Support PostgreSQL 17

[frost242]

Hello,

I've quickly tested all services, expect replication ones. Without surprise, bgwriter is broken with pg17 as pg_stat_bgwriter has changed :

check_pgactivity -s bgwriter -F human
Service        : CHECK_PGACTIVITY
Returns        : 3 (UNKNOWN)
Message        : Query failed !
psql:/tmp/check_pga-4F250z5u:9: ERREUR:  la colonne « checkpoints_timed » n'existe pas
LINE 1: SELECT checkpoints_timed, checkpoints_req,

[Krysztophe]

@frost242 : is it still in your todo list?

[blogh]

It's a little more complex than I expected, here is a quick recap of what I found.

The patch info :

• committers: https://www.postgresql.org/message-id/flat/E1qxGRf-0031eB-Ko%40gemulon.postgresql.org
• hackers: https://www.postgresql.org/message-id/flat/CALj2ACVxX2ii%3D66RypXRweZe2EsBRiPMj0aHfRfHUeXJcC7kHg%40mail.gmail.com

The query pre v17 :

SELECT checkpoints_timed, checkpoints_req,
       buffers_checkpoint * current_setting('block_size')::numeric,
       buffers_clean * current_setting('block_size')::numeric,
       maxwritten_clean,
       buffers_backend * current_setting('block_size')::numeric,
       buffers_alloc * current_setting('block_size')::numeric,
       buffers_backend_fsync,
       extract ('epoch' from stats_reset)
  FROM pg_stat_bgwriter;

The changes for the query are :

• pg_stat_bgwriter.checkpoints_timed => pg_stat_checkpointer.num_timed
• pg_stat_bgwriter.checkpoints_req => pg_stat_checkpointer.num_requested
• pg_stat_bgwriter.buffers_checkpoint => pg_stat_checkpointer.buffers_written
• pg_stat_bgwriter.buffers_backend => moved to pg_stat_io
• pg_stat_bgwriter.buffers_backend_fsync => moved to pg_stat_io & pg_stat_slru
• pg_stat_bgwriter.stats_reset => the column is also present in pg_stat_checkpointer, pg_stat_io & pg_stat_slru

[frost242]

@Krysztophe I have to admit that I forgot a bit about it. We still have no pg17 deployed at my work, we're awaiting pg18.