Hi,
On 8/7/23 10:23 AM, Drouvot, Bertrand wrote:
Hi,
On 8/4/23 5:08 PM, Tom Lane wrote:
"Drouvot, Bertrand" <bertranddrouvot...@gmail.com> writes:
Now that fa88928470 generates automatically code and documentation
related to wait events, why not exposing the wait events description
through a system catalog relation?
I think you'd be better off making this a view over a set-returning
function. The nearby work to allow run-time extensibility of the
set of wait events is not going to be happy with a static catalog.
Oh right, good point, thanks!: I'll come back with a new patch version to make
use of SRF instead.
Please find attached v2 making use of SRF.
v2:
- adds a new pg_wait_event.c that acts as the "template" for the SRF
- generates pg_wait_event_insert.c (through generate-wait_event_types.pl) that
is included into pg_wait_event.c
That way I think it's flexible enough to add more code if needed in the SRF.
The patch also:
- updates the doc
- works with autoconf and meson
- adds a simple test
I'm adding a new CF entry for it.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
From 63f1316b2c160b72bdc1bcff6272e2888fce0db4 Mon Sep 17 00:00:00 2001
From: bdrouvotAWS <bdrou...@amazon.com>
Date: Sat, 5 Aug 2023 12:39:42 +0000
Subject: [PATCH v2] pg_wait_event
Adding a new system view, namely pg_wait_event, that describes the wait events.
---
doc/src/sgml/system-views.sgml | 55 ++++++++++++++
src/backend/catalog/system_views.sql | 3 +
src/backend/utils/activity/.gitignore | 1 +
src/backend/utils/activity/Makefile | 6 +-
.../activity/generate-wait_event_types.pl | 76 +++++++++++++------
src/backend/utils/activity/meson.build | 1 +
src/backend/utils/activity/pg_wait_event.c | 41 ++++++++++
src/include/catalog/pg_proc.dat | 6 ++
src/include/utils/meson.build | 4 +-
src/test/regress/expected/rules.out | 3 +
src/test/regress/expected/sysviews.out | 8 ++
src/test/regress/sql/sysviews.sql | 4 +
src/tools/msvc/clean.bat | 1 +
13 files changed, 183 insertions(+), 26 deletions(-)
19.8% doc/src/sgml/
60.6% src/backend/utils/activity/
5.3% src/include/catalog/
5.7% src/test/regress/expected/
3.0% src/test/regress/sql/
5.3% src/
diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 57b228076e..e9cbeff682 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -221,6 +221,11 @@
<entry>views</entry>
</row>
+ <row>
+ <entry><link
linkend="view-pg-wait-event"><structname>pg_wait_event</structname></link></entry>
+ <entry>wait events</entry>
+ </row>
+
</tbody>
</tgroup>
</table>
@@ -4825,4 +4830,54 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</table>
</sect1>
+
+ <sect1 id="view-pg-wait-event">
+ <title><structname>pg_wait_event</structname></title>
+
+ <indexterm zone="view-pg-wait-event">
+ <primary>pg_wait_event</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_wait_event</structname> provides description about
the
+ wait events.
+ </para>
+
+ <table>
+ <title><structname>pg_wait_event</structname> Columns</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ Column Type
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>wait_event_name</structfield> <type>text</type>
+ </para>
+ <para>
+ Wait event name
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>description</structfield> <type>texte</type>
+ </para>
+ <para>
+ Wait event description
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
</chapter>
diff --git a/src/backend/catalog/system_views.sql
b/src/backend/catalog/system_views.sql
index af65af6bdd..f86a4dd770 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1342,3 +1342,6 @@ CREATE VIEW pg_stat_subscription_stats AS
ss.stats_reset
FROM pg_subscription as s,
pg_stat_get_subscription_stats(s.oid) as ss;
+
+CREATE VIEW pg_wait_event AS
+ SELECT * FROM pg_get_wait_events() AS we;
diff --git a/src/backend/utils/activity/.gitignore
b/src/backend/utils/activity/.gitignore
index d77079285b..ad089a0b63 100644
--- a/src/backend/utils/activity/.gitignore
+++ b/src/backend/utils/activity/.gitignore
