Extract Delta Lake deletion vectors #627
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This change extracts deletion vectors represented as roaring bitmaps in delta lake files and converts them into the XTable intermediate representation. Previously, XTable only detected tables changes that included adding or removing of data files. Now the detected table change also includes any deletion vectors files added in the commit. Note that, in Delta Lake, the Deletion vectors are represented in a compressed binary format. However, once extracted by Xtable, the offset are currently extracted into a list of long offsets. This representation is not the most efficient for large datasets. Optimization is pending to prioritize end-to-end conversion completion.
the-other-tim-brown
requested changes
Jan 23, 2025
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| public static class Builder { | ||
| public Builder deleteRecordSupplier(Supplier<Iterator<Long>> recordsSupplier) { | ||
| this.deleteRecordSupplier = recordsSupplier; |
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Why is this required? It seems very similar to what the Builder annotation will provide
| dataFilePath = getFullPathToFile(snapshot, dataFilePath); | ||
| Path deletionVectorFilePath = deletionVector.absolutePath(snapshot.deltaLog().dataPath()); | ||
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| // TODO assumes deletion vector file. Need to handle inlined deletion vectors |
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Is there a way to detect that it is not a file? Can we throw some unsupported operation exception for now if we hit that path?
| // A commit can add deletion vectors when some records are deleted. New deletion vectors can be | ||
| // added even if no new data files are added. However, as deletion vectors are always associated | ||
| // with a data file, they are implicitly removed when a corresponding data file is removed. | ||
| List<InternalDeletionVector> deletionVectorsAdded; |
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When we read a snapshot, will there be deletionVectors present there as well?
| long countRecordsDeleted; | ||
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| @Getter(AccessLevel.NONE) | ||
| Supplier<Iterator<Long>> deleteRecordSupplier; |
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Can you add a doc for this as well? What does the long represent?
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Fixes: #345
This change extracts deletion vectors represented as roaring bitmaps in delta lake files and converts them into the XTable intermediate representation.
Previously, XTable only detected tables changes that included adding or removing of data files. Now the detected table change also includes any deletion vectors files added in the commit.
Note that, in Delta Lake, the Deletion vectors are represented in a compressed binary format. However, once extracted by Xtable, the offset are currently extracted into a list of long offsets. This representation is not the most efficient for large datasets. Optimization is pending to prioritize end-to-end conversion completion.