Hello,I have a postgresql instance in primary/standby mode whith pgbackrest asynchronous WAL shipping in between.
Last week I did an upgrade do postgresql-16 in debian 12.Since then, the standby server has problems catching up with the primary. The lag is increasing.
I published the lag graph here: https://imgur.com/a/csyBWFP I tried to search following leads without success:- large transactions : I identified 2 last longing transactions, killed them, no success - network issue: both servers are close to each other in the network topology, no lag detected there - hardware configuration delta: both servers store they WAL on SSD. Standy server has a bit less RAM (312G vs 440G) and less CPU (20 vs 40), but there is no load nor high write rate in my monitoring system.
In the past I already experienced this issue on the same instance (postgresql 14) which went away by itself after some weeks.
Can you give me some advices on what else to check ? Here is the postgresql configuration of the standby: ``` restore_command = 'pgbackrest --stanza=production archive-get %f "%p"' listen_addresses = '*' max_connections = 200 tcp_keepalives_idle = 300 shared_buffers = 64GB temp_buffers = 16MB work_mem = 32MB maintenance_work_mem = 4GB dynamic_shared_memory_type = posix checkpoint_timeout = 900 max_wal_size = 6GB min_wal_size = 256MB checkpoint_completion_target = 0.9 max_wal_senders = 10 wal_keep_size = 128 max_replication_slots = 10 random_page_cost = 1.2 effective_cache_size = 48GB log_destination = 'syslog' logging_collector = off syslog_facility = 'LOCAL0' syslog_ident = 'postgres' syslog_sequence_numbers = on syslog_split_messages = on log_min_duration_statement = 1000 log_checkpoints = on log_connections = on log_disconnections = on log_lock_waits = on log_temp_files = 0 log_autovacuum_min_duration = 0 log_error_verbosity = default log_line_prefix = 'db=%d,user=%u,app=%a,client=%h ' log_timezone = 'Europe/Paris' track_activities = on track_counts = on track_functions = pl autovacuum = on datestyle = 'iso, mdy' timezone = 'UTC' lc_messages = 'en_US.UTF-8' lc_monetary = 'en_US.UTF-8' lc_numeric = 'en_US.UTF-8' lc_time = 'en_US.UTF-8' default_text_search_config = 'pg_catalog.english' shared_preload_libraries = 'timescaledb, pg_stat_statements' archive_mode = on archive_command = 'pgbackrest --stanza=production archive-push %p' archive_timeout = 30 hot_standby = on ``` Kind regards, -- Jonathan Schaeffer Observatoire des Sciences de l'Univers de Grenoble Responsable technique Résif-DC 🏢 Isterre, bureau 035, 1381 rue de la Piscine 38610 GIERES ✆ +33 4 76 63 51 37
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