Re: pg_restore scan - Mailing list pgsql-general

From R Wahyudi
Subject Re: pg_restore scan
Date
Msg-id CALWQLzTWUnA09cAfsuzuv5Kmb+S8gcC9uBypRYW0UtsQgMyPJg@mail.gmail.com
Whole thread Raw
In response to Re: pg_restore scan  (Adrian Klaver <adrian.klaver@aklaver.com>)
Responses Re: pg_restore scan
Re: pg_restore scan
List pgsql-general
pg_dump was done using the following command : 
pg_dump -Fc -Z 0 -h <host> -U <user> -w -d <database> 

On Wed, 17 Sept 2025 at 08:36, Adrian Klaver <adrian.klaver@aklaver.com> wrote:
On 9/16/25 15:25, R Wahyudi wrote:
>
> I'm trying to troubleshoot the slowness issue with pg_restore and
> stumbled across a recent post about pg_restore scanning the whole file :
>
>  > "scanning happens in a very inefficient way, with many seek calls and
> small block reads. Try strace to see them. This initial phase can take
> hours in a huge dump file, before even starting any actual restoration."
> see : https://www.postgresql.org/message-id/E48B611D-7D61-4575-A820-
> B2C3EC2E0551%40gmx.net <https://www.postgresql.org/message-id/
> E48B611D-7D61-4575-A820-B2C3EC2E0551%40gmx.net>

This was for pg_dump output that was streamed to a Borg archive and as
result had no object offsets in the TOC.

How are you doing your pg_dump?



--
Adrian Klaver
adrian.klaver@aklaver.com

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