core/filtermaps: document rowsPerBatch

core/filtermaps/map_renderer.go

@@ -31,8 +31,12 @@ import (
 const (
 	maxMapsPerBatch   = 32    // maximum number of maps rendered in memory
 	valuesPerCallback = 1024  // log values processed per event process callback
-	rowsPerBatch      = 1024  // number of rows written to db in a single batch
 	cachedRowMappings = 10000 // log value to row mappings cached during rendering
+
+	// Number of rows written to db in a single batch.
+	// The map renderer splits up writes like this to ensure that regular
+	// block processing latency is not affected by large batch writes.
+	rowsPerBatch = 1024
 )
 
 var (