Re: [Postgres-xc-developers] GTM Standby Crash

[Koichi S. <koi...@gm...>]

Thank you Pavan.

I think I added the lines in question.   Because you are the original
author if gtm, it's wonderful if you take a look at it.

Regards;
----------
Koichi Suzuki


2013/3/8 Pavan Deolasee <pav...@gm...>:
> On Thu, Mar 7, 2013 at 5:57 PM, Nikhil Sontakke <ni...@st...> wrote:
>> Hi,
>>
>> PFA, patch which fixes an obnoxious crash in GTM Standby. This one was
>> a tough nut to crack down. The crash is as below
>>
>> Program terminated with signal 11, Segmentation fault.
>> #0  0x00000000004253c9 in gtm_lappend ()
>> Missing separate debuginfos, use: debuginfo-install
>> glibc-2.12-1.80.el6_3.6.x86_64 libgcc-4.4.6-4.el6.x86_64
>> (gdb) bt
>> #0  0x00000000004253c9 in gtm_lappend ()
>> #1  0x000000000040ad77 in GTM_BkupBeginTransactionGetGXIDMulti.clone.0 ()
>> #2  0x000000000040aedb in ProcessBkupBeginTransactionGetGXIDCommand ()
>> #3  0x000000000040417c in GTM_ThreadMain ()
>>
>>
>>
>> IMHO, using TopMemoryContext to mean the top context of each thread is
>> pretty confusing. Bad choice of name for the memory context according
>> to me. Maybe we could have avoided this crash if we had used a
>> different name for the context.
>>
>> This "TopMemoryContext" goes away when that thread goes away. So ain't
>> nothing TOP about it.
>
> Well, let me at least try and defend because that's my baby :-) I
> think I chose name TopTransactionContext because I wanted to give a
> thread in GTM as much the same treatment as a process gets in
> Postgres. So I stick to the same names, but invented TopMost to mean
> the context which is global to the GTM process. My idea was and still
> is that we should avoid using TopMost as much as we can because that
> memory leaks will be hard to plug-in. Remember, we expect GTM to run
> as long as any one component of the cluster is running.. which pretty
> much means forever because while any one component of the cluster can
> go down, but not the entire cluster.
>
> But if its causing confusion, I won't mind adding a code commentary to
> explain the difference. Clearly my fault.
>
> Thanks,
> Pavan
>
> --
> Pavan Deolasee
> http://www.linkedin.com/in/pavandeolasee
>
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