fix: Fix deadlock in new streaming CSV / NDJSON sinks #21598
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added
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nameexhaustion
commented
Mar 5, 2025
| @@ -122,11 +122,14 @@ impl SinkNode for CsvSinkNode { | |||
| writer.write_batch(&df)?; | |||
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| allocation_size = allocation_size.max(buffer.len()); | |||
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| // Must drop before linearizer insert or will deadlock. | |||
| drop(consume_token); // Keep the consume_token until here to increase the | |||
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If the consume token is sent into the linearizer, we can end up in a deadlock state for a scan->sink query - given 2 workers from the source node (1 and 2):
- Worker 1 inserts the consume token into the linearizer buffer
- The linearizer is waiting for an insertion from worker 2
- Worker 2 is waiting for the channel of the next source phase
- Worker 1 is waiting for the consume token to be dropped while holding a ref to the current source phase, preventing it from ending
Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## main #21598 +/- ##
=======================================
Coverage 79.75% 79.75%
=======================================
Files 1604 1604
Lines 231519 231527 +8
Branches 2639 2639
=======================================
+ Hits 184640 184663 +23
+ Misses 46270 46255 -15
Partials 609 609 ☔ View full report in Codecov by Sentry. |
nameexhaustion
requested review from
ritchie46,
orlp and
c-peters
as code owners
|
This is really not a fix for the problem, and the deadlock still occurs. Just less often and more related to phase transitions. I fixed it properly in #21600. |
anath2
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to anath2/polars
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this pull request
Mar 5, 2025
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