Andy Fan <zhihuifan1...@163.com> writes:
> Andy Fan <zhihuifan1...@163.com> writes:
>
>> ..., I attached the 2 MemoryContext in
>> JoinState rather than MergeJoinState, which is for the "shared detoast
>> value"[0] more or less.
>>
In order to delimit the scope of this discussion, I attached the 2
MemoryContext to MergeJoinState. Since the code was writen by Tom at
2005, so add Tom to the cc-list.
>From 20068bdda00716da712fb3f1e554401e81924e19 Mon Sep 17 00:00:00 2001
From: "yizhi.fzh" <yizhi....@alibaba-inc.com>
Date: Sun, 17 Dec 2023 21:41:34 +0800
Subject: [PATCH v2 1/1] Use MemoryContext instead of ExprContext for
nodeMergejoin.c
MergeJoin needs to store the values in MergeJoinClause for a longer
lifespan, in the past it uses a dedicate ExprContext, however a
MemoryContext should be OK. This patch does this.
---
src/backend/executor/nodeMergejoin.c | 29 +++++++++++++++++-----------
src/include/nodes/execnodes.h | 5 +++--
2 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/src/backend/executor/nodeMergejoin.c b/src/backend/executor/nodeMergejoin.c
index 3cdab77dfc..4d45305482 100644
--- a/src/backend/executor/nodeMergejoin.c
+++ b/src/backend/executor/nodeMergejoin.c
@@ -294,7 +294,7 @@ MJExamineQuals(List *mergeclauses,
static MJEvalResult
MJEvalOuterValues(MergeJoinState *mergestate)
{
- ExprContext *econtext = mergestate->mj_OuterEContext;
+ ExprContext *econtext = mergestate->js.ps.ps_ExprContext;
MJEvalResult result = MJEVAL_MATCHABLE;
int i;
MemoryContext oldContext;
@@ -303,9 +303,9 @@ MJEvalOuterValues(MergeJoinState *mergestate)
if (TupIsNull(mergestate->mj_OuterTupleSlot))
return MJEVAL_ENDOFJOIN;
- ResetExprContext(econtext);
+ MemoryContextReset(mergestate->mj_outerTuple_memory);
- oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
+ oldContext = MemoryContextSwitchTo(mergestate->mj_outerTuple_memory);
econtext->ecxt_outertuple = mergestate->mj_OuterTupleSlot;
@@ -341,7 +341,7 @@ MJEvalOuterValues(MergeJoinState *mergestate)
static MJEvalResult
MJEvalInnerValues(MergeJoinState *mergestate, TupleTableSlot *innerslot)
{
- ExprContext *econtext = mergestate->mj_InnerEContext;
+ ExprContext *econtext = mergestate->js.ps.ps_ExprContext;
MJEvalResult result = MJEVAL_MATCHABLE;
int i;
MemoryContext oldContext;
@@ -350,9 +350,9 @@ MJEvalInnerValues(MergeJoinState *mergestate, TupleTableSlot *innerslot)
if (TupIsNull(innerslot))
return MJEVAL_ENDOFJOIN;
- ResetExprContext(econtext);
+ MemoryContextReset(mergestate->mj_innerTuple_memory);
- oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
+ oldContext = MemoryContextSwitchTo(mergestate->mj_innerTuple_memory);
econtext->ecxt_innertuple = innerslot;
@@ -1447,6 +1447,7 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
TupleDesc outerDesc,
innerDesc;
const TupleTableSlotOps *innerOps;
+ ExprContext *econtext;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
@@ -1471,13 +1472,19 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, int eflags)
*/
ExecAssignExprContext(estate, &mergestate->js.ps);
+ econtext = mergestate->js.ps.ps_ExprContext;
+
/*
- * we need two additional econtexts in which we can compute the join
- * expressions from the left and right input tuples. The node's regular
- * econtext won't do because it gets reset too often.
+ * we need two additional contexts in which we can compute the join
+ * expressions from the left and right input tuples. The econtext's
+ * regular ecxt_per_tuple_memory won't do because it gets reset too often.
*/
- mergestate->mj_OuterEContext = CreateExprContext(estate);
- mergestate->mj_InnerEContext = CreateExprContext(estate);
+ mergestate->mj_outerTuple_memory = AllocSetContextCreate(econtext->ecxt_per_query_memory,
+ "OuterTupleCtx",
+ ALLOCSET_SMALL_SIZES);
+ mergestate->mj_innerTuple_memory = AllocSetContextCreate(econtext->ecxt_per_query_memory,
+ "InnerTupleCtx",
+ ALLOCSET_SMALL_SIZES);
/*
* initialize child nodes
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 5d7f17dee0..e8af959c01 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -2064,8 +2064,9 @@ typedef struct MergeJoinState
TupleTableSlot *mj_MarkedTupleSlot;
TupleTableSlot *mj_NullOuterTupleSlot;
TupleTableSlot *mj_NullInnerTupleSlot;
- ExprContext *mj_OuterEContext;
- ExprContext *mj_InnerEContext;
+
+ MemoryContext mj_outerTuple_memory;
+ MemoryContext mj_innerTuple_memory;
} MergeJoinState;
/* ----------------
--
2.34.1
--
Best Regards
Andy Fan
