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[IcebergIO] Fix stale openWriters count in RecordWriterManager #39157

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Merged
ahmedabu98 merged 1 commit into from
Jun 29, 2026
Merged

[IcebergIO] Fix stale openWriters count in RecordWriterManager #39157

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5 changes: 4 additions & 1 deletion sdks/java/io/iceberg/src/main/java/org/apache/beam/sdk/io/iceberg/RecordWriterManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -163,7 +163,10 @@ boolean write(Record record) {

@Nullable RecordWriter writer = writers.getIfPresent(routingPartitionKey);
if (writer == null && openWriters >= maxNumWriters) {
return false;
writers.cleanUp();
if (openWriters >= maxNumWriters) {
return false;
}
}
Comment on lines 165 to 170

@gemini-code-assist gemini-code-assist Bot Jun 29, 2026

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medium

Calling writers.cleanUp() on every single write attempt that results in a spill can introduce significant CPU overhead and lock contention, especially when processing a large volume of records for partitions that exceed maxNumWriters. Since Guava's cleanUp() acquires locks on all cache segments, calling it repeatedly in a tight loop for every spilled record is inefficient.\n\nTo optimize this, consider rate-limiting the cleanUp() calls (e.g., at most once every second) by tracking the last cleanup time using a timestamp field (e.g., lastCleanupNanos) in DestinationState.\n\nNote: You will need to define private long lastCleanupNanos = 0L; as a field in the DestinationState class for this suggestion to compile.

      if (writer == null && openWriters >= maxNumWriters) {\n        long now = System.nanoTime();\n        if (now - lastCleanupNanos > 1000000000L) {\n          writers.cleanUp();\n          lastCleanupNanos = now;\n        }\n        if (openWriters >= maxNumWriters) {\n          return false;\n        }\n      }

writer = fetchWriterForPartition(routingPartitionKey, writer);
writer.write(record);
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