From: | Andrey Borodin <x4mmm(at)yandex-team(dot)ru> |
---|---|
To: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
Cc: | Gasper Zejn <zejn(at)owca(dot)info>, pgsql-hackers(at)lists(dot)postgresql(dot)org |
Subject: | Re: pglz performance |
Date: | 2019-09-28 08:29:18 |
Message-ID: | 3C62CD88-AEAC-4041-9BF3-ACCE70C3A5F8@yandex-team.ru |
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Lists: | pgsql-hackers |
Oleg, Peter, thanks for looking into this!
I hope to benchmark decompression on Silesian corpus soon.
PFA v2 with better comments.
> 27 сент. 2019 г., в 14:41, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> написал(а):
>
> After reviewing this thread and more testing, I think
> 0001-Use-memcpy-in-pglz-decompression.patch appears to be a solid win
> and we should move ahead with it.
>
> I don't, however, fully understand the code changes, and I think this
> could use more and better comments. In particular, I wonder about
>
> off *= 2;
I've changed this to
off += off;
>
> This is new logic that isn't explained anywhere.
>
> This whole function is commented a bit strangely. It begins with
> "Otherwise", but there is nothing before it. And what does "from OUTPUT
> to OUTPUT" mean? There is no "output" variable. We should make this
> match the code better.
I've added small example to illustrate what is going on.
Thanks!
--
Andrey Borodin
Open source RDBMS development team leader
Yandex.Cloud
Attachment | Content-Type | Size |
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v2-0001-Use-memcpy-in-pglz-decompression.patch | application/octet-stream | 3.2 KB |
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