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help / color / mirror / Atom feedFrom: Achilleas Mantzios - cloud <[email protected]>
To: [email protected]
Subject: Re: Suddenly all queries moved to seq scan
Date: Wed, 20 Nov 2024 14:56:05 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAOW_W8PZ7Op_vOT9szMnpZE4jOmP09NWfc3M1ORTFMzjebpK5w@mail.gmail.com>
References: <CAOW_W8PZ7Op_vOT9szMnpZE4jOmP09NWfc3M1ORTFMzjebpK5w@mail.gmail.com>
On 11/20/24 12:50, Sreejith P wrote:
> Hi,
>
> We are using PostgresQL 10 in our production database. We have around
> 890 req /s request on peak time.
>
> We have 1 primary and 4 slave databases as well in the same postgres
> cluster.
>
> 2 days back we applied some patches in the primary server and
> restarted. We didn't do anything on the secondary server.
>
> Next day, After 18 hours all our queries from secondary servers
> started taking too much time. queries were working in 2 sec started
> taking 80 seconds. Almost all queries behaved the same way.
>
> After half an hour of outage we restarted all db servers and system
> back to normal.
>
> Still we are not able to understand the root case. We couldn't find
> any error log or fatal errors. During the incident, in one of the
> read server disks was full. We couldn't see any replication lag or
> query cancellation due to replication.
>
> please help
Still you say seq scan, how do you know that? You run explain (buffers,
analyze, settings) ? If this is indeed the case, then you need to check
your indexes. Check when they were last used/scanned and if they are
usable. Did the disk error had any of your PostgreSQL tablespaces /
tables/indexes ?
>
> Regards
> Sreejith
>
>
>
>
>
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