Hi,
Thanks for your comments.
I updated the patch to v2.
* Update a comment instead writing documentation about
the wait events for pg_prewarm.
* Make the name of wait events which are different code
path different. Add DblinkGetConnect and PgPrewarmDumpShutdown.
* Make variable names shorter like pgfdw_we_receive.
* Update documents.
* Add some tests with pg_wait_events view.
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
From 025525eae164e33117d94f2a90a4219808072b3c Mon Sep 17 00:00:00 2001
From: Masahiro Ikeda <mshr.ik...@ntt.com>
Date: Mon, 21 Aug 2023 10:36:10 +0900
Subject: [PATCH] Make to use custom wait events for modules
---
contrib/dblink/dblink.c | 16 +++++++-
contrib/dblink/expected/dblink.out | 9 +++++
contrib/dblink/sql/dblink.sql | 4 ++
contrib/pg_prewarm/autoprewarm.c | 22 ++++++++++-
contrib/postgres_fdw/connection.c | 23 +++++++++--
.../postgres_fdw/expected/postgres_fdw.out | 12 ++++++
contrib/postgres_fdw/sql/postgres_fdw.sql | 7 ++++
doc/src/sgml/dblink.sgml | 28 +++++++++++++
doc/src/sgml/postgres-fdw.sgml | 39 +++++++++++++++++++
doc/src/sgml/xfunc.sgml | 6 +--
src/test/modules/test_shm_mq/setup.c | 9 ++++-
src/test/modules/test_shm_mq/test.c | 9 ++++-
.../modules/worker_spi/t/001_worker_spi.pl | 12 +++---
src/test/modules/worker_spi/worker_spi.c | 2 +-
14 files changed, 179 insertions(+), 19 deletions(-)
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 41e1f6c91d..104d6e9f37 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -130,6 +130,10 @@ static void restoreLocalGucs(int nestlevel);
static remoteConn *pconn = NULL;
static HTAB *remoteConnHash = NULL;
+/* value cached, fetched from shared memory */
+static uint32 dblink_we_get_conn = 0;
+static uint32 dblink_we_conn = 0;
+
/*
* Following is list that holds multiple remote connections.
* Calling convention of each dblink function changes to accept
@@ -202,8 +206,12 @@ dblink_get_conn(char *conname_or_str,
connstr = conname_or_str;
dblink_connstr_check(connstr);
+ /* first time, allocate or get the custom wait event */
+ if (dblink_we_get_conn == 0)
+ dblink_we_get_conn = WaitEventExtensionNew("DblinkGetConnect");
+
/* OK to make connection */
- conn = libpqsrv_connect(connstr, WAIT_EVENT_EXTENSION);
+ conn = libpqsrv_connect(connstr, dblink_we_get_conn);
if (PQstatus(conn) == CONNECTION_BAD)
{
@@ -292,8 +300,12 @@ dblink_connect(PG_FUNCTION_ARGS)
/* check password in connection string if not superuser */
dblink_connstr_check(connstr);
+ /* first time, allocate or get the custom wait event */
+ if (dblink_we_conn == 0)
+ dblink_we_conn = WaitEventExtensionNew("DblinkConnect");
+
/* OK to make connection */
- conn = libpqsrv_connect(connstr, WAIT_EVENT_EXTENSION);
+ conn = libpqsrv_connect(connstr, dblink_we_conn);
if (PQstatus(conn) == CONNECTION_BAD)
{
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index 7809f58d96..c17c7b1361 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -1209,6 +1209,15 @@ SHOW intervalstyle;
postgres
(1 row)
+-- Check custom wait events are registered
+SELECT name FROM pg_wait_events WHERE name ~ '^Dblink'
+ORDER BY name COLLATE "C";
+ name
+------------------
+ DblinkConnect
+ DblinkGetConnect
+(2 rows)
+
-- Clean up GUC-setting tests
SELECT dblink_disconnect('myconn');
dblink_disconnect
diff --git a/contrib/dblink/sql/dblink.sql b/contrib/dblink/sql/dblink.sql
index 7870ce5d5a..519b3f5266 100644
--- a/contrib/dblink/sql/dblink.sql
+++ b/contrib/dblink/sql/dblink.sql
@@ -627,6 +627,10 @@ FROM dblink_fetch('myconn','error_cursor', 1) AS t(i int);
SHOW datestyle;
SHOW intervalstyle;
+-- Check custom wait events are registered
+SELECT name FROM pg_wait_events WHERE name ~ '^Dblink'
+ORDER BY name COLLATE "C";
+
-- Clean up GUC-setting tests
SELECT dblink_disconnect('myconn');
RESET datestyle;
diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
index d0efc9e524..2160d40705 100644
--- a/contrib/pg_prewarm/autoprewarm.c
+++ b/contrib/pg_prewarm/autoprewarm.c
@@ -105,6 +105,16 @@ static AutoPrewarmSharedState *apw_state = NULL;
static bool autoprewarm = true; /* start worker? */
static int autoprewarm_interval = 300; /* dump interval */
+/*
+ * Cached custom wait events, fetched from shared memory.
