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keep fetch when merge FilterExec in FilterPushdown - #21070
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Thanks for you reviews @adriangb |
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## Which issue does this PR close? - Closes apache#21069 ## Rationale for this change - see apache#21069 ## What changes are included in this PR? When `FilterPushdown` merges/eliminates a `FilterExec`, it now correctly propagates the `fetch` limit that was on the FilterExec. Previously, if a `FilterExec` had a fetch (e.g., LIMIT 10) and all its predicates were fully pushed down to a under `FilterExec`, the FilterExec node was dropped — and the fetch was silently lost, potentially returning more rows than requested. The fix: - If the FilterExec being eliminated has a fetch, propagate it to the child node via `with_fetch()` - If both the outer and inner nodes have a fetch, use min(outer, inner) to preserve the tighter constraint ## Are these changes tested? yes, add some test cases, trying to reproduce use sql, current not able ## Are there any user-facing changes? <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. --> <!-- If there are any breaking changes to public APIs, please add the `api change` label. -->
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## Which issue does this PR close? - Closes apache#21069 ## Rationale for this change - see apache#21069 ## What changes are included in this PR? When `FilterPushdown` merges/eliminates a `FilterExec`, it now correctly propagates the `fetch` limit that was on the FilterExec. Previously, if a `FilterExec` had a fetch (e.g., LIMIT 10) and all its predicates were fully pushed down to a under `FilterExec`, the FilterExec node was dropped — and the fetch was silently lost, potentially returning more rows than requested. The fix: - If the FilterExec being eliminated has a fetch, propagate it to the child node via `with_fetch()` - If both the outer and inner nodes have a fetch, use min(outer, inner) to preserve the tighter constraint ## Are these changes tested? yes, add some test cases, trying to reproduce use sql, current not able ## Are there any user-facing changes? <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. --> <!-- If there are any breaking changes to public APIs, please add the `api change` label. -->
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Which issue does this PR close?
Rationale for this change
What changes are included in this PR?
When
FilterPushdownmerges/eliminates aFilterExec, it now correctly propagates thefetchlimit that was on the FilterExec.Previously, if a
FilterExechad a fetch (e.g., LIMIT 10) and all its predicates were fully pushed down to a underFilterExec, the FilterExec node was dropped — and the fetch was silently lost, potentially returning more rows than requested.The fix:
with_fetch(), if the clid node do not supportwith_fetchadd a local limit node.Are these changes tested?
yes, add some test cases, trying to reproduce use sql, current not able
Are there any user-facing changes?