From c058fc2a2b8ea25015b211186c88a6a3006f5937 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 13 Nov 2018 12:18:25 -0800 Subject: [PATCH] Rationalize expression context reset in ExecModifyTable(). The current pattern of reseting expressions both in ExecProcessReturning() and ExecOnConflictUpdate() makes it harder than necessary to reason about memory lifetimes. It also requires materializing slots unnecessarily, although this patch doesn't take advantage of the fact that that's not necessary anymore. Instead reset the expression context once for each input tuple. Author: Ashutosh Bapat Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de --- src/backend/executor/nodeModifyTable.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c index e2836b75ff..6ef694d5a4 100644 --- a/src/backend/executor/nodeModifyTable.c +++ b/src/backend/executor/nodeModifyTable.c @@ -163,12 +163,6 @@ ExecProcessReturning(ResultRelInfo *resultRelInfo, ProjectionInfo *projectReturning = resultRelInfo->ri_projectReturning; ExprContext *econtext = projectReturning->pi_exprContext; - /* - * Reset per-tuple memory context to free any expression evaluation - * storage allocated in the previous cycle. - */ - ResetExprContext(econtext); - /* Make tuple and any needed join variables available to ExecProject */ if (tupleSlot) econtext->ecxt_scantuple = tupleSlot; @@ -1453,13 +1447,7 @@ ExecOnConflictUpdate(ModifyTableState *mtstate, elog(ERROR, "unrecognized heap_lock_tuple status: %u", test); } - /* - * Success, the tuple is locked. - * - * Reset per-tuple memory context to free any expression evaluation - * storage allocated in the previous cycle. - */ - ResetExprContext(econtext); + /* Success, the tuple is locked. */ /* * Verify that the tuple is visible to our MVCC snapshot if the current @@ -2028,6 +2016,14 @@ ExecModifyTable(PlanState *pstate) */ ResetPerTupleExprContext(estate); + /* + * Reset per-tuple memory context used for processing on conflict and + * returning clauses, to free any expression evaluation storage + * allocated in the previous cycle. + */ + if (pstate->ps_ExprContext) + ResetExprContext(pstate->ps_ExprContext); + planSlot = ExecProcNode(subplanstate); if (TupIsNull(planSlot))