the process you see may be autovacuum worker process,you can tune the log_autovacuum_min_duration to log the autovacuum activities and check if the pids match http://www.postgresql.org/docs/9.2/static/runtime-config-autovacuum.html
2013/5/24 高健 <luckyjack...@gmail.com> > Hello all: > > I found that during postgresql running, there are so many processes > being created and then died. > I am interested in the reason. > > Here is the detail: > I installed from postgresql-9.2.1.tar.bz2. > I put some debug code in fd.c 's PathNameOpenFile function: > > fprintf(stderr,"+++While Calling PathNameOpenFile pid=%d.....",getpid(); > fprintf(stderr,"VfdCache Address is: %p \n\n",VfdCache); > > When it run, I open two termianal using psql(pid=22109 and pid=22114), > then I can got information like this: > [postgres@lex pgsql]$ ./bin/pg_ctl -D ./data start > server starting > [postgres@lex pgsql]$ LOG: database system was shut down at 2013-05-24 > 09:28:59 CST > LOG: autovacuum launcher started > +++While Calling PathNameOpenFile pid=22106.....VfdCache Address is: > 0xbfb3320 > > LOG: database system is ready to accept connections > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22109.....VfdCache Address is: > 0xbfb2de0 > > +++While Calling PathNameOpenFile pid=22114.....VfdCache Address is: > 0xbfba400 > > +++While Calling PathNameOpenFile pid=22114.....VfdCache Address is: > 0xbfba400 > > +++While Calling PathNameOpenFile pid=22114.....VfdCache Address is: > 0xbfba400 > > +++While Calling PathNameOpenFile pid=22114.....VfdCache Address is: > 0xbfba400 > > +++While Calling PathNameOpenFile pid=22120.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22120.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22120.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22127.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22127.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22127.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22134.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22134.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22134.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22142.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22142.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22142.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22149.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22149.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22149.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22156.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22156.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22156.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22165.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22165.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22165.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22171.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22171.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22171.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22178.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22178.....VfdCache Address is: > 0xbfe6700 > > +++While Calling PathNameOpenFile pid=22178.....VfdCache Address is: > 0xbfe6700 > > > But when I grep process information using ps command, I can't find process > such like 22120,22127,22134,22142,22149,22156,22178. > And the output is growing longer and longer... > > [root@lex ~]# ps -ef | grep post > root 4641 4621 0 08:28 pts/3 00:00:00 su - postgres > postgres 4642 4641 0 08:28 pts/3 00:00:00 -bash > root 4709 4688 0 08:28 pts/4 00:00:00 su - postgres > postgres 4710 4709 0 08:28 pts/4 00:00:00 -bash > root 4772 4751 0 08:29 pts/5 00:00:00 su - postgres > postgres 4773 4772 0 08:29 pts/5 00:00:00 -bash > postgres 22101 1 0 09:45 pts/3 00:00:00 > /usr/local/pgsql/bin/postgres -D ./data > postgres 22103 22101 0 09:45 ? 00:00:00 postgres: checkpointer > process > postgres 22104 22101 0 09:45 ? 00:00:00 postgres: writer process > > postgres 22105 22101 0 09:45 ? 00:00:00 postgres: wal writer > process > postgres 22106 22101 0 09:45 ? 00:00:00 postgres: autovacuum > launcher process > postgres 22107 22101 0 09:45 ? 00:00:00 postgres: stats collector > process > postgres 22108 4710 0 09:45 pts/4 00:00:00 ./psql > postgres 22109 22101 0 09:45 ? 00:00:00 postgres: postgres > postgres [local] idle > postgres 22113 4773 0 09:46 pts/5 00:00:00 ./psql > postgres 22114 22101 0 09:46 ? 00:00:00 postgres: postgres > postgres [local] idle > root 22187 6429 0 09:55 pts/6 00:00:00 grep post > [root@lex ~]# > > So I think that some process is created and then quickly died . But would > somebody can kindly say what are the purpose of those process? > How about using one worker process and keep it be alive? > -- Jov blog: http:amutu.com/blog <http://amutu.com/blog>
