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Date: Fri, 26 Feb 2016 16:46:42 +0800
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 <CAB0yrekZLSdBTE8gmPrego0uHE1TuUSgDT9n9eyn-U-C8Ciu7w@mail.gmail.com>
Subject: Re: how to debug hawq segment
From: Hubert Zhang <hzhang@pivotal.io>
To: dev@hawq.incubator.apache.org
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Hi Jin Tao,
   In hawq, QE(query executor) will be reused, so that after running the
first query, you can debug QE in the following queries.
   Your method works on debugging QE as well.

Thanks
Huan Zhang


On Fri, Feb 26, 2016 at 3:27 PM, jin tao <tonytao0505@outlook.com> wrote:

> hi folks,
>
> I'm now reading the source code and tried to review and debug some issues.
>
> I chose issue HAWQ-442 <https://issues.apache.org/jira/browse/HAWQ-442>,and
> using gdb to debug the code.
> my procedure is :
> 1.open a psql  and using select pg_backend_pid() to get the pid,
> 2.open another terminal  and using gdb postgres #pid# to debug the program.
> I could use backtrace to know the process of function exected,like:
> (gdb) bt
> #0  0x00007fa8623ab5bb in recv () from /lib64/libpthread.so.0
> #1  0x00000000006a8473 in secure_read ()
> #2  0x00000000006b06d6 in pq_recvbuf ()
> #3  0x00000000006b12c5 in pq_getbyte ()
> #4  0x00000000007d350c in SocketBackend ()
> #5  0x00000000007d9425 in PostgresMain ()
> #6  0x000000000078bf65 in ServerLoop ()
> #7  0x000000000078ec59 in PostmasterMain ()
> #8  0x00000000004a16bf in main ()
>
> It seems only waht happened in the master.How could I trace and debug each
> segement and konw the process of function called?
>
> Many thanks!
>
> Best regards!
> jin tao
>

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