Remove buffers_backend and buffers_backend_fsync from pg_stat_checkpointer

Two attributes related to checkpointer statistics are removed in this
commit:
- buffers_backend, that counts the number of buffers written directly by
a backend.
- buffers_backend_fsync, that counts the number of times a backend had
to do fsync() by its own.

These are actually not checkpointer properties but backend properties.
Also, pg_stat_io provides a more accurate and equivalent report of these
numbers, by tracking all the I/O stats related to backends, including
writes and fsyncs, so storing them in pg_stat_checkpointer was
redundant.

Thanks also to Robert Haas and Amit Kapila for their input.

Bump catalog version.

Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot, Andres Freund
Discussion: https://postgr.es/m/20230210004604.mcszbscsqs3bc5nx@awork3.anarazel.de

1 files changed, 0 insertions, 4 deletions

diff --git a/src/backend/utils/activity/pgstat_checkpointer.c b/src/backend/utils/activity/pgstat_checkpointer.c
index 26dec112f6c..03ed5dddda7 100644
--- a/src/backend/utils/activity/pgstat_checkpointer.c
+++ b/src/backend/utils/activity/pgstat_checkpointer.c
@@ -52,8 +52,6 @@ pgstat_report_checkpointer(void)
 	CHECKPOINTER_ACC(checkpoint_write_time);
 	CHECKPOINTER_ACC(checkpoint_sync_time);
 	CHECKPOINTER_ACC(buf_written_checkpoints);
-	CHECKPOINTER_ACC(buf_written_backend);
-	CHECKPOINTER_ACC(buf_fsync_backend);
 #undef CHECKPOINTER_ACC
 
 	pgstat_end_changecount_write(&stats_shmem->changecount);
@@ -120,7 +118,5 @@ pgstat_checkpointer_snapshot_cb(void)
 	CHECKPOINTER_COMP(checkpoint_write_time);
 	CHECKPOINTER_COMP(checkpoint_sync_time);
 	CHECKPOINTER_COMP(buf_written_checkpoints);
-	CHECKPOINTER_COMP(buf_written_backend);
-	CHECKPOINTER_COMP(buf_fsync_backend);
 #undef CHECKPOINTER_COMP
 }