[HIVE-11948] Investigate TxnHandler and CompactionTxnHandler to see where we improve concurrency

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.14.0
• Fix Version/s: 1.3.0
• Component/s: Transactions
• Assignee: Eugene Koifman
• Reporter: Eugene Koifman
• Created: 24/Sep/15 18:38
• Updated: 01/Oct/19 22:07
• Resolved: 18/Nov/15 01:28

Description

at least some operations (or parts of operations) can run at READ_COMMITTED.
CompactionTxnHandler.setRunAs()

CompactionTxnHandler.findNextToCompact()
if update stmt includes cq_state = '" + INITIATED_STATE + "'" in WHERE clause and logic to look for "next" candidate

CompactionTxnHandler.markCompacted()
perhaps add cq_state=WORKING_STATE in Where clause (mostly as an extra consistency check)

Issue Links

• blocks: HIVE-12389 CompactionTxnHandler.cleanEmptyAbortedTxns() should safeguard against huge IN clauses
• blocks: HIVE-13013 Further Improve concurrency in TxnHandler
• relates to: HIVE-12352 CompactionTxnHandler.markCleaned() may delete too much
• relates to: HIVE-12585 fix TxnHandler connection leak
• relates to: HIVE-12439 CompactionTxnHandler.markCleaned() and TxnHandler.openTxns() misc improvements
• links to: RB