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ASF GitHub Bot logged work on HIVE-26875: ----------------------------------------- Author: ASF GitHub Bot Created on: 22/Dec/22 13:28 Start Date: 22/Dec/22 13:28 Worklog Time Spent: 10m Work Description: sonarcloud[bot] commented on PR #3887: URL: https://github.com/apache/hive/pull/3887#issuecomment-1362841406 Kudos, SonarCloud Quality Gate passed! 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If there is a conflicting > transaction, it invalidates the snapshot, rolls-back the transaction, opens a > new transaction and tries to re-acquire locks (and then recompile). It then > checks again if a conflicting transaction has committed and if so, redoes the > above steps again, up to HIVE_TXN_MAX_RETRYSNAPSHOT_COUNT times. > However - isValidTxnState relies on getNonSharedLockedTable(): > [https://github.com/apache/hive/blob/ab4c53de82d4aaa33706510441167f2df55df15e/ql/src/java/org/apache/hadoop/hive/ql/DriverTxnHandler.java#L422] > which does: > {code:java} > private Set<String> getNonSharedLockedTables() { > if (CollectionUtils.isEmpty(driver.getContext().getHiveLocks())) { > return Collections.emptySet(); // Nothing to check > }{code} > getHiveLocks gets populated by lockAndRespond... HOWEVER - > compileInternal ends up calling compile which ends up calling > preparForCompile which ends up calling prepareContext which ends up > destroying the context with the information lockAndRespond populated. So when > the loop executes after all of this, it will never detect a 2nd conflict > because isValidTxnState will always return true (because it thinks there are > no locked objects). > This manifests as duplicate records being created during concurrent UPDATEs > if a transaction get conflicted twice. -- This message was sent by Atlassian Jira (v8.20.10#820010)