database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-12 13:01:09 +03:00
Code Activity

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

Browse Source 
used in queries.

FossilOrigin-Name: f5306ad6816cc377036685cdae227e762885229c
This commit is contained in:
dan
2017-02-03 19:16:39 +00:00
parent a7466205ca
commit 067cd837fb
3 changed files with 25 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
src/select.c
View File

@@ -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);
}