Refactor the SrcItem object so that information about subqueries is stored

in a separately allocated Subquery object.  This reduces the memory requirements
for SrcItem and makes the code run faster.  It also provides an expansion path
for subquery processing that does not burden simple queries.  The current
checking mostly works, but there are still issues that need to be tracked
down and fixed.

FossilOrigin-Name: 8ff5dda8448d7e1a533d7f27db2573ce68fa9956b9d9847ced45e83c1f06bab0

1 files changed, 109 insertions, 70 deletions

diff --git a/src/select.c b/src/select.c
index 5f55b402c..8bddc03bb 100644
--- a/src/select.c
+++ b/src/select.c
@@ -332,11 +332,13 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){
 */
 void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
   assert( pItem!=0 );
-  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem->sq.pSelect) );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
   if( pItem->fg.isNestedFrom ){
     ExprList *pResults;
-    assert( pItem->sq.pSelect!=0 );
-    pResults = pItem->sq.pSelect->pEList;
+    assert( pItem->fg.isSubquery );
+    assert( pItem->u4.pSubq!=0 );
+    assert( pItem->u4.pSubq->pSelect!=0 );
+    pResults = pItem->u4.pSubq->pSelect->pEList;
     assert( pResults!=0 );
     assert( iCol>=0 && iCol<pResults->nExpr );
     pResults->a[iCol].fg.bUsed = 1;
@@ -1931,7 +1933,11 @@ static const char *columnTypeImpl(
         for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
         if( j<pTabList->nSrc ){
           pTab = pTabList->a[j].pSTab;
-          pS = pTabList->a[j].sq.pSelect;
+          if( pTabList->a[j].fg.isSubquery ){
+            pS = pTabList->a[j].u4.pSubq->pSelect;
+          }else{
+            pS = 0;
+          }
         }else{
           pNC = pNC->pNext;
         }
@@ -3983,7 +3989,9 @@ static void substSelect(
     pSrc = p->pSrc;
     assert( pSrc!=0 );
     for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
-      substSelect(pSubst, pItem->sq.pSelect, 1);
+      if( pItem->fg.isSubquery ){
+        substSelect(pSubst, pItem->u4.pSubq->pSelect, 1);
+      }
       if( pItem->fg.isTabFunc ){
         substExprList(pSubst, pItem->u1.pFuncArg);
       }
@@ -4054,8 +4062,10 @@ static void srclistRenumberCursors(
         aCsrMap[pItem->iCursor+1] = pParse->nTab++;
       }
       pItem->iCursor = aCsrMap[pItem->iCursor+1];
-      for(p=pItem->sq.pSelect; p; p=p->pPrior){
-        srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+      if( pItem->fg.isSubquery ){
+        for(p=pItem->u4.pSubq->pSelect; p; p=p->pPrior){
+          srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+        }
       }
     }
   }
@@ -4366,7 +4376,8 @@ static int flattenSubquery(
   assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
   pSubitem = &pSrc->a[iFrom];
   iParent = pSubitem->iCursor;
-  pSub = pSubitem->sq.pSelect;
+  assert( pSubitem->fg.isSubquery );
+  pSub = pSubitem->u4.pSubq->pSelect;
   assert( pSub!=0 );
 
 #ifndef SQLITE_OMIT_WINDOWFUNC
@@ -4505,7 +4516,12 @@ static int flattenSubquery(
   pParse->zAuthContext = zSavedAuthContext;
 
   /* Delete the transient structures associated with the subquery */
-  pSub1 = pSubitem->sq.pSelect;
+  
+  if( ALWAYS(pSubitem->fg.isSubquery) ){
+    pSub1 = sqlite3SubqueryDetach(db, pSubitem);
+  }else{
+    pSub1 = 0;
+  }
   if( pSubitem->fg.fixedSchema==0 ){
     sqlite3DbFree(db, pSubitem->u4.zDatabase);
     pSubitem->u4.zDatabase = 0;
@@ -4514,7 +4530,6 @@ static int flattenSubquery(
   sqlite3DbFree(db, pSubitem->zAlias);
   pSubitem->zName = 0;
   pSubitem->zAlias = 0;
-  pSubitem->sq.pSelect = 0;
   assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 );
 
