diff options
Diffstat (limited to 'doc/development/database/client_side_connection_pool.md')
| -rw-r--r-- | doc/development/database/client_side_connection_pool.md | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/doc/development/database/client_side_connection_pool.md b/doc/development/database/client_side_connection_pool.md index dc52a551407..3cd0e836a8d 100644 --- a/doc/development/database/client_side_connection_pool.md +++ b/doc/development/database/client_side_connection_pool.md @@ -10,8 +10,8 @@ Ruby processes accessing the database through ActiveRecord, automatically calculate the connection-pool size for the process based on the concurrency. -Because of the way [Ruby on Rails manages database -connections](#connection-lifecycle), it is important that we have at +Because of the way [Ruby on Rails manages database connections](#connection-lifecycle), +it is important that we have at least as many connections as we have threads. While there is a 'pool' setting in [`database.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/config/database.yml.postgresql), it is not very practical because you need to maintain it in tandem with the number of application threads. For this @@ -28,9 +28,8 @@ because connections are instantiated lazily. ## Troubleshooting connection-pool issues -The connection-pool usage can be seen per environment in the [connection-pool -saturation -dashboard](https://dashboards.gitlab.net/d/alerts-sat_rails_db_connection_pool/alerts-rails_db_connection_pool-saturation-detail?orgId=1). +The connection-pool usage can be seen per environment in the +[connection-pool saturation dashboard](https://dashboards.gitlab.net/d/alerts-sat_rails_db_connection_pool/alerts-rails_db_connection_pool-saturation-detail?orgId=1). If the connection-pool is too small, this would manifest in `ActiveRecord::ConnectionTimeoutError`s from the application. Because we alert @@ -41,8 +40,8 @@ hardcoded value (10). At this point, we need to investigate what is using more connections than we anticipated. To do that, we can use the -`gitlab_ruby_threads_running_threads` metric. For example, [this -graph](https://thanos.gitlab.net/graph?g0.range_input=1h&g0.max_source_resolution=0s&g0.expr=sum%20by%20(thread_name)%20(%20gitlab_ruby_threads_running_threads%7Buses_db_connection%3D%22yes%22%7D%20)&g0.tab=0) +`gitlab_ruby_threads_running_threads` metric. For example, +[this graph](https://thanos.gitlab.net/graph?g0.range_input=1h&g0.max_source_resolution=0s&g0.expr=sum%20by%20(thread_name)%20(%20gitlab_ruby_threads_running_threads%7Buses_db_connection%3D%22yes%22%7D%20)&g0.tab=0) shows all running threads that connect to the database by their name. Threads labeled `puma worker` or `sidekiq_worker_thread` are the threads that define `Gitlab::Runtime.max_threads` so those are |