No parallelism for children of ordered distinct #1864
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zachmu
approved these changes
Jul 5, 2023
| if !isParallelizable(c.Node) { | ||
| foundOrderedDistinct := false | ||
| newNode, same, err := transform.NodeWithCtx(node, nil, func(c transform.Context) (sql.Node, transform.TreeIdentity, error) { | ||
| if _, ok := c.Node.(*plan.OrderedDistinct); ok { |
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Can't this go in isParallelizable?
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That's what i tried first, but we check bottom-up. Nested children are still parallelized there.
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We permitted parallelism into an OrderedDistinct node, which is a specialized Distinct node that expects results sorted on a specific index key. This change prevents parallelizing children of OrderedDistinct.