+ *
+ * Note that they are not reported on pg_stat_activity. pgstat_bestart() isn't
+ * called because the autoprewarm worker isn't an auxiliary process and it
+ * doesn't connect to a database.
+ */
+static uint32 autoprewarm_we_shutdown = 0;
+static uint32 autoprewarm_we_delay = 0;
+
/*
* Module load callback.
*/
@@ -233,11 +243,15 @@ autoprewarm_main(Datum main_arg)
if (autoprewarm_interval <= 0)
{
+ /* first time, allocate or get the custom wait event */
+ if (autoprewarm_we_shutdown == 0)
+ autoprewarm_we_shutdown = WaitEventExtensionNew("PgPrewarmDumpShutdown");
+
/* We're only dumping at shutdown, so just wait forever. */
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_EXIT_ON_PM_DEATH,
-1L,
- WAIT_EVENT_EXTENSION);
+ autoprewarm_we_shutdown);
}
else
{
@@ -260,11 +274,15 @@ autoprewarm_main(Datum main_arg)
continue;
}
+ /* first time, allocate or get the custom wait event */
+ if (autoprewarm_we_delay == 0)
+ autoprewarm_we_delay = WaitEventExtensionNew("PgPrewarmDumpDelay");
+
/* Sleep until the next dump time. */
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
delay_in_ms,
- WAIT_EVENT_EXTENSION);
+ autoprewarm_we_delay);
}
/* Reset the latch, loop. */
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 7e12b722ec..7d6fbc56a1 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -83,6 +83,11 @@ static unsigned int prep_stmt_number = 0;
/* tracks whether any work is needed in callback functions */
static bool xact_got_connection = false;
+/* value cached, fetched from shared memory */
+static uint32 pgfdw_we_connect = 0;
+static uint32 pgfdw_we_receive = 0;
+static uint32 pgfdw_we_cleanup_receive = 0;
+
/*
* Milliseconds to wait to cancel an in-progress query or execute a cleanup
* query; if it takes longer than 30 seconds to do these, we assume the
@@ -527,10 +532,14 @@ connect_pg_server(ForeignServer *server, UserMapping *user)
/* verify the set of connection parameters */
check_conn_params(keywords, values, user);
+ /* first time, allocate or get the custom wait event */
+ if (pgfdw_we_connect == 0)
+ pgfdw_we_connect = WaitEventExtensionNew("PostgresFdwConnect");
+
/* OK to make connection */
conn = libpqsrv_connect_params(keywords, values,
false, /* expand_dbname */
- WAIT_EVENT_EXTENSION);
+ pgfdw_we_connect);
if (!conn || PQstatus(conn) != CONNECTION_OK)
ereport(ERROR,
@@ -858,12 +867,16 @@ pgfdw_get_result(PGconn *conn, const char *query)
{
int wc;
+ /* first time, allocate or get the custom wait event */
+ if (pgfdw_we_receive == 0)
+ pgfdw_we_receive = WaitEventExtensionNew("PostgresFdwReceive");
+
/* Sleep until there's something to do */
wc = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | WL_SOCKET_READABLE |
WL_EXIT_ON_PM_DEATH,
PQsocket(conn),
- -1L, WAIT_EVENT_EXTENSION);
+ -1L, pgfdw_we_receive);
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
@@ -1562,12 +1575,16 @@ pgfdw_get_cleanup_result(PGconn *conn, TimestampTz endtime, PGresult **result,
goto exit;
}
+ /* first time, allocate or get the custom wait event */
+ if (pgfdw_we_cleanup_receive == 0)
+ pgfdw_we_cleanup_receive = WaitEventExtensionNew("PostgresFdwCleanupReceive");
+
/* Sleep until there's something to do */
wc = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | WL_SOCKET_READABLE |
WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
PQsocket(conn),
- cur_timeout, WAIT_EVENT_EXTENSION);
+ cur_timeout, pgfdw_we_cleanup_receive);
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 77df7eb8e4..616fb55d8b 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -11901,6 +11901,18 @@ ALTER SERVER loopback OPTIONS (SET analyze_sampling 'random');
ANALYZE analyze_table;
ALTER SERVER loopback OPTIONS (SET analyze_sampling 'off');
ANALYZE analyze_table;
+-- ===================================================================
+-- test for custom wait events
+-- ===================================================================
+SELECT name FROM pg_wait_events WHERE name ~ '^PostgresFdw'
+ORDER BY name COLLATE "C";
+ name
