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, 12 deletions

diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 3b44af80066..6468b6a8057 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1234,18 +1234,6 @@ pg_stat_get_bgwriter_stat_reset_time(PG_FUNCTION_ARGS)
 }
 
 Datum
-pg_stat_get_buf_written_backend(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buf_written_backend);
-}
-
-Datum
-pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buf_fsync_backend);
-}
-
-Datum
 pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->buf_alloc);