unistore: add small buffer of watched events (#100431)

* change log level

* Add a small buffer when watching events

pkg/storage/unified/search/bleve.go

@@ -218,7 +218,7 @@ func (b *bleveBackend) cleanOldIndexes(dir string, skip string) {
 			if err != nil {
 				b.log.Error("Unable to remove old index folder", "directory", fpath, "error", err)
 			} else {
-				b.log.Error("Removed old index folder", "directory", fpath)
+				b.log.Info("Removed old index folder", "directory", fpath)
 			}
 		}
 	}

pkg/storage/unified/sql/backend.go

@@ -26,6 +26,7 @@ import (
 
 const tracePrefix = "sql.resource."
 const defaultPollingInterval = 100 * time.Millisecond
+const defaultWatchBufferSize = 100 // number of events to buffer in the watch stream
 
 type Backend interface {
 	resource.StorageBackend
@@ -37,6 +38,7 @@ type BackendOptions struct {
 	DBProvider      db.DBProvider
 	Tracer          trace.Tracer
 	PollingInterval time.Duration
+	WatchBufferSize int
 }
 
 func NewBackend(opts BackendOptions) (Backend, error) {
@@ -52,6 +54,9 @@ func NewBackend(opts BackendOptions) (Backend, error) {
 	if pollingInterval == 0 {
 		pollingInterval = defaultPollingInterval
 	}
+	if opts.WatchBufferSize == 0 {
+		opts.WatchBufferSize = defaultWatchBufferSize
+	}
 	return &backend{
 		done:            ctx.Done(),
 		cancel:          cancel,
@@ -59,6 +64,7 @@ func NewBackend(opts BackendOptions) (Backend, error) {
 		tracer:          opts.Tracer,
 		dbProvider:      opts.DBProvider,
 		pollingInterval: pollingInterval,
+		watchBufferSize: opts.WatchBufferSize,
 		batchLock:       &batchLock{running: make(map[string]bool)},
 	}, nil
 }
@@ -83,6 +89,7 @@ type backend struct {
 	// watch streaming
 	//stream chan *resource.WatchEvent
 	pollingInterval time.Duration
+	watchBufferSize int
 }
 
 func (b *backend) Init(ctx context.Context) error {
@@ -706,7 +713,7 @@ func (b *backend) WatchWriteEvents(ctx context.Context) (<-chan *resource.Writte
 		return nil, fmt.Errorf("watch, get latest resource version: %w", err)
 	}
 	// Start the poller
-	stream := make(chan *resource.WrittenEvent)
+	stream := make(chan *resource.WrittenEvent, b.watchBufferSize)
 	go b.poller(ctx, since, stream)
 	return stream, nil
 }