apache / apache/arrow-java

[Java/Python] in-process vector sharing from Java to Python

Aperta
#420 3 commenti 0 reazioni 0 assegnatari Vedi su GitHub
Type: enhancement
Lingua principale
Java
Stelle
94
Fork
152
Merge medio
3g 16h
PR unite (30g)
11

Descrizione

Currently we seem to use in all applications of Arrow the IPC capabilities to move data between a Java process and a Python process. While this is 0-serialization, it is not zero-copy. By taking the address and offset, we can already create Python buffers from Java buffers: https://github.com/apache/arrow/pull/1693. This is still a very low-level interface and we should provide the user with:

- A guide on how to load Apache Arrow java libraries in Python (either through a fat-jar that was shipped with Arrow or how he should integrate it into its Java packaging)
- `pyarrow.Array.from_jvm`, `pyarrow.RecordBatch.from_jvm`, … functions that take the respective Java objects and emit Python objects. These Python objects should also ensure that the underlying memory regions are kept alive as long as the Python objects exist.

This issue can also be used as a tracker for the various sub-tasks that will need to be done to complete this rather large milestone.

**Reporter**: [Uwe Korn](https://issues.apache.org/jira/browse/ARROW-2249) / @xhochy
#### Related issues:
- [[Python] Create buffer from address, size and base](https://github.com/apache/arrow/issues/18211) (is blocked by)
- [[Java/Python] Add unit test for pyarrow.timeX types in Array.from_jvm](https://github.com/apache/arrow/issues/44875) (is a parent of)
- [[Java/Python]  Add unit test for pyarrow.decimal128 in Array.from_jvm](https://github.com/apache/arrow/issues/44874) (is a parent of)
- [[Java/Python] Support VarCharVector / StringArray in pyarrow.Array.from_jvm](https://github.com/apache/arrow/issues/44873) (is a parent of)
- [[Java/Python] Complex type conversion in pyarrow.Field.from_jvm](https://github.com/apache/arrow/issues/19009) (is a parent of)
- [[Java/Python] Add support for dictionary type to pyarrow.Field.from_jvm](https://github.com/apache/arrow/issues/15719) (is a parent of)
- [[Java/Python] Add pyarrow.{Array,Field}.from_jvm / jvm_buffer](https://github.com/apache/arrow/issues/19008) (is a parent of)
- [[Java] Add method overload for VarCharVector.set(int,String)](https://github.com/apache/arrow/issues/19004) (is related to)
- [[Java] Java implementation of Arrow C data interface](https://github.com/apache/arrow/issues/28685) (is related to)

**Note**: *This issue was originally created as [ARROW-2249](https://issues.apache.org/jira/browse/ARROW-2249). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*

Guida per i contributori

Apri la guida per i contributori

Direzione di ricerca

Iniziare con gli entry point proposti pyarrow.Array.from_jvm e pyarrow.RecordBatch.from_jvm, quindi esaminare l’issue correlata al supporto per pyarrow.Array, Field e jvm_buffer. Consultare la documentazione sulla migrazione e l’issue del buffer bloccato prima di scegliere una sottoattività. Il completamento richiede un percorso di conversione definito da Java a Python con gestione zero-copy della durata di vita della memoria.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
java, python
Ambito
data, distributed-systems
Tipo di issue
Funzionalità
Difficoltà
5/5
Tempo stimato
Più di una settimana
Stato di attività
Ferma
Chiarezza
Da chiarire
Idoneità per principianti
25/100

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