public inbox for [email protected]
help / color / mirror / Atom feedFrom: Tomas Vondra <[email protected]>
To: [email protected]
Subject: pgsql: Allow parallel CREATE INDEX for GIN indexes
Date: Mon, 03 Mar 2025 16:10:28 +0000
Message-ID: <[email protected]> (raw)
Allow parallel CREATE INDEX for GIN indexes
Allow using parallel workers to build a GIN index, similarly to BTREE
and BRIN. For large tables this may result in significant speedup when
the build is CPU-bound.
The work is divided so that each worker builds index entries on a subset
of the table, determined by the regular parallel scan used to read the
data. Each worker uses a local tuplesort to sort and merge the entries
for the same key. The TID lists do not overlap (for a given key), which
means the merge sort simply concatenates the two lists. The merged
entries are written into a shared tuplesort for the leader.
The leader needs to merge the sorted entries again, before writing them
into the index. But this way a significant part of the work happens in
the workers, and the leader is left with merging fewer large entries,
which is more efficient.
Most of the parallelism infrastructure is a simplified copy of the code
used by BTREE indexes, omitting the parts irrelevant for GIN indexes
(e.g. uniqueness checks).
Original patch by me, with reviews and substantial improvements by
Matthias van de Meent, certainly enough to make him a co-author.
Author: Tomas Vondra, Matthias van de Meent
Reviewed-by: Matthias van de Meent, Andy Fan, Kirill Reshke
Discussion: https://postgr.es/m/6ab4003f-a8b8-4d75-a67f-f25ad98582dc%40enterprisedb.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/8492feb98f6df3f0f03e84ed56f0d1cbb2ac514c
Modified Files
--------------
src/backend/access/gin/gininsert.c | 1649 +++++++++++++++++++++++++++-
src/backend/access/gin/ginutil.c | 30 +-
src/backend/access/transam/parallel.c | 4 +
src/backend/utils/sort/tuplesortvariants.c | 198 ++++
src/include/access/gin.h | 15 +
src/include/access/gin_private.h | 1 +
src/include/access/gin_tuple.h | 44 +
src/include/utils/tuplesort.h | 8 +
src/tools/pgindent/typedefs.list | 4 +
9 files changed, 1937 insertions(+), 16 deletions(-)
view thread (4+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: pgsql: Allow parallel CREATE INDEX for GIN indexes
In-Reply-To: <[email protected]>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox