Flink: Avoid unnecessary TableLoader.loadTable() in IcebergCommitter subtasks > 0#17251
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Guosmilesmile wants to merge 3 commits into
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Flink: Avoid unnecessary TableLoader.loadTable() in IcebergCommitter subtasks > 0#17251Guosmilesmile wants to merge 3 commits into
Guosmilesmile wants to merge 3 commits into
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mxm
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Jul 16, 2026
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| @TestTemplate | ||
| public void testCommitterOnSubtaskZeroLoadsTable() throws Exception { | ||
| TableLoader spyLoader = spy(tableLoader); | ||
| IcebergFilesCommitterMetrics metric = mock(IcebergFilesCommitterMetrics.class); | ||
| IcebergCommitter committer = | ||
| new IcebergCommitter( | ||
| spyLoader, branch, Collections.emptyMap(), false, 10, "sinkId", metric, false, 0); | ||
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| verify(spyLoader).open(); | ||
| verify(spyLoader).loadTable(); | ||
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| committer.close(); | ||
| } | ||
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| @TestTemplate | ||
| public void testCommitterOnNonZeroSubtaskSkipsTableLoad() throws Exception { | ||
| TableLoader spyLoader = spy(tableLoader); | ||
| IcebergFilesCommitterMetrics metric = mock(IcebergFilesCommitterMetrics.class); | ||
| IcebergCommitter committer = | ||
| new IcebergCommitter( | ||
| spyLoader, branch, Collections.emptyMap(), false, 10, "sinkId", metric, false, 1); | ||
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| verify(spyLoader, never()).open(); | ||
| verify(spyLoader, never()).loadTable(); | ||
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| committer.close(); | ||
| } |
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I would prefer more of an end-to-end test, e.g. using a Minicluster or a TestHarness which utilizes the entire path. This is a critical code path and a simple unit test IMHO is not enough.
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Make sense. Change ut to use TestHarness
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| if (subtaskId == 0) { | ||
| if (!tableLoader.isOpen()) { | ||
| tableLoader.open(); | ||
| } | ||
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| this.table = tableLoader.loadTable(); | ||
| this.maxContinuousEmptyCommits = | ||
| PropertyUtil.propertyAsInt(table.properties(), MAX_CONTINUOUS_EMPTY_COMMITS, 10); | ||
| Preconditions.checkArgument( | ||
| maxContinuousEmptyCommits > 0, MAX_CONTINUOUS_EMPTY_COMMITS + " must be positive"); | ||
| this.workerPool = | ||
| ThreadPools.newFixedThreadPool( | ||
| "iceberg-committer-pool-" + table.name() + "-" + sinkId, workerPoolSize); |
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Can we add a comment why we are only initializing for subtaskId == 0?
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Right, add comment on it.
mxm
approved these changes
Jul 17, 2026
mxm
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mxm
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LGTM. Thanks @Guosmilesmile!
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Closes #17140
IcebergSink#addPreCommitTopologyuses a.global()shuffle to force all committables to subtask 0 of the downstream committer operator, so that commits only happen on a single subtask.Even though only subtask 0 will ever receive a
CommitRequest, every committer subtask still eagerly loads the Iceberg table and creates a worker thread pool in its constructor.This pr add code to avoid unnecessary TableLoader.loadTable() in IcebergCommitter subtasks > 0 .