tenantsettings: delete overrides when removing tenant

Release note: None

pkg/ccl/logictestccl/testdata/logic_test/tenant_settings

@@ -101,3 +101,21 @@ query T retry
 SHOW CLUSTER SETTING kv.protectedts.reconciliation.interval
 ----
 00:00:45
+
+user host-cluster-root
+
+# Verify that destroying a tenant cleans up any tenant-specific overrides.
+statement ok
+SELECT crdb_internal.create_tenant(1234)
+
+# TODO(radu): replace with ALTER TENANT when it's available.
+statement ok
+INSERT INTO system.tenant_settings (tenant_id, name, value, value_type) VALUES (1234, 'sql.notices.enabled', 'true', 'b')
+
+statement ok
+SELECT crdb_internal.destroy_tenant(1234, true)
+
+query I
+SELECT count(*) FROM system.tenant_settings WHERE tenant_id = 1234
+----
+0

pkg/sql/tenant.go

@@ -448,6 +448,15 @@ func GCTenantSync(ctx context.Context, execCfg *ExecutorConfig, info *descpb.Ten
 			return errors.Wrapf(err, "deleting tenant %d usage", info.ID)
 		}
 
+		if execCfg.Settings.Version.IsActive(ctx, clusterversion.TenantSettingsTable) {
+			if _, err := execCfg.InternalExecutor.ExecEx(
+				ctx, "delete-tenant-settings", txn, sessiondata.NodeUserSessionDataOverride,
+				`DELETE FROM system.tenant_settings WHERE tenant_id = $1`, info.ID,
+			); err != nil {
+				return errors.Wrapf(err, "deleting tenant %d settings", info.ID)
+			}
+		}
+
 		if !execCfg.Settings.Version.IsActive(ctx, clusterversion.PreSeedTenantSpanConfigs) {
 			return nil
 		}