Robert Haas wrote:
> On Mon, Aug 7, 2017 at 8:14 PM, Alvaro Herrera <alvhe...@2ndquadrant.com>
> wrote:
> > BTW, I noticed that the PG_WAIT_LOCK value that we're using for wait
> > event here (and in the replication slot case) is bogus. We probably
> > need something new here.
>
> Yeah, if you're adding a new wait point, you should add document a new
> constant in the appropriate section, probably something under
> PG_WAIT_IPC in this case.
Here's a patch. It turned to be a bit larger than I initially expected.
Wait events are a maintainability fail IMO. I think we need to rethink
this stuff; using generated files from a single source containing the C
symbol, text name and doc blurb sounds better. That can wait for pg11
though.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>From e050ef66956935e6dba41fc18e11632ff9f0068f Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvhe...@alvh.no-ip.org>
Date: Tue, 8 Aug 2017 13:33:47 -0400
Subject: [PATCH] Fix various inadequacies in wait events
In commit 9915de6c1cb2, we introduced a new wait point for replication
slots and incorrectly labelled it as wait event PG_WAIT_LOCK. That's
wrong, so invent an appropriate new wait event instead, and document it
properly.
While at it, fix numerous other problems in the vicinity:
- two different walreceiver wait events were being mixed up in a single
wait event; split it out so that they can be distinguished, and
document the new symbols properly.
- ParallelBitmapPopulate was documented but didn't exist.
- ParallelBitmapScan was not documented
- Logical replication wait events weren't documented
- various symbols had been added in dartboard order in various places.
Put them back in alphabetical order, as was originally intended.
---
doc/src/sgml/monitoring.sgml | 32 +++++++++++++++++--
src/backend/postmaster/pgstat.c | 36 +++++++++++++---------
.../libpqwalreceiver/libpqwalreceiver.c | 4 +--
src/backend/replication/slot.c | 3 +-
src/include/pgstat.h | 16 +++++-----
5 files changed, 64 insertions(+), 27 deletions(-)
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index be3dc672bc..eb20c9c543 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1176,6 +1176,14 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss
11:34 0:00 postgres: ser
<entry>Waiting in main loop of checkpointer process.</entry>
</row>
<row>
+ <entry><literal>LogicalLauncherMain</></entry>
+ <entry>Waiting in main loop of logical launcher process.</entry>
+ </row>
+ <row>
+ <entry><literal>LogicalApplyMain</></entry>
+ <entry>Waiting in main loop of logical apply process.</entry>
+ </row>
+ <row>
<entry><literal>PgStatMain</></entry>
<entry>Waiting in main loop of the statistics collector
process.</entry>
</row>
@@ -1213,6 +1221,14 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss
11:34 0:00 postgres: ser
<entry>Waiting to write data from the client.</entry>
</row>
<row>
+ <entry><literal>LibPQWalReceiverConnect</></entry>
+ <entry>Waiting in WAL receiver to establish connection to remote
server.<entry>
+ </row>
+ <row>
+ <entry><literal>LibPQWalReceiverReceive</></entry>
+ <entry>Waiting in WAL receiver to receive data from remote
server.<entry>
+ </row>
+ <row>
<entry><literal>SSLOpenServer</></entry>
<entry>Waiting for SSL while attempting connection.</entry>
</row>
@@ -1251,6 +1267,14 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss
11:34 0:00 postgres: ser
