Add example of using PruningPredicate to datafusion-examples
#9183
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| // File 2: `x = 5 AND y = 10` can never evaluate to true because y | ||
| // has only the value of 7. Thus this file can be skipped. | ||
| false, | ||
| // File 3: `x = 5 AND y = 10` can never evaluate to true because x |
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FYI @appletreeisyellow here is an actual example showing that the pruning predicate does the right thing with unknown column values
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File 3 example makes sense to me 👍
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I'm curious what the result will be for a file 4 like:
File 4: x has values between 4 and 6
nothing is known about the value of y
Same the predicate x = 5 AND y = 10, my understanding is that it will evaluate to true.
x = 5 AND y = 10
--> true AND null
--> null
Since y is unknown, so there is a possibility that y is 10 in this file / partition / row group of data. Thus this file can not be skipped and the result is true
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Same the predicate x = 5 AND y = 10, my understanding is that it will evaluate to true.
Yes, this is my understanding too (that the PruningPredicate will return true for this container)
Since y is unknown, so there is a possibility that y is 10 in this file / partition / row group of data. Thus this file can not be skipped and the result is true
Yes, that is my understanding as well
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Thank you for adding examples @alamb. Super helpful! I left a question for a new example and a suggestion
| // File 2: `x = 5 AND y = 10` can never evaluate to true because y | ||
| // has only the value of 7. Thus this file can be skipped. | ||
| false, | ||
| // File 3: `x = 5 AND y = 10` can never evaluate to true because x |
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File 3 example makes sense to me 👍
| // Note, returning null means the value isn't known, NOT | ||
| // that we know the entire column is null. | ||
| (None, None), |
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That probably looks familiar :)
| // File 2: `x = 5 AND y = 10` can never evaluate to true because y | ||
| // has only the value of 7. Thus this file can be skipped. | ||
| false, | ||
| // File 3: `x = 5 AND y = 10` can never evaluate to true because x |
There was a problem hiding this comment.
I'm curious what the result will be for a file 4 like:
File 4: x has values between 4 and 6
nothing is known about the value of y
Same the predicate x = 5 AND y = 10, my understanding is that it will evaluate to true.
x = 5 AND y = 10
--> true AND null
--> null
Since y is unknown, so there is a possibility that y is 10 in this file / partition / row group of data. Thus this file can not be skipped and the result is true
Co-authored-by: Chunchun Ye <14298407+appletreeisyellow@users.noreply.github.com>
Which issue does this PR close?
Part of #7013
Related to #7869 and #9171
Rationale for this change
What changes are included in this PR?
pruning.rsexample to datafusion-examples with an annotated guide to using `PruningPredicatePruningPredicateAPI docsAre these changes tested?
Yes, as part of CI
Are there any user-facing changes?
A new example, no code changes