Date: Thu, 20 Dec 2018 12:37:43 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Devendra Yadav <devendraydba@gmail.com>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: Stats getting corrupted
Message-ID: <20181220153743.slaxsk4vjcvwwe6h@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: 
 <CAGQOD0mu3u-k3oRJdrhrJJwBNK0An7nG02jUypgqiMxoRvZ5Ug@mail.gmail.com>
User-Agent: NeoMutt/20180716
Precedence: bulk

On 2018-Dec-20, Devendra Yadav wrote:

> Dear All,
> 
> The stats file in *pg_stat_tmp *are getting corrupted. Even earlier the
> files in *pg_stat* got corrupted. They show ?? ?? when you list the files
> in folder. Also we can see them in the error log.
> it says " *could not open statistics file 'pg_stat_tml/db_0.tmp': to
> 'pg_stat_tmp/db_0.stat': Input/output error".*

You have problems related to the disk or operating system.  This is not
PostgreSQL's fault.  See `dmesg` or whatever OS diagnostics you have.

I suggest never to transcribe error messages manually.  Copy & paste instead.
When transcribing you're likely to make mistakes that obscure important
details.

> After doing e2fsck (file system scan ) it is fixed but that needs downtime
> and also it removes the file. What is the impact if the file is being
> removed ?

Deleting those files will lose some statistical counters, but it's not
critical data; you're advised to run ANALYZE on all databases after
making the disk work properly again.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services