<screen>

$ ps auxww | grep ^postgres

postgres 960 0.0 1.1 6104 1480 pts/1 SN 13:17 0:00 postgres -i

postgres 963 0.0 1.1 7084 1472 pts/1 SN 13:17 0:00 postgres: writer process

postgres 965 0.0 1.1 6152 1512 pts/1 SN 13:17 0:00 postgres: stats collector process

postgres 998 0.0 2.3 6532 2992 pts/1 SN 13:18 0:00 postgres: tgl runbug 127.0.0.1 idle

postgres 1003 0.0 2.4 6532 3128 pts/1 SN 13:19 0:00 postgres: tgl regression [local] SELECT waiting

postgres 1016 0.1 2.4 6532 3080 pts/1 SN 13:19 0:00 postgres: tgl regression [local] idle in transaction

postgres 15551 0.0 0.1 57536 7132 pts/0 S 18:02 0:00 postgres -i

postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: writer process

postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer process

postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: wal writer process

postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher process

postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector process

postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle

postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting

postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction

</screen>

(The appropriate invocation of <command>ps</> varies across different

platforms, as do the details of what is shown. This example is from a

recent Linux system.) The first process listed here is the

master server process. The command arguments

shown for it are the same ones used when it was launched. The nexttwo

shown for it are the same ones used when it was launched. The nextfive

processes are background worker processes automatically launched by the

master process. (The <quote>stats collector</> process will not be present

if you have set

the system not to start the statistics collector.) Each of the remaining

if you have set the system not to start the statistics collector; likewise

the <quote>autovacuum launcher</> process can be disabled.)

Each of the remaining

processes is a server process handling one client connection. Each such

process sets its command line display in the form

or a command type name such as <literal>SELECT</>. Also,

<literal>waiting</> is appended if the server process is presently waiting

on a lock held by another session. In the above example we can infer

that process 1003 is waiting for process 1016 to complete its transaction and

thereby release some lock.

that process 15606 is waiting for process 15610 to complete its transaction

and thereby release some lock. (Process 15610 must be the blocker, because

there is no other active session. In more complicated cases it would be

necessary to look into the

<link linkend="view-pg-locks"><structname>pg_locks</structname></link>

system view to determine who is blocking whom.)

</para>

<para>