Date: Thu, 26 Jun 2025 12:25:45 +0900 (JST)
Message-Id: <20250626.122545.1937425176692913230.ishii@postgresql.org>
To: laurenz.albe@cybertec.at
Cc: jamespang886@gmail.com, frits.hoogland@gmail.com,
 pgsql-performance@lists.postgresql.org
Subject: Re: many sessions waiting DataFileRead and extend
From: Tatsuo Ishii <ishii@postgresql.org>
In-Reply-To: <fa9bda2e74987d819fc99bfc8533cc349e50dc03.camel@cybertec.at>
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> On Thu, 2025-06-26 at 10:32 +0800, James Pang wrote:
>> thans for you suggestions, we have iowait from sar command too, copy=
 here, checking with infra team not found abnormal IO activities either=
.=A0=A0
>> 02:00:01 PM =A0CPU =A0 =A0%usr =A0 %nice =A0 =A0%sys %iowait =A0 =A0=
%irq =A0 %soft =A0%steal =A0%guest =A0%gnice =A0 %idle
>> 02:00:03 PM =A0all=A0 =A015.92 =A0 =A00.00 =A0 43.02 =A0 =A00.65 =A0=
 =A00.76 =A0 =A02.56 =A0 =A00.00 =A0 =A00.00 =A0 =A00.00 =A0 37.09
> =

> Crazy high system time.
> =

> If it is not transparent hugepages, the other suspect is fork().

Can we use starce -S to collect system call statistics to find out
which system call is taking time?

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp