Hi hackers!
$subj was recently observed on one of our installations.
Startup process backtrace
#0 0x00007fd216660d27 in epoll_wait (epfd=525, events=0x55c688dfbde8,
maxevents=maxevents@entry=1, timeout=timeout@entry=-1)
#1 0x000055c687264be9 in WaitEventSetWaitBlock (nevents=1,
occurred_events=0x7ffdf8089f00, cur_timeout=-1, set=0x55c688dfbd78)
#2 WaitEventSetWait (set=set@entry=0x55c688dfbd78, timeout=timeout@entry=-1,
occurred_events=occurred_events@entry=0x7ffdf8089f00, nevents=nevents@entry=1,
wait_event_info=wait_event_info@entry=67108864) at
/build/../src/backend/storage/ipc/latch.c:1000
#3 0x000055c687265038 in WaitLatchOrSocket (latch=0x7fd1fa735454,
wakeEvents=wakeEvents@entry=1, sock=sock@entry=-1, timeout=-1, timeout@entry=0,
wait_event_info=wait_event_info@entry=67108864)
#4 0x000055c6872650f5 in WaitLatch (latch=<optimized out>,
wakeEvents=wakeEvents@entry=1, timeout=timeout@entry=0,
wait_event_info=wait_event_info@entry=67108864
#5 0x000055c687276399 in ProcWaitForSignal
(wait_event_info=wait_event_info@entry=67108864)
#6 0x000055c68726c898 in ResolveRecoveryConflictWithBufferPin ()
#7 0x000055c6872582c5 in LockBufferForCleanup (buffer=292159)
#8 0x000055c687259447 in ReadBuffer_common (smgr=0x55c688deae40,
relpersistence=relpersistence@entry=112 'p', forkNum=forkNum@entry=MAIN_FORKNUM,
blockNum=blockNum@entry=3751242, mode=mode@entry=RBM_ZERO_AND_CLEANUP_LOCK,
strategy=strategy@entry=0x0, hit=0x7ffdf808a117 "\001")
#9 0x000055c687259b6b in ReadBufferWithoutRelcache (rnode=...,
forkNum=forkNum@entry=MAIN_FORKNUM, blockNum=blockNum@entry=3751242,
mode=mode@entry=RBM_ZERO_AND_CLEANUP_LOCK, strategy=strategy@entry=0x0)
#10 0x000055c68705655f in XLogReadBufferExtended (rnode=...,
forknum=MAIN_FORKNUM, blkno=3751242, mode=RBM_ZERO_AND_CLEANUP_LOCK)
#11 0x000055c687056706 in XLogReadBufferForRedoExtended
(record=record@entry=0x55c688dd2378, block_id=block_id@entry=0 '\000',
mode=mode@entry=RBM_NORMAL, get_cleanup_lock=get_cleanup_lock@entry=1 '\001',
buf=buf@entry=0x7ffdf808a218)
#12 0x000055c68700728b in heap_xlog_clean (record=0x55c688dd2378)
#13 heap2_redo (record=0x55c688dd2378)
#14 0x000055c68704a7eb in StartupXLOG ()
Backend holding the buffer pin:
#0 0x00007fd216660d27 in epoll_wait (epfd=5, events=0x55c688d67ca8,
maxevents=maxevents@entry=1, timeout=timeout@entry=-1)
#1 0x000055c687264be9 in WaitEventSetWaitBlock (nevents=1,
occurred_events=0x7ffdf808e070, cur_timeout=-1, set=0x55c688d67c38)
#2 WaitEventSetWait (set=0x55c688d67c38, timeout=timeout@entry=-1,
occurred_events=occurred_events@entry=0x7ffdf808e070, nevents=nevents@entry=1,
wait_event_info=wait_event_info@entry=100663297)
#3 0x000055c687185d7e in secure_write (port=0x55c688db4a60,
ptr=ptr@entry=0x55c688dd338e, len=len@entry=2666)
#4 0x000055c687190f4c in internal_flush ()
#5 0x000055c68719118a in internal_putbytes (s=0x55c68f8dcc35 "", s@entry=0x55c68f8dcc08
"", len=65)
#6 0x000055c687191262 in socket_putmessage (msgtype=<optimized out>, s=0x55c68f8dcc08
"", len=<optimized out>)
#7 0x000055c687193431 in pq_endmessage (buf=buf@entry=0x7ffdf808e1a0)
#8 0x000055c686fd1442 in printtup (slot=0x55c6894c2dc0, self=0x55c689326b40)
#9 0x000055c687151962 in ExecutePlan (execute_once=<optimized out>, dest=0x55c689326b40,
direction=<optimized out>, numberTuples=0, sendTuples=<optimized out>,
operation=CMD_SELECT, use_parallel_mode=<optimized out>, planstate=0x55c689281a28,
estate=0x55c6892816f8)
#10 standard_ExecutorRun (queryDesc=0x55c689289628, direction=<optimized out>,
count=0, execute_once=<optimized out>)
#11 0x00007fd2074100c5 in pgss_ExecutorRun (queryDesc=0x55c689289628,
direction=ForwardScanDirection, count=0, execute_once=<optimized out>)
#12 0x000055c68728a356 in PortalRunSelect (portal=portal@entry=0x55c688d858b8,
forward=forward@entry=1 '\001', count=0, count@entry=9223372036854775807,
dest=dest@entry=0x55c689326b40)
#13 0x000055c68728b988 in PortalRun (portal=portal@entry=0x55c688d858b8,
count=count@entry=9223372036854775807, isTopLevel=isTopLevel@entry=1 '\001',
run_once=run_once@entry=1 '\001', dest=dest@entry=0x55c689326b40,
altdest=altdest@entry=0x55c689326b40, completionTag=0x7ffdf808e580 "")
#14 0x000055c687287425 in exec_simple_query (query_string=0x55c688ec5e38
"select\n '/capacity/created-at-counter-by-time-v2' as sensor,\n
round(extract(epoch from shipment_date))
#15 0x000055c687289418 in PostgresMain (argc=<optimized out>,
argv=argv@entry=0x55c688dd3e28, dbname=<optimized out>, username=<optimized out>)
I think the problem here is that secure_write() uses infinite timeout.
