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https://issues.apache.org/jira/browse/ARROW-10368?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Remi Dettai updated ARROW-10368:
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Description:
The first intention was to refactor InMemoryScan to use an iterator.
{quote}Currently, InMemoryScan takes a Vec<Vec<RecordBatch>> as data.
- the outer Vec separates the partitions
- the inner Vec contains all the RecordBatch for one partition
The inner Vec is then converted into an iterator when the LogicalPlan is turned
into a PhysicalPlan.
I suggest that InMemoryScan should take Vec<Iter<RecordBatch>>. This would
make it possible to plug custom Scan implementations into datafusion without
the need to read them entirely into memory. It would still work pretty
seamlessly with Vec<Vec<RecordBatch>> that would just need a to be converted
with data.map(|x| x.iter()) first.{quote}
After further inspection (see discussion below), it seems more appropriate to
completely refactor the way scan operation works. The idea is to replace all
specific XxxScan nodes with a generic SourceScan node:
was:
Currently, InMemoryScan takes a Vec<Vec<RecordBatch>> as data.
- the outer Vec separates the partitions
- the inner Vec contains all the RecordBatch for one partition
The inner Vec is then converted into an iterator when the LogicalPlan is turned
into a PhysicalPlan.
I suggest that InMemoryScan should take Vec<Iter<RecordBatch>>. This would
make it possible to plug custom Scan implementations into datafusion without
the need to read them entirely into memory. It would still work pretty
seamlessly with Vec<Vec<RecordBatch>> that would just need a to be converted
with data.map(|x| x.iter()) first.
> [Rust][DataFusion] Refactor scan nodes to allow extensions
> ----------------------------------------------------------
>
> Key: ARROW-10368
> URL: https://issues.apache.org/jira/browse/ARROW-10368
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Rust, Rust - DataFusion
> Reporter: Remi Dettai
> Priority: Major
>
> The first intention was to refactor InMemoryScan to use an iterator.
> {quote}Currently, InMemoryScan takes a Vec<Vec<RecordBatch>> as data.
> - the outer Vec separates the partitions
> - the inner Vec contains all the RecordBatch for one partition
> The inner Vec is then converted into an iterator when the LogicalPlan is
> turned into a PhysicalPlan.
> I suggest that InMemoryScan should take Vec<Iter<RecordBatch>>. This would
> make it possible to plug custom Scan implementations into datafusion without
> the need to read them entirely into memory. It would still work pretty
> seamlessly with Vec<Vec<RecordBatch>> that would just need a to be converted
> with data.map(|x| x.iter()) first.{quote}
> After further inspection (see discussion below), it seems more appropriate to
> completely refactor the way scan operation works. The idea is to replace all
> specific XxxScan nodes with a generic SourceScan node:
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