diff options
Diffstat (limited to 'src/backend/executor/execMain.c')
| -rw-r--r-- | src/backend/executor/execMain.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index a825c281618..3a86d311629 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -26,7 +26,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.241.4.1 2005/08/25 19:45:00 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.241.4.2 2006/01/12 21:49:17 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1159,7 +1159,8 @@ lnext: ; newSlot = EvalPlanQual(estate, erm->rti, &update_ctid, - update_xmax); + update_xmax, + estate->es_snapshot->curcid); if (!TupIsNull(newSlot)) { slot = newSlot; @@ -1470,7 +1471,8 @@ ldelete:; epqslot = EvalPlanQual(estate, resultRelInfo->ri_RangeTableIndex, &update_ctid, - update_xmax); + update_xmax, + estate->es_snapshot->curcid); if (!TupIsNull(epqslot)) { *tupleid = update_ctid; @@ -1615,7 +1617,8 @@ lreplace:; epqslot = EvalPlanQual(estate, resultRelInfo->ri_RangeTableIndex, &update_ctid, - update_xmax); + update_xmax, + estate->es_snapshot->curcid); if (!TupIsNull(epqslot)) { *tupleid = update_ctid; @@ -1770,6 +1773,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo, * rti - rangetable index of table containing tuple * *tid - t_ctid from the outdated tuple (ie, next updated version) * priorXmax - t_xmax from the outdated tuple + * curCid - command ID of current command of my transaction * * *tid is also an output parameter: it's modified to hold the TID of the * latest version of the tuple (note this may be changed even on failure) @@ -1779,7 +1783,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo, */ TupleTableSlot * EvalPlanQual(EState *estate, Index rti, - ItemPointer tid, TransactionId priorXmax) + ItemPointer tid, TransactionId priorXmax, CommandId curCid) { evalPlanQual *epq; EState *epqstate; @@ -1856,6 +1860,24 @@ EvalPlanQual(EState *estate, Index rti, } /* + * If tuple was inserted by our own transaction, we have to check + * cmin against curCid: cmin >= curCid means our command cannot + * see the tuple, so we should ignore it. Without this we are + * open to the "Halloween problem" of indefinitely re-updating + * the same tuple. (We need not check cmax because + * HeapTupleSatisfiesDirty will consider a tuple deleted by + * our transaction dead, regardless of cmax.) We just checked + * that priorXmax == xmin, so we can test that variable instead + * of doing HeapTupleHeaderGetXmin again. + */ + if (TransactionIdIsCurrentTransactionId(priorXmax) && + HeapTupleHeaderGetCmin(tuple.t_data) >= curCid) + { + ReleaseBuffer(buffer); + return NULL; + } + + /* * We got tuple - now copy it for use by recheck query. */ copyTuple = heap_copytuple(&tuple); |