On Thu, May 13, 2021 at 7:00 PM Masahiko Sawada <sawada.m...@gmail.com> wrote:
> > > Yeah, I get it. Even if users don't specify a parallel option there
> > > are chances that parallelism is picked. So the parallel degree is the
> > > final number of workers that are chosen by the server for vacuuming
> > > indexes. And, I think that parallel degree is something internal to
> > > the server, and it's better we replace it in the vacuumdb.sgml, change
> > > PARALLEL_DEGREE to PARALLEL_WORKERS in vacuumdb.c and change the error
> > > message "parallel vacuum degree must be a non-negative integer" to
> > > "parallel workers for vacuum must be greater than or equal to zero".
> > >
> > > Thoughts?
>
> I'm fine with this change.
Thanks.
> is important here but another idea to improve the error message would
> be to change "parallel vacuum degree must be between 0 and %d” to "the
> number of parallel workers must be between 0 and %d” (or using
> “parallel workers for vacuum” instead of “the number of parallel
> workers”) while leaving another message as it is.
Done that way.
PSA patch.
With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com
From 514128927d51a5b0578e9b1ce969a68fe8d62b1c Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddy@enterprisedb.com>
Date: Thu, 13 May 2021 20:29:38 +0530
Subject: [PATCH v1] Parallel Vacuum-Reword Error Messages and Docs
---
doc/src/sgml/ref/vacuumdb.sgml | 2 +-
src/backend/commands/vacuum.c | 2 +-
src/bin/scripts/vacuumdb.c | 4 ++--
src/test/regress/expected/vacuum.out | 2 +-
4 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/doc/src/sgml/ref/vacuumdb.sgml b/doc/src/sgml/ref/vacuumdb.sgml
index 843a82e871..05249c4772 100644
--- a/doc/src/sgml/ref/vacuumdb.sgml
+++ b/doc/src/sgml/ref/vacuumdb.sgml
@@ -279,7 +279,7 @@ PostgreSQL documentation
<term><option>--parallel=<replaceable class="parameter">parallel_degree</replaceable></option></term>
<listitem>
<para>
- Specify the parallel degree of <firstterm>parallel vacuum</firstterm>.
+ Specify the number of parallel workers for <firstterm>parallel vacuum</firstterm>.
This allows the vacuum to leverage multiple CPUs to process indexes.
See <xref linkend="sql-vacuum"/>.
</para>
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d549d0d86f..7421d7cfbd 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -165,7 +165,7 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel)
if (nworkers < 0 || nworkers > MAX_PARALLEL_WORKER_LIMIT)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("parallel vacuum degree must be between 0 and %d",
+ errmsg("parallel workers for vacuum must be between 0 and %d",
MAX_PARALLEL_WORKER_LIMIT),
parser_errposition(pstate, opt->location)));
diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c
index 7901c41f16..069a861aab 100644
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -200,7 +200,7 @@ main(int argc, char *argv[])
vacopts.parallel_workers = atoi(optarg);
if (vacopts.parallel_workers < 0)
{
- pg_log_error("parallel vacuum degree must be a non-negative integer");
+ pg_log_error("parallel workers for vacuum must be greater than or equal to zero");
exit(1);
}
break;
@@ -1000,7 +1000,7 @@ help(const char *progname)
printf(_(" --no-index-cleanup don't remove index entries that point to dead tuples\n"));
printf(_(" --no-process-toast skip the TOAST table associated with the table to vacuum\n"));
printf(_(" --no-truncate don't truncate empty pages at the end of the table\n"));
- printf(_(" -P, --parallel=PARALLEL_DEGREE use this many background workers for vacuum, if available\n"));
+ printf(_(" -P, --parallel=PARALLEL_WORKERS use this many background workers for vacuum, if available\n"));
printf(_(" -q, --quiet don't write any messages\n"));
printf(_(" --skip-locked skip relations that cannot be immediately locked\n"));
printf(_(" -t, --table='TABLE[(COLUMNS)]' vacuum specific table(s) only\n"));
diff --git a/src/test/regress/expected/vacuum.out b/src/test/regress/expected/vacuum.out
index 90cea6caa8..5e657849aa 100644
--- a/src/test/regress/expected/vacuum.out
+++ b/src/test/regress/expected/vacuum.out
@@ -110,7 +110,7 @@ VACUUM (PARALLEL 2) pvactst;
UPDATE pvactst SET i = i WHERE i < 1000;
VACUUM (PARALLEL 0) pvactst; -- disable parallel vacuum
VACUUM (PARALLEL -1) pvactst; -- error
-ERROR: parallel vacuum degree must be between 0 and 1024
+ERROR: parallel workers for vacuum must be between 0 and 1024
LINE 1: VACUUM (PARALLEL -1) pvactst;
^
VACUUM (PARALLEL 2, INDEX_CLEANUP FALSE) pvactst;
--
2.25.1
