Running Postgres Containers
Running Multiple Postgres Containers
docker run -d --name postgres1 -e POSTGRES_PASSWORD=dev -p 5432:5432 postgres:latest
docker run -d --name postgres2 -e POSTGRES_PASSWORD=dev -p 5433:5432 postgres:13
docker run -d --name postgres3 -e POSTGRES_PASSWORD=dev -p 5434:5432 postgres:12
Open Docker Dashboard and run the following commands:
# psql -d postgres -U postgres -W
Password:
psql (17.2 (Debian 17.2-1.pgdg120+1))
Type "help" for help.
postgres=#
The above command includes three flags:
- -d - specifies the name of the database to connect to
- -U - specifies the name of the user to connect as
- -W - forces psql to ask for the user password before connecting to the database
Listing all the databases - \l
List of databases
Name | Owner | Encoding | Locale Provider | Collate | Ctype | Locale | ICU Rules | Access privileges
-----------+----------+----------+-----------------+------------+------------+--------+-----------+-----------------------
postgres | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
template0 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/po
stgres +
| | | | | | | | postg
res=CTc/postgres
template1 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/po
stgres +
| | | | | | | | postg
res=CTc/postgres
(3 rows)
List all schemas
The \dn psql command lists all the database schemas.
postgres=# \dn
List of schemas
Name | Owner
--------+-------------------
public | pg_database_owner
(1 row)
postgres=#
Run the following command to show the database activity:
SELECT * from pg_stat_activity; <--- DONT FORGET ";"
Result:
datid | datname | pid | leader_pid | usesysid | usename | application_name | client_addr | client_host
name | client_port | backend_start | xact_start | query_start
| state_change | wait_event_type | wait_event | state | backend_xid
| backend_xmin | query_id | query | backend_type
-------+----------+-----+------------+----------+----------+------------------+-------------+------------
-----+-------------+-------------------------------+-------------------------------+---------------------
----------+-------------------------------+-----------------+---------------------+--------+-------------
+--------------+----------+---------------------------------+------------------------------
5 | postgres | 85 | | 10 | postgres | psql | |
| -1 | 2025-01-08 11:40:22.778949+00 | | 2025-01-08 11:40:56.
590114+00 | 2025-01-08 11:41:26.598462+00 | Client | ClientRead | idle |
| | | SELECT pg_sleep(30); | client backend
5 | postgres | 92 | | 10 | postgres | psql | |
| -1 | 2025-01-08 11:41:14.359414+00 | 2025-01-08 11:43:52.615603+00 | 2025-01-08 11:43:52.
615603+00 | 2025-01-08 11:43:52.61561+00 | | | active |
| 750 | | SELECT * FROM pg_stat_activity; | client backend
| | 64 | | | | | |
| | 2025-01-08 11:38:28.74611+00 | |
| | Activity | AutovacuumMain | |
| | | | autovacuum launcher
| | 65 | | 10 | postgres | | |
:
Method 2: Using "Ask Gordon"
Run a multiple version of postgres with the standard port and POSTGRES_PASSWORD set to dev
Remove the container
Open Docker Dashboard > Selecting all the running Postgres containsrs and delete them in a single step.