Horton

Re: WIP: Covering + unique indexes.

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Teodor Sigaev <teodor@sigaev.ru>
Cc: Jeff Janes <jeff.janes@gmail.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-04-10T02:30:14Z
Lists: pgsql-hackers 
On Sun, Apr 8, 2018 at 11:19 PM, Teodor Sigaev <teodor@sigaev.ru> wrote:
> Thank you, pushed.

I noticed a few more issues following another pass-through of the patch:

* There is no pfree() within _bt_buildadd() for truncated tuples, even
though that's a context where it's clearly not okay.

* It might be a good idea to also pfree() the truncated tuple for most
other _bt_buildadd() callers. Even though it's arguably okay in other
cases, it seems worth being consistent about it (consistent with old
nbtree code).

* There should probably be some documentation around why it's okay
that we call index_truncate_tuple() with an exclusive buffer lock held
(during a page split). For example, there should probably be a comment
on the VARATT_IS_EXTERNAL() situation.

* Not sure that all calls to BTreeInnerTupleGetDownLink() are limited
to inner tuples, which might be worth doing something about (perhaps
just renaming the macro).

I do not have the time to write a patch right away, but I should be
able to post one in a few days. I want to avoid sending several small
patches.

-- 
Peter Geoghegan

Commits

  1. Adjust INCLUDE index truncation comments and code.

  2. Add commentary explaining why MaxIndexTuplesPerPage calculation is safe.

  3. Indexes with INCLUDE columns and their support in B-tree

  4. Add amcheck verification of heap relations belonging to btree indexes.

  5. Doc: move info for btree opclass implementors into main documentation.

  6. Doc: mention that you can't PREPARE TRANSACTION after NOTIFY.

  7. Remove dedicated B-tree root-split record types.

  8. Restructure index access method API to hide most of it at the C level.

  9. Split _bt_insertonpg to two functions.

  10. Major overhaul of btree index code. Eliminate special BTP_CHAIN logic for