Wire per-trace flush limit into span buffer

cursoragent · cursoragent · commit db48e43bb4ed · 2026-03-16T16:18:07.000Z
diff --git a/src/sentry/options/defaults.py b/src/sentry/options/defaults.py
@@ -3214,6 +3214,13 @@
     default=500,
     flags=FLAG_PRIORITIZE_DISK | FLAG_AUTOMATOR_MODIFIABLE,
 )
+# Maximum number of segments per trace to flush in one cycle. 0 disables the limit.
+register(
+    "spans.buffer.max-flush-segments-per-trace",
+    type=Int,
+    default=0,
+    flags=FLAG_PRIORITIZE_DISK | FLAG_AUTOMATOR_MODIFIABLE,
+)
 # Maximum memory percentage for the span buffer in Redis before rejecting messages.
 register(
     "spans.buffer.max-memory-percentage",
diff --git a/src/sentry/spans/buffer.py b/src/sentry/spans/buffer.py
@@ -568,6 +568,7 @@ def flush_segments(self, now: int) -> dict[SegmentKey, FlushedSegment]:
         queue_keys = []
         shard_factor = max(1, len(self.assigned_shards))
         max_flush_segments = options.get("spans.buffer.max-flush-segments")
+        max_flush_segments_per_trace = options.get("spans.buffer.max-flush-segments-per-trace")
         flusher_logger_enabled = options.get("spans.buffer.flusher-cumulative-logger-enabled")
         max_segments_per_shard = math.ceil(max_flush_segments / shard_factor)
 
@@ -589,6 +590,8 @@ def flush_segments(self, now: int) -> dict[SegmentKey, FlushedSegment]:
             for segment_key, score in keys_with_scores:
                 segment_keys.append((shard, queue_key, segment_key, score))
 
+        segment_keys = self._apply_per_trace_limit(segment_keys, max_flush_segments_per_trace, now)
+
         data_start = time.monotonic()
         with metrics.timer("spans.buffer.flush_segments.load_segment_data"):
             segments, ingested_counts = self._load_segment_data([k for _, _, k, _ in segment_keys])
