fix(scan): preserve snapshot id for empty data evolution index plans - #258
fix(scan): preserve snapshot id for empty data evolution index plans#258wangyong9999 wants to merge 1 commit into
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| std::optional<int64_t> snapshot_id = core_options_.GetScanSnapshotId(); | ||
| if (snapshot_id) { | ||
| return snapshot_id; | ||
| } |
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Please validate the snapshot before returning the empty plan. With a pre-supplied empty GlobalIndexResult, a nonexistent scan.snapshot-id (for example, 999) is currently copied directly into a successful plan. Please resolve/load the snapshot here and add a regression test for nonexistent or expired snapshot IDs.
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This behavior seems to predate the PR: the global-index scan already appears to ignore tag- and timestamp-based time travel and fall back to the latest snapshot. What changes here is that the new resolver makes this more visible by attaching that latest snapshot ID to an empty plan. Since global-index time travel does not seem to be supported at the moment, would it make sense to reject these modes explicitly instead of silently scanning and reporting the latest snapshot?
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Purpose
Linked issue: none.
A global-index miss on a non-empty DataEvolution table currently returns
PlanImpl::EmptyPlan(). The query result is correctly empty, but the plan loses the snapshot used by the index scan; a null snapshot is otherwise reserved for a table with no snapshot.This change resolves the explicit or latest snapshot once before creating
GlobalIndexScan, passes that same ID to the scan, and returns a zero-split plan carrying the resolved ID on a miss. The fast-miss path still does not invoke the data batch scan or read data manifests. A truly empty table continues to return an empty plan with no snapshot.For a pre-supplied empty
GlobalIndexResult, the existingScanContextremains the snapshot source: an explicit scan snapshot is preserved, otherwise the current latest snapshot is resolved when the plan is created.Tests
GlobalIndexTest.TestDataEvolutionBatchScanandGlobalIndexTest.TestDataEvolutionGlobalIndexMissPreservesResolvedSnapshot: 8/8 parameterized cases passed.DataEvolutionBatchScanTest.*andTableScanTest.TestNoSnapshot: 4/4 cases passed.git diff --checkpassed.The new test covers internally evaluated and pre-supplied empty index results with both latest and explicit snapshots.
TableScanTest.TestNoSnapshotkeeps the empty-table boundary covered.API and Format
No public API, ABI, storage-format, or protocol change. The modified scan helpers are private implementation details and no class data member is added.
Documentation
No new feature or user-facing configuration; no documentation change is required.
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