[MongoDB Storage] Checksum calculation improvements #346
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🦋 Changeset detectedLatest commit: 5833e17 The changes in this PR will be included in the next version bump. This PR includes changesets to release 11 packages
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simolus3
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modules/module-mongodb-storage/src/storage/implementation/MongoChecksums.ts
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…c-service into checksum-stability
simolus3
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Sep 1, 2025
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Follow-up to #343. That PR implemented a "fallback" query when the checksum query timed out, which would then query each bucket individually, and limit the number of operations we aggregate on for each bucket. That approach is less likely to time out, but slower when there are many buckets.
This now merges the two approaches: We always limit the number of operations we're aggregating on, but still do the query across multiple buckets at a time. This reduces the worst-case runtime, since we don't have to wait for the first query to timeout, and can handle multiple buckets efficiently.
This fixes a specific bug in the old approach (regression in 1.15.1): The fallback query did not handle the case correctly where we already have a partial checksum for a bucket, which could result in an incorrect checksum being returned and cached. It should have been rare since it would only happen when both:
Since the query is much less likely to time out when we have partial checksums available, it should not be common.
This also adds a couple additional tests (which would have failed with the bug above), and splits some of the larger test files into smaller ones.