cache getFinishedSync result to eliminate N+1 query pattern (#604)

* cache getFinishedSync result to eliminate N+1 query pattern

* add tracing

Author: arreyder

pkg/dotc1z/c1file.go

@@ -46,6 +46,11 @@ type C1File struct {
 	readOnly           bool
 	encoderConcurrency int
 
+	// Cached sync run for listConnectorObjects (avoids N+1 queries)
+	cachedViewSyncRun  *syncRun
+	cachedViewSyncOnce sync.Once
+	cachedViewSyncErr  error
+
 	// Slow query tracking
 	slowQueryLogTimes     map[string]time.Time
 	slowQueryLogTimesMu   sync.Mutex

pkg/dotc1z/sql_helpers.go

@@ -194,20 +194,12 @@ func listConnectorObjects[T proto.Message](ctx context.Context, c *C1File, table
 	case reqSyncID != "":
 		q = q.Where(goqu.C("sync_id").Eq(reqSyncID))
 	default:
-		var latestSyncRun *syncRun
-		var err error
-		latestSyncRun, err = c.getFinishedSync(ctx, 0, connectorstore.SyncTypeFull)
+		// Use cached sync run to avoid N+1 queries during pagination
+		latestSyncRun, err := c.getCachedViewSyncRun(ctx)
 		if err != nil {
 			return nil, "", err
 		}
 
-		if latestSyncRun == nil {
-			latestSyncRun, err = c.getLatestUnfinishedSync(ctx, connectorstore.SyncTypeAny)
-			if err != nil {
-				return nil, "", err
-			}
-		}
-
 		if latestSyncRun != nil {
 			q = q.Where(goqu.C("sync_id").Eq(latestSyncRun.ID))
 		}

pkg/dotc1z/sync_runs.go

@@ -95,6 +95,29 @@ type syncRun struct {
 	ParentSyncID string
 }
 
+// getCachedViewSyncRun returns the cached sync run for read operations.
+// This avoids N+1 queries when paginating through listConnectorObjects.
+// The result is computed once and cached for the lifetime of the C1File.
+func (c *C1File) getCachedViewSyncRun(ctx context.Context) (*syncRun, error) {
+	ctx, span := tracer.Start(ctx, "C1File.getCachedViewSyncRun")
+	defer span.End()
+
+	c.cachedViewSyncOnce.Do(func() {
+		// First try to get a finished full sync
+		c.cachedViewSyncRun, c.cachedViewSyncErr = c.getFinishedSync(ctx, 0, connectorstore.SyncTypeFull)
+		if c.cachedViewSyncErr != nil {
+			return
+		}
+
+		// If no finished sync, try to get an unfinished one
+		if c.cachedViewSyncRun == nil {
+			c.cachedViewSyncRun, c.cachedViewSyncErr = c.getLatestUnfinishedSync(ctx, connectorstore.SyncTypeAny)
+		}
+	})
+
+	return c.cachedViewSyncRun, c.cachedViewSyncErr
+}
+
 func (c *C1File) getLatestUnfinishedSync(ctx context.Context, syncType connectorstore.SyncType) (*syncRun, error) {
 	ctx, span := tracer.Start(ctx, "C1File.getLatestUnfinishedSync")
 	defer span.End()