Re: Performance Enhancement/Fix for Array Utility Functions

From: Daniel Farina <drfarina(at)acm(dot)org>
To: Mike Lewis <mikelikespie(at)gmail(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Performance Enhancement/Fix for Array Utility Functions
Date: 2010-06-02 00:32:46
Message-ID: AANLkTik9buaDpg8XDfE73sj6EdGFNbtlRF69ZIYuXyJy@mail.gmail.com
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On Wed, Mar 31, 2010 at 9:47 AM, Mike Lewis <mikelikespie(at)gmail(dot)com> wrote:
> Thanks. Added it.
>
> https://commitfest.postgresql.org/action/patch_view?id=292

I have reviewed this patch; this is my review:

Regression tests pass with assertions enabled.

Performance gains reported by author confirmed.

The existence and naming of ARR_MAX_HEADER_SIZE is somewhat dubious,
as it is:

* Used in exactly one place (not necessarily a reason why it should
not be reified into a stand-alone definition, though, but
something to consider)

* The array header refers to the NULL bitmap as well, but the
interpretation used by the patch does not.

I think this patch is safe, as all the array fields required are
before the null bitmap, but I think the naming of this definition
is very misleading.

Generally I think the delimited untoasting of metadata from arrays
separately from the payload is Not A Bad Idea.

fdr

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