# Which Problems Are Solved
Add the ability to keep track of the current counts of projection
resources. We want to prevent calling `SELECT COUNT(*)` on tables, as
that forces a full scan and sudden spikes of DB resource uses.
# How the Problems Are Solved
- A resource_counts table is added
- Triggers that increment and decrement the counted values on inserts
and deletes
- Triggers that delete all counts of a table when the source table is
TRUNCATEd. This is not in the business logic, but prevents wrong counts
in case someone want to force a re-projection.
- Triggers that delete all counts if the parent resource is deleted
- Script to pre-populate the resource_counts table when a new source
table is added.
The triggers are reusable for any type of resource, in case we choose to
add more in the future.
Counts are aggregated by a given parent. Currently only `instance` and
`organization` are defined as possible parent. This can later be
extended to other types, such as `project`, should the need arise.
I deliberately chose to use `parent_id` to distinguish from the
de-factor `resource_owner` which is usually an organization ID. For
example:
- For users the parent is an organization and the `parent_id` matches
`resource_owner`.
- For organizations the parent is an instance, but the `resource_owner`
is the `org_id`. In this case the `parent_id` is the `instance_id`.
- Applications would have a similar problem, where the parent is a
project, but the `resource_owner` is the `org_id`
# Additional Context
Closes https://github.com/zitadel/zitadel/issues/9957
