Re: pg_restore scan

Sorry for not including the full command - yes , its piping to a
compression command :
| lbzip2 -n <threadsforbzipgoeshere>--best > <filenamegoeshere>

I think we found the issue! I'll do further testing and see how it goes !

On Wed, 17 Sept 2025 at 11:02, Ron Johnson <ronljohnsonjr(at)gmail(dot)com> wrote:

> So, piping or redirecting to a file? If so, then that's the problem.
>
> pg_dump directly to a file puts file offsets in the TOC.
>
> This how I do custom dumps:
> cd $BackupDir
> pg_dump -Fc --compress=zstd:long -v -d${db} -f ${db}.dump 2> ${db}.log
>
> On Tue, Sep 16, 2025 at 8:54 PM R Wahyudi <rwahyudi(at)gmail(dot)com> wrote:
>
>> 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(dot)klaver(at)aklaver(dot)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(dot)klaver(at)aklaver(dot)com
>>>
>>
>
> --
> Death to <Redacted>, and butter sauce.
> Don't boil me, I'm still alive.
> <Redacted> lobster!
>