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[Kernel] Remove SnapshotHint; Fix CRCInfo caching bug in LogReplay; Simplify LogReplay - #5276
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scottsand-db merged 2 commits intoSep 30, 2025
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Sep 30, 2025
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| /** Returns the CRC info persisted in the logSegment's lastSeenChecksum File */ | ||
| public Optional<CRCInfo> getLastSeenCrcInfo() { | ||
| if (!cachedLastSeenCrcInfo.isPresent()) { |
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Bug! What if there is no CRC at version N? Then we will check the cache -- see that this is EMPTY -- and then try and load it! And then what happens if someone invokes this method again? Well, we will repeat the same load attempt!
This really just needed to be an Optional<Optional<CRCInfo>> or a Lazy<Optional<CRC<Info>>
scottsand-db
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September 30, 2025 20:21
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huan233usc
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Sep 30, 2025
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Apr 24, 2026
…implify LogReplay (delta-io#5276) ## 🥞 Stacked PR Use this [link](https://github.com/delta-io/delta/pull/5276/files) to review incremental changes. - [**stack/kernel_remove_snapshot_hint**](delta-io#5276) [[Files changed](https://github.com/delta-io/delta/pull/5276/files)] --------- #### Which Delta project/connector is this regarding? - [ ] Spark - [ ] Standalone - [ ] Flink - [X] Kernel - [ ] Other (fill in here) ## Description This PR removes SnapshotHint. This was a legacy optimization -- in the future, we don't plan to have a persisted `Table` that holds on to cached information like previous snapshots. That should be done by the connector. While cleaning up SnapshotHint, I realized that we could significatintly simplify our CRCInfo logic and caching in LogReplay. I also noticed a bug where we were treating `Optional<CRCInfo>` as both (a) we have never checked to load the crcInfo at this version, and (b) there is no CRC info at this version. I've fixed that here by just using a `Lazy<Optional<CRCInfo>>` ## How was this patch tested? Just a refactor. Existing UTs. ## Does this PR introduce _any_ user-facing changes? No.
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🥞 Stacked PR
Use this link to review incremental changes.
Which Delta project/connector is this regarding?
Description
This PR removes SnapshotHint. This was a legacy optimization -- in the future, we don't plan to have a persisted
Tablethat holds on to cached information like previous snapshots. That should be done by the connector.While cleaning up SnapshotHint, I realized that we could significatintly simplify our CRCInfo logic and caching in LogReplay. I also noticed a bug where we were treating
Optional<CRCInfo>as both (a) we have never checked to load the crcInfo at this version, and (b) there is no CRC info at this version. I've fixed that here by just using aLazy<Optional<CRCInfo>>How was this patch tested?
Just a refactor. Existing UTs.
Does this PR introduce any user-facing changes?
No.