Allow pause/resuming all pools

[tommyzli]

Hi - this updates the behaviour of PAUSE and RESUME to more closely match pgbouncers. A simple PAUSE; or RESUME; statement will now affect all pools. The previous behaviour of PAUSE db,user; is still supported and will only affect a single pool.

I'd like to use pgcat to replace some pgbouncers that have many pools, and being able to pause them all with one command would go a long way in simplifying the operations :)
example:

pgcat=> show databases;
           name            |   host    | port | database  | force_user | pool_size | min_pool_size | reserve_pool |  pool_mode  | max_connections | current_connections | paused | disabled
---------------------------+-----------+------+-----------+------------+-----------+---------------+--------------+-------------+-----------------+---------------------+--------+----------
 test_db_1_shard_0_primary | 127.0.0.1 | 5432 | postgres  | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
 test_db_2_shard_0_primary | 127.0.0.1 | 5432 | template1 | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
(2 rows)

pgcat=> pause;
PAUSE
pgcat=> show databases;
           name            |   host    | port | database  | force_user | pool_size | min_pool_size | reserve_pool |  pool_mode  | max_connections | current_connections | paused | disabled
---------------------------+-----------+------+-----------+------------+-----------+---------------+--------------+-------------+-----------------+---------------------+--------+----------
 test_db_1_shard_0_primary | 127.0.0.1 | 5432 | postgres  | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      1 |        0
 test_db_2_shard_0_primary | 127.0.0.1 | 5432 | template1 | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      1 |        0
(2 rows)

pgcat=> resume;
RESUME
pgcat=> show databases;
           name            |   host    | port | database  | force_user | pool_size | min_pool_size | reserve_pool |  pool_mode  | max_connections | current_connections | paused | disabled
---------------------------+-----------+------+-----------+------------+-----------+---------------+--------------+-------------+-----------------+---------------------+--------+----------
 test_db_1_shard_0_primary | 127.0.0.1 | 5432 | postgres  | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
 test_db_2_shard_0_primary | 127.0.0.1 | 5432 | template1 | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
(2 rows)

pgcat=> pause test_db_1,postgres;
PAUSE test_db_1,postgres
pgcat=> show databases;
           name            |   host    | port | database  | force_user | pool_size | min_pool_size | reserve_pool |  pool_mode  | max_connections | current_connections | paused | disabled
---------------------------+-----------+------+-----------+------------+-----------+---------------+--------------+-------------+-----------------+---------------------+--------+----------
 test_db_1_shard_0_primary | 127.0.0.1 | 5432 | postgres  | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      1 |        0
 test_db_2_shard_0_primary | 127.0.0.1 | 5432 | template1 | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
(2 rows)

pgcat=> resume;
RESUME
pgcat=> show databases;
           name            |   host    | port | database  | force_user | pool_size | min_pool_size | reserve_pool |  pool_mode  | max_connections | current_connections | paused | disabled
---------------------------+-----------+------+-----------+------------+-----------+---------------+--------------+-------------+-----------------+---------------------+--------+----------
 test_db_1_shard_0_primary | 127.0.0.1 | 5432 | postgres  | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
 test_db_2_shard_0_primary | 127.0.0.1 | 5432 | template1 | postgres   |        10 |             0 |            0 | transaction |              10 |                   1 |      0 |        0
(2 rows)

[levkk]

Really cool, thanks!