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Add replaceWhere functionality #1957

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MrPowers opened this issue Dec 11, 2023 · 10 comments
Closed

Add replaceWhere functionality #1957

MrPowers opened this issue Dec 11, 2023 · 10 comments
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enhancement New feature or request

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@MrPowers
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Description

PySpark has a cool replaceWhere function that lets you override existing data in a Delta table that matches a predicate with new data. Here's an example of the replaceWhere functionality:

df2 = spark.createDataFrame(
    [
        ("x", 7),
        ("y", 8),
        ("z", 9),
    ]
).toDF("letter", "number")

(
    df2.write.format("delta")
    .option("replaceWhere", "number >= 2")
    .mode("overwrite")
    .save("tmp/my_data")
)

What do folks think about adding replaceWhere functionality to Python deltalake.

It's possible that the Rust predicate argument in write_deltalake already exposes this functionality.

@MrPowers MrPowers added the enhancement New feature or request label Dec 11, 2023
@ion-elgreco
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I exposed the predicate parameter for the rust engine writer but it's currently not doing anything because the functionality in Rust is not built yet

@r3stl355
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take

@r3stl355
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I'll give this a try

@r3stl355
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WriteBuilder uses predicate: Option<String> but has no implementation for it yet whereas DeleteBuilder uses predicate: Option<Expression>. I suggest harmonising by changing WriteBuilder to use predicate: Option<Expression>. Though this is a breaking change, predicate handling is not implemented in WriteBuilder so changing the type should not cause issues

@roeap
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roeap commented Dec 23, 2023

It would be great to do this usig logical expressions rather then the physical ones - much like @Blajda recently updated for merge. The good thing there is we get some type coercion for free, which has been a hassle with expressions.

In python we will likely have to accept strings and do the parsing..

@ion-elgreco
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@roeap I think we can start allowing arrow expressions as input, which we can serialize as substrait and then deserialize with Datafusion-substrait

@roeap
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roeap commented Dec 23, 2023

This would be a great goal, but I would say lets be consistent in that and make a deliberate API choice.

I.e not have substrait supported in one method but not the other...

Good news is substrait plans are of course logical plans :)

@r3stl355
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I'll try that @roeap. As for

It would be great to do this usig logical expressions rather then the physical ones - much like @Blajda recently updated for merge.

is this the David's PR you are referring to? #1969

@ion-elgreco
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@roeap we should be able to add this to merge, update, delete and write and then just add the conversion inside the pyo3 binding, so it's a Python only feature.

@roeap
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roeap commented Dec 23, 2023

@r3stl355 its #1720 had been up for a while before it got merged.

@ion-elgreco - sure to get started, and as you said right now this could just be internal. Substrait is a nice feature for rust as well, of course as alternative path since we are lookig to integrate into datafusions internal planning.

ion-elgreco added a commit that referenced this issue Jan 31, 2024
# Description
First/naive implementation of `replaceWhere` for `write`. Code compiles
and there is a test to verify the outcome. I would appreciate any
feedback on improving the structure/implementation. For example, I
copied the part of code from `delete` operation because there is no way
to call that code in `delete` directly from `write` - should I look into
extracting that code from `delete` to somewhere central?

Seems to also works with partitions columns.

# Related Issue(s)
#1957

# Documentation
Added a section in docs

---------

Signed-off-by: Nikolay Ulmasov <[email protected]>
Co-authored-by: Ion Koutsouris <[email protected]>
RobinLin666 pushed a commit to RobinLin666/delta-rs that referenced this issue Feb 2, 2024
# Description
First/naive implementation of `replaceWhere` for `write`. Code compiles
and there is a test to verify the outcome. I would appreciate any
feedback on improving the structure/implementation. For example, I
copied the part of code from `delete` operation because there is no way
to call that code in `delete` directly from `write` - should I look into
extracting that code from `delete` to somewhere central?

Seems to also works with partitions columns.

# Related Issue(s)
delta-io#1957

# Documentation
Added a section in docs

---------

Signed-off-by: Nikolay Ulmasov <[email protected]>
Co-authored-by: Ion Koutsouris <[email protected]>
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