fix: VectorHasher timestamp precision handling in value-id paths - #18598
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rui-mo wants to merge 1 commit into
Open
fix: VectorHasher timestamp precision handling in value-id paths#18598rui-mo wants to merge 1 commit into
rui-mo wants to merge 1 commit into
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Yuhta
reviewed
Aug 21, 2026
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| inline int64_t toInt64(Timestamp timestamp) const { |
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Remove this seems no longer used
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@rui-mo thanks for following up on this. Question on this: since now you added support for wide 128 bit integers, could we use that for timestamps - I suppose we could fit the two 64 integers from the timestamp side by side, and not lose any precision? |
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Problem
VectorHasher maps timestamps to value ids using millisecond precision. The
direct
valueId(Timestamp)andlookupValueId(Timestamp)paths already rejecttimestamps that cannot be represented losslessly in milliseconds, but the range
fast path and row-wise analyze path could call
toInt64(Timestamp), whichuses
timestamp.toMillis()directly. This could silently map distinct sub-millisecond timestamps to the same millisecond value id while still reporting that
value-id mapping was usable.
Changes
This PR fixes the issue by:
millisecond values.
millisecond check.
VectorHasher::empty()so a hasher that has overflowed distinctvalue tracking is not treated as empty during merge. This is required for
timestamp precision overflow.
Issue related: #18597.