Thanks again, the reason is found.
The following statement frees all the context for aggregation, including the
transValue and tempTransValue:
MemoryContextResetAndDeleteChildren(winstate-aggcontext);
-Original Message-
From: Tom Lane [mailto:t...@sss.pgh.pa.us]
Sent: 2012年8月22日 9:47
To: Wang, Chaoyong
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] problem when optimizing the window aggregation
Wang, Chaoyong chaoyong.w...@emc.com writes:
I used the function datumCopy as following:
peraggstate-transValue = datumCopy(peraggstate-tempTransValue,
peraggstate-transtypeByVal, peraggstate-transtypeLen);
You need to guard that with an is-null check, because datumCopy isn't
designed to cope with null values. (Which is historical, I guess, but
we're not likely to change it now.) If you look around you will find
plenty of examples of this coding pattern.
regards, tom lane
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