Follow the procedure below to close a connection using a standard Unix tool (ps command).

1. Execute the ps command.
   Note that "<x>" indicates the product version.

   > ps axwfo user,pid,ppid,tty,command | grep postgres
   fsepuser 19174 18027 pts/1                 \_ grep postgres
   fsepuser 20517     1 ?      /opt/fsepv<x>server64/bin/postgres -D /disk01/data  
   fsepuser 20518 20517 ?       \_ postgres: logger
   fsepuser 20520 20517 ?       \_ postgres: checkpointer
   fsepuser 20521 20517 ?       \_ postgres: background writer
   fsepuser 20522 20517 ?       \_ postgres: walwriter
   fsepuser 20523 20517 ?       \_ postgres: autovacuum launcher
   fsepuser 20524 20517 ?       \_ postgres: archiver
   fsepuser 20525 20517 ?       \_ postgres: logical replication launcher
   fsepuser 18673 20517 ?       \_ postgres: fsepuser postgres 192.168.100.1(49448) idle
   fsepuser 16643 20517 ?       \_ postgres: fsepuser db01 192.168.100.11(49449) UPDATE waiting
   fsepuser 16644 20517 ?         \_ postgres: fsepuser db01 192.168.100.12(49450) idle in transaction

   Process ID 16643 may be a connection that was established a considerable time ago by the UPDATE statement, or a connection that has occupied resources (waiting).

2. Close connections from clients that have been in the waiting state for an extended period.

   Use pg_terminate_backend() to close the connection with the process ID identified in step 1 above.

   The example below disconnects the process with ID 16643.

   However, when considering continued compatibility of applications, do not reference or use system catalogs and functions directly in SQL statements.

   postgres=# SELECT pg_terminate_backend (16643);
    pg_terminate_backend
   -------------------
   t
   (1 row)