khakhlyuk opened a new pull request, #52973:
URL: https://github.com/apache/spark/pull/52973

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   ### What changes were proposed in this pull request?
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   This PR adds several fixes and improvements over 
https://github.com/apache/spark/pull/52613 which added support for 2GB+ local 
relations in Spark Connect.
   
   #### Uploading batches of chunks
   Currently, before caching the local relation on the server via 
`ChunkedCachedLocalRelation`, the client materializes all chunks in memory (1 
schema chunk and N data chunks). This can lead to high memory pressure on the 
client when uploading very large local relations.
   
   In this PR, I'm changing how the client uploads the local relation. Instead 
of materializing all chunks in memory, the client will materialize a batch of 
chunks in memory, upload the batch of chunks to the server, and proceed to 
collecting the next batch of chunks. The size of the batch of chunks is 
controlled via `spark.sql.session.localRelationBatchOfChunksSizeBytes` (1GB by 
default). This way, the uploading mechanism only consumes 1GB of memory at each 
point in time. Alternatives to this approach are:
   a) uploading each chunk separately - would require one pair of 
`ArtifactStatuses` and `AddArtifactsRequest` RPC calls for each chunk, which is 
inefficient.
   b) (current implementation) materializing all chunks in memory and uploading 
them via a single pair of `ArtifactStatuses` and `AddArtifactsRequest` RPC 
calls. This can lead to high memory pressure on the client.
   Uploading batches of chunks is a middle-ground solution.
   
   Changes are implemented both for the python and scala clients.
   
   
   #### Minor fixes and improvements
   - Replace `ArraySeq.unsafeWrapArray(data.map(_.copy()).toArray))` with 
`data.map(_.copy()).toArray.toImmutableArraySeq` in 
`SparkConnectPlanner.scala`. The latter is compatible with both scala 2.13 and 
scala 2.12 and is consistent with how arrays are converted to sequences in 
other places in the code base.
   - Improved asserts and tests in the python client.
   
   
   ### Why are the changes needed?
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   Reduce memory pressure in the spark connect python and scala clients when 
uploading very large local relations to the server.
   
   
   ### Does this PR introduce _any_ user-facing change?
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   Note that it means *any* user-facing change including all aspects such as 
new features, bug fixes, or other behavior changes. Documentation-only updates 
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   No
   
   
   ### How was this patch tested?
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   Existing tests.
   
   
   ### Was this patch authored or co-authored using generative AI tooling?
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   No
   


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