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Allow SQL-language functions to return the output of an INSERT/UPDATE/DELETE

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RETURNING clause, not just a SELECT as formerly.

A side effect of this patch is that when a set-returning SQL function is used
in a FROM clause, performance is improved because the output is collected into
a tuplestore within the function, rather than using the less efficient
value-per-call mechanism.
This commit is contained in:
Tom Lane
2008-10-31 19:37:56 +00:00
parent cd97f98844
commit 9b46abb7c4
11 changed files with 833 additions and 312 deletions
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60
src/backend/executor/execQual.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.235 2008/10/29 00:00:38 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.236 2008/10/31 19:37:56 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1334,7 +1334,8 @@ ExecMakeFunctionResult(FuncExprState *fcache,
{
List *arguments;
Datum result;
FunctionCallInfoData fcinfo;
FunctionCallInfoData fcinfo_data;
FunctionCallInfo fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo; /* for functions returning sets */
ExprDoneCond argDone;
@ -1384,6 +1385,20 @@ restart:
Assert(!fcache->setArgsValid);
}
/*
* For non-set-returning functions, we just use a local-variable
* FunctionCallInfoData. For set-returning functions we keep the callinfo
* record in fcache->setArgs so that it can survive across multiple
* value-per-call invocations. (The reason we don't just do the latter
* all the time is that plpgsql expects to be able to use simple expression
* trees re-entrantly. Which might not be a good idea, but the penalty
* for not doing so is high.)
*/
if (fcache->func.fn_retset)
fcinfo = &fcache->setArgs;
else
fcinfo = &fcinfo_data;
/*
* arguments is a list of expressions to evaluate before passing to the
* function manager. We skip the evaluation if it was already done in the
@ -1394,8 +1409,8 @@ restart:
if (!fcache->setArgsValid)
{
/* Need to prep callinfo structure */
InitFunctionCallInfoData(fcinfo, &(fcache->func), 0, NULL, NULL);
argDone = ExecEvalFuncArgs(&fcinfo, arguments, econtext);
InitFunctionCallInfoData(*fcinfo, &(fcache->func), 0, NULL, NULL);
argDone = ExecEvalFuncArgs(fcinfo, arguments, econtext);
if (argDone == ExprEndResult)
{
/* input is an empty set, so return an empty set. */
@ -1412,8 +1427,7 @@ restart:
}
else
{
/* Copy callinfo from previous evaluation */
memcpy(&fcinfo, &fcache->setArgs, sizeof(fcinfo));
/* Re-use callinfo from previous evaluation */
hasSetArg = fcache->setHasSetArg;
/* Reset flag (we may set it again below) */
fcache->setArgsValid = false;
@ -1424,12 +1438,12 @@ restart:
*/
if (fcache->func.fn_retset)
{
fcinfo.resultinfo = (Node *) &rsinfo;
fcinfo->resultinfo = (Node *) &rsinfo;
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = fcache->funcResultDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
/* note we do not set SFRM_Materialize_Random */
/* note we do not set SFRM_Materialize_Random or _Preferred */
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
@ -1468,9 +1482,9 @@ restart:
if (fcache->func.fn_strict)
{
for (i = 0; i < fcinfo.nargs; i++)
for (i = 0; i < fcinfo->nargs; i++)
{
if (fcinfo.argnull[i])
if (fcinfo->argnull[i])
{
callit = false;
break;
@ -1480,12 +1494,12 @@ restart:
if (callit)
{
pgstat_init_function_usage(&fcinfo, &fcusage);
pgstat_init_function_usage(fcinfo, &fcusage);
fcinfo.isnull = false;
fcinfo->isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(&fcinfo);
*isNull = fcinfo.isnull;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
*isDone = rsinfo.isDone;
pgstat_end_function_usage(&fcusage,
@ -1511,7 +1525,7 @@ restart:
if (fcache->func.fn_retset &&
*isDone == ExprMultipleResult)
{
memcpy(&fcache->setArgs, &fcinfo, sizeof(fcinfo));
Assert(fcinfo == &fcache->setArgs);
fcache->setHasSetArg = hasSetArg;
fcache->setArgsValid = true;
/* Register cleanup callback if we didn't already */
@ -1567,7 +1581,7 @@ restart:
break; /* input not a set, so done */
/* Re-eval args to get the next element of the input set */
argDone = ExecEvalFuncArgs(&fcinfo, arguments, econtext);
argDone = ExecEvalFuncArgs(fcinfo, arguments, econtext);
if (argDone != ExprMultipleResult)
{
@ -1605,9 +1619,9 @@ restart:
*/
if (fcache->func.fn_strict)
{
for (i = 0; i < fcinfo.nargs; i++)
for (i = 0; i < fcinfo->nargs; i++)
{
if (fcinfo.argnull[i])
if (fcinfo->argnull[i])
{
*isNull = true;
return (Datum) 0;
@ -1615,11 +1629,11 @@ restart:
}
}
pgstat_init_function_usage(&fcinfo, &fcusage);
pgstat_init_function_usage(fcinfo, &fcusage);
fcinfo.isnull = false;
result = FunctionCallInvoke(&fcinfo);
*isNull = fcinfo.isnull;
fcinfo->isnull = false;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
pgstat_end_function_usage(&fcusage, true);
}
@ -1737,7 +1751,7 @@ ExecMakeTableFunctionResult(ExprState *funcexpr,
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = expectedDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize | SFRM_Materialize_Preferred);
if (randomAccess)
rsinfo.allowedModes |= (int) SFRM_Materialize_Random;
rsinfo.returnMode = SFRM_ValuePerCall;