Re: remove more archiving overhead

David Steele <david@pgmasters.net>

From: David Steele <david@pgmasters.net>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, robertmhaas@gmail.com, masao.fujii@oss.nttdata.com, pgsql-hackers@postgresql.org
Date: 2022-07-08T17:02:51Z
Lists: pgsql-hackers
On 7/8/22 12:54, Nathan Bossart wrote:
> On Fri, Jul 08, 2022 at 08:20:09AM -0400, David Steele wrote:
> 
>> Nathan, I don't see the language about being sure to persist to storage
>> here?
> 
> It's here:
> 	When an archive library encounters a pre-existing file, it may return
> 	true if the WAL file has identical contents to the pre-existing archive
> 	and the pre-existing archive is fully persisted to storage.
> 
> Since you didn't catch it, I wonder if it needs improvement.  At the very
> least, perhaps we should note that one way to do the latter is to persist
> it yourself before returning true, and we could point to basic_archive.c as
> an example.  However, I'm hesitant to make these docs too much more
> complicated than they already are.  WDYT?

I think I wrote this before I'd had enough coffee. "fully persisted to 
storage" can mean many things depending on the storage (Posix, CIFS, S3, 
etc.) so I think this is fine. The basic_archive module is there for 
people who would like implementation details for Posix.

Regards,
-David



Commits

  1. Be more prescriptive in new doc about re-archiving of same WAL file.

  2. doc: Add note about re-archiving of same WAL files in docs.

  3. Reduce overhead of renaming archive status files.