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Commite990b9c

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The original patch to avoid building a hash join's hashtable when the

outer relation is empty did not work, per test case from Patrick Welche.It tried to use nodeHashjoin.c's high-level mechanisms for fetching anouter-relation tuple, but that code expected the hash table to be filledalready. As patched, the code failed in corner cases such as having noouter-relation tuples for the first hash batch. Revert and rewrite.

1 parentdd102d3 commite990b9cCopy full SHA for e990b9c

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3 files changed

+94

-163

lines changed

src
- backend/executor
  - nodeHash.c
  - nodeHashjoin.c
- include/nodes
  - execnodes.h

3 files changed

+94

-163

lines changed

`‎src/backend/executor/nodeHash.c`

Lines changed: 8 additions & 44 deletions

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.94 2005/06/15 07:27:44 neilc Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.95 2005/09/25 19:37:34 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -37,22 +37,14 @@ static void ExecHashIncreaseNumBatches(HashJoinTable hashtable);`
`37`	`37`	`/* ----------------------------------------------------------------`
`38`	`38`	`*ExecHash`
`39`	`39`	`*`
`40`		`- *produce the first tuple from our child node (and _only_ the`
`41`		`- *first tuple). This is of limited general use -- it does not`
`42`		`- *hash its output, and produces only a single tuple. It is`
`43`		`- *provided so that hash join can probe the inner hash input to`
`44`		`- *determine whether it is empty without needing to build the`
`45`		`- *entire hash table first, which is what MultiExecHash() would`
`46`		`- *do.`
	`40`	`+ *stub for pro forma compliance`
`47`	`41`	`* ----------------------------------------------------------------`
`48`	`42`	`*/`
`49`	`43`	`TupleTableSlot*`
`50`	`44`	`ExecHash(HashState*node)`
`51`	`45`	`{`
`52`		`-if (TupIsNull(node->firstTuple))`
`53`		`-node->firstTuple=ExecProcNode(outerPlanState(node));`
`54`		`-`
`55`		`-returnnode->firstTuple;`
	`46`	`+elog(ERROR,"Hash node does not support ExecProcNode call convention");`
	`47`	`+returnNULL;`
`56`	`48`	`}`
`57`	`49`
`58`	`50`	`/* ----------------------------------------------------------------`
`@@ -71,7 +63,6 @@ MultiExecHash(HashState *node)`
`71`	`63`	`TupleTableSlot*slot;`
`72`	`64`	`ExprContext*econtext;`
`73`	`65`	`uint32hashvalue;`
`74`		`-boolcleared_first_tuple= false;`
`75`	`66`
`76`	`67`	`/* must provide our own instrumentation support */`
`77`	`68`	`if (node->ps.instrument)`
`@@ -94,19 +85,9 @@ MultiExecHash(HashState *node)`
`94`	`85`	`*/`
`95`	`86`	`for (;;)`
`96`	`87`	`{`
`97`		`-/* use and clear the tuple produced by ExecHash(), if any */`
`98`		`-if (!TupIsNull(node->firstTuple))`
`99`		`-{`
`100`		`-slot=node->firstTuple;`
`101`		`-node->firstTuple=NULL;`
`102`		`-cleared_first_tuple= true;`
`103`		`-}`
`104`		`-else`
`105`		`-{`
`106`		`-slot=ExecProcNode(outerNode);`
`107`		`-if (TupIsNull(slot))`
`108`		`-break;`
`109`		`-}`
	`88`	`+slot=ExecProcNode(outerNode);`
	`89`	`+if (TupIsNull(slot))`
	`90`	`+break;`
`110`	`91`	`hashtable->totalTuples+=1;`
`111`	`92`	`/* We have to compute the hash value */`
`112`	`93`	`econtext->ecxt_innertuple=slot;`
`@@ -116,19 +97,7 @@ MultiExecHash(HashState *node)`
`116`	`97`
`117`	`98`	`/* must provide our own instrumentation support */`
`118`	`99`	`if (node->ps.instrument)`
`119`		`-{`
`120`		`-/*`
`121`		`- * XXX: kludge -- if ExecHash() was invoked, we've already`
`122`		`- * included the tuple that it produced in the row output count`
`123`		`- * for this node, so subtract 1 from the # of hashed tuples.`
`124`		`- */`
`125`		`-if (cleared_first_tuple)`
`126`		`-InstrStopNodeMulti(node->ps.instrument,`
`127`		`-hashtable->totalTuples-1);`
`128`		`-else`
`129`		`-InstrStopNodeMulti(node->ps.instrument,`
`130`		`-hashtable->totalTuples);`
`131`		`-}`
	`100`	`+InstrStopNodeMulti(node->ps.instrument,hashtable->totalTuples);`
`132`	`101`
`133`	`102`	`/*`
`134`	`103`	`* We do not return the hash table directly because it's not a subtype`
`@@ -161,7 +130,6 @@ ExecInitHash(Hash node, EState estate)`
`161`	`130`	`hashstate->ps.state=estate;`
`162`	`131`	`hashstate->hashtable=NULL;`
`163`	`132`	`hashstate->hashkeys=NIL;/* will be set by parent HashJoin */`
`164`		`-hashstate->firstTuple=NULL;`
`165`	`133`
`166`	`134`	`/*`
`167`	`135`	`* Miscellaneous initialization`
`@@ -221,8 +189,6 @@ ExecEndHash(HashState *node)`
`221`	`189`	`{`
`222`	`190`	`PlanState*outerPlan;`
`223`	`191`
`224`		`-node->firstTuple=NULL;`
`225`		`-`
`226`	`192`	`/*`
`227`	`193`	`* free exprcontext`
`228`	`194`	`*/`
`@@ -864,8 +830,6 @@ ExecHashTableReset(HashJoinTable hashtable)`
`864`	`830`	`void`
`865`	`831`	`ExecReScanHash(HashStatenode,ExprContextexprCtxt)`
`866`	`832`	`{`
`867`		`-node->firstTuple=NULL;`
`868`		`-`
`869`	`833`	`/*`
`870`	`834`	`* if chgParam of subnode is not null then plan will be re-scanned by`
`871`	`835`	`* first ExecProcNode.`

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Commite990b9c

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3 files changed

3 files changed

`‎src/backend/executor/nodeHash.c`

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