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feat: support table sample #16505

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feat: support table sample #16505

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chenkovsky
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@chenkovsky chenkovsky commented Jun 23, 2025 •
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Which issue does this PR close?

Close #16533

Rationale for this change

Currently table sample is not supported.

What changes are included in this PR?

support table sample.
it's row level.
three sample methods are supported.

  1. fixed row counts
  2. bernoulli sample
  3. poisson sample

Are these changes tested?

UT

Are there any user-facing changes?

Yes, If the user uses the match statement for logical plan, the user needs to add sample into match statement.

@github-actions github-actions bot added sql SQL Planner logical-expr Logical plan and expressions optimizer Optimizer rules core Core DataFusion crate sqllogictest SQL Logic Tests (.slt) substrait Changes to the substrait crate proto Related to proto crate physical-plan Changes to the physical-plan crate labels Jun 23, 2025
@chenkovsky chenkovsky changed the title Feat/sample feat: support table sample Jun 23, 2025
@xudong963
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It would be better to add more details about the PR, such as:
sample levels: block level or row level
sample ways: fixed row counts or percent?

@chenkovsky
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It would be better to add more details about the PR, such as: sample levels: block level or row level sample ways: fixed row counts or percent?
@xudong963 updated

@2010YOUY01
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I suggest to first open an issue to describe full syntax and semantics of this table sample feature, and also include the reference system (like postgres). After we have reached some agreement, then we can start implementing.

There is another implementation that seems to have several syntax difference than this PR #16325 @theirix

We had a previous discussion that DF can include features for postgres syntax. However if it's referencing other systems, then it might need more discussion and wider approval.

@chenkovsky
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I suggest to first open an issue to describe full syntax and semantics of this table sample feature, and also include the reference system (like postgres). After we have reached some agreement, then we can start implementing.

There is another implementation that seems to have several syntax difference than this PR #16325 @theirix

We had a previous discussion that DF can include features for postgres syntax. However if it's referencing other systems, then it might need more discussion and wider approval.

Updated, and this PR implements Spark style sample.

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core Core DataFusion crate logical-expr Logical plan and expressions optimizer Optimizer rules physical-plan Changes to the physical-plan crate proto Related to proto crate sql SQL Planner sqllogictest SQL Logic Tests (.slt) substrait Changes to the substrait crate
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Feature: Support Sample
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@chenkovsky @xudong963 @2010YOUY01