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authorTom Lane2014-06-20 02:14:00 +0000
committerTom Lane2014-06-20 02:14:00 +0000
commitd297c91d43798d19b80d5465349bb0f53fc9499a (patch)
treeda69484a5b8b2fd1ffda229a746edb773a3e20f8 /src/backend/executor/nodeFunctionscan.c
parent2f69338bdeadc000abdfec964e38a4956d327ecb (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.c15
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;
}