   /* If the sub-query is a compound SELECT statement, then (by restrictions
@@ -4579,11 +4594,14 @@ static int flattenSubquery(
       TREETRACE(0x4,pParse,p,("compound-subquery flattener"
                               " creates %u as peer\n",pNew->selId));
     }
-    assert( pSubitem->sq.pSelect==0 );
+    assert( pSubitem->fg.isSubquery==0 );
   }
   sqlite3DbFree(db, aCsrMap);
   if( db->mallocFailed ){
-    pSubitem->sq.pSelect = pSub1;
+    assert( pSubitem->fg.fixedSchema==0 );
+    assert( pSubitem->fg.isSubquery==0 );
+    assert( pSubitem->u4.zDatabase==0 );
+    sqlite3SrcItemAttachSubquery(pParse, pSubitem, pSub1, 0);
     return 1;
   }
 
@@ -4659,8 +4677,11 @@ static int flattenSubquery(
     */
     for(i=0; i<nSubSrc; i++){
       SrcItem *pItem = &pSrc->a[i+iFrom];
-      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
       assert( pItem->fg.isTabFunc==0 );
+      assert( pItem->fg.isSubquery
+           || pItem->fg.fixedSchema
+           || pItem->u4.zDatabase==0 );
+      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
       *pItem = pSubSrc->a[i];
       pItem->fg.jointype |= ltorj;
       iNewParent = pSubSrc->a[i].iCursor;
@@ -5346,8 +5367,8 @@ static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
   }
   assert( pItem->pSTab!=0 );
   pTab = pItem->pSTab;
-  assert( pItem->sq.pSelect!=0 );
-  pSub = pItem->sq.pSelect;
+  assert( pItem->fg.isSubquery );
+  pSub = pItem->u4.pSubq->pSelect;
   assert( pSub->pEList->nExpr==pTab->nCol );
   for(pX=pSub; pX; pX=pX->pPrior){
     if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
@@ -5476,7 +5497,7 @@ static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
   if( p->pWhere
    || p->pEList->nExpr!=1
    || p->pSrc->nSrc!=1
-   || p->pSrc->a[0].sq.pSelect
+   || p->pSrc->a[0].fg.isSubquery
    || pAggInfo->nFunc!=1
    || p->pHaving
   ){
@@ -5776,10 +5797,12 @@ static int resolveFromTermToCte(
     pTab->iPKey = -1;
     pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
     pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
-    pFrom->sq.pSelect = sqlite3SelectDup(db, pCte->pSelect, 0);
+    sqlite3SrcItemAttachSubquery(pParse, pFrom, pCte->pSelect, 1);
     if( db->mallocFailed ) return 2;
-    assert( pFrom->sq.pSelect );
-    pFrom->sq.pSelect->selFlags |= SF_CopyCte;
+    assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+    pSel = pFrom->u4.pSubq->pSelect;
+    assert( pSel!=0 );
+    pSel->selFlags |= SF_CopyCte;
     if( pFrom->fg.isIndexedBy ){
       sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
       return 2;
@@ -5789,7 +5812,7 @@ static int resolveFromTermToCte(
     pCteUse->nUse++;
 
     /* Check if this is a recursive CTE. */
-    pRecTerm = pSel = pFrom->sq.pSelect;
+    pRecTerm = pSel;
     bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
     while( bMayRecursive && pRecTerm->op==pSel->op ){
       int i;
@@ -5904,9 +5927,12 @@ void sqlite3SelectPopWith(Walker *pWalker, Select *p){
 ** SQLITE_NOMEM.
 */
 int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){
-  Select *pSel = pFrom->sq.pSelect;
+  Select *pSel;
   Table *pTab;
 
