Re: Teach pg_receivewal to use lz4 compression

On Wed, Nov 24, 2021 at 10:55 AM Michael Paquier <michael@paquier.xyz>
wrote:

> On Mon, Nov 22, 2021 at 09:02:47AM -0500, Robert Haas wrote:
> > On Mon, Nov 22, 2021 at 12:46 AM Jeevan Ladhe
> > <jeevan.ladhe@enterprisedb.com> wrote:
> >> Fair enough. But, still I have a doubt in mind what benefit would that
> >> really bring to us here, because we are immediately also freeing the
> >> lz4buf without using it anywhere.
> >
> > Yeah, I'm also doubtful about that. If we're freeng the compression
> > context, we shouldn't need to guarantee that it's in any particular
> > state before doing so. Why would any critical cleanup be part of
> > LZ4F_compressEnd() rather than LZ4F_freeCompressionContext()? The
> > point of LZ4F_compressEnd() is to make sure all of the output bytes
> > get written, and it would be stupid to force people to write the
> > output bytes even when they've decided that they no longer care about
> > them due to some error.
>
> Hmm.  I have double-checked all that, and I agree that we could just
> skip LZ4F_compressEnd() in this error code path.  From what I can see
> in the upstream code, what we have now is not broken either, but the
> compressEnd() call does some work that's not needed here.


Yes I agree that we are not broken, but as you said we are doing some
an extra bit of work here.

Regards,
Jeevan Ladhe