Hi. https://coverage.postgresql.org/contrib/pg_prewarm/autoprewarm.c.gcov.html function autoprewarm_start_worker never gets tested, but autoprewarm_start_worker listed in our doc (https://www.postgresql.org/docs/16/pgprewarm.html) Maybe we should test it.
also this part in function autoprewarm_main not tested. 247 : /* Compute the next dump time. */ 248 0 : next_dump_time = 249 0 : TimestampTzPlusMilliseconds(last_dump_time, 250 : autoprewarm_interval * 1000); 251 : delay_in_ms = 252 0 : TimestampDifferenceMilliseconds(GetCurrentTimestamp(), 253 : next_dump_time); 254 : 255 : /* Perform a dump if it's time. */ 256 0 : if (delay_in_ms <= 0) 257 : { 258 0 : last_dump_time = GetCurrentTimestamp(); 259 0 : apw_dump_now(true, false); 260 0 : continue; 261 : } 262 : 263 : /* Sleep until the next dump time. */ 264 0 : (void) WaitLatch(MyLatch, 265 : WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, 266 : delay_in_ms, 267 : WAIT_EVENT_EXTENSION); I don't fully understand this module, but I kind of get the meaning of the worker_spi module. i didn't configure shared_preload_libraries. I changed from worker.bgw_flags = BGWORKER_SHMEM_ACCESS; to worker.bgw_flags = BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION; but still, the following query will not list the autoprewarm background worker. SELECT datname, pid, state, backend_type, wait_event_type, wait_event FROM pg_stat_activity; I thought pg_stat_activity will list all related pid for this cluster. but it seems not in this case. So here, is it a good idea to make the autoprewarm background worker listed in pg_stat_activity?