database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-19 13:42:17 +03:00
Code Activity

Change shutdown sequence to terminate checkpointer last

Browse Source 
The main motivation for this change is to have a process that can serialize
stats after all other processes have terminated. Serializing stats already
happens in checkpointer, even though walsenders can be active longer.

The only reason the current shutdown sequence does not actively cause problems
is that walsender currently does not generate any stats. However, there is an
upcoming patch changing that.

Another need for this change originates in the AIO patchset, where IO
workers (which, in some edge cases, can emit stats of their own) need to run
while the shutdown checkpoint is being written.

This commit changes the shutdown sequence so checkpointer is signalled (via
SIGINT) to trigger writing the shutdown checkpoint without also causing
checkpointer to exit.  Once checkpointer wrote the shutdown checkpoint it
notifies postmaster via PMSIGNAL_XLOG_IS_SHUTDOWN and waits for the
termination signal (SIGUSR2, as before).  Checkpointer now is terminated after
all children, other than dead-end children and logger, have been terminated,
tracked using the new PM_WAIT_CHECKPOINTER PMState.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/kgng5nrvnlv335evmsuvpnh354rw7qyazl73kdysev2cr2v5zu@m3cfzxicm5kp
This commit is contained in:
Andres Freund
2025-01-25 11:37:13 -05:00
parent 04ace176e0
commit 87a6690cc6
4 changed files with 201 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
src/backend/utils/activity/wait_event_names.txt
View File

@@ -56,6 +56,7 @@ AUTOVACUUM_MAIN "Waiting in main loop of autovacuum launcher process."
BGWRITER_HIBERNATE "Waiting in background writer process, hibernating."
BGWRITER_MAIN "Waiting in main loop of background writer process."
CHECKPOINTER_MAIN "Waiting in main loop of checkpointer process."
CHECKPOINTER_SHUTDOWN "Waiting for checkpointer process to be terminated."
LOGICAL_APPLY_MAIN "Waiting in main loop of logical replication apply process."
LOGICAL_LAUNCHER_MAIN "Waiting in main loop of logical replication launcher process."
LOGICAL_PARALLEL_APPLY_MAIN "Waiting in main loop of logical replication parallel apply process."