From: Johannes Truschnigg <johannes@truschnigg.info>
To: Jerry Sievers <gsievers19@comcast.net>
Cc: pgsql-admin@postgresql.org
Subject: Re: Odd OS, SAN or related throughput issue affecting large streamer
Date: Tue, 23 Mar 2021 19:07:20 +0100
Message-ID: <20210323180719.GB8871@vault.lan> (raw)
In-Reply-To: <87o8f9n5o0.fsf@jsievers.enova.com>
References: <87o8f9n5o0.fsf@jsievers.enova.com>
Hi Jerry.
On Tue, Mar 23, 2021 at 12:25:35PM -0500, Jerry Sievers wrote:
> Greetings!
>
> [...]
> Suggestions re where to look next?
Have you looked at the usual OS-level metrics yet?
Does the process that applies the streamed WAL to the secondary's database
exhibit high CPU load when the slowdown starts becoming noticeable? Check by
using `top` and `mpstat`.
Does I/O latency spike/increase during that time? Maybe your system is
beginning to page data in and out? Check by using `iostat` and `vmstat`.
If you can identify a/the metric that changes when your troubles begin to
manifest, we should be able to help you drill down to the root cause of it all
much better.
--
with best regards:
- Johannes Truschnigg ( johannes@truschnigg.info )
www: https://johannes.truschnigg.info/
phone: +43 650 2 133337
xmpp: johannes@truschnigg.info
Please do not bother me with HTML-email or attachments. Thank you.
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To: pgsql-admin@postgresql.org
Cc: johannes@truschnigg.info, gsievers19@comcast.net
Subject: Re: Odd OS, SAN or related throughput issue affecting large streamer
In-Reply-To: <20210323180719.GB8871@vault.lan>
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