Re: RDS No free space

We've dug a little further and we feel somewhat confident that it's retaining WAL logs forever. Our free storage starts to drop steadily/precipitously when we enabled WAL. Could someone point me to some settings/queries to dig a bit on that?

On Sun, May 21, 2023 at 11:14 AM Wells Oliver <wells.oliver@gmail.com> wrote:

Dustin, how did you come to see the incomplete vacuum and the orphaned files?

On Sun, May 21, 2023 at 10:59 AM Dustin Jantz <djantz@frontporch.com> wrote:

To check the replication slots run the following query. The lag is how much the WAL file is holding on to data. If the slot is not active you can remove the slot and that will free up the space the WAL file is holding on to.

SELECT

rps.slot_name,

pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), restart_lsn)) pretty_replication_slot_lag,

pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), confirmed_flush_lsn)) pretty_confirmed_lag,

rps.active slot_active,pg_wal_lsn_diff(pg_current_wal_lsn(), restart_lsn) as replication_slot_

lag,pg_wal_lsn_diff(pg_current_wal_lsn(),

confirmed_flush_lsn) as confirmed_lag,

rps.active_pid

FROM pg_replication_slots rps

 

 

Remove the inactive replication slot:

 

                SELECT pg_drop_replication_slot('<slot_name>');

 

 

 

The only other time I had this issue was because of an incomplete vacuum full on a large table. This caused there to be orphaned files which took up a lot of space.

 

 

 

Kind regards,

 

 

Dustin Jantz

djantz@frontporch.com

 

From: Wells Oliver <wells.oliver@gmail.com>
Sent: Sunday, May 21, 2023 10:48 AM
To: Jim Mlodgenski <jimmy76@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>; pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: RDS No free space

 

I'm not too familiar with that. Can you point me in the direction of some config settings and maybe queries to execute?

 

On Sun, May 21, 2023 at 10:43 AM Jim Mlodgenski <jimmy76@gmail.com> wrote:

 

 

On Sun, May 21, 2023 at 1:38 PM Wells Oliver <wells.oliver@gmail.com> wrote:

So we run on RDS, and we clearly used up all of our provisioned storage. However, I am baffled, and while I am emailing our AWS support, I wondered if this list might point me in some direction too.

 

Our provisioned storage was 15TB. The size of our database -- shown in pg_database -- is only 6TB. What in the world could be using that remaining space? I am at a loss, that's a _ton_ of space being used up. Is it some temporary allocation during script execution (seems ginormous, impossible)? It it some WAL log thing?

 

A fairly common cause of this is orphan replication slots so WAL files are retained. Check

to see if there is an inactive slot that may be preventing the files to be removed.

 

 

--

Wells Oliver
wells.oliver@gmail.com

--

Wells Oliver
wells.oliver@gmail.com

--

Wells Oliver
wells.oliver@gmail.com