Re: [BUGS] 9.6rc1 Background worker starting multiple times - Mailing list pgsql-bugs

So, attached is my naive attempt to try and handle SIGUSR1. Can at least confirm this is the source of the problem, but I'm unable to figure out how to work around it. Handling it does in fact stop the background worker from going nuts anymore. But it also completely stops the maintenance loop from working properly. It runs once, then never again. It seems to get stuck after the call to WaitForBackgroundWorkerStartup() and never even gets to my WaitLatch() call. There is logging that it successfully unregisters the dynamic BGW, but never seems to go further than that. I tried adding latch_sigusr1_handler() similar to how the handler in procsignal.c does, but didn't seem to fix it. With some additional debugging I added, it doesn't even appear to be calling my custom signal handler function at all. got_sigusr1 is never set to true.
it goes back to doing what it was doing before.

Guessing there's a lot more to SIGUSR1 than I can see right now. But figured I'd at least try to provide some additional investigation. I noticed in the BGW code, it mentions using SIGUSR1 on start/stop.

https://doxygen.postgresql.org/bgworker_8h_source.html#l00099

Perhaps that's part of the issue when I try and handle it instead?

partman maintenance timer is set for 10 seconds so the timestamp on the log entries shows it's not running on time.

2016-12-20 11:56:46 EST [] [14486]: [7-1] user=,db=,e=00000 LOG:  database system is ready to accept connections
2016-12-20 11:56:46 EST [] [14495]: [1-1] user=,db=,e=00000 LOG:  pg_partman master background worker master process initialized with role keith
2016-12-20 11:56:46 EST [] [14495]: [2-1] user=,db=,e=00000 DEBUG:  Latch status just before for loop: 1
2016-12-20 11:56:46 EST [] [14495]: [3-1] user=,db=,e=00000 DEBUG:  Latch status inside for loop before reset: 1
2016-12-20 11:56:46 EST [] [14495]: [4-1] user=,db=,e=00000 DEBUG:  Latch status just after reset before interupt check: 0
2016-12-20 11:56:46 EST [] [14495]: [5-1] user=,db=,e=00000 DEBUG:  Latch status just after reset after interupt check: 0
2016-12-20 11:56:46 EST [] [14495]: [6-1] user=,db=,e=00000 DEBUG:  After sighup check: 0
2016-12-20 11:56:46 EST [] [14495]: [7-1] user=,db=,e=00000 DEBUG:  After sigterm check: 0
2016-12-20 11:56:46 EST [] [14495]: [8-1] user=,db=,e=00000 DEBUG:  Before sigusr1 check: 0
2016-12-20 11:56:46 EST [] [14495]: [9-1] user=,db=,e=00000 DEBUG:  After sigusr1 check: 0
2016-12-20 11:56:46 EST [] [14495]: [10-1] user=,db=,e=00000 DEBUG:  Dynamic bgw launch begun for keith (0)
2016-12-20 11:56:46 EST [] [14495]: [11-1] user=,db=,e=00000 DEBUG:  Registering dynamic background worker...
2016-12-20 11:56:46 EST [] [14495]: [12-1] user=,db=,e=00000 DEBUG:  Waiting for BGW startup...
2016-12-20 11:56:46 EST [] [14486]: [8-1] user=,db=,e=00000 DEBUG:  registering background worker "pg_partman dynamic background worker (dbname=keith)"
2016-12-20 11:56:46 EST [] [14486]: [9-1] user=,db=,e=00000 DEBUG:  starting background worker process "pg_partman dynamic background worker (dbname=keith)"
2016-12-20 11:56:46 EST [] [14493]: [1-1] user=,db=,e=00000 LOG:  autovacuum launcher started
2016-12-20 11:56:46 EST [] [14496]: [1-1] user=,db=,e=00000 DEBUG:  Before parsing dbname GUC in dynamic main func: keith
2016-12-20 11:56:46 EST [] [14496]: [2-1] user=,db=,e=00000 DEBUG:  GUC rawstring copy: keith
2016-12-20 11:56:46 EST [] [14496]: [3-1] user=,db=,e=00000 DEBUG:  Entered foreach loop: name (keith), db_main_counter (0), dbcounter (0)
2016-12-20 11:56:46 EST [] [14496]: [4-1] user=,db=,e=00000 DEBUG:  Parsing list: keith (0)
2016-12-20 11:56:46 EST [] [14496]: [5-1] user=,db=,e=00000 DEBUG:  Before run_maint initialize connection for db keith
2016-12-20 11:56:46 EST [] [14496]: [6-1] user=,db=,e=00000 DEBUG:  After run_maint initialize connection for db keith
2016-12-20 11:56:46 EST [] [14496]: [7-1] user=,db=,e=00000 DEBUG:  Checking if pg_partman extension is installed in database: keith
2016-12-20 11:56:46 EST [] [14496]: [8-1] user=,db=,e=00000 LOG:  pg_partman dynamic background worker (dbname=keith) dynamic background worker initialized with role keith on database keith
2016-12-20 11:56:46 EST [] [14496]: [9-1] user=,db=,e=00000 LOG:  pg_partman dynamic background worker (dbname=keith): SELECT "partman".run_maintenance(p_analyze := true, p_jobmon := true) called by role keith on database keith
2016-12-20 11:56:46 EST [] [14496]: [10-1] user=,db=,e=00000 DEBUG:  pg_partman dynamic BGW shutting down gracefully for database keith.
2016-12-20 11:56:46 EST [] [14486]: [10-1] user=,db=,e=00000 DEBUG:  worker process: pg_partman dynamic background worker (dbname=keith) (PID 14496) exited with exit code 0
2016-12-20 11:56:46 EST [] [14486]: [11-1] user=,db=,e=00000 DEBUG:  unregistering background worker "pg_partman dynamic background worker (dbname=keith)"
2016-12-20 11:57:16 EST [] [14506]: [1-1] user=,db=,e=00000 DEBUG:  autovacuum: processing database "keith"
2016-12-20 11:57:46 EST [] [14515]: [1-1] user=,db=,e=00000 DEBUG:  autovacuum: processing database "postgres"
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