Hi,
On 17.11.2024 11:28, Egor Rogov wrote:
Hi everyone,
This thread doesn't seem to have attracted attention, so let me try
again. Two documentation pages claim that B-tree is the only access
method that supports parallel building, which is no longer true. I
propose to fix it in a way like this:
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d54f9049569..b5b1580dee7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2835,7 +2835,7 @@ include_dir 'conf.d'
Sets the maximum number of parallel workers that can be
started by a single utility command. Currently, the parallel
utility commands that support the use of parallel workers are
- <command>CREATE INDEX</command> only when building a B-tree
index,
+ <command>CREATE INDEX</command> when building a B-tree or
BRIN index,
and <command>VACUUM</command> without <literal>FULL</literal>
option. Parallel workers are taken from the pool of processes
established by <xref linkend="guc-max-worker-processes"/>,
limited
diff --git a/doc/src/sgml/ref/create_index.sgml
b/doc/src/sgml/ref/create_index.sgml
index 621bc0e253c..208389e8006 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -808,7 +808,7 @@ Indexes:
leveraging multiple CPUs in order to process the table rows faster.
This feature is known as <firstterm>parallel index
build</firstterm>. For index methods that support building indexes
- in parallel (currently, only B-tree),
+ in parallel (currently, B-tree and BRIN),
<varname>maintenance_work_mem</varname> specifies the maximum
amount of memory that can be used by each index build operation as
a whole, regardless of how many worker processes were started.
I've spotted another mention of B-tree being the only AM that supports
parallel builds: comment in src/backend/catalog/index.c. As this mention
is not visible to the users, I'd propose removing it altogether rather
than fixing it. Updated patch is attached.
Thanks,
Egor
On 05.11.2024 12:12, Egor Rogov wrote:
Hi,
Commit b4375717 introduced parallel CREATE INDEX for BRIN. I've
noticed that a couple of documentation pages need to be updated
accordingly. A small patch is attached.
Thanks,
Egor
From 625fa1fbdce1746285d00dd26c632845ab775a51 Mon Sep 17 00:00:00 2001
From: Egor Rogov <e.ro...@postgrespro.ru>
Date: Sun, 8 Dec 2024 17:45:19 +0300
Subject: [PATCH] Doc and comment: parallel CREATE INDEX is allowed for BRIN
Commit b4375717 introduced parallel index build for BRIN,
but missed updating the documentation and code comment about it.
---
doc/src/sgml/config.sgml | 2 +-
doc/src/sgml/ref/create_index.sgml | 2 +-
src/backend/catalog/index.c | 3 +--
3 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index e0c8325a39c..24bd504c213 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2843,7 +2843,7 @@ include_dir 'conf.d'
Sets the maximum number of parallel workers that can be
started by a single utility command. Currently, the parallel
utility commands that support the use of parallel workers are
- <command>CREATE INDEX</command> only when building a B-tree index,
+ <command>CREATE INDEX</command> when building a B-tree or BRIN index,
and <command>VACUUM</command> without <literal>FULL</literal>
option. Parallel workers are taken from the pool of processes
established by <xref linkend="guc-max-worker-processes"/>, limited
diff --git a/doc/src/sgml/ref/create_index.sgml
b/doc/src/sgml/ref/create_index.sgml
index 621bc0e253c..208389e8006 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -808,7 +808,7 @@ Indexes:
leveraging multiple CPUs in order to process the table rows faster.
This feature is known as <firstterm>parallel index
build</firstterm>. For index methods that support building indexes
- in parallel (currently, only B-tree),
+ in parallel (currently, B-tree and BRIN),
<varname>maintenance_work_mem</varname> specifies the maximum
amount of memory that can be used by each index build operation as
a whole, regardless of how many worker processes were started.
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 1c3a9e06d37..fc1c2a8d026 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2988,8 +2988,7 @@ index_build(Relation heapRelation,
Assert(PointerIsValid(indexRelation->rd_indam->ambuildempty));
/*
- * Determine worker process details for parallel CREATE INDEX.
Currently,
- * only btree has support for parallel builds.
+ * Determine worker process details for parallel CREATE INDEX.
*
* Note that planner considers parallel safety for us.
*/
--
2.37.1 (Apple Git-137.1)