+---------------------------
+ PostgresFdwCleanupReceive
+ PostgresFdwConnect
+ PostgresFdwReceive
+(3 rows)
+
-- cleanup
DROP FOREIGN TABLE analyze_ftable;
DROP TABLE analyze_table;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index cfb1b57e33..bab922aeae 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -4039,6 +4039,13 @@ ANALYZE analyze_table;
ALTER SERVER loopback OPTIONS (SET analyze_sampling 'off');
ANALYZE analyze_table;
+-- ===================================================================
+-- test for custom wait events
+-- ===================================================================
+
+SELECT name FROM pg_wait_events WHERE name ~ '^PostgresFdw'
+ORDER BY name COLLATE "C";
+
-- cleanup
DROP FOREIGN TABLE analyze_ftable;
DROP TABLE analyze_table;
diff --git a/doc/src/sgml/dblink.sgml b/doc/src/sgml/dblink.sgml
index 7d25f24f49..7800b80bdb 100644
--- a/doc/src/sgml/dblink.sgml
+++ b/doc/src/sgml/dblink.sgml
@@ -13,6 +13,34 @@
session.
</para>
+ <para>
+ <filename>dblink</filename> can report the following wait events under the wait
+ event type <literal>Extension</literal>.
+ </para>
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>DblinkConnect</literal></term>
+ <listitem>
+ <para>
+ Waiting to establish a connection to a remote server. It can be reported when calling
+ <function>dblink_connect</function>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>DblinkGetConnect</literal></term>
+ <listitem>
+ <para>
+ Waiting to establish a connection to a remote server when it can't look up the
+ specified persistent connection's name. It can be reported when calling
+ <function>dblink</function> and <function>dblink_exec</function>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
<para>
See also <xref linkend="postgres-fdw"/>, which provides roughly the same
functionality using a more modern and standards-compliant infrastructure.
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 5062d712e7..f38136e94f 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1042,6 +1042,45 @@ postgres=# SELECT postgres_fdw_disconnect_all();
</para>
</sect2>
+ <sect2 id="postgres-fdw-wait-events">
+ <title>Wait Events</title>
+
+ <para>
+ <filename>postgres_fdw</filename> can report the following wait events under the wait
+ event type <literal>Extension</literal>.
+ </para>
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>PostgresFdwConnect</literal></term>
+ <listitem>
+ <para>
+ Waiting to establish a connection to a remote server.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>PostgresFdwReceive</literal></term>
+ <listitem>
+ <para>
+ Waiting to receive the results of a query from a remote server.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>PostgresFdwCleanupReceive</literal></term>
+ <listitem>
+ <para>
+ Waiting for transaction abort on remote server.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </sect2>
+
<sect2 id="postgres-fdw-configuration-parameters">
<title>Configuration Parameters</title>
diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 281c178b0e..96ba95818c 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3472,9 +3472,9 @@ uint32 WaitEventExtensionNew(const char *wait_event_name)
<screen>
=# SELECT wait_event_type, wait_event FROM pg_stat_activity
WHERE backend_type ~ 'worker_spi';
- wait_event_type | wait_event
------------------+-----------------
- Extension | worker_spi_main
+ wait_event_type | wait_event
+-----------------+---------------
+ Extension | WorkerSpiMain
(1 row)
</screen>
</para>
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 192e5cc2ab..abc79352b9 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -40,6 +40,9 @@ static void wait_for_workers_to_become_ready(worker_state *wstate,
volatile test_shm_mq_header *hdr);
static bool check_worker_status(worker_state *wstate);
+/* value cached, fetched from shared memory */
+static uint32 we_bgworker_startup = 0;
+
/*
* Set up a dynamic shared memory segment and zero or more background workers
* for a test run.