@@ -1,2 +1,3 @@
/pgstat_wait_event.c
/wait_event_types.h
+/pg_wait_event_insert.c
diff --git a/src/backend/utils/activity/Makefile
b/src/backend/utils/activity/Makefile
index f1117745d4..8595e6ea77 100644
--- a/src/backend/utils/activity/Makefile
+++ b/src/backend/utils/activity/Makefile
@@ -32,10 +32,14 @@ OBJS = \
pgstat_subscription.o \
pgstat_wal.o \
pgstat_xact.o \
+ pg_wait_event.o \
wait_event.o
include $(top_srcdir)/src/backend/common.mk
+pg_wait_event.o: pg_wait_event_insert.c
+pg_wait_event_insert.c: wait_event_types.h
+
wait_event.o: pgstat_wait_event.c
pgstat_wait_event.c: wait_event_types.h
touch $@
@@ -44,4 +48,4 @@ wait_event_types.h:
$(top_srcdir)/src/backend/utils/activity/wait_event_names.tx
$(PERL) $(srcdir)/generate-wait_event_types.pl --code $<
maintainer-clean: clean
- rm -f wait_event_types.h pgstat_wait_event.c
+ rm -f wait_event_types.h pgstat_wait_event.c pg_wait_event_insert.c
diff --git a/src/backend/utils/activity/generate-wait_event_types.pl
b/src/backend/utils/activity/generate-wait_event_types.pl
index 56335e8730..6f2b823b6b 100644
--- a/src/backend/utils/activity/generate-wait_event_types.pl
+++ b/src/backend/utils/activity/generate-wait_event_types.pl
@@ -4,6 +4,7 @@
# Generate wait events support files from wait_event_names.txt:
# - wait_event_types.h (if --code is passed)
# - pgstat_wait_event.c (if --code is passed)
+# - pg_wait_event_insert.c (if --code is passed)
# - wait_event_types.sgml (if --docs is passed)
#
# Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
@@ -98,8 +99,10 @@ if ($gen_code)
# multiple times.
my $htmp = "$output_path/wait_event_types.h.tmp$$";
my $ctmp = "$output_path/pgstat_wait_event.c.tmp$$";
+ my $ictmp = "$output_path/pg_wait_event_insert.c.tmp$$";
open my $h, '>', $htmp or die "Could not open $htmp: $!";
open my $c, '>', $ctmp or die "Could not open $ctmp: $!";
+ open my $ic, '>', $ictmp or die "Could not open $ictmp: $!";
my $header_comment =
'/*-------------------------------------------------------------------------
@@ -129,16 +132,17 @@ if ($gen_code)
printf $c $header_comment, 'pgstat_wait_event.c';
+ printf $ic $header_comment, 'pg_wait_event_insert.c';
+
# uc() is being used to force the comparison to be case-insensitive.
foreach my $waitclass (sort { uc($a) cmp uc($b) } keys %hashwe)
{
- # Don't generate .c and .h files for Extension, LWLock and
- # Lock, these are handled independently.
- next
- if ( $waitclass eq 'WaitEventExtension'
- || $waitclass eq 'WaitEventLWLock'
- || $waitclass eq 'WaitEventLock');
+ # Don't generate .c (except pg_wait_event_insert.c) and .h
files for
+ # Extension, LWLock and Lock, these are handled independently.
+ my $is_exception = $waitclass eq 'WaitEventExtension' ||
+ $waitclass eq
'WaitEventLWLock' ||
+ $waitclass eq
'WaitEventLock';
my $last = $waitclass;
$last =~ s/^WaitEvent//;
@@ -147,50 +151,76 @@ if ($gen_code)
my $firstpass = 1;
my $pg_wait_class;
- printf $c
- "static const char *\npgstat_get_wait_$lastlc($waitclass
w)\n{\n";
- printf $c "\tconst char *event_name = \"unknown wait
event\";\n\n";
- printf $c "\tswitch (w)\n\t{\n";
+ if (!$is_exception)
+ {
+ printf $c
+ "static const char
*\npgstat_get_wait_$lastlc($waitclass w)\n{\n";
+ printf $c "\tconst char *event_name = \"unknown wait
event\";\n\n";
+ printf $c "\tswitch (w)\n\t{\n";
+ }
foreach my $wev (@{ $hashwe{$waitclass} })
{
- if ($firstpass)
+ if ($firstpass && !$is_exception)
{
printf $h "typedef enum\n{\n";
$pg_wait_class = "PG_WAIT_" . $lastuc;
printf $h "\t%s = %s", $wev->[0],
$pg_wait_class;
$continue = ",\n";
}
- else
+ elsif (!$is_exception)
{
printf $h "%s\t%s", $continue, $wev->[0];
$continue = ",\n";
}
- $firstpass = 0;
- printf $c "\t\t case %s:\n", $wev->[0];
- # Apply quotes to the wait event name string.
- printf $c "\t\t\t event_name = \"%s\";\n\t\t\t
break;\n",
- $wev->[1];
+ if (!$is_exception)
+ {
+ $firstpass = 0;
+
+ printf $c "\t\t case %s:\n", $wev->[0];
+ # Apply quotes to the wait event name string.
