Avoid a performance problem when very large "VALUES(..), (..), (..)" terms are

used in queries.

FossilOrigin-Name: f5306ad6816cc377036685cdae227e762885229c

diff --git a/manifest b/manifest
index 24ce068e9ce8ecdd0a072ef91e2d695ff07d0baf..9a2d78f7e174f57c34d5d1f831376334863fa53b 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Modify\sthe\ssqlite3SelectDup()\sroutine\sto\savoid\srecursing\son\sSelect.pPrior.
-D 2017-02-03T14:44:52.406
+C Avoid\sa\sperformance\sproblem\swhen\svery\slarge\s"VALUES(..),\s(..),\s(..)"\sterms\sare\nused\sin\squeries.
+D 2017-02-03T19:16:39.919
 F Makefile.in 5f415e7867296d678fed2e6779aea10c1318b4bc
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc ba953c8921fc7e18333f61898007206de7e23964
@@ -393,7 +393,7 @@ F src/printf.c ff10a9b9902cd2afe5f655f3013c6307d969b1fd
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c f9bc0de45a30a450da47b3766de00be89bf9be79
 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
-F src/select.c 3856db523b942062bca8722ba03b61c324ff94d6
+F src/select.c d12f3539f80db38b09015561b569e0eb1c4b6c5f
 F src/shell.c a84e453c213f3e0d6935a582024da4e242f85a19
 F src/sqlite.h.in 751ff125eb159c8f92c182b8df980a5e4f50e966
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1552,10 +1552,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8e03a8e95fada5c24d369672a71f6e02288051da
-R c80f7dbbf5f0044354e4b463e716c13e
-T *branch * recursive-selectdup
-T *sym-recursive-selectdup *
-T -sym-trunk *
+P a7674ead5be986c66f7d61d598adc7e5728bcd30
+R 1275850dbdc882ce3db2a9a335b19414
 U dan
-Z f43da81961eb4c39992192293f7e5a2c
+Z aab63e41186ee170ee1c431b74360517

diff --git a/manifest.uuid b/manifest.uuid
index a72c232e1b053196d5e400be97ce9a8ff4d8e94c..c0409900d61d0d1dd49befc53543df48b577210a 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-a7674ead5be986c66f7d61d598adc7e5728bcd30
\ No newline at end of file
+f5306ad6816cc377036685cdae227e762885229c
\ No newline at end of file

diff --git a/src/select.c b/src/select.c
index ed6221309f5500f491000143829704085b55a8a0..d817ebd074f39c616d5287af89cd2397655dc061 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -4186,7 +4186,15 @@ static int withExpand(
     pCte->zCteErr = "circular reference: %s";
     pSavedWith = pParse->pWith;
     pParse->pWith = pWith;
-    sqlite3WalkSelect(pWalker, bMayRecursive ? pSel->pPrior : pSel);
+    if( bMayRecursive ){
+      Select *pPrior = pSel->pPrior;
+      assert( pPrior->pWith==0 );
+      pPrior->pWith = pSel->pWith;
+      sqlite3WalkSelect(pWalker, pPrior);
+      pPrior->pWith = 0;
+    }else{
+      sqlite3WalkSelect(pWalker, pSel);
+    }
     pParse->pWith = pWith;
 
     for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior);
@@ -4230,10 +4238,12 @@ static int withExpand(
 */
 static void selectPopWith(Walker *pWalker, Select *p){
   Parse *pParse = pWalker->pParse;
-  With *pWith = findRightmost(p)->pWith;
-  if( pWith!=0 ){
-    assert( pParse->pWith==pWith );
-    pParse->pWith = pWith->pOuter;
+  if( pParse->pWith && p->pPrior==0 ){
+    With *pWith = findRightmost(p)->pWith;
+    if( pWith!=0 ){
+      assert( pParse->pWith==pWith );
+      pParse->pWith = pWith->pOuter;
+    }
   }
 }
 #else
@@ -4283,8 +4293,8 @@ static int selectExpander(Walker *pWalker, Select *p){
   }
   pTabList = p->pSrc;
   pEList = p->pEList;
-  if( pWalker->xSelectCallback2==selectPopWith ){
-    sqlite3WithPush(pParse, findRightmost(p)->pWith, 0);
+  if( p->pWith ){
+    sqlite3WithPush(pParse, p->pWith, 0);
   }
 
   /* Make sure cursor numbers have been assigned to all entries in
@@ -4571,9 +4581,7 @@ static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
     sqlite3WalkSelect(&w, pSelect);
   }
   w.xSelectCallback = selectExpander;
-  if( (pSelect->selFlags & SF_MultiValue)==0 ){
-    w.xSelectCallback2 = selectPopWith;
-  }
+  w.xSelectCallback2 = selectPopWith;
   sqlite3WalkSelect(&w, pSelect);
 }