+  assert( pFrom->fg.isSubquery );
+  assert( pFrom->u4.pSubq!=0 );
+  pSel = pFrom->u4.pSubq->pSelect;
   assert( pSel );
   pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
   if( pTab==0 ) return SQLITE_NOMEM;
@@ -6033,7 +6059,9 @@ static int selectExpander(Walker *pWalker, Select *p){
     assert( pFrom->fg.isRecursive==0 );
     if( pFrom->zName==0 ){
 #ifndef SQLITE_OMIT_SUBQUERY
-      Select *pSel = pFrom->sq.pSelect;
+      Select *pSel;
+      assert( pFrom->fg.isSubquery && pFrom->u4.pSubq!=0 );
+      pSel = pFrom->u4.pSubq->pSelect;
       /* A sub-query in the FROM clause of a SELECT */
       assert( pSel!=0 );
       assert( pFrom->pSTab==0 );
@@ -6066,7 +6094,7 @@ static int selectExpander(Walker *pWalker, Select *p){
         i16 nCol;
         u8 eCodeOrig = pWalker->eCode;
         if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
-        assert( pFrom->sq.pSelect==0 );
+        assert( pFrom->fg.isSubquery==0 );
         if( IsView(pTab) ){
           if( (db->flags & SQLITE_EnableView)==0
            && pTab->pSchema!=db->aDb[1].pSchema
@@ -6074,7 +6102,7 @@ static int selectExpander(Walker *pWalker, Select *p){
             sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
               pTab->zName);
           }
-          pFrom->sq.pSelect = sqlite3SelectDup(db, pTab->u.view.pSelect, 0);
+          sqlite3SrcItemAttachSubquery(pParse, pFrom, pTab->u.view.pSelect, 1);
         }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
         else if( ALWAYS(IsVirtual(pTab))
@@ -6090,7 +6118,9 @@ static int selectExpander(Walker *pWalker, Select *p){
         nCol = pTab->nCol;
         pTab->nCol = -1;
         pWalker->eCode = 1;  /* Turn on Select.selId renumbering */
-        sqlite3WalkSelect(pWalker, pFrom->sq.pSelect);
+        if( pFrom->fg.isSubquery ){
+          sqlite3WalkSelect(pWalker, pFrom->u4.pSubq->pSelect);
+        }
         pWalker->eCode = eCodeOrig;
         pTab->nCol = nCol;
       }
@@ -6188,11 +6218,11 @@ static int selectExpander(Walker *pWalker, Select *p){
             zTabName = pTab->zName;
           }
           if( db->mallocFailed ) break;
-          assert( (int)pFrom->fg.isNestedFrom ==
-                                         IsNestedFrom(pFrom->sq.pSelect) );
+          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom) );
           if( pFrom->fg.isNestedFrom ){
-            assert( pFrom->sq.pSelect!=0 );
-            pNestedFrom = pFrom->sq.pSelect->pEList;
+            assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+            assert( pFrom->u4.pSubq->pSelect!=0 );
+            pNestedFrom = pFrom->u4.pSubq->pSelect->pEList;
             assert( pNestedFrom!=0 );
             assert( pNestedFrom->nExpr==pTab->nCol );
             assert( VisibleRowid(pTab)==0 || ViewCanHaveRowid );
@@ -6433,12 +6463,10 @@ static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
   for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
     Table *pTab = pFrom->pSTab;
     assert( pTab!=0 );
-    if( (pTab->tabFlags & TF_Ephemeral)!=0 ){
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 && pFrom->fg.isSubquery ){
       /* A sub-query in the FROM clause of a SELECT */
-      Select *pSel = pFrom->sq.pSelect;
-      if( pSel ){
-        sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
-      }
+      Select *pSel = pFrom->u4.pSubq->pSelect;
+      sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
     }
   }
 }
@@ -7085,25 +7113,28 @@ static SrcItem *isSelfJoinView(
   int iFirst, int iEnd        /* Range of FROM-clause entries to search. */
 ){
   SrcItem *pItem;
-  assert( pThis->sq.pSelect!=0 );
-  if( pThis->sq.pSelect->selFlags & SF_PushDown ) return 0;
+  Select *pSel;
+  assert( pThis->fg.isSubquery );
+  pSel = pThis->u4.pSubq->pSelect;
+  assert( pSel!=0 );
+  if( pSel->selFlags & SF_PushDown ) return 0;
   while( iFirst<iEnd ){
     Select *pS1;
     pItem = &pTabList->a[iFirst++];
-    if( pItem->sq.pSelect==0 ) continue;
+    if( !pItem->fg.isSubquery ) continue;
     if( pItem->fg.viaCoroutine ) continue;
     if( pItem->zName==0 ) continue;
     assert( pItem->pSTab!=0 );
     assert( pThis->pSTab!=0 );
     if( pItem->pSTab->pSchema!=pThis->pSTab->pSchema ) continue;
     if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue;
-    pS1 = pItem->sq.pSelect;
-    if( pItem->pSTab->pSchema==0 && pThis->sq.pSelect->selId!=pS1->selId ){
+    pS1 = pItem->u4.pSubq->pSelect;
+    if( pItem->pSTab->pSchema==0 && pSel->selId!=pS1->selId ){
       /* The query flattener left two different CTE tables with identical
       ** names in the same FROM clause. */
       continue;
     }
-    if( pItem->sq.pSelect->selFlags & SF_PushDown ){
+    if( pS1->selFlags & SF_PushDown ){
       /* The view was modified by some other optimization such as
       ** pushDownWhereTerms() */
       continue;
@@ -7147,6 +7178,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   Expr *pExpr;
   Expr *pCount;
   sqlite3 *db;
+  SrcItem *pFrom;
   if( (p->selFlags & SF_Aggregate)==0 ) return 0;   /* This is an aggregate */
   if( p->pEList->nExpr!=1 ) return 0;               /* Single result column */
   if( p->pWhere ) return 0;
@@ -7161,8 +7193,9 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   if( pExpr->x.pList!=0 ) return 0;                 /* Must be count(*) */
   if( p->pSrc->nSrc!=1 ) return 0;                  /* One table in FROM  */
   if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */
-  pSub = p->pSrc->a[0].sq.pSelect;
-  if( pSub==0 ) return 0;                           /* The FROM is a subquery */
+  pFrom = p->pSrc->a;
+  if( pFrom->fg.isSubquery==0 ) return 0;    /* FROM is a subquery */
+  pSub = pFrom->u4.pSubq->pSelect;
   if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
   if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
   do{
@@ -7171,7 +7204,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
     if( pSub->pLimit ) return 0;                      /* No LIMIT clause */
     if( pSub->selFlags & SF_Aggregate ) return 0;     /* Not an aggregate */
     assert( pSub->pHaving==0 );  /* Due to the previous */
-   pSub = pSub->pPrior;                              /* Repeat over compound */
+    pSub = pSub->pPrior;                              /* Repeat over compound */
   }while( pSub );
 
