diff options
Diffstat (limited to 'src/backend/executor/nodeAgg.c')
| -rw-r--r-- | src/backend/executor/nodeAgg.c | 76 |
1 files changed, 58 insertions, 18 deletions
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index b06e1c1562a..28c15bab99e 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -91,10 +91,13 @@ * transition value or a previous function result, and in either case its * value need not be preserved. See int8inc() for an example. Notice that * advance_transition_function() is coded to avoid a data copy step when - * the previous transition value pointer is returned. Also, some - * transition functions want to store working state in addition to the - * nominal transition value; they can use the memory context returned by - * AggCheckCallContext() to do that. + * the previous transition value pointer is returned. It is also possible + * to avoid repeated data copying when the transition value is an expanded + * object: to do that, the transition function must take care to return + * an expanded object that is in a child context of the memory context + * returned by AggCheckCallContext(). Also, some transition functions want + * to store working state in addition to the nominal transition value; they + * can use the memory context returned by AggCheckCallContext() to do that. * * Note: AggCheckCallContext() is available as of PostgreSQL 9.0. The * AggState is available as context in earlier releases (back to 8.1), @@ -791,8 +794,10 @@ advance_transition_function(AggState *aggstate, /* * If pass-by-ref datatype, must copy the new value into aggcontext and - * pfree the prior transValue. But if transfn returned a pointer to its - * first input, we don't need to do anything. + * free the prior transValue. But if transfn returned a pointer to its + * first input, we don't need to do anything. Also, if transfn returned a + * pointer to a R/W expanded object that is already a child of the + * aggcontext, assume we can adopt that value without copying it. */ if (!pertrans->transtypeByVal && DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue)) @@ -800,12 +805,25 @@ advance_transition_function(AggState *aggstate, if (!fcinfo->isnull) { MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory); - newVal = datumCopy(newVal, - pertrans->transtypeByVal, - pertrans->transtypeLen); + if (DatumIsReadWriteExpandedObject(newVal, + false, + pertrans->transtypeLen) && + MemoryContextGetParent(DatumGetEOHP(newVal)->eoh_context) == CurrentMemoryContext) + /* do nothing */ ; + else + newVal = datumCopy(newVal, + pertrans->transtypeByVal, + pertrans->transtypeLen); } if (!pergroupstate->transValueIsNull) - pfree(DatumGetPointer(pergroupstate->transValue)); + { + if (DatumIsReadWriteExpandedObject(pergroupstate->transValue, + false, + pertrans->transtypeLen)) + DeleteExpandedObject(pergroupstate->transValue); + else + pfree(DatumGetPointer(pergroupstate->transValue)); + } } pergroupstate->transValue = newVal; @@ -1053,8 +1071,11 @@ advance_combine_function(AggState *aggstate, /* * If pass-by-ref datatype, must copy the new value into aggcontext and - * pfree the prior transValue. But if the combine function returned a - * pointer to its first input, we don't need to do anything. + * free the prior transValue. But if the combine function returned a + * pointer to its first input, we don't need to do anything. Also, if the + * combine function returned a pointer to a R/W expanded object that is + * already a child of the aggcontext, assume we can adopt that value + * without copying it. */ if (!pertrans->transtypeByVal && DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue)) @@ -1062,12 +1083,25 @@ advance_combine_function(AggState *aggstate, if (!fcinfo->isnull) { MemoryContextSwitchTo(aggstate->aggcontexts[aggstate->current_set]->ecxt_per_tuple_memory); - newVal = datumCopy(newVal, - pertrans->transtypeByVal, - pertrans->transtypeLen); + if (DatumIsReadWriteExpandedObject(newVal, + false, + pertrans->transtypeLen) && + MemoryContextGetParent(DatumGetEOHP(newVal)->eoh_context) == CurrentMemoryContext) + /* do nothing */ ; + else + newVal = datumCopy(newVal, + pertrans->transtypeByVal, + pertrans->transtypeLen); } if (!pergroupstate->transValueIsNull) - pfree(DatumGetPointer(pergroupstate->transValue)); + { + if (DatumIsReadWriteExpandedObject(pergroupstate->transValue, + false, + pertrans->transtypeLen)) + DeleteExpandedObject(pergroupstate->transValue); + else + pfree(DatumGetPointer(pergroupstate->transValue)); + } } pergroupstate->transValue = newVal; @@ -1333,7 +1367,9 @@ finalize_aggregate(AggState *aggstate, (void *) aggstate, NULL); /* Fill in the transition state value */ - fcinfo.arg[0] = pergroupstate->transValue; + fcinfo.arg[0] = MakeExpandedObjectReadOnly(pergroupstate->transValue, + pergroupstate->transValueIsNull, + pertrans->transtypeLen); fcinfo.argnull[0] = pergroupstate->transValueIsNull; anynull |= pergroupstate->transValueIsNull; @@ -1360,6 +1396,7 @@ finalize_aggregate(AggState *aggstate, } else { + /* Don't need MakeExpandedObjectReadOnly; datumCopy will copy it */ *resultVal = pergroupstate->transValue; *resultIsNull = pergroupstate->transValueIsNull; } @@ -1410,7 +1447,9 @@ finalize_partialaggregate(AggState *aggstate, { FunctionCallInfo fcinfo = &pertrans->serialfn_fcinfo; - fcinfo->arg[0] = pergroupstate->transValue; + fcinfo->arg[0] = MakeExpandedObjectReadOnly(pergroupstate->transValue, + pergroupstate->transValueIsNull, + pertrans->transtypeLen); fcinfo->argnull[0] = pergroupstate->transValueIsNull; *resultVal = FunctionCallInvoke(fcinfo); @@ -1419,6 +1458,7 @@ finalize_partialaggregate(AggState *aggstate, } else { + /* Don't need MakeExpandedObjectReadOnly; datumCopy will copy it */ *resultVal = pergroupstate->transValue; *resultIsNull = pergroupstate->transValueIsNull; } |