+ printf $c "\t\t\t event_name = \"%s\";\n\t\t\t
break;\n",
+ $wev->[1];
+ }
+
+ my $new_desc = substr $wev->[2], 1, -2;
+ $new_desc =~ s/'/\\'/g;
+ $new_desc =~ s/<.*>(.*?)<.*>/$1/g;
+ $new_desc =~ s/<xref linkend="guc-(.*?)"\/>/$1/g;
+ $new_desc =~ s/; see.*$//;
+
+ printf $ic "\tmemset(values, 0, sizeof(values));\n";
+ printf $ic "\tmemset(nulls, 0, sizeof(nulls));\n\n";
+ printf $ic "\tvalues[0] =
CStringGetTextDatum(\"%s\");\n", $wev->[1];
+ printf $ic "\tvalues[1] =
CStringGetTextDatum(\"%s\");\n\n", $new_desc;
+
+ printf $ic "\ttuplestore_putvalues(rsinfo->setResult,
rsinfo->setDesc, values, nulls);\n\n";
}
- printf $h "\n} $waitclass;\n\n";
+ if (!$is_exception)
+ {
+ printf $h "\n} $waitclass;\n\n";
- printf $c
- "\t\t\t /* no default case, so that compiler will warn */\n";
- printf $c "\t}\n\n";
- printf $c "\treturn event_name;\n";
- printf $c "}\n\n";
+ printf $c
+ "\t\t\t /* no default case, so that compiler will
warn */\n";
+ printf $c "\t}\n\n";
+ printf $c "\treturn event_name;\n";
+ printf $c "}\n\n";
+ }
}
printf $h "#endif /* WAIT_EVENT_TYPES_H */\n";
close $h;
close $c;
+ close $ic;
rename($htmp, "$output_path/wait_event_types.h")
|| die "rename: $htmp to $output_path/wait_event_types.h: $!";
rename($ctmp, "$output_path/pgstat_wait_event.c")
|| die "rename: $ctmp to $output_path/pgstat_wait_event.c: $!";
+ rename($ictmp, "$output_path/pg_wait_event_insert.c")
+ || die "rename: $ictmp to $output_path/pg_wait_event_insert.c: $!";
}
# Generate the .sgml file.
elsif ($gen_docs)
diff --git a/src/backend/utils/activity/meson.build
b/src/backend/utils/activity/meson.build
index 9633f3623c..774e0bd348 100644
--- a/src/backend/utils/activity/meson.build
+++ b/src/backend/utils/activity/meson.build
@@ -23,6 +23,7 @@ backend_sources += files(
# seems nicer to not add that as an include path for the whole backend.
waitevent_sources = files(
'wait_event.c',
+ 'pg_wait_event.c',
)
wait_event = static_library('wait_event_names',
diff --git a/src/backend/utils/activity/pg_wait_event.c
b/src/backend/utils/activity/pg_wait_event.c
new file mode 100644
index 0000000000..9407d18254
--- /dev/null
+++ b/src/backend/utils/activity/pg_wait_event.c
@@ -0,0 +1,41 @@
+/* ----------
+ * pg_wait_event.c
+ * Wait event reporting infrastructure.
+ *
+ * Copyright (c) 2001-2023, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/utils/activity/pg_wait_event.c
+ *
+ * NOTES
+ *
+ * The "pg_wait_event_insert.c" included in this file is generated by
+ * src/backend/utils/activity/generate-wait_event_types.pl
+ *
+ */
+#include "postgres.h"
+
+#include "funcapi.h"
+#include "utils/builtins.h"
+
+/*
+ * This function lists the wait events and their descriptions.
+ *
+ * The system view pg_wait_event provides a user interface to this
+ * SRF.
+ */
+Datum
+pg_get_wait_events(PG_FUNCTION_ARGS)
+{
+#define NUM_WAIT_EVENT_TABLES_ELEM 2
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+ Datum values[NUM_WAIT_EVENT_TABLES_ELEM];
+ bool nulls[NUM_WAIT_EVENT_TABLES_ELEM];
+
+ /* Build tuplestore to hold the result rows */
+ InitMaterializedSRF(fcinfo, 0);
+
+ #include "pg_wait_event_insert.c"
+ return (Datum) 0;
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 6996073989..57d8875dee 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5417,6 +5417,12 @@
proargmodes =>
'{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
proargnames =>
'{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,ssl_client_dn,ssl_client_serial,ssl_issuer_dn,gss_auth,gss_princ,gss_enc,gss_delegation,leader_pid,query_id}',
prosrc => 'pg_stat_get_activity' },
+{ oid => '8403', descr => 'describe wait events',
+ proname => 'pg_get_wait_events', procost => '10', prorows => '100',
+ proretset => 't', provolatile => 's', prorettype => 'record',
+ proargtypes => '', proallargtypes => '{text,text}',
+ proargmodes => '{o,o}', proargnames => '{wait_event_name,description}',
+ prosrc => 'pg_get_wait_events' },
{ oid => '3318',
descr => 'statistics: information about progress of backends running
maintenance command',
proname => 'pg_stat_get_progress_info', prorows => '100', proretset => 't',
diff --git a/src/include/utils/meson.build b/src/include/utils/meson.build
index 6de5d93799..4f14f770ef 100644
--- a/src/include/utils/meson.build
+++ b/src/include/utils/meson.build
@@ -1,6 +1,6 @@
# Copyright (c) 2022-2023, PostgreSQL Global Development Group
-wait_event_output = ['wait_event_types.h', 'pgstat_wait_event.c']
+wait_event_output = ['wait_event_types.h', 'pgstat_wait_event.c',
'pg_wait_event_insert.c']
wait_event_target = custom_target('wait_event_names',
input: files('../../backend/utils/activity/wait_event_names.txt'),
output: wait_event_output,
@@ -11,7 +11,7 @@ wait_event_target = custom_target('wait_event_names',
],
build_by_default: true,
install: true,
- install_dir: [dir_include_server / 'utils', false],
+ install_dir: [dir_include_server / 'utils', false, false],
)
wait_event_types_h = wait_event_target[0]
diff --git a/src/test/regress/expected/rules.out
b/src/test/regress/expected/rules.out
index e07afcd4aa..23b5f7dbca 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2631,6 +2631,9 @@ pg_views| SELECT n.nspname AS schemaname,
FROM (pg_class c
LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace)))
WHERE (c.relkind = 'v'::"char");
+pg_wait_event| SELECT wait_event_name,
+ description
+ FROM pg_get_wait_events() we(wait_event_name, description);
SELECT tablename, rulename, definition FROM pg_rules
WHERE schemaname = 'pg_catalog'
ORDER BY tablename, rulename;
diff --git a/src/test/regress/expected/sysviews.out
b/src/test/regress/expected/sysviews.out
index 001c6e7eb9..12309be267 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -134,6 +134,14 @@ select name, setting from pg_settings where name like
'enable%';
enable_tidscan | on
(21 rows)
+-- There will surely be at least 240 wait events and at least 27 related to WAL
+select count(*) > 239 as ok, count(*) FILTER (WHERE description like '%WAL%')
> 26 AS ok_wal_desc
+ from pg_wait_event;
+ ok | ok_wal_desc
+----+-------------
+ t | t
+(1 row)
+
-- Test that the pg_timezone_names and pg_timezone_abbrevs views are
-- more-or-less working. We can't test their contents in any great detail
-- without the outputs changing anytime IANA updates the underlying data,
diff --git a/src/test/regress/sql/sysviews.sql
b/src/test/regress/sql/sysviews.sql
index 351e469c77..6bc6bd1322 100644
--- a/src/test/regress/sql/sysviews.sql
+++ b/src/test/regress/sql/sysviews.sql
@@ -55,6 +55,10 @@ select count(*) = 0 as ok from pg_stat_wal_receiver;
-- a regression test run.
select name, setting from pg_settings where name like 'enable%';
+-- There will surely be at least 240 wait events and at least 27 related to WAL
+select count(*) > 239 as ok, count(*) FILTER (WHERE description like '%WAL%')
> 26 AS ok_wal_desc
+ from pg_wait_event;
+
-- Test that the pg_timezone_names and pg_timezone_abbrevs views are
-- more-or-less working. We can't test their contents in any great detail
-- without the outputs changing anytime IANA updates the underlying data,
diff --git a/src/tools/msvc/clean.bat b/src/tools/msvc/clean.bat
index 7cb23ea894..028d174d87 100755
--- a/src/tools/msvc/clean.bat
+++ b/src/tools/msvc/clean.bat
@@ -55,6 +55,7 @@ if exist src\include\catalog\header-stamp del /q
src\include\catalog\header-stam
if exist doc\src\sgml\version.sgml del /q doc\src\sgml\version.sgml
if %DIST%==1 if exist src\backend\utils\activity\pgstat_wait_event.c del /q
src\backend\utils\activity\pgstat_wait_event.c
+if %DIST%==1 if exist src\backend\utils\activity\pg_wait_event_insert.c del /q
src\backend\utils\activity\pg_wait_event_insert.c
if %DIST%==1 if exist src\backend\utils\activity\wait_event_types.h del /q
src\backend\utils\activity\wait_event_types.h
if %DIST%==1 if exist src\backend\utils\fmgroids.h del /q
src\backend\utils\fmgroids.h
if %DIST%==1 if exist src\backend\utils\fmgrprotos.h del /q
src\backend\utils\fmgrprotos.h
--
2.34.1
