Обсуждение: Finding detailed information about LOCKS

On Fri, 2024-05-03 at 10:54 +0530, Siraj G wrote:
> I come from Oracle background. In Oracle there is a licensed feature (Diagnostics + Tuning)
> upon using which the system keeps historic session records, which gives a better way
> to find out locking related details- like the blocking session, total sessions blocked
> and the time the blocking event was active. I am finding it a little hard in PgSQL
> to find this information. 
>
> I am seeking help in finding a detailed analysis on the locks that happened yesterday,
> 2 days back or in the last week. Can someone assist please.

PostgreSQL doesn't keep historical information on these things.

You need a monitoring tool like pgwatch2 that takes regular snapshots of these data
and allows you to access this information.

Yours,
Laurenz Albe

On Fri, 2024-05-03 at 11:52 +0530, Wasim Devale wrote:
> On Fri, 3 May, 2024, 11:46 am Laurenz Albe, <laurenz.albe@cybertec.at> wrote:
> > On Fri, 2024-05-03 at 10:54 +0530, Siraj G wrote:
> > > I come from Oracle background. In Oracle there is a licensed feature (Diagnostics + Tuning)
> > > upon using which the system keeps historic session records, which gives a better way
> > > to find out locking related details- like the blocking session, total sessions blocked
> > > and the time the blocking event was active. I am finding it a little hard in PgSQL
> > > to find this information. 
> > >
> > > I am seeking help in finding a detailed analysis on the locks that happened yesterday,
> > > 2 days back or in the last week. Can someone assist please.
> >
> > PostgreSQL doesn't keep historical information on these things.
> >
> > You need a monitoring tool like pgwatch2 that takes regular snapshots of these data
> > and allows you to access this information.
>
> Can we not use pgbadger?

pgBadger can only collect what is in the log file.  How would you get that information
into the log file?  The best you can get in the log file is the information from
"log_lock_waits = on", which is information about situations where somebody had to
wait for a lock for more than a second.  Definitely useful, but capturing "pg_stat_activity"
snapshots will provide more infrmation.

Yours,
Laurenz Albe

If you can't get pgwatch2

Cron job that runs every hour:

grep -E "lock" (or whatever search term) postgresql.log > lock_history.txt

Or something to that effect, not as good as the tool obviously, but a workingperson's solution.

-----Original Message-----
From: Laurenz Albe <laurenz.albe@cybertec.at> 
Sent: Thursday, May 2, 2024 11:16 PM
To: Siraj G <tosiraj.g@gmail.com>; Pgsql-admin <pgsql-admin@lists.postgresql.org>
Subject: [EXTERNAL] Re: Finding detailed information about LOCKS

On Fri, 2024-05-03 at 10:54 +0530, Siraj G wrote:
> I come from Oracle background. In Oracle there is a licensed feature 
> (Diagnostics + Tuning) upon using which the system keeps historic 
> session records, which gives a better way to find out locking related 
> details- like the blocking session, total sessions blocked and the 
> time the blocking event was active. I am finding it a little hard in PgSQL to find this information.
> 
> I am seeking help in finding a detailed analysis on the locks that 
> happened yesterday,
> 2 days back or in the last week. Can someone assist please.

PostgreSQL doesn't keep historical information on these things.

You need a monitoring tool like pgwatch2 that takes regular snapshots of these data and allows you to access this
information.

Yours,
Laurenz Albe