From: Ron <ronljohnsonjr@gmail.com>
To: pgsql-admin@lists.postgresql.org
Subject: Re: how to debug the postgres performance issue
Date: Sat, 15 Sep 2018 03:21:18 -0500
Message-ID: <96eaac9a-83fe-b4bd-8e3a-8b1e93082f77@gmail.com> (raw)
In-Reply-To: <c48da347e2b048a5b4cff2f048c5330b@EX01.highgo.com>
References: <c48da347e2b048a5b4cff2f048c5330b@EX01.highgo.com>
On 09/14/2018 04:34 AM, 范国腾 wrote:
>
> Hi,
>
> We are doing the performance test in two nodes system(active/standby).
> Now we find that the disk IO is very high but the CPU is low.
>
On both nodes or just one (and if so, which one)?
If you incrementally increase the workload, starting from the quiescent
state, when do you see this happening?
> Is there any method or tool to help us debug to find which function
> makes this issue?
>
> We try to use the gprof but it does not help us. The result show the
> LWLockAssign（the shared buffer init）is called the most time. The other
> function is called no more that 33139. That seems no problem.
>
> Could you please give any suggestion how to debug the high IO/low CPU
> issue?
>
> Thanks
>
> Steven
>
> ===================================
>
> no time accumulated
>
> % cumulative self self total
>
> time seconds seconds calls Ts/call Ts/call name
>
> 0.00 0.00 0.00 9240928 0.00 0.00 LWLockAssign
>
> 0.00 0.00 0.00 33139 0.00 0.00 ShmemAlloc
>
> 0.00 0.00 0.00 33084 0.00 0.00 seg_alloc
>
> ….
>
--
Angular momentum makes the world go 'round.
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Subject: Re: how to debug the postgres performance issue
In-Reply-To: <96eaac9a-83fe-b4bd-8e3a-8b1e93082f77@gmail.com>
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