On Wed, Jun 18, 2025 at 4:15 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Wed, Jun 18, 2025 at 4:38 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
Here is the first WIP version of the patch set. Commit message in
each patch explains in detail what exactly it does so not adding the
description in email. Patches applies on the latest head
(732061150b004385810e522f8629f5bf91d977b7)
Open issues yet to be handled:
=========================
1) Vacuum optimization as I described above is still highly unstable
patch so not attached here, so with this patch set if you create
global index with large table with a lot of partition then there will
be a huge regression in vacuum performance, which should be resolved
after vacuum optimization patch which I am planning to post by this
month.
2) If you are attaching a partition which has a different column order
than the parent and create a global index on that, it will not work,
still working on it.
3) For unique checking in btree, global index may get conflicting
tuple belongs to different partitions so relation open is done on the
fly, ideally that description should have been done in executor and
pass down to btree but still identifying how to do that with minimum
changes in AM interfaces, or can it be done without AM changes.
4) Need to write more test cases for REINDEX TABLE, TRUNCATE TABLE and
need to tighten up the global index rebuild so that it doesn't get
rebuilt multiple times or doesn't skip rebuilding when needed.
5) ALTER COLUMN SET TYPE, which triggers global index rewrite is not
handled properly. This needs some more work, in the alter table
machinery where we identify the list of indexes to rebuild.
6) Need to perform a performance test, for SELECT/UPDATE/INSERT cases,
we already know the VACUUM performance.
7) global_index.sql is taking a long time to execute as I have kept a
high data load, so that needs to be simplified.
Note: Patches are still WIP and might have many loose ends, for now,
make check-world is passing, including the global index test cases
Credit: I have already mentioned while sending the first design email
but missed some, so adding it again here.
1. Robert: for many of the key design ideas and regular discussion
throughout designing this.
2. Joe: Also has regular discussion on this and many suggestions,
specially related to vacuum
3. Peter Geoghegan, Alvaro, and Masahiko Sawada for discussing the
independent issues with me offlist.
4. I got the idea of syntax for creating global indexes and also
keeping a cache of mapping from reloid to relation descriptor during
the global index scan, from some of the very old thread related to
global index (not able to find the thread now).
--
Regards,
Dilip Kumar
Google