<entry>Waiting for activity from child process when executing
<literal>Gather</> node.</entry>
</row>
<row>
+ <entry><literal>LogicalSyncData</></entry>
+ <entry>Waiting for logical replication remote server to send data for
initial table synchronization.</entry>
+ </row>
+ <row>
+ <entry><literal>LogicalSyncStateChange</></entry>
+ <entry>Waiting for logical replication remote server to change
state.</entry>
+ </row>
+ <row>
<entry><literal>MessageQueueInternal</></entry>
<entry>Waiting for other process to be attached in shared message
queue.</entry>
</row>
@@ -1271,14 +1295,18 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss
11:34 0:00 postgres: ser
<entry>Waiting for parallel workers to finish computing.</entry>
</row>
<row>
- <entry><literal>ParallelBitmapPopulate</></entry>
- <entry>Waiting for the leader to populate the TidBitmap.</entry>
+ <entry><literal>ParallelBitmapScan</></entry>
+ <entry>Waiting for parallel bitmap scan to become initialized.</entry>
</row>
<row>
<entry><literal>ProcArrayGroupUpdate</></entry>
<entry>Waiting for group leader to clear transaction id at
transaction end.</entry>
</row>
<row>
+ <entry><literal>ReplicationSlotDrop</></entry>
+ <entry>Waiting for a replication slot to become inactive to be
dropped.</entry>
+ </row>
+ <row>
<entry><literal>SafeSnapshot</></entry>
<entry>Waiting for a snapshot for a <literal>READ ONLY DEFERRABLE</>
transaction.</entry>
</row>
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index a0b0eecbd5..3f5fb796a5 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3481,6 +3481,12 @@ pgstat_get_wait_activity(WaitEventActivity w)
case WAIT_EVENT_CHECKPOINTER_MAIN:
event_name = "CheckpointerMain";
break;
+ case WAIT_EVENT_LOGICAL_LAUNCHER_MAIN:
+ event_name = "LogicalLauncherMain";
+ break;
+ case WAIT_EVENT_LOGICAL_APPLY_MAIN:
+ event_name = "LogicalApplyMain";
+ break;
case WAIT_EVENT_PGSTAT_MAIN:
event_name = "PgStatMain";
break;
@@ -3502,12 +3508,6 @@ pgstat_get_wait_activity(WaitEventActivity w)
case WAIT_EVENT_WAL_WRITER_MAIN:
event_name = "WalWriterMain";
break;
- case WAIT_EVENT_LOGICAL_LAUNCHER_MAIN:
- event_name = "LogicalLauncherMain";
- break;
- case WAIT_EVENT_LOGICAL_APPLY_MAIN:
- event_name = "LogicalApplyMain";
- break;
/* no default case, so that compiler will warn */
}
@@ -3533,15 +3533,18 @@ pgstat_get_wait_client(WaitEventClient w)
case WAIT_EVENT_CLIENT_WRITE:
event_name = "ClientWrite";
break;
+ case WAIT_EVENT_LIBPQWALRECEIVER_CONNECT:
+ event_name = "LibPQWalReceiverConnect";
+ break;
+ case WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE:
+ event_name = "LibPQWalReceiverReceive";
+ break;
case WAIT_EVENT_SSL_OPEN_SERVER:
event_name = "SSLOpenServer";
break;
case WAIT_EVENT_WAL_RECEIVER_WAIT_START:
event_name = "WalReceiverWaitStart";
break;
- case WAIT_EVENT_LIBPQWALRECEIVER:
- event_name = "LibPQWalReceiver";
- break;
case WAIT_EVENT_WAL_SENDER_WAIT_WAL:
event_name = "WalSenderWaitForWAL";
break;
@@ -3579,6 +3582,12 @@ pgstat_get_wait_ipc(WaitEventIPC w)
case WAIT_EVENT_EXECUTE_GATHER:
event_name = "ExecuteGather";
break;
+ case WAIT_EVENT_LOGICAL_SYNC_DATA:
+ event_name = "LogicalSyncData";
+ break;
+ case WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE:
+ event_name = "LogicalSyncStateChange";
+ break;
case WAIT_EVENT_MQ_INTERNAL:
event_name = "MessageQueueInternal";
break;