@@ -278,9 +281,13 @@ wait_for_workers_to_become_ready(worker_state *wstate,
break;
}
+ /* first time, allocate or get the custom wait event */
+ if (we_bgworker_startup == 0)
+ we_bgworker_startup = WaitEventExtensionNew("TestShmMqBgWorkerStartup");
+
/* Wait to be signaled. */
(void) WaitLatch(MyLatch, WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, 0,
- WAIT_EVENT_EXTENSION);
+ we_bgworker_startup);
/* Reset the latch so we don't spin. */
ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index d9be703350..cb52a680a5 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -28,6 +28,9 @@ PG_FUNCTION_INFO_V1(test_shm_mq_pipelined);
static void verify_message(Size origlen, char *origdata, Size newlen,
char *newdata);
+/* value cached, fetched from shared memory */
+static uint32 we_message_queue = 0;
+
/*
* Simple test of the shared memory message queue infrastructure.
*
@@ -225,6 +228,10 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
if (wait)
{
+ /* first time, allocate or get the custom wait event */
+ if (we_message_queue == 0)
+ we_message_queue = WaitEventExtensionNew("TestShmMqMessageQueue");
+
/*
* If we made no progress, wait for one of the other processes to
* which we are connected to set our latch, indicating that they
@@ -232,7 +239,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
* for us to do.
*/
(void) WaitLatch(MyLatch, WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, 0,
- WAIT_EVENT_EXTENSION);
+ we_message_queue);
ResetLatch(MyLatch);
CHECK_FOR_INTERRUPTS();
}
diff --git a/src/test/modules/worker_spi/t/001_worker_spi.pl b/src/test/modules/worker_spi/t/001_worker_spi.pl
index 2965acd789..f3ef395554 100644
--- a/src/test/modules/worker_spi/t/001_worker_spi.pl
+++ b/src/test/modules/worker_spi/t/001_worker_spi.pl
@@ -43,15 +43,15 @@ is($result, qq(total|1), 'dynamic bgworker correctly consumed tuple data');
$result = $node->poll_query_until(
'postgres',
qq[SELECT wait_event FROM pg_stat_activity WHERE backend_type ~ 'worker_spi';],
- qq[worker_spi_main]);
+ qq[WorkerSpiMain]);
is($result, 1,
- 'dynamic bgworker has reported "worker_spi_main" as wait event');
+ 'dynamic bgworker has reported "WorkerSpiMain" as wait event');
# Check the wait event used by the dynamic bgworker appears in pg_wait_events
$result = $node->safe_psql('postgres',
- q[SELECT count(*) > 0 from pg_wait_events where type = 'Extension' and name = 'worker_spi_main';]
+ q[SELECT count(*) > 0 from pg_wait_events where type = 'Extension' and name = 'WorkerSpiMain';]
);
-is($result, 't', '"worker_spi_main" is reported in pg_wait_events');
+is($result, 't', '"WorkerSpiMain" is reported in pg_wait_events');
note "testing bgworkers loaded with shared_preload_libraries";
@@ -74,7 +74,7 @@ ok( $node->poll_query_until(
'mydb',
qq[SELECT datname, count(datname), wait_event FROM pg_stat_activity
WHERE backend_type = 'worker_spi' GROUP BY datname, wait_event;],
- 'mydb|3|worker_spi_main'),
+ 'mydb|3|WorkerSpiMain'),
'bgworkers all launched'
) or die "Timed out while waiting for bgworkers to be launched";
@@ -89,7 +89,7 @@ ok( $node->poll_query_until(
qq[SELECT datname, count(datname), wait_event FROM pg_stat_activity
WHERE backend_type = 'worker_spi dynamic' AND
pid IN ($worker1_pid, $worker2_pid) GROUP BY datname, wait_event;],
- 'mydb|2|worker_spi_main'),
+ 'mydb|2|WorkerSpiMain'),
'dynamic bgworkers all launched'
) or die "Timed out while waiting for dynamic bgworkers to be launched";
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 98f8d4194b..2e3114990e 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -194,7 +194,7 @@ worker_spi_main(Datum main_arg)
/* First time, allocate or get the custom wait event */
if (worker_spi_wait_event_main == 0)
- worker_spi_wait_event_main = WaitEventExtensionNew("worker_spi_main");
+ worker_spi_wait_event_main = WaitEventExtensionNew("WorkerSpiMain");
/*
* Background workers mustn't call usleep() or any direct equivalent:
--
2.25.1
