fix: Add limit to stream partitions query to avoid loading old cell v…

[jackdingilian]

Add a cell version limit of 1 when loading stream partitions. This prevents loading unnecessary old watermark and token data that can substantially increase the query size despite being ignored.

This is already covered pretty well by testReadingExistingStreamPartitions but I added a test to ensure we only load 1 version per cell

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Summary of Changes

Hello @jackdingilian, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces an optimization to how stream partitions are loaded from the Bigtable metadata table. By limiting the query to retrieve only the latest cell version for watermarks and tokens, it aims to reduce the amount of data transferred and processed, thereby improving the efficiency of the change streams connector.

Highlights

• Query Optimization: A cell version limit of 1 has been added to the query for loading stream partitions. This prevents loading old, unnecessary watermark and token data, which can significantly increase query size.
• Code Refactoring: The logic for reading stream partition rows has been extracted into a new @VisibleForTesting method, readAllStreamPartitionRows(), which applies the cellsPerColumn(1) filter.
• New Test Case: A new test, readAllStreamPartitionRowsOnlyReadsLatestVersion, has been added to MetadataTableDaoTest to explicitly verify that only the latest version of watermarks and tokens is loaded for stream partitions.

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[jackdingilian]

@tonytanger for bigtable review

[tonytanger]

LGTM from bigtable.

[github-actions]

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R: @chamikaramj for label java.
R: @igorbernstein2 for label bigtable.

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