HIVE-30044: LLAP delete delta tail is read from the filesystem even on a cache hit - #6778
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deniskuzZ wants to merge 1 commit into
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HIVE-30044: LLAP delete delta tail is read from the filesystem even on a cache hit#6778deniskuzZ wants to merge 1 commit into
deniskuzZ wants to merge 1 commit into
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…n a cache hit getOrcReaderData asks the LLAP metadata cache for the delete delta's OrcTail and builds a reader from it, then falls through and re-reads both from the filesystem, discarding what the cache returned. HIVE-23553 dropped the early return when it adapted the method to ORC 1.6.7, so since then hive.llap.io.cache.deletedeltas=metadata has had no effect and the 'all' level re-reads every delete delta footer once per split. Restore the early return, and cover it: the test serves a known OrcTail from a mocked LLAP IO and asserts the reader is handed that instance. Without the return it gets a freshly read one.
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🟡 Changes recommended
Close the returned ReaderData in the test to prevent resource leaks.
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Pull request overview
Restores LLAP cached delete-delta tail reuse and adds regression coverage.
Changes:
- Restores the cache-hit early return.
- Adds a cached-tail reuse test.
File summaries
| File | Summary |
|---|---|
ql/src/test/org/apache/hadoop/hive/ql/io/orc/TestVectorizedOrcAcidRowBatchReaderTailCache.java |
Adds cache-hit coverage; ReaderData should be closed with try-with-resources. |
ql/src/java/org/apache/hadoop/hive/ql/io/orc/VectorizedOrcAcidRowBatchReader.java |
Reuses cached metadata without rereading the filesystem. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 1
- Review effort level: Lite
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| ReaderData readerData = VectorizedOrcAcidRowBatchReader.getOrcReaderData(path, conf, null, null); | ||
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| assertSame("the cached tail must not be replaced by a filesystem read", cachedTail, readerData.orcTail); | ||
| assertNotNull(readerData.reader); |
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What changes were proposed in this pull request?
getOrcReaderData asks the LLAP metadata cache for the delete delta's OrcTail and builds a reader from it, then falls through and re-reads both from the filesystem, discarding what the cache returned.
HIVE-23553 dropped the early return when it adapted the method to ORC 1.6.7, so since then hive.llap.io.cache.deletedeltas=metadata has had no effect and the 'all' level re-reads every delete delta footer once per split.
Restore the early return
Why are the changes needed?
LLAP delete delta tail is read from the filesystem even on a cache hit
Does this PR introduce any user-facing change?
No
How was this patch tested?
mvn -o -pl ql -Dtest=TestVectorizedOrcAcidRowBatchReaderTailCache test