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author | Tom Lane | 2014-06-20 02:14:00 +0000 |
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committer | Tom Lane | 2014-06-20 02:14:00 +0000 |
commit | d297c91d43798d19b80d5465349bb0f53fc9499a (patch) | |
tree | da69484a5b8b2fd1ffda229a746edb773a3e20f8 /src/backend/executor/nodeFunctionscan.c | |
parent | 2f69338bdeadc000abdfec964e38a4956d327ecb (diff) |
Avoid leaking memory while evaluating arguments for a table function.
ExecMakeTableFunctionResult evaluated the arguments for a function-in-FROM
in the query-lifespan memory context. This is insignificant in simple
cases where the function relation is scanned only once; but if the function
is in a sub-SELECT or is on the inside of a nested loop, any memory
consumed during argument evaluation can add up quickly. (The potential for
trouble here had been foreseen long ago, per existing comments; but we'd
not previously seen a complaint from the field about it.) To fix, create
an additional temporary context just for this purpose.
Per an example from MauMau. Back-patch to all active branches.
Diffstat (limited to 'src/backend/executor/nodeFunctionscan.c')
-rw-r--r-- | src/backend/executor/nodeFunctionscan.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c index 8cb02b31edb..fe06cb26b41 100644 --- a/src/backend/executor/nodeFunctionscan.c +++ b/src/backend/executor/nodeFunctionscan.c @@ -25,6 +25,7 @@ #include "executor/nodeFunctionscan.h" #include "funcapi.h" #include "utils/builtins.h" +#include "utils/memutils.h" static TupleTableSlot *FunctionNext(FunctionScanState *node); @@ -64,6 +65,7 @@ FunctionNext(FunctionScanState *node) node->tuplestorestate = tuplestorestate = ExecMakeTableFunctionResult(node->funcexpr, node->ss.ps.ps_ExprContext, + node->argcontext, node->tupdesc, node->eflags & EXEC_FLAG_BACKWARD); } @@ -217,6 +219,19 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags) ExecAssignResultTypeFromTL(&scanstate->ss.ps); ExecAssignScanProjectionInfo(&scanstate->ss); + /* + * Create a memory context that ExecMakeTableFunctionResult can use to + * evaluate function arguments in. We can't use the per-tuple context for + * this because it gets reset too often; but we don't want to leak + * evaluation results into the query-lifespan context either. We just + * need one context, because we evaluate each function separately. + */ + scanstate->argcontext = AllocSetContextCreate(CurrentMemoryContext, + "Table function arguments", + ALLOCSET_DEFAULT_MINSIZE, + ALLOCSET_DEFAULT_INITSIZE, + ALLOCSET_DEFAULT_MAXSIZE); + return scanstate; } |