RE: refcnt leak ?

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От Hiroshi Inoue
Тема RE: refcnt leak ?
Дата
Msg-id EKEJJICOHDIEMGPNIFIJMENECMAA.Inoue@tpf.co.jp
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Ответ на Re: refcnt leak ?  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: refcnt leak ?  (Tom Lane <tgl@sss.pgh.pa.us>)
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> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> 
> Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> > While examining recursive use of catalog cache,I found
> > a refcnt leak of relations.
> > After further investigation,I found that the following seems
> > to be the cause.
> 
> > [ in EndAppend() in nodeAppend.c ]
> 
> appendstate-> as_result_relation_info_list = NIL;
> 

Oh no,my point isn't on this line but on the line
estate->es_result_relation_info = NULL;

As the comment says,it depends on the assumption that 
estate->es_result_relation_info points to one of the node
of appendstate->as_result_relation_info_list(before set to
NIL). However ISTM appendstate->as_result_relation_info
_list is for inheritance and in the case "INSERT INTO ..
SELECT .. FROM .." it's not used. 

> That doesn't look like a problem to me --- the result relations *have*
> been closed, just above this line.
> 
> > BTW,doesn't EndAppend() neglect to call ExecCloseIndices()
> > for RelationInfos of appendstate->as_result_relation_info_list ?
> 
> Comparing nodeAppend to EndPlan(), I think you are right --- each
> resultinfo should have ExecCloseIndices applied too, in the loop just
> above the line you quote.  This did not use to be a problem because
> Append plans were readonly, but now that we have UPDATE/DELETE on
> inheritance hierarchies, there's a missing step here.  Was your test
> query of that kind?
>

I first changed this part but rd_refcnt leak didn't disappaear.
I have no refcnt leak example which is caused due to this flaw(?).
After that I found " estate->es_result_relation_info = NULL; "
in EndAppend() . I changed it to not do so when appendstate->
as_result_relation_info_list is NIL and rd_refcnt leak disappeared.

Regards.
Hiroshi Inoue


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