Re: WIP: Avoid creation of the free space map for small tables

From: John Naylor <john(dot)naylor(at)2ndquadrant(dot)com>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: WIP: Avoid creation of the free space map for small tables
Date: 2019-01-10 22:24:10
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On Wed, Jan 9, 2019 at 10:50 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> Thanks, Mithun for performance testing, it really helps us to choose
> the right strategy here. Once John provides next version, it would be
> good to see the results of regular pgbench (read-write) runs (say at
> 50 and 300 scale factor) and the results of large copy. I don't think
> there will be any problem, but we should just double check that.

Attached is v12 using the alternating-page strategy. I've updated the
comments and README as needed. In addition, I've

-handled a possible stat() call failure during pg_upgrade
-added one more assertion
-moved the new README material into a separate paragraph
-added a comment to FSMClearLocalMap() about transaction abort
-corrected an outdated comment that erroneously referred to extension
rather than creation
-fleshed out the draft commit messages

Attachment Content-Type Size
v12-0001-Avoid-creation-of-the-free-space-map-for-small-h.patch text/x-patch 37.6 KB
v12-0002-During-pg_upgrade-conditionally-skip-transfer-of.patch text/x-patch 7.5 KB

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