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Make sure that INSERT INTO ... SELECT ... always uses an ephemeral

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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
This commit is contained in:
drh
2007-11-23 15:02:19 +00:00
parent f4ce8ed048
commit 48d1178ad8
4 changed files with 132 additions and 24 deletions
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50
src/insert.c
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@@ -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 @@ void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
}
/*
** 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 @@ void sqlite3Insert(
** 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 @@ void sqlite3Insert(
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) ){