Skip dimension slices when we have empty dimension restriction - #9728
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During hypertable expansion, we process the qualifiers to derive the range for a dimension variable that encloses all matching rows. This range is used to find the chunks that could possibly contain these rows. When the qualifiers are contradictory, an invalid range can arise, with upper bound below lower bound. At the moment such a range can still match some dimension slices, because the dimension slice ends are checked against this range separately. The chunk will then be excluded by the Postgres chunk exclusion that handles contradictory clauses. Add a simple check to not match such contradictory search ranges, to save some work.
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akuzm
marked this pull request as ready for review
May 6, 2026 12:22
akuzm
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@dbeck, @melihmutlu: please review this pull request.
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dbeck
approved these changes
May 6, 2026
natalya-aksman
approved these changes
May 6, 2026
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During hypertable expansion, we process the qualifiers to derive the range for a dimension variable that encloses all matching rows. This range is used to find the chunks that could possibly contain these rows. When the qualifiers are contradictory, an invalid range can arise, with upper bound below lower bound. At the moment such a range can still match some dimension slices, because the dimension slice ends are checked against this range separately. The chunk will then be excluded by the Postgres constraint exclusion that handles contradictory clauses.
Add a simple check to not match such contradictory search ranges, to save some work. In the long run, this moves the hypertable expansion closer to feature parity with Postgres constraint exclusion, which is costly and maybe could be avoided eventually.
This is not visible in any tests, because the Postgres constrain exclusion compensates for whatever our hypertable expansion might miss.
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