Propagate consider_startup flag to compressed chunk table - #9738
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It seems at the moment it's just not set, which might lead to suboptimal plan choice. We also have an heuristic to trigger it for queries that might need SkipScan, so move this to happen earlier.
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@Poroma-Banerjee, @dbeck: please review this pull request.
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| * First, check if this query is candidate for SELECT DISTINCT SkipScan. | ||
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| const bool potential_select_distinct = list_length(root->distinct_pathkeys) == 1; |
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I meant to fix this at some time and now it's a good time. We now allow multicolumn SkipScan for DISTINCT for nonnullable distinct outputs. Let's change the above to:
const bool potential_select_distinct = list_length(root->distinct_pathkeys) >= 1;
For DISTINCT aggregates below we still allow only one distinct aggregate for SkipScan so below code is correct.
natalya-aksman
approved these changes
May 8, 2026
Poroma-Banerjee
approved these changes
May 8, 2026
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It seems at the moment it's just not set, which might lead to suboptimal plan choice.
We also have an heuristic to trigger it for queries that might need SkipScan, so move this to happen earlier. Also update it to work for multicolumn DISTINCT.
The flag propagation itself doesn't influence anything at the moment, because the Index paths are still kept based on pathkeys. But logically it's more correct.
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