public inbox for pgsql-performance@postgresql.org  

help / color / mirror / Atom feed

From: Kristjan Mustkivi <sonicmonkey@gmail.com>
To: James Pang <jamespang886@gmail.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: table bloat very fast and free space can not be reused
Date: Sun, 19 Apr 2026 14:43:47 +0300
Message-ID: <CAOQPKatQ0NCP5vDCZ_pz_JQkyM+AP=nPL5wPY3awWVoZXA4T1A@mail.gmail.com> (raw)
In-Reply-To: <CAHgTRff=eH1GwVb=ENMzX6hBEajdTccCQbeVRkj4OtYLm69a9g@mail.gmail.com>
References: <CAHgTRff=eH1GwVb=ENMzX6hBEajdTccCQbeVRkj4OtYLm69a9g@mail.gmail.com>

On Sun, Apr 19, 2026 at 4:28 AM James Pang <jamespang886@gmail.com> wrote:
>
> experts:
>      source database v14 ,  pglogical extension 2.4.5 replication to new 17, source table very frequent UPDATEs /DELETES /INSERTS and has two text and jsonb. in source database, application update/delete/insert through SQL, table size did not increased quickly. but in target pg v17 , by pglogical apply, we found table increased very quickly , table size got doubled in days.
>     Vacuum analyze did not help , only vacuum full can help. pgstattuple show most of space are free space , that much more than source.  it looks like these replicate DML always asking new pages instead of reuse existing freespace.

Hi,

We have had the exact same problem in the past - a large json column
getting very frequent updates (hundreds even thousand per minute) on
the source and the replica side table bloating up. No amount of tuning
attempts made any difference (conversion of json to text, different
table specific autovacuum settings etc). Eventually, the table was
taken out of the replication and later on made UNLOGGED which also
freed up a giant swathes of storage from WAL written. Such design was
then called an antipattern and has not been allowed since.

With best regards,

Kristjan

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: sonicmonkey@gmail.com, jamespang886@gmail.com, pgsql-performance@lists.postgresql.org
  Subject: Re: table bloat very fast and free space can not be reused
  In-Reply-To: <CAOQPKatQ0NCP5vDCZ_pz_JQkyM+AP=nPL5wPY3awWVoZXA4T1A@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox