Tuning

oddk’s default parameter group calculates memory and worker settings from the RAM and CPU cores assigned to each instance. These are starting points; adjust them for your workload and connection pool.

Default parameters

For the default group default:2025-08-27, RAM below is the instance’s assigned memory in MB, and cores is its assigned CPU count. Memory calculations and max_connections are rounded to whole numbers.

Parameter	Default calculation
`shared_buffers`	RAM ÷ 4, in MB
`effective_cache_size`	RAM × 0.75, in MB
`max_connections`	RAM ÷ 16
`maintenance_work_mem`	5% of RAM, clamped to 64–2048 MB
`effective_io_concurrency`	cores × 8
`max_worker_processes`	cores × 2, with a minimum of 8
`work_mem`	25% of RAM ÷ max_connections, clamped to 4–64 MB

With the default connection calculation, work_mem resolves to 4 MB for the 8 GB instance in the Quickstart.

Create a parameter group

Groups are named and cannot be edited in place. Export a group to use as your starting point:

oddk parameters get --name default:2025-08-27 --json > app-params.json

Edit the parameters entries in app-params.json. For example, to use a fixed connection limit, replace the existing max_connections entry with:

{
  "name": "max_connections",
  "type": "postgres_cli_arg",
  "valueType": "numeric",
  "value": "200"
}

This is an example limit, not a workload recommendation. Keep the other entries and choose a group name you have not used before:

oddk parameters put app-tuned --file app-params.json

The name passed to put names the new group. The exported object and a bare parameter array are both accepted as input.

Apply to an instance

Applying a group recreates the container while keeping its data volume. Plan for a connection interruption, and take a snapshot first:

oddk snapshot make --comment "before tuning"
oddk instance apply app --parameter-group app-tuned
oddk checklist

Before removing the running container, oddk checks that the parameters resolve and that the estimated shared memory fits the instance’s RAM. If the new container cannot become ready, it attempts to rebuild the previous configuration and returns the error.

To deliberately return to the default group:

oddk instance apply app --parameter-group default:2025-08-27

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