244 lines
11 KiB
Markdown
244 lines
11 KiB
Markdown
---
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type: reference
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---
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# Working with the bundle Pgbouncer service
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As part of its High Availability stack, GitLab Premium includes a bundled version of [Pgbouncer](https://pgbouncer.github.io/) that can be managed through `/etc/gitlab/gitlab.rb`.
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In a High Availability setup, Pgbouncer is used to seamlessly migrate database connections between servers in a failover scenario.
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Additionally, it can be used in a non-HA setup to pool connections, speeding up response time while reducing resource usage.
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It is recommended to run pgbouncer alongside the `gitlab-rails` service, or on its own dedicated node in a cluster.
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## Operations
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### Running Pgbouncer as part of an HA GitLab installation
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1. Make sure you collect [`CONSUL_SERVER_NODES`](database.md#consul-information), [`CONSUL_PASSWORD_HASH`](database.md#consul-information), and [`PGBOUNCER_PASSWORD_HASH`](database.md#pgbouncer-information) before executing the next step.
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1. Edit `/etc/gitlab/gitlab.rb` replacing values noted in the `# START user configuration` section:
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```ruby
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# Disable all components except Pgbouncer and Consul agent
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roles ['pgbouncer_role']
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# Configure Pgbouncer
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pgbouncer['admin_users'] = %w(pgbouncer gitlab-consul)
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# Configure Consul agent
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consul['watchers'] = %w(postgresql)
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# START user configuration
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# Please set the real values as explained in Required Information section
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# Replace CONSUL_PASSWORD_HASH with with a generated md5 value
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# Replace PGBOUNCER_PASSWORD_HASH with with a generated md5 value
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pgbouncer['users'] = {
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'gitlab-consul': {
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password: 'CONSUL_PASSWORD_HASH'
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},
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'pgbouncer': {
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password: 'PGBOUNCER_PASSWORD_HASH'
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}
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}
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# Replace placeholders:
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#
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# Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
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# with the addresses gathered for CONSUL_SERVER_NODES
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consul['configuration'] = {
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retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z)
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}
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#
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# END user configuration
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```
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> `pgbouncer_role` was introduced with GitLab 10.3
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1. Run `gitlab-ctl reconfigure`
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1. Create a `.pgpass` file so Consul is able to
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reload pgbouncer. Enter the `PGBOUNCER_PASSWORD` twice when asked:
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```sh
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gitlab-ctl write-pgpass --host 127.0.0.1 --database pgbouncer --user pgbouncer --hostuser gitlab-consul
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```
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#### PGBouncer Checkpoint
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1. Ensure the node is talking to the current master:
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```sh
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gitlab-ctl pgb-console # You will be prompted for PGBOUNCER_PASSWORD
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```
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If there is an error `psql: ERROR: Auth failed` after typing in the
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password, ensure you previously generated the MD5 password hashes with the correct
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format. The correct format is to concatenate the password and the username:
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`PASSWORDUSERNAME`. For example, `Sup3rS3cr3tpgbouncer` would be the text
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needed to generate an MD5 password hash for the `pgbouncer` user.
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1. Once the console prompt is available, run the following queries:
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```sh
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show databases ; show clients ;
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```
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The output should be similar to the following:
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```
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name | host | port | database | force_user | pool_size | reserve_pool | pool_mode | max_connections | current_connections
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---------------------+-------------+------+---------------------+------------+-----------+--------------+-----------+-----------------+---------------------
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gitlabhq_production | MASTER_HOST | 5432 | gitlabhq_production | | 20 | 0 | | 0 | 0
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pgbouncer | | 6432 | pgbouncer | pgbouncer | 2 | 0 | statement | 0 | 0
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(2 rows)
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type | user | database | state | addr | port | local_addr | local_port | connect_time | request_time | ptr | link | remote_pid | tls
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------+-----------+---------------------+---------+----------------+-------+------------+------------+---------------------+---------------------+-----------+------+------------+-----
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C | pgbouncer | pgbouncer | active | 127.0.0.1 | 56846 | 127.0.0.1 | 6432 | 2017-08-21 18:09:59 | 2017-08-21 18:10:48 | 0x22b3880 | | 0 |
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(2 rows)
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```
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### Running Pgbouncer as part of a non-HA GitLab installation
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1. Generate PGBOUNCER_USER_PASSWORD_HASH with the command `gitlab-ctl pg-password-md5 pgbouncer`
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1. Generate SQL_USER_PASSWORD_HASH with the command `gitlab-ctl pg-password-md5 gitlab`. We'll also need to enter the plaintext SQL_USER_PASSWORD later
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1. On your database node, ensure the following is set in your `/etc/gitlab/gitlab.rb`
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```ruby
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postgresql['pgbouncer_user_password'] = 'PGBOUNCER_USER_PASSWORD_HASH'
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postgresql['sql_user_password'] = 'SQL_USER_PASSWORD_HASH'
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postgresql['listen_address'] = 'XX.XX.XX.Y' # Where XX.XX.XX.Y is the ip address on the node postgresql should listen on
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postgresql['md5_auth_cidr_addresses'] = %w(AA.AA.AA.B/32) # Where AA.AA.AA.B is the IP address of the pgbouncer node
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```
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1. Run `gitlab-ctl reconfigure`
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**Note:** If the database was already running, it will need to be restarted after reconfigure by running `gitlab-ctl restart postgresql`.
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1. On the node you are running pgbouncer on, make sure the following is set in `/etc/gitlab/gitlab.rb`
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```ruby
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pgbouncer['enable'] = true
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pgbouncer['databases'] = {
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gitlabhq_production: {
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host: 'DATABASE_HOST',
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user: 'pgbouncer',
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password: 'PGBOUNCER_USER_PASSWORD_HASH'
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}
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}
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```
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1. Run `gitlab-ctl reconfigure`
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1. On the node running unicorn, make sure the following is set in `/etc/gitlab/gitlab.rb`
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```ruby
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gitlab_rails['db_host'] = 'PGBOUNCER_HOST'
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gitlab_rails['db_port'] = '6432'
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gitlab_rails['db_password'] = 'SQL_USER_PASSWORD'
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```
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1. Run `gitlab-ctl reconfigure`
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1. At this point, your instance should connect to the database through pgbouncer. If you are having issues, see the [Troubleshooting](#troubleshooting) section
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## Enable Monitoring
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> [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/issues/3786) in GitLab 12.0.
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If you enable Monitoring, it must be enabled on **all** pgbouncer servers.
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1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
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```ruby
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# Enable service discovery for Prometheus
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consul['enable'] = true
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consul['monitoring_service_discovery'] = true
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# Replace placeholders
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# Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
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# with the addresses of the Consul server nodes
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consul['configuration'] = {
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retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
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}
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# Set the network addresses that the exporters will listen on
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node_exporter['listen_address'] = '0.0.0.0:9100'
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pgbouncer_exporter['listen_address'] = '0.0.0.0:9188'
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```
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1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.
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### Interacting with pgbouncer
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#### Administrative console
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As part of omnibus-gitlab, we provide a command `gitlab-ctl pgb-console` to automatically connect to the pgbouncer administrative console. Please see the [pgbouncer documentation](https://pgbouncer.github.io/usage.html#admin-console) for detailed instructions on how to interact with the console.
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To start a session, run
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```shell
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# gitlab-ctl pgb-console
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Password for user pgbouncer:
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psql (9.6.8, server 1.7.2/bouncer)
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Type "help" for help.
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pgbouncer=#
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```
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The password you will be prompted for is the PGBOUNCER_USER_PASSWORD
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To get some basic information about the instance, run
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```shell
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pgbouncer=# show databases; show clients; show servers;
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name | host | port | database | force_user | pool_size | reserve_pool | pool_mode | max_connections | current_connections
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---------------------+-----------+------+---------------------+------------+-----------+--------------+-----------+-----------------+---------------------
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gitlabhq_production | 127.0.0.1 | 5432 | gitlabhq_production | | 100 | 5 | | 0 | 1
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pgbouncer | | 6432 | pgbouncer | pgbouncer | 2 | 0 | statement | 0 | 0
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(2 rows)
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type | user | database | state | addr | port | local_addr | local_port | connect_time | request_time | ptr | link
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| remote_pid | tls
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------+-----------+---------------------+--------+-----------+-------+------------+------------+---------------------+---------------------+-----------+------
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+------------+-----
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44590 | 127.0.0.1 | 6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x12444c0 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44592 | 127.0.0.1 | 6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x12447c0 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44594 | 127.0.0.1 | 6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x1244940 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44706 | 127.0.0.1 | 6432 | 2018-04-24 22:14:22 | 2018-04-24 22:16:31 | 0x1244ac0 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44708 | 127.0.0.1 | 6432 | 2018-04-24 22:14:22 | 2018-04-24 22:15:15 | 0x1244c40 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44794 | 127.0.0.1 | 6432 | 2018-04-24 22:15:15 | 2018-04-24 22:15:15 | 0x1244dc0 |
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| 0 |
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C | gitlab | gitlabhq_production | active | 127.0.0.1 | 44798 | 127.0.0.1 | 6432 | 2018-04-24 22:15:15 | 2018-04-24 22:16:31 | 0x1244f40 |
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| 0 |
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C | pgbouncer | pgbouncer | active | 127.0.0.1 | 44660 | 127.0.0.1 | 6432 | 2018-04-24 22:13:51 | 2018-04-24 22:17:12 | 0x1244640 |
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| 0 |
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(8 rows)
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type | user | database | state | addr | port | local_addr | local_port | connect_time | request_time | ptr | link | rem
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ote_pid | tls
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------+--------+---------------------+-------+-----------+------+------------+------------+---------------------+---------------------+-----------+------+----
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--------+-----
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S | gitlab | gitlabhq_production | idle | 127.0.0.1 | 5432 | 127.0.0.1 | 35646 | 2018-04-24 22:15:15 | 2018-04-24 22:17:10 | 0x124dca0 | |
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19980 |
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(1 row)
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```
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## Troubleshooting
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In case you are experiencing any issues connecting through pgbouncer, the first place to check is always the logs:
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```shell
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# gitlab-ctl tail pgbouncer
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```
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Additionally, you can check the output from `show databases` in the [Administrative console](#administrative-console). In the output, you would expect to see values in the `host` field for the `gitlabhq_production` database. Additionally, `current_connections` should be greater than 1.
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