Hello, I setup a new 3-node cluster with the following specifications:
2x Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz (2*20 cores) 128 GB RAM 8x Crucial MX500 1TB SSD's FS is ZFS, the dataset with the PGDATA directory on it has the following properties (only non-default listed): NAME PROPERTY VALUE SOURCE tank/pgsql used 234G - tank/pgsql available 3.28T - tank/pgsql referenced 234G - tank/pgsql compressratio 2.68x - tank/pgsql compression lz4 inherited from tank tank/pgsql atime off inherited from tank tank/pgsql canmount on local tank/pgsql xattr sa inherited from tank My postgresql.conf (only changed from default listed): hba_file = '/var/lib/pgsql/pg_hba.conf' listen_addresses = '*' max_connections = 800 shared_buffers = 8GB work_mem = 64MB maintenance_work_mem = 2GB autovacuum_work_mem = 1GB dynamic_shared_memory_type = posix effective_io_concurrency = 200 max_worker_processes = 50 max_parallel_maintenance_workers = 8 max_parallel_workers_per_gather = 8 max_parallel_workers = 40 wal_level = replica synchronous_commit = off full_page_writes = on wal_log_hints = on wal_buffers = 128MB checkpoint_timeout = 60min max_wal_size = 8GB min_wal_size = 1GB checkpoint_completion_target = 0.9 archive_mode = on archive_command = 'pgbackrest --stanza=pgdb2 archive-push %p' max_wal_senders = 10 wal_keep_segments = 20 hot_standby = on hot_standby_feedback = on random_page_cost = 1.5 effective_cache_size = 48GB default_statistics_target = 500 # range 1-10000 idle_in_transaction_session_timeout = 30min # in milliseconds, 0 is disabled shared_preload_libraries = 'timescaledb, pg_cron' max_locks_per_transaction = 512 timescaledb.max_background_workers = 8 My problem is that checkpoints are taking a long time. Even when I run a few manual checkpoints one after the other, they keep taking very long, up to 10 minutes: 2019-06-14 15:21:10.351 CEST [23657] LOG: checkpoint starting: immediate force wait 2019-06-14 15:25:57.655 CEST [23657] LOG: checkpoint complete: wrote 139831 buffers (13.3%); 0 WAL file(s) added, 148 removed, 40 recycled; write=284.751 s, sync=0.532 s, total=287.304 s; sync files=537, longest=0.010 s, average=0.000 s; distance=2745065 kB, estimate=2841407 kB 2019-06-14 15:26:01.988 CEST [23657] LOG: checkpoint starting: immediate force wait 2019-06-14 15:30:30.430 CEST [23657] LOG: checkpoint complete: wrote 238322 buffers (22.7%); 0 WAL file(s) added, 0 removed, 172 recycled; write=264.794 s, sync=0.415 s, total=268.441 s; sync files=378, longest=0.011 s, average=0.001 s; distance=2834018 kB, estimate=2840668 kB 2019-06-14 15:30:44.097 CEST [23657] LOG: checkpoint starting: immediate force wait 2019-06-14 15:37:01.438 CEST [23657] LOG: checkpoint complete: wrote 132286 buffers (12.6%); 0 WAL file(s) added, 54 removed, 96 recycled; write=366.614 s, sync=2.975 s, total=377.341 s; sync files=467, longest=0.095 s, average=0.006 s; distance=2444291 kB, estimate=2801030 kB What is going on? It doesn't seem like normal behaviour?