   /* If we reach this point then it is OK to perform the transformation */
@@ -7179,8 +7212,7 @@ static int countOfViewOptimization(Parse *pParse, Select *p){
   db = pParse->db;
   pCount = pExpr;
   pExpr = 0;
-  pSub = p->pSrc->a[0].sq.pSelect;
-  p->pSrc->a[0].sq.pSelect = 0;
+  pSub = sqlite3SubqueryDetach(db, pFrom);
   sqlite3SrcListDelete(db, p->pSrc);
   p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc));
   while( pSub ){
@@ -7228,9 +7260,9 @@ static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
     if( p0->pSTab==p1->pSTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
       return 1;
     }
-    if( p1->sq.pSelect
-     && (p1->sq.pSelect->selFlags & SF_NestedFrom)!=0
-     && sameSrcAlias(p0, p1->sq.pSelect->pSrc)
+    if( p1->fg.isSubquery
+     && (p1->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
+     && sameSrcAlias(p0, p1->u4.pSubq->pSelect->pSrc)
     ){
       return 1;
     }
@@ -7295,7 +7327,7 @@ static int fromClauseTermCanBeCoroutine(
     if( i==0 ) break;
     i--;
     pItem--;
-    if( pItem->sq.pSelect!=0 ) return 0;                          /* (1c-i) */
+    if( pItem->fg.isSubquery ) return 0;                          /* (1c-i) */
   }
   return 1;
 }
@@ -7445,7 +7477,7 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
   for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
     SrcItem *pItem = &pTabList->a[i];
-    Select *pSub = pItem->sq.pSelect;
+    Select *pSub = pItem->fg.isSubquery ? pItem->u4.pSubq->pSelect : 0;
     Table *pTab = pItem->pSTab;
 
     /* The expander should have already created transient Table objects
@@ -7664,6 +7696,7 @@ int sqlite3Select(
     SrcItem *pItem = &pTabList->a[i];
     SrcItem *pPrior;
     SelectDest dest;
+    Subquery *pSubq;
     Select *pSub;
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
     const char *zSavedAuthContext;
@@ -7699,11 +7732,14 @@ int sqlite3Select(
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
     /* Generate code for all sub-queries in the FROM clause
     */
-    pSub = pItem->sq.pSelect;
-    if( pSub==0 || pItem->sq.addrFillSub!=0 ) continue;
+    if( pItem->fg.isSubquery==0 ) continue;
+    pSubq = pItem->u4.pSubq;
+    assert( pSubq!=0 );
+    pSub = pSubq->pSelect;
+    if( pSubq->addrFillSub!=0 ) continue;
 
     /* The code for a subquery should only be generated once. */
-    assert( pItem->sq.addrFillSub==0 );
+    assert( pSubq->addrFillSub==0 );
 
