feat(compaction): avoid count_deltas() call if nothing changed
#6868
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…ove backwards This PR enforces aspects of `Timeline::repartition` that were already true at runtime: - it's not called concurrently, so, bail out if it is anyway (see comment why it's not called concurrently) - the `lsn` should never be moving backwards over the lifetime of a Timeline object, because last_record_lsn() can only move forwards over the lifetime of a Timeline object part of #6861
…bail-on-concurrent-call
…bail-on-concurrent-call
…bail-on-concurrent-call
…lame/avoid-count-deltas-if-no-changes
2466 tests run: 2267 passed, 78 failed, 121 skipped (full report)Failures on Postgres 16
Failures on Postgres 15
Failures on Postgres 14
Test coverage report is not availableThe comment gets automatically updated with the latest test results
98d0bca at 2024-02-21T19:33:39.656Z :recycle: |
Base automatically changed from
problame/repartition-bail-on-concurrent-call
to
main
February 26, 2024 10:22
5 tasks
|
superseded by #7230 |
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Changes
repartition()rebuildscreate_image_layersThe skipping logic is simple: if we've seen the same repartioning & layermap version before, bail early.
The underlying invariant is that only these two inputs determine whether we would produce any new image layers.
Effectively, this is a cache invalidation problem.
These are notoriously hard to get right, and even harder to maintain.
Counter-measures that we could implement in a later PR:
part of #6861