Make sure that INSERT INTO ... SELECT ... always uses an ephemeral
intermediate table if the SELECT clause refers to the destination table,
even if the SELECT clause is compound or uses the destination table
in a subquery. This fixes a long-standing bug that can cause an
infinite loop for some SQL statements. (CVS 4552)
FossilOrigin-Name: 492b39b6a8bf4ad8792d7a7949f77827a5047fd8
diff --git a/src/insert.c b/src/insert.c
index 9d68c95..b77dffc 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
-** $Id: insert.c,v 1.192 2007/09/03 17:30:07 danielk1977 Exp $
+** $Id: insert.c,v 1.193 2007/11/23 15:02:19 drh Exp $
*/
#include "sqliteInt.h"
@@ -99,22 +99,38 @@
}
/*
-** Return non-zero if SELECT statement p opens the table with rootpage
-** iTab in database iDb. This is used to see if a statement of the form
-** "INSERT INTO <iDb, iTab> SELECT ..." can run without using temporary
-** table for the results of the SELECT.
-**
-** No checking is done for sub-selects that are part of expressions.
+** Return non-zero if the table pTab in database iDb or any of its indices
+** have been opened at any point in the VDBE program beginning at location
+** iStartAddr throught the end of the program. This is used to see if
+** a statement of the form "INSERT INTO <iDb, pTab> SELECT ..." can
+** run without using temporary table for the results of the SELECT.
*/
-static int selectReadsTable(Select *p, Schema *pSchema, int iTab){
+static int readsTable(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
int i;
- struct SrcList_item *pItem;
- if( p->pSrc==0 ) return 0;
- for(i=0, pItem=p->pSrc->a; i<p->pSrc->nSrc; i++, pItem++){
- if( pItem->pSelect ){
- if( selectReadsTable(pItem->pSelect, pSchema, iTab) ) return 1;
- }else{
- if( pItem->pTab->pSchema==pSchema && pItem->pTab->tnum==iTab ) return 1;
+ int iEnd = sqlite3VdbeCurrentAddr(v);
+ for(i=iStartAddr; i<iEnd; i++){
+ VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
+ if( pOp->opcode==OP_OpenRead ){
+ VdbeOp *pPrior = &pOp[-1];
+ int tnum = pOp->p2;
+ assert( i>iStartAddr );
+ assert( pPrior->opcode==OP_Integer );
+ if( pPrior->p1==iDb ){
+ Index *pIndex;
+ if( tnum==pTab->tnum ){
+ return 1;
+ }
+ for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+ if( tnum==pIndex->tnum ){
+ return 1;
+ }
+ }
+ }
+ }
+ if( pOp->opcode==OP_VOpen && pOp->p3==(const char*)pTab->pVtab ){
+ assert( pOp->p3!=0 );
+ assert( pOp->p3type==P3_VTAB );
+ return 1;
}
}
return 0;
@@ -481,7 +497,7 @@
** of the tables being read by the SELECT statement. Also use a
** temp table in the case of row triggers.
*/
- if( triggers_exist || selectReadsTable(pSelect,pTab->pSchema,pTab->tnum) ){
+ if( triggers_exist || readsTable(v, iSelectLoop, iDb, pTab) ){
useTempTable = 1;
}
@@ -517,7 +533,7 @@
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
srcTab = -1;
- useTempTable = 0;
+ assert( useTempTable==0 );
nColumn = pList ? pList->nExpr : 0;
for(i=0; i<nColumn; i++){
if( sqlite3ExprResolveNames(&sNC, pList->a[i].pExpr) ){