Improve default bucket count in FTE #21977
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CI: #18697 |
losipiuk
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May 15, 2024
core/trino-main/src/main/java/io/trino/sql/planner/NodePartitioningManager.java
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losipiuk
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May 15, 2024
We observed high skew in FTE tasks due to overly low bucket count.
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sopel39
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| // then each task gets one bucket. So let's return the total number of tasks here. This number, unfortunately, is hard to know precisely because of the variety of ways in | ||
| // which schedulers create tasks. We therefore have to estimate. | ||
| if (getRetryPolicy(session) != RetryPolicy.TASK) { | ||
| // Pipeline schedulers typically create as many tasks as there are nodes. |
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this is too low even for pipeline mode as it affects local scaling too
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Can you say more? What is "local scaling"? I see that stages schedulers create a task per stage; can this exceed the node count and is it relevant?
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I've created follow up PR #22000
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See
bufferCount is larger than bucket count, then we are not fully utilizing writer concurrency within a task
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Description
We observed high skew in FTE tasks due to overly low bucket count.
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