回复：回复：BUG #19040: Memory leak in hashed subplan node due to missing hashtempcxt reset
| От | 李海洋(陌痕) |
|---|---|
| Тема | 回复：回复：BUG #19040: Memory leak in hashed subplan node due to missing hashtempcxt reset |
| Дата | |
| Msg-id | bfb8be51-18e5-4839-a555-5c3d0ccd32d0.mohen.lhy@alibaba-inc.com обсуждение исходный текст |
| Ответ на | Re: 回复：BUG #19040: Memory leak in hashed subplan node due to missing hashtempcxt reset (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: BUG #19040: Memory leak in hashed subplan node due to missing hashtempcxt reset
|
| Список | pgsql-bugs |
On 2025-09-06 20:31:53 Tom Lane <tgl@sss.pgh.pa.us> writes:
> After contemplating things for awhile, I think that feichanghong’s
> idea is the right one after all: in each of the functions that switch
> into hashtable->tempcxt, let's do a reset on the way out, as attached.
> That's straightforward and visibly related to the required data
> lifespan.
> idea is the right one after all: in each of the functions that switch
> into hashtable->tempcxt, let's do a reset on the way out, as attached.
> That's straightforward and visibly related to the required data
> lifespan.
I have considered this approach as well, but my concern is that "tempcxt"
is not always an independent memory context. In some cases, it references
another context — for example, in nodeSetOp.c’s "build_hash_table", “tempcxt"
points to "setopstate->ps.ps_ExprContext->ecxt_per_tuple_memory". There is
similar usage in nodeAgg.c as well. I’m not entirely sure that this approach would
not discard data we still need, because the lifespan of
"ps_ExprContext->ecxt_per_tuple_memory" seems to be longer than “tempcxt”.
Should we make tempcxt a completely independent memory context?
—
Thanks
Haiyang Li
В списке pgsql-bugs по дате отправления: