On Thu, Aug 10, 2023 at 08:09:34PM +0200, Drouvot, Bertrand wrote: > Agree that's worth it given the fact that iterating one more time is not that > costly here.
I have reviewed v4, and finished by putting my hands on it to see what
I could do.
+ printf $wc "\telement = (wait_event_element *)
palloc(sizeof(wait_event_element));\n";
+
+ printf $wc "\telement->wait_event_type = \"%s\";\n", $last;
+ printf $wc "\telement->wait_event_name = \"%s\";\n", $wev->[1];
+ printf $wc "\telement->wait_event_description = \"%s\";\n\n",
$new_desc;
+
+ printf $wc "\twait_event = lappend(wait_event, element);\n\n";
+ }
This is simpler than the previous versions, still I am not much a fan
of implying the use of a list and these pallocs. There are two things
that we could do:
- Hide that behind a macro defined in wait_event_funcs.c.
- Feed the data generated here into a static structure, like:
+static const struct
+{
+ const char *type;
+ const char *name;
+ const char *description;
+}
After experimenting with both, I've found the latter a tad cleaner, so
the attached version does that.
+ <structfield>description</structfield> <type>texte</type>
This one was difficult to see..
I am not sure that "pg_wait_event" is a good idea for the name if the
new view. How about "pg_wait_events" instead, in plural form? There
is more than one wait event listed.
One log entry in Solution.pm has missed the addition of a reference to
wait_event_funcs_data.c.
And.. src/backend/Makefile missed two updates for maintainer-clean & co,
no?
One thing that the patch is still missing is the handling of custom
wait events for extensions. So this still requires more code. I was
thinking about listed these events as:
- Type: "Extension"
- Name: What a module has registered.
- Description: "Custom wait event \"%Name%\" defined by extension".
For now I am attaching a v5.
--
Michael
From 4f0172e216bfa7b929b9ca3465d66088b2ac1566 Mon Sep 17 00:00:00 2001
From: bdrouvotAWS <bdrou...@amazon.com>
Date: Sat, 5 Aug 2023 12:39:42 +0000
Subject: [PATCH v5] Add catalog pg_wait_events
Adding a new system view, namely pg_wait_event, that describes the wait
events.
---
src/include/catalog/pg_proc.dat | 6 ++
src/include/utils/meson.build | 4 +-
src/backend/Makefile | 3 +-
src/backend/catalog/system_views.sql | 3 +
src/backend/utils/activity/.gitignore | 1 +
src/backend/utils/activity/Makefile | 8 ++-
.../activity/generate-wait_event_types.pl | 46 +++++++++++--
src/backend/utils/activity/meson.build | 1 +
src/backend/utils/activity/wait_event_funcs.c | 69 +++++++++++++++++++
src/test/regress/expected/rules.out | 4 ++
src/test/regress/expected/sysviews.out | 16 +++++
src/test/regress/sql/sysviews.sql | 4 ++
doc/src/sgml/system-views.sgml | 64 +++++++++++++++++
src/tools/msvc/Solution.pm | 3 +-
src/tools/msvc/clean.bat | 1 +
15 files changed, 223 insertions(+), 10 deletions(-)
create mode 100644 src/backend/utils/activity/wait_event_funcs.c
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 6996073989..1a942c678c 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,text}',
+ proargmodes => '{o,o,o}', proargnames => '{type,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..c179478611 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', 'wait_event_funcs_data.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/backend/Makefile b/src/backend/Makefile
index 1c929383c4..3e275ac759 100644
--- a/src/backend/Makefile
+++ b/src/backend/Makefile
@@ -134,7 +134,7 @@ storage/lmgr/lwlocknames.h: storage/lmgr/generate-lwlocknames.pl storage/lmgr/lw
$(MAKE) -C storage/lmgr lwlocknames.h lwlocknames.c
utils/activity/wait_event_types.h: utils/activity/generate-wait_event_types.pl utils/activity/wait_event_names.txt
- $(MAKE) -C utils/activity wait_event_types.h pgstat_wait_event.c
+ $(MAKE) -C utils/activity wait_event_types.h pgstat_wait_event.c wait_event_funcs_data.c
# run this unconditionally to avoid needing to know its dependencies here:
submake-catalog-headers:
@@ -311,6 +311,7 @@ maintainer-clean: distclean
storage/lmgr/lwlocknames.c \
storage/lmgr/lwlocknames.h \
utils/activity/pgstat_wait_event.c \
+ utils/activity/wait_event_funcs_data.c \
utils/activity/wait_event_types.h \
utils/adt/jsonpath_gram.c \
utils/adt/jsonpath_gram.h \
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index af65af6bdd..362b1ea8d5 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_events 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..bd0c0c7772 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
+/wait_event_funcs_data.c
diff --git a/src/backend/utils/activity/Makefile b/src/backend/utils/activity/Makefile
index f1117745d4..f57cf3958c 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 \
- wait_event.o
+ wait_event.o \
+ wait_event_funcs.o
include $(top_srcdir)/src/backend/common.mk
+wait_event_funcs.o: wait_event_funcs_data.c
+wait_event_funcs_data.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 $<
maintainer-clean: clean
- rm -f wait_event_types.h pgstat_wait_event.c
+ rm -f wait_event_types.h pgstat_wait_event.c wait_event_funcs_data.c
diff --git a/src/backend/utils/activity/generate-wait_event_types.pl b/src/backend/utils/activity/generate-wait_event_types.pl
index 56335e8730..6483966c6a 100644
--- a/src/backend/utils/activity/generate-wait_event_types.pl
+++ b/src/backend/utils/activity/generate-wait_event_types.pl
@@ -4,6 +4,7 @@
# Generate wait events support files from wait_event_names.txt:
# - wait_event_types.h (if --code is passed)
# - pgstat_wait_event.c (if --code is passed)
+# - wait_event_funcs_data.c (if --code is passed)
# - wait_event_types.sgml (if --docs is passed)
#
# Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
@@ -98,8 +99,10 @@ if ($gen_code)
# multiple times.
my $htmp = "$output_path/wait_event_types.h.tmp$$";
my $ctmp = "$output_path/pgstat_wait_event.c.tmp$$";
+ my $wctmp = "$output_path/wait_event_funcs_data.c.tmp$$";
open my $h, '>', $htmp or die "Could not open $htmp: $!";
open my $c, '>', $ctmp or die "Could not open $ctmp: $!";
+ open my $wc, '>', $wctmp or die "Could not open $wctmp: $!";
my $header_comment =
'/*-------------------------------------------------------------------------
@@ -129,12 +132,14 @@ if ($gen_code)
printf $c $header_comment, 'pgstat_wait_event.c';
+ printf $wc $header_comment, 'wait_event_funcs_data.c';
+
+ # Generate the pgstat_wait_event.c and wait_event_types.h files
# 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.
+ # Don't generate the pgstat_wait_event.c and wait_event_types.h files
+ # for Extension, LWLock and Lock, these are handled independently.
next
if ( $waitclass eq 'WaitEventExtension'
|| $waitclass eq 'WaitEventLWLock'
@@ -183,14 +188,47 @@ if ($gen_code)
printf $c "}\n\n";
}
+ # Generate wait_event_funcs_data.c, for the contents of static C
+ # structure holding all the information about the wait events.
+ # uc() is being used to force the comparison to be case-insensitive,
+ # even though it is not strictly mandatory here.
+ foreach my $waitclass (sort { uc($a) cmp uc($b) } keys %hashwe)
+ {
+ my $last = $waitclass;
+ $last =~ s/^WaitEvent//;
+
+ foreach my $wev (@{ $hashwe{$waitclass} })
+ {
+ my $new_desc = substr $wev->[2], 1, -2;
+ # Escape single quotes.
+ $new_desc =~ s/'/\\'/g;
+
+ # Remove SGML markups
+ $new_desc =~ s/<.*>(.*?)<.*>/$1/g;
+
+ # Tweak contents about links <xref linkend="text"/> on GUCs,
+ # then remove any reference to "see <xref linkend="text"/>".
+ $new_desc =~ s/<xref linkend="guc-(.*?)"\/>/$1/g;
+ $new_desc =~ s/; see.*$//;
+
+ # One element to the C structure holding the wait event
+ # info, as of (type, name, description).
+ printf $wc "\t{\"%s\", \"%s\", \"%s\"},\n", $last, $wev->[1],
+ $new_desc;
+ }
+ }
+
printf $h "#endif /* WAIT_EVENT_TYPES_H */\n";
close $h;
close $c;
+ close $wc;
rename($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: $!";
+ rename($wctmp, "$output_path/wait_event_funcs_data.c")
+ || die "rename: $ctmp to $output_path/wait_event_funcs_data.c: $!";
}
# Generate the .sgml file.
elsif ($gen_docs)
@@ -249,7 +287,7 @@ Usage: perl [--output <path>] [--code ] [ --sgml ] input_file
Options:
--outdir Output directory (default '.')
- --code Generate wait_event_types.h and pgstat_wait_event.c.
+ --code Generate C and header files.
--sgml Generate wait_event_types.sgml.
generate-wait_event_types.pl generates the SGML documentation and code
diff --git a/src/backend/utils/activity/meson.build b/src/backend/utils/activity/meson.build
index 9633f3623c..46a27e7548 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',
+ 'wait_event_funcs.c',
)
wait_event = static_library('wait_event_names',
diff --git a/src/backend/utils/activity/wait_event_funcs.c b/src/backend/utils/activity/wait_event_funcs.c
new file mode 100644
index 0000000000..19d13c0dcd
--- /dev/null
+++ b/src/backend/utils/activity/wait_event_funcs.c
@@ -0,0 +1,69 @@
+/*------------------------------------------------------------------------
+ *
+ * wait_event_funcs.c
+ * Functions for accessing wait event data.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/utils/activity/wait_event_funcs.c
+ *
+ *------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "funcapi.h"
+#include "utils/builtins.h"
+
+/*
+ * Each wait event has one corresponding entry in this structure, fed to
+ * the SQL function of this file.
+ */
+static const struct
+{
+ const char *type;
+ const char *name;
+ const char *description;
+}
+
+ waitEventData[] =
+{
+#include "wait_event_funcs_data.c"
+ /* end of list */
+ {NULL, NULL, NULL}
+};
+
+
+/*
+ * pg_get_wait_events
+ *
+ * List all the wait events (type, name) and their descriptions.
+ */
+Datum
+pg_get_wait_events(PG_FUNCTION_ARGS)
+{
+#define PG_GET_WAIT_EVENTS_COLS 3
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+
+ /* Build tuplestore to hold the result rows */
+ InitMaterializedSRF(fcinfo, 0);
+
+ /* Iterate over the list of wait events */
+ for (int idx = 0; waitEventData[idx].type != NULL; idx++)
+ {
+ Datum values[PG_GET_WAIT_EVENTS_COLS] = {0};
+ bool nulls[PG_GET_WAIT_EVENTS_COLS] = {0};
+
+ values[0] = CStringGetTextDatum(waitEventData[idx].type);
+ values[1] = CStringGetTextDatum(waitEventData[idx].name);
+ values[2] = CStringGetTextDatum(waitEventData[idx].description);
+
+ tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
+ }
+
+ /* XXX: this needs to handle custom wait events, not yet in the tree */
+
+ return (Datum) 0;
+}
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index e07afcd4aa..55447d8090 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2631,6 +2631,10 @@ 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_events| SELECT type,
+ name,
+ description
+ FROM pg_get_wait_events() we(type, 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..f3ac8dfe94 100644
--- a/src/test/regress/expected/sysviews.out
+++ b/src/test/regress/expected/sysviews.out
@@ -134,6 +134,22 @@ select name, setting from pg_settings where name like 'enable%';
enable_tidscan | on
(21 rows)
+-- There are always wait event descriptions for various types.
+select type, count(*) > 0 as ok FROM pg_wait_events
+ group by type order by type;
+ type | ok
+-----------+----
+ Activity | t
+ BufferPin | t
+ Client | t
+ Extension | t
+ IO | t
+ IPC | t
+ Lock | t
+ LWLock | t
+ Timeout | t
+(9 rows)
+
-- 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..853daa85eb 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 are always wait event descriptions for various types.
+select type, count(*) > 0 as ok FROM pg_wait_events
+ group by type order by type;
+
-- 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/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 57b228076e..2b35c2f91b 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-events"><structname>pg_wait_events</structname></link></entry>
+ <entry>wait events</entry>
+ </row>
+
</tbody>
</tgroup>
</table>
@@ -4825,4 +4830,63 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</table>
</sect1>
+
+ <sect1 id="view-pg-wait-events">
+ <title><structname>pg_wait_events</structname></title>
+
+ <indexterm zone="view-pg-wait-events">
+ <primary>pg_wait_events</primary>
+ </indexterm>
+
+ <para>
+ The view <structname>pg_wait_events</structname> provides description about the
+ wait events.
+ </para>
+
+ <table>
+ <title><structname>pg_wait_events</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>type</structfield> <type>text</type>
+ </para>
+ <para>
+ Wait event type
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>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>text</type>
+ </para>
+ <para>
+ Wait event description
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
</chapter>
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index c98a1e9f9a..a50f730260 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -588,7 +588,8 @@ sub GenerateFiles
'src/include/utils/wait_event_types.h',
'src/backend/utils/activity/wait_event_names.txt'))
{
- print "Generating pgstat_wait_event.c and wait_event_types.h...\n";
+ print
+ "Generating pgstat_wait_event.c, wait_event_types.h and wait_event_funcs_data.c...\n";
my $activ = 'src/backend/utils/activity';
system(
"perl $activ/generate-wait_event_types.pl --outdir $activ --code $activ/wait_event_names.txt"
diff --git a/src/tools/msvc/clean.bat b/src/tools/msvc/clean.bat
index 7cb23ea894..ac8da581e4 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\wait_event_funcs_data.c del /q src\backend\utils\activity\wait_event_funcs_data.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
--
2.40.1
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