Re: [HACKERS] aggregation memory leak and fix - Mailing list pgsql-hackers

> I am interested to see if it fixes the expression leak you saw.  I have
> not committed this yet.  I want to look at it some more.
>  
I'm afraid that this doesn't seem to have any effect on my query.

Looking at your code, I think the problem is that most of the
allocations in my query are on the top part of the if statement that
you modified (i.e. the == SQLlanguageId part).  Below is a snippet of
a trace from my query, with approximate line numbers for execQual.c
with your patch applied:

(execQual) language == SQLlanguageId (execQual.c:757)
(execQual) execute postquel_function (execQual.c:759)
(mcxt) MemoryContextAlloc 32 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 16 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 528 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 56 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 88 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 24 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 8 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 65 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 48 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 8 bytes in ** Blank Portal **-heap
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(execQual) exit qual context (execQual.c:862)
(mcxt) MemoryContextAlloc 60 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 16 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 64 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 64 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 528 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 16 bytes
(execQual) return from postquel_function (execQual.c:764)
(execQual) return from ExecEvalFuncArgs (execQual.c:792)
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(execQual) exit qual context (execQual.c:862)
(mcxt) MemoryContextAlloc 108 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 108 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 128 bytes
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(mcxt) MemoryContextAlloc 8 bytes in <Qual manager>-heap
(execQual) exit qual context (execQual.c:862)

<pattern repeats>

(execQual) language == SQLlanguageId (execQual.c:757)
(execQual) execute postquel_function (execQual.c:759)
(mcxt) MemoryContextAlloc 32 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 16 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 528 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 56 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 88 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 24 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 8 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 65 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 48 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 8 bytes in ** Blank Portal **-heap
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(execQual) exit qual context (execQual.c:862)
(mcxt) MemoryContextAlloc 60 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 16 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 64 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 64 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 528 bytes
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 16 bytes
(execQual) return from postquel_function (execQual.c:764)
(execQual) return from ExecEvalFuncArgs (execQual.c:792)
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(execQual) exit qual context (execQual.c:862)
(mcxt) MemoryContextAlloc 108 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextAlloc 108 bytes in ** Blank Portal **-heap
(mcxt) MemoryContextFree in ** Blank Portal **-heap freed 128 bytes
(execQual) else clause NOT SQLlanguageId (execQual.c:822)
(execQual) install qual memory context (execQual.c:858)
(mcxt) MemoryContextAlloc 8 bytes in <Qual manager>-heap
(execQual) exit qual context (execQual.c:862)


the MemoryContext lines give the name of the portal where each
allocation is happening - you see that your Qual manager only captures
a very small number (one) of the allocations, the rest are in the
upper part of the if statement.

Note that I also placed a printf next to your EndPortalAllocMode() and
StartPortalAllocMode() fix in ExecQual() - I believe this is what is
supposed to clear the portal and free the memory - and that printf
never appears in the above trace.

Sorry if the trace is a little confusing, but I hope that it helps you
zero in.

Erik