From: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
To: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: LogicalChanges* and LogicalSubxact* wait events are never reported
Date: Wed, 20 Oct 2021 14:12:20 +0900
Message-ID: <ff077840-3ab2-04dd-bbe4-4f5dfd2ad481@oss.nttdata.com> (raw)
Hi,
When I read the documents and source code of wait evens,
I found that the following wait events are never reported.
* LogicalChangesRead: Waiting for a read from a logical changes file.
* LogicalChangesWrite: Waiting for a write to a logical changes file.
* LogicalSubxactRead: Waiting for a read from a logical subxact file.
* LogicalSubxactWrite: Waiting for a write to a logical subxact file.
The wait events are introduced in the following patch.
Add support for streaming to built-in logical replication.
Amit Kapila on 2020/9/3 11:24:07
464824323e57dc4b397e8b05854d779908b55304
I read the above discussion and found the wait events were reported at first.
But they seemed to be removed because they are not necessary because
BufFileWrite/BufFileRead are enough([1]).
If my understanding is right, it's better to remove them since they make
users confused. Please see the attached patch. I confirmed that to make
check-world passes all tests.
[1]
https://www.postgresql.org/message-id/CAA4eK1JV37jXUT5LeWzkBDNNnSntwQbLUZAj6m82QMiR1ZuuHQ%40mail.gma...
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
Attachments:
[text/x-patch] v1_remove_unreported_wait_events.patch (2.3K, ../ff077840-3ab2-04dd-bbe4-4f5dfd2ad481@oss.nttdata.com/2-v1_remove_unreported_wait_events.patch)
download | inline diff:diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgmlindex 7355835202..3173ec2566 100644--- a/doc/src/sgml/monitoring.sgml+++ b/doc/src/sgml/monitoring.sgml@@ -1549,22 +1549,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
<entry><literal>WALWrite</literal></entry>
<entry>Waiting for a write to a WAL file.</entry>
</row>
- <row>- <entry><literal>LogicalChangesRead</literal></entry>- <entry>Waiting for a read from a logical changes file.</entry>- </row>- <row>- <entry><literal>LogicalChangesWrite</literal></entry>- <entry>Waiting for a write to a logical changes file.</entry>- </row>- <row>- <entry><literal>LogicalSubxactRead</literal></entry>- <entry>Waiting for a read from a logical subxact file.</entry>- </row>- <row>- <entry><literal>LogicalSubxactWrite</literal></entry>- <entry>Waiting for a write to a logical subxact file.</entry>- </row>
</tbody>
</tgroup>
</table>
diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.cindex ef7e6bfb77..4a5b7502f5 100644--- a/src/backend/utils/activity/wait_event.c+++ b/src/backend/utils/activity/wait_event.c@@ -717,18 +717,6 @@ pgstat_get_wait_io(WaitEventIO w)
case WAIT_EVENT_WAL_WRITE:
event_name = "WALWrite";
break;
- case WAIT_EVENT_LOGICAL_CHANGES_READ:- event_name = "LogicalChangesRead";- break;- case WAIT_EVENT_LOGICAL_CHANGES_WRITE:- event_name = "LogicalChangesWrite";- break;- case WAIT_EVENT_LOGICAL_SUBXACT_READ:- event_name = "LogicalSubxactRead";- break;- case WAIT_EVENT_LOGICAL_SUBXACT_WRITE:- event_name = "LogicalSubxactWrite";- break;
/* no default case, so that compiler will warn */
}
diff --git a/src/include/utils/wait_event.h b/src/include/utils/wait_event.hindex 6007827b44..c22142365f 100644--- a/src/include/utils/wait_event.h+++ b/src/include/utils/wait_event.h@@ -221,11 +221,7 @@ typedef enum
WAIT_EVENT_WAL_READ,
WAIT_EVENT_WAL_SYNC,
WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN,
- WAIT_EVENT_WAL_WRITE,- WAIT_EVENT_LOGICAL_CHANGES_READ,- WAIT_EVENT_LOGICAL_CHANGES_WRITE,- WAIT_EVENT_LOGICAL_SUBXACT_READ,- WAIT_EVENT_LOGICAL_SUBXACT_WRITE+ WAIT_EVENT_WAL_WRITE
} WaitEventIO;
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To: pgsql-hackers@postgresql.org
Cc: ikedamsh@oss.nttdata.com
Subject: Re: LogicalChanges* and LogicalSubxact* wait events are never reported
In-Reply-To: <ff077840-3ab2-04dd-bbe4-4f5dfd2ad481@oss.nttdata.com>
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