Deadlock occurred in PostgreSQL tracking checkpointer

Gdb tracking checkpointer process, there is a deadlock, Mark.

Track checkpointer processes and view messages in shared memory (heckpointerShmem- > requests)

(gdb) p CheckpointerShmem- > requests [1663]... $16 = {rnode = {spcNode = 1663, dbNode = 16402, relNode = 26185}, forknum = MAIN_FORKNUM, segno = 0} (gdb) p CheckpointerShmem- > requests [200] Cannot access memory at address 0xf9fb18.

Then, the process that requests the checkpoint reports an error

Testdb=# update t_wal_ckpt set c2 = 'C2Jing' | | substr (c2jing4 Magazine 40); UPDATE 8192 testdb=# checkpoint; 2019-01-07 12 UPDATE 30 testdb=# checkpoint; 32.114 CST [1418] PANIC: stuck spinlock detected at RequestCheckpoint, checkpointer.c:1050 2019-01-07 12 Fringe 30 UPDATE 32.114 CST [1418] STATEMENT: checkpoint 2019-01-07 12 stuck spinlock detected at FirstCallSinceLastCheckpoint 30 37.081 CST [1390] Checkpointer.c:1376 2019-01-07 12 checkpointer.c:1376 30 CST 38.610 CST [1370] LOG: background writer process (PID 1390) was terminated by signal 6: Aborted 2019-01-07 12 WARNING 30 CST [1392] DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit Because another server process exited abnormally and possibly corrupted shared memory. 2019-01-07 12 In a moment you should be able to reconnect to the database and repeat your command 30 CST 38.611 HINT: In a moment you should be able to reconnect to the database and repeat your command. 2019-01-07 12 CST 30 CST [1558] DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory. WARNING: terminating connection because of crash of another server process 2019-01-07 12. 2019-01-07 12 In a moment you should be able to reconnect to the database and repeat your command 30 CST 38.613 HINT: In a moment you should be able to reconnect to the database and repeat your command. PANIC: stuck spinlock detected at RequestCheckpoint, checkpointer.c:1050 server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. The connection to the server was lost. Attempting reset: 2019-01-07 12 FATAL: the database system is in recovery mode Failed. ! >

Try to reconnect and find that DB has been coredump.

[xdb@localhost ~] $[xdb@localhost ~] $psql-d testdb 2019-01-07 14 psql CST [1629] FATAL: the database system is in recovery mode psql: FATAL: the database system is in recovery mode

Perform recovery

[xdb@localhost ~] $pg_ctl start pg_ctl: another server might be running; trying to start server anyway waiting for server to start....2019-01-07 14 another server might be running; trying to start server anyway waiting for server to start....2019 11 CST 50.821 CST [1632] FATAL: lock file "postmaster.pid" already exists 2019-01-07 14 14 another server might be running; trying to start server anyway waiting for server to start....2019 50.821 CST [1632] HINT: Is another postmaster (PID 1370) running in data directory "/ data/xdb/pg111db"? Stopped waiting pg_ctl: could not start server Examine the log output. [xdb@localhost ~] $find / data/xdb-name postmaster.pid / data/xdb/pg111db/postmaster.pid [xdb@localhost ~] $rm-rf / data/xdb/pg111db/postmaster.pid [xdb@localhost ~] $pg_ctl start waiting for server to start....2019-01-07 14 purge 44.578 CST [1639] LOG ":: 1": Address already in use [xdb@localhost ~] $ps-ef | grep postgres xdb 1370 1 0 12:01 pts/0 00:00:02 / appdb/atlasdb/pg11.1/bin/postgres xdb 1389 1370 0 12:01? 00:00:00 [postgres] xdb 1641 1332 0 14:12 pts/0 00:00:00 grep-- color=auto postgres [xdb@localhost ~] $kill-9 1370 [xdb@localhost ~] $pg_ctl start waiting for server to start....2019-01-07 14 xdb 33.125 CST [1648] LOG: listening on IPv6 address ":: 1" Port 5432 2019-01-07 14 listening on IPv4 address 1315 33.125 CST [1648] LOG: listening on IPv4 address "127.0.0.1", port 5432 2019-01-07 14 LOG 1315 33. 142 CST [1648] LOG: listening on Unix socket "/ tmp/.s.PGSQL.5432". 2019-01-07 14 13 listening on IPv4 address 361 CST [1649] LOG: database system was interrupted Last known up at 2019-01-07 12:26:22 CST 2019-01-07 14 purl 13purl 34.818 CST [1649] LOG: database system was not properly shut down Automatic recovery in progress 2019-01-07 14 LOG 13 redo starts at 1/48F9ED08 34.863 CST [1649] LOG: redo starts at 1/48F9ED08. 2019-01-07 14 LOG 1313 charge 35.467 CST [1649] LOG: invalid record length at 1/4914FF58: wanted 24 Got 0 2019-01-07 14 LOG 13 purl 35.467 CST [1649] LOG: redo done at 1/4914FF30 2019-01-07 14 purge 1313 purl 35.467 CST [1649] LOG: last completed transaction was at log time 2019-01-07 12 Vera 28 Vera 37.521542 got 08 2019-01-07 14 purge 1335.977 CST [1648] LOG: database system is ready to accept connections done server started

After analysis, it is caused by the CheckpointerShmem- > ckpt_lck in the shared memory structure.

When tracking the checkpointer process, execute

SpinLockRelease (& CheckpointerShmem- > ckpt_lck)

After the release of lock, the above problem no longer occurs.