Re: Suddenly all queries moved to seq scan - Mailing list pgsql-general

From Achilleas Mantzios - cloud
Subject Re: Suddenly all queries moved to seq scan
Date
Msg-id a2a12fe8-0be8-458b-8098-b129f63c4ea2@cloud.gatewaynet.com
Whole thread Raw
In response to Suddenly all queries moved to seq scan  (Sreejith P <sreejith@lifetrenz.com>)
List pgsql-general

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





 

Solutions for Care Anywhere


dWise HealthCare IT Solutions Pvt. Ltd. | www.lifetrenz.com
Disclaimer: The information and attachments contained in this email are intended for exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender immediately and destroy all copies of this message and any attachments. The views expressed in this email are, unless otherwise stated, those of the author and not those of dWise HealthCare IT Solutions or its management.

pgsql-general by date:

Previous
From: Philip Couling
Date:
Subject: Re: Validating check constraints without a table scan?
Next
From: Daniel Gustafsson
Date:
Subject: Re: Suddenly all queries moved to seq scan