testdb=# SELECT * FROM pg_stat_activity;
-[ RECORD 1 ]----+--------------------------------------------------------------
datid            | 16458
datname          | testdb
pid              | 16248
usesysid         | 10
usename          | tsuka
application_name | psql
client_addr      |
client_hostname  |
client_port      | -1
backend_start    | 2013-09-19 19:29:00.685596+09
xact_start       | 2013-09-19 19:29:23.117776+09
query_start      | 2013-09-19 19:29:23.117776+09
state_change     | 2013-09-19 19:29:23.11778+09
waiting          | f
state            | active
query            | SELECT * FROM pg_stat_activity;
-[ RECORD 2 ]----+--------------------------------------------------------------
datid            | 16458
datname          | testdb
pid              | 19670
usesysid         | 10
usename          | tsuka
application_name | psql
client_addr      |
client_hostname  |
client_port      | -1
backend_start    | 2013-09-19 19:29:19.907824+09
xact_start       | 2013-09-19 19:29:19.910575+09
query_start      | 2013-09-19 19:29:19.916775+09
state_change     | 2013-09-19 19:29:19.916776+09
waiting          | t
state            | active
query            | UPDATE /* SELECTandUPDATE */ t SET col2 = 'A' WHERE col1 = 1;
-[ RECORD 3 ]----+--------------------------------------------------------------
datid            | 16458
datname          | testdb
pid              | 19671
usesysid         | 10
usename          | tsuka
application_name | psql
client_addr      |
client_hostname  |
client_port      | -1
backend_start    | 2013-09-19 19:29:19.911065+09
xact_start       | 2013-09-19 19:29:19.913637+09
query_start      | 2013-09-19 19:29:19.913746+09
state_change     | 2013-09-19 19:29:19.913747+09
waiting          | t
state            | active
query            | UPDATE /* onlyUPDATE      */ t SET col2 = 'A' WHERE col1 = 1;
-[ RECORD 4 ]----+--------------------------------------------------------------
datid            | 16458
datname          | testdb
pid              | 19673
usesysid         | 10
usename          | tsuka
application_name | psql
client_addr      |
client_hostname  |
client_port      | -1
backend_start    | 2013-09-19 19:29:19.919346+09
xact_start       | 2013-09-19 19:29:19.921483+09
query_start      | 2013-09-19 19:29:19.921602+09
state_change     | 2013-09-19 19:29:19.921603+09
waiting          | t
state            | active
query            | UPDATE /* onlyUPDATE      */ t SET col2 = 'A' WHERE col1 = 1;