Horton

Re: tableam vs. TOAST

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Prabhat Sahu <prabhat.sahu@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-09-05T14:52:25Z
Lists: pgsql-hackers

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On 2019-Aug-05, Robert Haas wrote:

> > Shouldn't this condition be the other way round?
> 
> I had to fight pretty hard to stop myself from tinkering with the
> algorithm -- this can clearly be done better, but I wanted to make it
> match the existing structure as far as possible. It also only needs to
> be tested once, not on every loop iteration, so if we're going to
> start changing things, we should go further than just swapping the
> order of the tests.  For now I prefer to draw a line in the sand and
> change nothing.

I agree, and can we move forward with this 0001?  The idea here is to
change no code (as also suggested by Tom elsewhere), and it's the
largest patch in this series by a mile.  I checked --color-moved=zebra
and I think the patch looks fine, and also it compiles fine.  I ran
src/tools/pginclude/headerscheck on it and found no complaints.

So here's a rebased version, where the DETOAST_H whitespace has been
removed.  No other changes from your original.  Will you please push
soon?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. tableam: New callback relation_fetch_toast_slice.

  2. tableam: Allow choice of toast AM.

  3. Move heap-specific detoasting logic into a separate function.

  4. Code cleanup for toast_fetch_datum and toast_fetch_datum_slice.

  5. Rename some toasting functions based on whether they are heap-specific.

  6. Create an API for inserting and deleting rows in TOAST tables.

  7. Split tuptoaster.c into three separate files.

  8. tableam: Move heap-specific logic from needs_toast_table below tableam.