[SPARK-57839][SQL] Support the nanosecond-precision timestamp types in CBO statistics estimation#56941
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[SPARK-57839][SQL] Support the nanosecond-precision timestamp types in CBO statistics estimation#56941yadavay-amzn wants to merge 1 commit into
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…n CBO statistics estimation
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What changes were proposed in this pull request?
Adds cost-based optimizer (CBO) statistics estimation support for the nanosecond-precision timestamp types (
TimestampNTZNanosType,TimestampLTZNanosType), mirroring the existing microsecondTimestampTypehandling at every CBO site:EstimationUtils.toDouble/fromDouble,FilterEstimation.evaluateBinary/evaluateInSet,UnionEstimation.isTypeSupported, andCatalogColumnStatmin/max (de)serialization. Values are converted on the nanosecond scale (epochMicros * 1000 + nanosWithinMicro). Column-stat min/max are serialized with a fraction-preserving 9-digit nanosecond formatter so they round-trip losslessly.Why are the changes needed?
Filters/joins/unions over nanosecond-precision timestamp columns previously fell back to default selectivity because these types were not among the types CBO estimates. They have a natural numeric ordering, so they can be estimated the same way as microsecond timestamps.
Does this PR introduce any user-facing change?
No. Affects CBO estimation / plan costing only; query results are unchanged.
How was this patch tested?
New
FilterEstimationSuitetests (range /=/INselectivity) for the nanosecond types, nanosecond columns added to the Union/Join estimation tests, and a dedicated lossless min/max round-trip test inStatisticsCollectionSuite(a sub-microsecond value survivestoExternalString->fromExternalString). All CBO estimation suites pass.Was this patch authored or co-authored using generative AI tooling?
Authored with assistance by Claude Opus 4.8.