On Fri, Jun 3, 2016 at 11:03 PM, Robert Haas <robertmh...@gmail.com> wrote:
> On Thu, Jun 2, 2016 at 11:24 AM, Masahiko Sawada <sawada.m...@gmail.com>
>> Attached patch optimises skipping pages logic so that blkno can jump to
>> next_unskippable_block directly while counting the number of all_visible
>> and all_frozen pages. So we can avoid double checking visibility map.
> I think this is 9.7 material. This patch has already won the
> "scariest patch" tournament. Changing the logic more than necessary
> at this late date seems like it just increases the scariness. I think
> this is an opportunity for further optimization, not a defect.
I agree with you.
I'll submit this as a improvement for 9.7.
That patch also incorporates the following review comment.
We can push at least this fix.
>> * Compute whether we actually scanned the whole relation. If we
>> did, we
>> * can adjust relfrozenxid and relminmxid.
>> * NB: We need to check this before truncating the relation, because
>> * will change ->rel_pages.
>> Comment is out-of-date now.
I'm address the review comment of 7087166 commit, and will post the patch.
And testing feature for freeze map is under the discussion.
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