteral\sdoes\snot\strick\nthe\soptimizer\sinto\susing\sa\scorrelated\ssubquery\swhen\sa\sstatic\nsubquery\swould\ssuffice.\s(CVS\s2477)
+D 2005-05-23T15:06:39
 F Makefile.in 5c00d0037104de2a50ac7647a5f12769795957a3
 F Makefile.linux-gcc 06be33b2a9ad4f005a5f42b22c4a19dab3cbb5c7
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -36,7 +36,7 @@ F src/build.c 6770abc63df9f3ed9f44c50411bb63692cb4589f
 F src/date.c 2134ef4388256e8247405178df8a61bd60dc180a
 F src/delete.c 75b53db21aa1879d3655bbbc208007db31d58a63
 F src/experimental.c 50c1e3b34f752f4ac10c36f287db095c2b61766d
-F src/expr.c bef1589dbd9481b88f26d7908fc70bad9576e541
+F src/expr.c f2ff12d9970d844564ec8b3ce4ea702bf6730b6a
 F src/func.c d09df82e35ef988cd28a3ffd63cd772271b7def9
 F src/hash.c 2b1b13f7400e179631c83a1be0c664608c8f021f
 F src/hash.h 1b0c445e1c89ff2aaad9b4605ba61375af001e84
@@ -189,7 +189,7 @@ F test/select5.test 2d414f712bff8e590091e08f9b7287600731be00
 F test/select6.test 6e5a1a70a788cdbe515d1252dd0917d7e9d1d71e
 F test/select7.test 1bf795b948c133a15a2a5e99d3270e652ec58ce6
 F test/sort.test 312eade533cb3c7667110ccfa6e818db1078fd6c
-F test/subquery.test 6274cce7617bc7f625490759cbe4f0c0eef24895
+F test/subquery.test 0e37f0f032799c28aa8fcc0dc04ee28a78e5ce8b
 F test/subselect.test 3f3f7a940dc3195c3139f4d530385cb54665d614
 F test/table.test e87fb2211b97c6a3a367fbc116e8572091b53160
 F test/tableapi.test 6a66d58b37d46dc0f2b3c7d4bd2617d209399bd1
@@ -279,7 +279,7 @@ F www/tclsqlite.tcl 425be741b8ae664f55cb1ef2371aab0a75109cf9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
 F www/whentouse.tcl 528299b8316726dbcc5548e9aa0648c8b1bd055b
-P 2a8ac869671b627d4d01655bbce7a781bc74af44
-R b1031030db9f7c66e26c25de4a342f36
-U danielk1977
-Z ceb8d3cc11da91ad4514aeaf74501d5d
+P f7b76d02e003faf0310b87949d3cb0f38062853f
+R 7f9d3157fe368f24bc8a9f1b20f7fe23
+U drh
+Z b4157a0f7dc132bb0373ae1877998e51

diff --git a/manifest.uuid b/manifest.uuid
index ad7b209bae08427b817dc6cdb5316d04c1e9f6a2..f9adbff574b7aeb1f9fb05161054939255855a27 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-f7b76d02e003faf0310b87949d3cb0f38062853f
\ No newline at end of file
+ef4059e3afa1a61a9e59df00cdfedc57d8df9fec
\ No newline at end of file

diff --git a/src/expr.c b/src/expr.c
index 79c7b59e2acbe0a41d9c3bac95f0515b0013127e..6237e75d21698ee0f10c87893b29f75d4e7289bd 100644 (file)
--- a/src/expr.c
+++ b/src/expr.c
@@ -12,7 +12,7 @@
 ** This file contains routines used for analyzing expressions and
 ** for generating VDBE code that evaluates expressions in SQLite.
 **
-** $Id: expr.c,v 1.198 2005/04/22 02:38:38 drh Exp $
+** $Id: expr.c,v 1.199 2005/05/23 15:06:39 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -790,7 +790,6 @@ static int lookupName(
     SrcList *pSrcList = pNC->pSrcList;
     ExprList *pEList = pNC->pEList;
 
-    pNC->nRef++;
     /* assert( zTab==0 || pEList==0 ); */
     if( pSrcList ){
       for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
@@ -898,9 +897,9 @@ static int lookupName(
           pExpr->op = TK_AS;
           pExpr->iColumn = j;
           pExpr->pLeft = sqlite3ExprDup(pEList->a[j].pExpr);
-          sqliteFree(zCol);
+          cnt = 1;
           assert( zTab==0 && zDb==0 );
-          return 0;
+          goto lookupname_end_2;
         }
       } 
     }
@@ -919,6 +918,9 @@ static int lookupName(
   ** Z is a string literal if it doesn't match any column names.  In that
   ** case, we need to return right away and not make any changes to
   ** pExpr.
+  **
+  ** Because no reference was made to outer contexts, the pNC->nRef
+  ** fields are not changed in any context.
   */
   if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
     sqliteFree(zCol);
@@ -965,20 +967,31 @@ lookupname_end:
   */
   sqliteFree(zDb);
   sqliteFree(zTab);
-  sqliteFree(zCol);
   sqlite3ExprDelete(pExpr->pLeft);
   pExpr->pLeft = 0;
   sqlite3ExprDelete(pExpr->pRight);
   pExpr->pRight = 0;
   pExpr->op = TK_COLUMN;
+lookupname_end_2:
+  sqliteFree(zCol);
   if( cnt==1 ){
     assert( pNC!=0 );
     sqlite3AuthRead(pParse, pExpr, pNC->pSrcList);
     if( pMatch && !pMatch->pSelect ){
       pExpr->pTab = pMatch->pTab;
     }
+    /* Increment the nRef value on all name contexts from TopNC up to
+    ** the point where the name matched. */
+    for(;;){
+      assert( pTopNC!=0 );
+      pTopNC->nRef++;
+      if( pTopNC==pNC ) break;
+      pTopNC = pTopNC->pNext;
+    }
+    return 0;
+  } else {
+    return 1;
   }
-  return cnt!=1;
 }
 
 /*

diff --git a/test/subquery.test b/test/subquery.test
index fb98f7ce374a21d0d9b4571d4936b2670325a2b2..4b626ed83acb70512f4f94fcd0f45c824160e904 100644 (file)
--- a/test/subquery.test
+++ b/test/subquery.test
@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is testing correlated subqueries
 #
-# $Id: subquery.test,v 1.8 2005/02/14 06:38:40 danielk1977 Exp $
+# $Id: subquery.test,v 1.9 2005/05/23 15:06:39 drh Exp $
 #
 
 set testdir [file dirname $argv0]
@@ -335,8 +335,46 @@ do_test subquery-4.2.2 {
   execsql {INSERT INTO t3 VALUES((SELECT max(a) FROM t3)+1)}
 } {}
 
+#------------------------------------------------------------------
+# The subquery-5.* tests make sure string literals in double-quotes
+# are handled efficiently.  Double-quote literals are first checked
+# to see if they match any column names.  If there is not column name
+# match then those literals are used a string constants.  When a
+# double-quoted string appears, we want to make sure that the search
+# for a matching column name did not cause an otherwise static subquery
+# to become a dynamic (correlated) subquery.
+#
+do_test subquery-5.1 {
+  proc callcntproc {n} {
+    incr ::callcnt
+    return $n
+  }
+  set callcnt 0
+  db function callcnt callcntproc
+  execsql {
+    CREATE TABLE t4(x,y);
+    INSERT INTO t4 VALUES('one',1);
+    INSERT INTO t4 VALUES('two',2);
+    INSERT INTO t4 VALUES('three',3);
+    INSERT INTO t4 VALUES('four',4);
+    CREATE TABLE t5(a,b);
+    INSERT INTO t5 VALUES(1,11);
+    INSERT INTO t5 VALUES(2,22);
+    INSERT INTO t5 VALUES(3,33);
+    INSERT INTO t5 VALUES(4,44);
+    SELECT b FROM t5 WHERE a IN 
+       (SELECT callcnt(y)+0 FROM t4 WHERE x="two")
+  }
+} {22}
+do_test subquery-5.2 {
+  # This is the key test.  The subquery should have only run once.  If
+  # The double-quoted identifier "two" were causing the subquery to be
+  # processed as a correlated subquery, then it would have run 4 times.
+  set callcnt
+} {1}
+
 
 
-finish_test
 
 
+finish_test