feat(projections): resource counters (#9979)

# 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

cmd/setup/trigger_steps.go

@@ -0,0 +1,125 @@
+package setup
+
+import (
+	"fmt"
+
+	"github.com/zitadel/zitadel/internal/database"
+	"github.com/zitadel/zitadel/internal/domain"
+	"github.com/zitadel/zitadel/internal/migration"
+	"github.com/zitadel/zitadel/internal/query/projection"
+)
+
+// triggerSteps defines the repeatable migrations that set up triggers
+// for counting resources in the database.
+func triggerSteps(db *database.DB) []migration.RepeatableMigration {
+	return []migration.RepeatableMigration{
+		// Delete parent count triggers for instances and organizations
+		migration.DeleteParentCountsTrigger(db,
+			projection.InstanceProjectionTable,
+			domain.CountParentTypeInstance,
+			projection.InstanceColumnID,
+			projection.InstanceColumnID,
+			"instance",
+		),
+		migration.DeleteParentCountsTrigger(db,
+			projection.OrgProjectionTable,
+			domain.CountParentTypeOrganization,
+			projection.OrgColumnInstanceID,
+			projection.OrgColumnID,
+			"organization",
+		),
+
+		// Count triggers for all the resources
+		migration.CountTrigger(db,
+			projection.OrgProjectionTable,
+			domain.CountParentTypeInstance,
+			projection.OrgColumnInstanceID,
+			projection.OrgColumnInstanceID,
+			"organization",
+		),
+		migration.CountTrigger(db,
+			projection.ProjectProjectionTable,
+			domain.CountParentTypeOrganization,
+			projection.ProjectColumnInstanceID,
+			projection.ProjectColumnResourceOwner,
+			"project",
+		),
+		migration.CountTrigger(db,
+			projection.UserTable,
+			domain.CountParentTypeOrganization,
+			projection.UserInstanceIDCol,
+			projection.UserResourceOwnerCol,
+			"user",
+		),
+		migration.CountTrigger(db,
+			projection.InstanceMemberProjectionTable,
+			domain.CountParentTypeInstance,
+			projection.MemberInstanceID,
+			projection.MemberResourceOwner,
+			"iam_admin",
+		),
+		migration.CountTrigger(db,
+			projection.IDPTable,
+			domain.CountParentTypeInstance,
+			projection.IDPInstanceIDCol,
+			projection.IDPInstanceIDCol,
+			"identity_provider",
+		),
+		migration.CountTrigger(db,
+			projection.IDPTemplateLDAPTable,
+			domain.CountParentTypeInstance,
+			projection.LDAPInstanceIDCol,
+			projection.LDAPInstanceIDCol,
+			"identity_provider_ldap",
+		),
+		migration.CountTrigger(db,
+			projection.ActionTable,
+			domain.CountParentTypeInstance,
+			projection.ActionInstanceIDCol,
+			projection.ActionInstanceIDCol,
+			"action_v1",
+		),
+		migration.CountTrigger(db,
+			projection.ExecutionTable,
+			domain.CountParentTypeInstance,
+			projection.ExecutionInstanceIDCol,
+			projection.ExecutionInstanceIDCol,
+			"execution",
+		),
+		migration.CountTrigger(db,
+			fmt.Sprintf("%s_%s", projection.ExecutionTable, projection.ExecutionTargetSuffix),
+			domain.CountParentTypeInstance,
+			projection.ExecutionTargetInstanceIDCol,
+			projection.ExecutionTargetInstanceIDCol,
+			"execution_target",
+		),
+		migration.CountTrigger(db,
+			projection.LoginPolicyTable,
+			domain.CountParentTypeInstance,
+			projection.LoginPolicyInstanceIDCol,
+			projection.LoginPolicyInstanceIDCol,
+			"login_policy",
+		),
+		migration.CountTrigger(db,
+			projection.PasswordComplexityTable,
+			domain.CountParentTypeInstance,
+			projection.ComplexityPolicyInstanceIDCol,
+			projection.ComplexityPolicyInstanceIDCol,
+			"password_complexity_policy",
+		),
+		migration.CountTrigger(db,
+			projection.PasswordAgeTable,
+			domain.CountParentTypeInstance,
+			projection.AgePolicyInstanceIDCol,
+			projection.AgePolicyInstanceIDCol,
+			"password_expiry_policy",
+		),
+		migration.CountTrigger(db,
+			projection.LockoutPolicyTable,
+			domain.CountParentTypeInstance,
+			projection.LockoutPolicyInstanceIDCol,
+			projection.LockoutPolicyInstanceIDCol,
+			"lockout_policy",
+		),
+	}
+}