     /* Increment Parse.nHeight by the height of the largest expression
     ** tree referred to by this, the parent select. The child select
@@ -7729,8 +7765,7 @@ int sqlite3Select(
         sqlite3TreeViewSelect(0, p, 0);
       }
 #endif
-      assert( pItem->sq.pSelect 
-           && (pItem->sq.pSelect->selFlags & SF_PushDown)!=0 );
+      assert( pSubq->pSelect && (pSub->selFlags & SF_PushDown)!=0 );
     }else{
       TREETRACE(0x4000,pParse,p,("WHERE-lcause push-down not possible\n"));
     }
@@ -7762,17 +7797,17 @@ int sqlite3Select(
       */
       int addrTop = sqlite3VdbeCurrentAddr(v)+1;
     
-      pItem->sq.regReturn = ++pParse->nMem;
-      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->sq.regReturn, 0, addrTop);
+      pSubq->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pSubq->regReturn, 0, addrTop);
       VdbeComment((v, "%!S", pItem));
-      pItem->sq.addrFillSub = addrTop;
-      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->sq.regReturn);
+      pSubq->addrFillSub = addrTop;
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
       ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem));
       sqlite3Select(pParse, pSub, &dest);
       pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       pItem->fg.viaCoroutine = 1;
-      pItem->sq.regResult = dest.iSdst;
-      sqlite3VdbeEndCoroutine(v, pItem->sq.regReturn);
+      pSubq->regResult = dest.iSdst;
+      sqlite3VdbeEndCoroutine(v, pSubq->regReturn);
       sqlite3VdbeJumpHere(v, addrTop-1);
       sqlite3ClearTempRegCache(pParse);
     }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){
@@ -7790,12 +7825,16 @@ int sqlite3Select(
     }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
       /* This view has already been materialized by a prior entry in
       ** this same FROM clause.  Reuse it. */
-      if( pPrior->sq.addrFillSub ){
-        sqlite3VdbeAddOp2(v, OP_Gosub, pPrior->sq.regReturn,
-                                       pPrior->sq.addrFillSub);
+      Subquery *pPriorSubq;
+      assert( pPrior->fg.isSubquery );
+      pPriorSubq = pPrior->u4.pSubq;
+      assert( pPriorSubq!=0 );
+      if( pPriorSubq->addrFillSub ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pPriorSubq->regReturn,
+                                       pPriorSubq->addrFillSub);
       }
       sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor);
-      pSub->nSelectRow = pPrior->sq.pSelect->nSelectRow;
+      pSub->nSelectRow = pPriorSubq->pSelect->nSelectRow;
     }else{
       /* Materialize the view.  If the view is not correlated, generate a
       ** subroutine to do the materialization so that subsequent uses of
@@ -7806,9 +7845,9 @@ int sqlite3Select(
       int addrExplain;
 #endif
 
-      pItem->sq.regReturn = ++pParse->nMem;
+      pSubq->regReturn = ++pParse->nMem;
       topAddr = sqlite3VdbeAddOp0(v, OP_Goto);
-      pItem->sq.addrFillSub = topAddr+1;
+      pSubq->addrFillSub = topAddr+1;
       pItem->fg.isMaterialized = 1;
       if( pItem->fg.isCorrelated==0 ){
         /* If the subquery is not correlated and if we are not inside of
@@ -7825,15 +7864,15 @@ int sqlite3Select(
       sqlite3Select(pParse, pSub, &dest);
       pItem->pSTab->nRowLogEst = pSub->nSelectRow;
       if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
-      sqlite3VdbeAddOp2(v, OP_Return, pItem->sq.regReturn, topAddr+1);
+      sqlite3VdbeAddOp2(v, OP_Return, pSubq->regReturn, topAddr+1);
       VdbeComment((v, "end %!S", pItem));
       sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
       sqlite3VdbeJumpHere(v, topAddr);
       sqlite3ClearTempRegCache(pParse);
       if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){
         CteUse *pCteUse = pItem->u2.pCteUse;
-        pCteUse->addrM9e = pItem->sq.addrFillSub;
-        pCteUse->regRtn = pItem->sq.regReturn;
+        pCteUse->addrM9e = pSubq->addrFillSub;
+        pCteUse->regRtn = pSubq->regReturn;
         pCteUse->iCur = pItem->iCursor;
         pCteUse->nRowEst = pSub->nSelectRow;
       }