From: | gkokolatos(at)pm(dot)me |
---|---|
To: | Michael Paquier <michael(at)paquier(dot)xyz> |
Cc: | Jeevan Ladhe <jeevan(dot)ladhe(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Magnus Hagander <magnus(at)hagander(dot)net>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
Subject: | Re: Teach pg_receivewal to use lz4 compression |
Date: | 2021-11-19 10:07:50 |
Message-ID: | UNDEJfRFUIxXIS78sze4y5e4EXRSOtFlXqFuzAYiE2KhcXBkogVxNprmyHDkGax1MON1tOzQUWjQ6PivDV9WKgzTnqEviVIEaX90ZeO9c9s=@pm.me |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, November 19th, 2021 at 3:07 AM, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> On Thu, Nov 18, 2021 at 07:54:37PM +0530, Jeevan Ladhe wrote:
>
> > In dir_open_for_write() I observe that we are writing the header
> > and then calling LZ4F_compressEnd() in case there is an error
> > while writing the buffer to the file, and the output buffer of
> > LZ4F_compressEnd() is not written anywhere. Why should this be
> > necessary? To flush the contents of the internal buffer? But, then we
> > are calling LZ4F_freeCompressionContext() immediately after the
> > LZ4F_compressEnd() call. I might be missing something, will be
> > happy to get more insights.
>
> My concern here was symmetry, where IMO it makes sense to have a
> compressEnd call each time there is a successful compressBegin call
> done for the LZ4 state data, as there is no way to know if in the
> future LZ4 won't change some of its internals to do more than just an
> internal flush.
Agreed.
Although the library does provide an interface for simply flushing contents, it
also assumes that each initializing call will have a finilizing call. If my
memory serves me right, earlier versions of the patch, did not have this
summetry, but that got ammended.
Cheers,
//Georgios
> ---
> Michael
From | Date | Subject | |
---|---|---|---|
Next Message | Amit Kapila | 2021-11-19 10:09:32 | Re: Skipping logical replication transactions on subscriber side |
Previous Message | Fujii Masao | 2021-11-19 10:01:26 | Shouldn't postgres_fdw report warning when it gives up getting result from foreign server? |