diff options
Diffstat (limited to 'src/backend/executor/nodeMergejoin.c')
| -rw-r--r-- | src/backend/executor/nodeMergejoin.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/src/backend/executor/nodeMergejoin.c b/src/backend/executor/nodeMergejoin.c index ad4aace6536..794871e5ba4 100644 --- a/src/backend/executor/nodeMergejoin.c +++ b/src/backend/executor/nodeMergejoin.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeMergejoin.c,v 1.87 2007/02/02 00:07:03 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeMergejoin.c,v 1.88 2007/05/21 17:57:33 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -706,6 +706,9 @@ ExecMergeJoin(MergeJoinState *node) } else { + /* Mark before advancing, if wanted */ + if (node->mj_ExtraMarks) + ExecMarkPos(innerPlan); /* Stay in same state to fetch next inner tuple */ if (doFillInner) { @@ -830,6 +833,9 @@ ExecMergeJoin(MergeJoinState *node) * now we get the next inner tuple, if any. If there's none, * advance to next outer tuple (which may be able to join to * previously marked tuples). + * + * NB: must NOT do "extraMarks" here, since we may need to + * return to previously marked tuples. */ innerTupleSlot = ExecProcNode(innerPlan); node->mj_InnerTupleSlot = innerTupleSlot; @@ -1140,6 +1146,9 @@ ExecMergeJoin(MergeJoinState *node) break; /* + * SKIPOUTER_ADVANCE: advance over an outer tuple that is + * known not to join to any inner tuple. + * * Before advancing, we check to see if we must emit an * outer-join fill tuple for this outer tuple. */ @@ -1204,6 +1213,9 @@ ExecMergeJoin(MergeJoinState *node) break; /* + * SKIPINNER_ADVANCE: advance over an inner tuple that is + * known not to join to any outer tuple. + * * Before advancing, we check to see if we must emit an * outer-join fill tuple for this inner tuple. */ @@ -1225,6 +1237,10 @@ ExecMergeJoin(MergeJoinState *node) return result; } + /* Mark before advancing, if wanted */ + if (node->mj_ExtraMarks) + ExecMarkPos(innerPlan); + /* * now we get the next inner tuple, if any */ @@ -1295,6 +1311,10 @@ ExecMergeJoin(MergeJoinState *node) return result; } + /* Mark before advancing, if wanted */ + if (node->mj_ExtraMarks) + ExecMarkPos(innerPlan); + /* * now we get the next inner tuple, if any */ @@ -1425,6 +1445,22 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags) innerPlanState(mergestate) = ExecInitNode(innerPlan(node), estate, eflags | EXEC_FLAG_MARK); + /* + * For certain types of inner child nodes, it is advantageous to issue + * MARK every time we advance past an inner tuple we will never return + * to. For other types, MARK on a tuple we cannot return to is a waste + * of cycles. Detect which case applies and set mj_ExtraMarks if we + * want to issue "unnecessary" MARK calls. + * + * Currently, only Material wants the extra MARKs, and it will be helpful + * only if eflags doesn't specify REWIND. + */ + if (IsA(innerPlan(node), Material) && + (eflags & EXEC_FLAG_REWIND) == 0) + mergestate->mj_ExtraMarks = true; + else + mergestate->mj_ExtraMarks = false; + #define MERGEJOIN_NSLOTS 4 /* |