From: drh <>
Date: Fri, 25 Nov 2022 17:05:55 +0000 (+0000)
Subject: Relax restriction (8) on the push-down optimization so that it only applies
X-Git-Tag: version-3.41.0~370
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=902ea8392536b729c4c4553613dae9f65a4c1bf3;p=thirdparty%2Fsqlite.git

Relax restriction (8) on the push-down optimization so that it only applies
if one or more columns uses a collating sequence other than BINARY.
See [forum:/forumpost/3824ced748baa808|forum post 3824ced748baa808] and
check-in [346a3b12b861ce7b].

FossilOrigin-Name: adbca3448e2099f0d6149a073978f230ed9a92a2f384779879ef89e672231bcf
---

diff --git a/manifest b/manifest
index 8852b478ad..3a6ab9396c 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\s#ifdefs\sso\sthat\srestrictions\s(8)\sand\s(9)\sof\sthe\spush-down\soptimization\nare\sstill\senforced\seven\sif\scompiled\swith\sSQLITE_OMIT_WINDOWFUNC.\s\sThis\nfixes\sa\sbug\sintroduced\sby\scheck-in\s[346a3b12b861ce7b].
-D 2022-11-25T16:32:59.610
+C Relax\srestriction\s(8)\son\sthe\spush-down\soptimization\sso\sthat\sit\sonly\sapplies\nif\sone\sor\smore\scolumns\suses\sa\scollating\ssequence\sother\sthan\sBINARY.\nSee\s[forum:/forumpost/3824ced748baa808|forum\spost\s3824ced748baa808]\sand\ncheck-in\s[346a3b12b861ce7b].
+D 2022-11-25T17:05:55.692
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -641,7 +641,7 @@ F src/printf.c e99ee9741e79ae3873458146f59644276657340385ade4e76a5f5d1c25793764
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c efea4e5fbecfd6d0a9071b0be0d952620991673391b6ffaaf4c277b0bb674633
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c e0a04b10826637f826e0f9edb9c6cebdc0031f4093cec2553030f39e0b751109
+F src/select.c 934c37455762579dcef5ce37f6abf04facaa61ef04cde207ac170b28c4780113
 F src/shell.c.in 09cb15d7421c475f2d308f6a4312d8d690916ea5cb62ea1618f2f4ce5703af35
 F src/sqlite.h.in 100fc660c2f19961b8ed8437b9d53d687de2f8eb2b96437ec6da216adcb643ca
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -2060,8 +2060,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b9190d3da70c41717eb188474fd225ee43d0b46646e1b03de5967bd332553870
-R ba0c31d84a1008c246f9efb185042449
+P 09e1e42e0ff26f9a71cbd128169f060a66425828d637bf8f781490ca38d99103
+R 051f7bebeb695c93dfdb45030ad5b532
 U drh
-Z 98b0ad17c9260369ac5243663e0dc610
+Z 0a4a218169578e69e7b7469760b002aa
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 1de8ddd5c0..76e9e654c1 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-09e1e42e0ff26f9a71cbd128169f060a66425828d637bf8f781490ca38d99103
\ No newline at end of file
+adbca3448e2099f0d6149a073978f230ed9a92a2f384779879ef89e672231bcf
\ No newline at end of file
diff --git a/src/select.c b/src/select.c
index bc9ae25ce8..2bedfb9da0 100644
--- a/src/select.c
+++ b/src/select.c
@@ -5046,12 +5046,9 @@ static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
 **       be materialized.  (This restriction is implemented in the calling
 **       routine.)
 **
-**   (8) The subquery may not be a compound that uses UNION, INTERSECT,
-**       or EXCEPT.  (We could, perhaps, relax this restriction to allow
-**       this case if none of the comparisons operators between left and
-**       right arms of the compound use a collation other than BINARY.
-**       But it is a lot of work to check that case for an obscure and
-**       minor optimization, so we omit it for now.)
+**   (8) If the subquery is a compound that uses UNION, INTERSECT,
+**       or EXCEPT, then all of the result set columns for all arms of
+**       the compound must use the BINARY collating sequence.
 **
 **   (9) If the subquery is a compound, then all arms of the compound must
 **       have the same affinity.  (This is the same as restriction (17h)
@@ -5075,11 +5072,14 @@ static int pushDownWhereTerms(
 
   if( pSubq->pPrior ){
     Select *pSel;
+    int notUnionAll = 0;
     for(pSel=pSubq; pSel; pSel=pSel->pPrior){
       u8 op = pSel->op;
       assert( op==TK_ALL || op==TK_SELECT 
            || op==TK_UNION || op==TK_INTERSECT || op==TK_EXCEPT );
-      if( op!=TK_ALL && op!=TK_SELECT ) return 0;  /* restriction (8) */
+      if( op!=TK_ALL && op!=TK_SELECT ){
+        notUnionAll = 1;
+      }
 #ifndef SQLITE_OMIT_WINDOWFUNC
       if( pSel->pWin ) return 0;    /* restriction (6b) */
 #endif
@@ -5087,6 +5087,22 @@ static int pushDownWhereTerms(
     if( compoundHasDifferentAffinities(pSubq) ){
       return 0;  /* restriction (9) */
     }
+    if( notUnionAll ){
+      /* If any of the compound arms are connected using UNION, INTERSECT,
+      ** or EXCEPT, then we must ensure that none of the columns use a
+      ** non-BINARY collating sequence. */
+      for(pSel=pSubq; pSel; pSel=pSel->pPrior){
+        int ii;
+        const ExprList *pList = pSel->pEList;
+        assert( pList!=0 );
+        for(ii=0; ii<pList->nExpr; ii++){
+          CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[ii].pExpr);
+          if( !sqlite3IsBinary(pColl) ){
+            return 0;  /* Restriction (8) */
+          }
+        }
+      }
+    }
   }else{
 #ifndef SQLITE_OMIT_WINDOWFUNC
     if( pSubq->pWin && pSubq->pWin->pPartition==0 ) return 0;