Speed up analyze MCV tracking with hash table lookups#1
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Reminiscent wants to merge 1 commit intomasterfrom
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Speed up analyze MCV tracking with hash table lookups#1Reminiscent wants to merge 1 commit intomasterfrom
Reminiscent wants to merge 1 commit intomasterfrom
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compute_distinct_stats() tracks possible MCVs for datatypes that have an equality operator but no ordering. Finding a match currently requires a linear scan of the tracking array for every sampled row, which can become very expensive when statistics targets are set high. When the tracking array is large enough and the type's default hash support matches the equality operator, maintain a simplehash table that maps a tracked value to its current track[] slot. This reduces match lookups from O(n) to O(1) on average while keeping the existing linear path as a fallback. Add a regression test exercising the hashed path.
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Summary
Testing
Codex Task