public inbox for [email protected]  

help / color / mirror / Atom feed

From: Laurenz Albe <[email protected]>
To: sud <[email protected]>
To: Ron Johnson <[email protected]>
Cc: pgsql-general <[email protected]>
Subject: Re: Dropping column from big table
Date: Thu, 11 Jul 2024 10:06:47 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAD=mzVXK+4tLMbENMecruPbk8cmeE4smD=ENUrwx5wh4N7hZhA@mail.gmail.com>
References: <CAD=mzVUGj2Zg0RY9YJwgDzAeghPjuT0FOnNs-aysTBGss87Yyw@mail.gmail.com>
	<[email protected]>
	<CAD=mzVUS8mFK42zmVUUC3JkiN=9QSUZ_Qxayd6=KJwbqdd0HzA@mail.gmail.com>
	<CANzqJaBAOzCjXaBFLa6cYweVNf5LbBvLYFkWx_hb3YezOP3quw@mail.gmail.com>
	<CAD=mzVXK+4tLMbENMecruPbk8cmeE4smD=ENUrwx5wh4N7hZhA@mail.gmail.com>

On Thu, 2024-07-11 at 13:10 +0530, sud wrote:
> Dropping will take it's own time for post vacuum however as you
> rightly said, it won't be blocking which should be fine. 

I am not certain if you understood this correctly.

Dropping a column is fast, but doesn't reclaim the space.
VACUUM won't block anything, but won't reclaim the space.
VACUUM (FULL) will block everything, but will also not reclaim the space.

You'd need to use a form of ALTER TABLE that rewrites the table,
as indicated in the documentation.  However, such an operation
will block all access to the table for a long time, and it will
temporarily need much more space, because it has to hold both the
old and the new copy of the table.

Yours,
Laurenz Albe

view thread (4+ messages)  latest in thread

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: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Dropping column from big table
  In-Reply-To: <[email protected]>

* 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