From: drh <>
Date: Thu, 16 Feb 2023 18:04:49 +0000 (+0000)
Subject: Provide an optimization-disable mask for this optimization.  Do not do the
X-Git-Tag: version-3.42.0~332^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7defd20cb0ac85b629ad5b2a7db235464838b193;p=thirdparty%2Fsqlite.git

Provide an optimization-disable mask for this optimization.  Do not do the
optimization if the subquery is an aggregate or is distinct, but allow it to
be an ephemeral subquery.  Do not omit columns that are used in the ORDER BY
of the subquery.

FossilOrigin-Name: 6b1a1f374d1372f11f5420d99645b218867100bf070bd3a8885bf5f00c189dff
---

diff --git a/manifest b/manifest
index 4067e40b48..75fd2e6d0e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Do\snot\sperform\sthe\somit-unused-subquery-columns\soptimizations\son\sa\nsubquery\sthat\sis\sDISTINCT,\sas\sthat\scan\slead\sto\sincorrect\sresults.
-D 2023-02-16T15:54:55.738
+C Provide\san\soptimization-disable\smask\sfor\sthis\soptimization.\s\sDo\snot\sdo\sthe\noptimization\sif\sthe\ssubquery\sis\san\saggregate\sor\sis\sdistinct,\sbut\sallow\sit\sto\nbe\san\sephemeral\ssubquery.\s\sDo\snot\somit\scolumns\sthat\sare\sused\sin\sthe\sORDER\sBY\nof\sthe\ssubquery.
+D 2023-02-16T18:04:49.549
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -621,12 +621,12 @@ F src/printf.c ff4b05e38bf928ff1b80d3dda4f977b10fe39ecbfe69c018224c7e5594fb2455
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c d62c5665279cc7485f9d45b5e20911cc7b19c203f268321a90d05d74f4725750
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c a723a35366d7fc695371dd80b2ea4dbc306d5fb75df81d3e6ce7e200794f7622
+F src/select.c fa66a61608731b4842fb2a2799ddeccbb56b4ec863f8b36d8b08b898ff62067a
 F src/shell.c.in 5cb750dc00bb8b20b020031fd1bb0cb8759a6e567c27aee6b0af31d187984985
 F src/sqlite.h.in c060f9e6f646fd817abf273c068666e079fc6e8467ea1d3e8b20f355f82722e9
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h da473ce2b3d0ae407a6300c4a164589b9a6bfdbec9462688a8593ff16f3bb6e4
-F src/sqliteInt.h 4dcc36b21dd0c77efeb0bb38b0d31916bc63fb429c8a89d186c945eba0816447
+F src/sqliteInt.h 25f38ade2d93828231d6cd8614f635c0b084bee004360d970542861ad2e3e3d8
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
 F src/status.c 160c445d7d28c984a0eae38c144f6419311ed3eace59b44ac6dafc20db4af749
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -2045,8 +2045,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 77b220a7240425fa83e142ceef78505208e6e38d797070e146b9f7d255f753c7
-R e479bead84e886f8b2c21d0d027a081a
+P cc148503db8ef180bce984328da7e84959afadd6a9613c2d03bc1eafeb95dfad
+R 90e53b2f21c8456ed0ad4d26c75d661a
 U drh
-Z 0b93f878d511033e2fa0d6dd3c9e8431
+Z aa83be3d588d7cfee260c5a1a1ab587b
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 3b17642550..1e9696bac9 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cc148503db8ef180bce984328da7e84959afadd6a9613c2d03bc1eafeb95dfad
\ No newline at end of file
+6b1a1f374d1372f11f5420d99645b218867100bf070bd3a8885bf5f00c189dff
\ No newline at end of file
diff --git a/src/select.c b/src/select.c
index ae320b697b..b8cae155f3 100644
--- a/src/select.c
+++ b/src/select.c
@@ -5249,17 +5249,20 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
   Table *pTab;       /* The table that describes the subquery */
   int j;             /* Column number */
   int nChng = 0;     /* Number of columns converted to NULL */
+  Bitmask colUsed;   /* Columns that may not be NULLed out */
 
   assert( pItem!=0 );
-  assert( pItem->pTab!=0 );
-  pTab = pItem->pTab;
-  if( pTab->tabFlags & TF_Ephemeral ){
+  if( pItem->fg.isCorrelated || pItem->fg.isCte ){
     return 0;
   }
+  assert( pItem->pTab!=0 );
+  pTab = pItem->pTab;
   assert( pItem->pSelect!=0 );
   pSub = pItem->pSelect;
   assert( pSub->pEList->nExpr==pTab->nCol );
-  if( pSub->selFlags & SF_Distinct ){
+  if( (pSub->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
+    testcase( pSub->selFlags & SF_Distinct );
+    testcase( pSub->selFlags & SF_Aggregate );
     return 0;
   }
   for(pX=pSub; pX; pX=pX->pPrior){
@@ -5274,11 +5277,22 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
       return 0;
     }
   }
+ colUsed = pItem->colUsed;
+  if( pSub->pOrderBy ){
+    ExprList *pList = pSub->pOrderBy;
+    for(j=0; j<pList->nExpr; j++){
+      u16 iCol = pList->a[j].u.x.iOrderByCol;
+      if( iCol>0 ){
+        iCol--;
+        colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+      }
+    }
+  }
   nCol = pTab->nCol;
   for(j=0; j<nCol; j++){
     Select *pX;
     Bitmask m = j<BMS-1 ? MASKBIT(j) : TOPBIT;
-    if( (m & pItem->colUsed)!=0 ) continue;
+    if( (m & colUsed)!=0 ) continue;
     for(pX=pSub; pX; pX=pX->pPrior) {
       Expr *pY = pX->pEList->a[j].pExpr;
       if( pY->op==TK_NULL ) continue;
@@ -7392,7 +7406,9 @@ int sqlite3Select(
     /* Convert unused result columns of the subquery into simple NULL
     ** expressions, to avoid unneeded searching and computation.
     */
-    if( disableUnusedSubqueryResultColumns(pItem) ){
+    if( OptimizationEnabled(db, SQLITE_NullUnusedCols)
+     && disableUnusedSubqueryResultColumns(pItem)
+    ){
 #if TREETRACE_ENABLED
       if( sqlite3TreeTrace & 0x4000 ){
         TREETRACE(0x4000,pParse,p,
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 9af38e8df4..459af6b4ed 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1839,6 +1839,7 @@ struct sqlite3 {
    /* TH3 expects this value  ^^^^^^^^^^ See flatten04.test */
 #define SQLITE_IndexedExpr    0x01000000 /* Pull exprs from index when able */
 #define SQLITE_Coroutines     0x02000000 /* Co-routines for subqueries */
+#define SQLITE_NullUnusedCols 0x04000000 /* NULL unused columns in subqueries */
 #define SQLITE_AllOpts        0xffffffff /* All optimizations */
 
 /*