@@ -3600,18 +3609,15 @@ pgstat_get_wait_ipc(WaitEventIPC w)
case WAIT_EVENT_PROCARRAY_GROUP_UPDATE:
event_name = "ProcArrayGroupUpdate";
break;
+ case WAIT_EVENT_REPLICATION_SLOT_DROP:
+ event_name = "ReplicationSlotDrop";
+ break;
case WAIT_EVENT_SAFE_SNAPSHOT:
event_name = "SafeSnapshot";
break;
case WAIT_EVENT_SYNC_REP:
event_name = "SyncRep";
break;
- case WAIT_EVENT_LOGICAL_SYNC_DATA:
- event_name = "LogicalSyncData";
- break;
- case WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE:
- event_name = "LogicalSyncStateChange";
- break;
/* no default case, so that compiler will warn */
}
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 93dd7b5c17..de03362c91 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -181,7 +181,7 @@ libpqrcv_connect(const char *conninfo, bool logical, const
char *appname,
WL_LATCH_SET |
io_flag,
PQsocket(conn->streamConn),
0,
-
WAIT_EVENT_LIBPQWALRECEIVER);
+
WAIT_EVENT_LIBPQWALRECEIVER_CONNECT);
/* Emergency bailout? */
if (rc & WL_POSTMASTER_DEATH)
@@ -582,7 +582,7 @@ libpqrcv_PQexec(PGconn *streamConn, const char *query)
WL_LATCH_SET,
PQsocket(streamConn),
0,
-
WAIT_EVENT_LIBPQWALRECEIVER);
+
WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE);
/* Emergency bailout? */
if (rc & WL_POSTMASTER_DEATH)
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 08c0b1b285..63e1aaa910 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -391,7 +391,8 @@ retry:
name, active_pid)));
/* Wait here until we get signaled, and then restart */
- ConditionVariableSleep(&slot->active_cv, PG_WAIT_LOCK);
+ ConditionVariableSleep(&slot->active_cv,
+
WAIT_EVENT_REPLICATION_SLOT_DROP);
ConditionVariableCancelSleep();
goto retry;
}
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 6bffe63ad6..43ea55e9eb 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -759,15 +759,15 @@ typedef enum
WAIT_EVENT_BGWRITER_HIBERNATE,
WAIT_EVENT_BGWRITER_MAIN,
WAIT_EVENT_CHECKPOINTER_MAIN,
+ WAIT_EVENT_LOGICAL_LAUNCHER_MAIN,
+ WAIT_EVENT_LOGICAL_APPLY_MAIN,
WAIT_EVENT_PGSTAT_MAIN,
WAIT_EVENT_RECOVERY_WAL_ALL,
WAIT_EVENT_RECOVERY_WAL_STREAM,
WAIT_EVENT_SYSLOGGER_MAIN,
WAIT_EVENT_WAL_RECEIVER_MAIN,
WAIT_EVENT_WAL_SENDER_MAIN,
- WAIT_EVENT_WAL_WRITER_MAIN,
- WAIT_EVENT_LOGICAL_LAUNCHER_MAIN,
- WAIT_EVENT_LOGICAL_APPLY_MAIN
+ WAIT_EVENT_WAL_WRITER_MAIN
} WaitEventActivity;
/* ----------
@@ -782,9 +782,10 @@ typedef enum
{
WAIT_EVENT_CLIENT_READ = PG_WAIT_CLIENT,
WAIT_EVENT_CLIENT_WRITE,
+ WAIT_EVENT_LIBPQWALRECEIVER_CONNECT,
+ WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE,
WAIT_EVENT_SSL_OPEN_SERVER,
WAIT_EVENT_WAL_RECEIVER_WAIT_START,
- WAIT_EVENT_LIBPQWALRECEIVER,
WAIT_EVENT_WAL_SENDER_WAIT_WAL,
WAIT_EVENT_WAL_SENDER_WRITE_DATA
} WaitEventClient;
@@ -802,6 +803,8 @@ typedef enum
WAIT_EVENT_BGWORKER_STARTUP,
WAIT_EVENT_BTREE_PAGE,
WAIT_EVENT_EXECUTE_GATHER,
+ WAIT_EVENT_LOGICAL_SYNC_DATA,
+ WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE,
WAIT_EVENT_MQ_INTERNAL,
WAIT_EVENT_MQ_PUT_MESSAGE,
WAIT_EVENT_MQ_RECEIVE,
@@ -809,10 +812,9 @@ typedef enum
WAIT_EVENT_PARALLEL_FINISH,
WAIT_EVENT_PARALLEL_BITMAP_SCAN,
WAIT_EVENT_PROCARRAY_GROUP_UPDATE,
+ WAIT_EVENT_REPLICATION_SLOT_DROP,
WAIT_EVENT_SAFE_SNAPSHOT,
- WAIT_EVENT_SYNC_REP,
- WAIT_EVENT_LOGICAL_SYNC_DATA,
- WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE
+ WAIT_EVENT_SYNC_REP
} WaitEventIPC;
/* ----------
--
2.11.0
--
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