sql,config: tenant zone config lookup is broken

[ajwerner]

Describe the problem

In #74612 we made it so that the tenant has access to its own zone configs via the SystemConfig object provided by the systemconfigwatcher. Unfortunately this did not go far enough to actually fully address #70558 because of this special case logic:

cockroach/pkg/config/system.go

Lines 371 to 385 in 4b8258c

	func (s *SystemConfig) GetZoneConfigForObject(
	codec keys.SQLCodec, id uint32,
	) (*zonepb.ZoneConfig, error) {
	var sysID SystemTenantObjectID
	if codec.ForSystemTenant() {
	sysID = SystemTenantObjectID(id)
	} else {
	sysID = keys.TenantsRangesID
	}
	entry, err := s.getZoneEntry(sysID)
	if err != nil {
	return nil, err
	}
	return entry.combined, nil
	}

Solution

We need to either remove the above logic or make it conditional on where the config is coming from and more generally make sure that the SystemConfig methods work for the tenant.

Epic: CRDB-10489

Jira issue: CRDB-12864

[ajwerner]

h/t to @arulajmani

[ajwerner]

This affects the optimizer's ability to do locality aware search, and nothing else.

[ajwerner]

Also, this only affects serverless, so we can backport if the need arises.

[irfansharif]

It also affects the SQL GC job, right?

cockroach/pkg/sql/gcjob/refresh_statuses.go

Lines 278 to 295 in d61df4c

	// refreshTenant updates the status of tenant that is waiting to be GC'd. It
	// returns whether or the tenant has expired or the duration until it expires.
	func refreshTenant(
	ctx context.Context,
	execCfg *sql.ExecutorConfig,
	dropTime int64,
	details *jobspb.SchemaChangeGCDetails,
	progress *jobspb.SchemaChangeGCProgress,
	) (expired bool, deadline time.Time) {
	if progress.Tenant.Status != jobspb.SchemaChangeGCProgress_WAITING_FOR_GC {
	return true, time.Time{}
	}
	tenantTTLSeconds := execCfg.DefaultZoneConfig.GC.TTLSeconds
	tenID := details.Tenant.ID
	cfg := execCfg.SystemConfig.GetSystemConfig()
	zoneCfg, err := cfg.GetZoneConfigForObject(keys.MakeSQLCodec(roachpb.MakeTenantID(tenID)), 0)
	if err == nil {
	tenantTTLSeconds = zoneCfg.GC.TTLSeconds

[blathers-crl]

Hi @ajwerner, please add branch-* labels to identify which branch(es) this release-blocker affects.

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is otan.}

[ajwerner]

😬 yes, that's legit.