[HIVE-13013] Further Improve concurrency in TxnHandler

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.0.0
• Fix Version/s: 1.3.0, 2.1.0
• Component/s: Metastore, Transactions
• Target Version/s: 1.3.0, 2.1.0
• Assignee: Eugene Koifman
• Reporter: Eugene Koifman
• Created: 05/Feb/16 18:03
• Updated: 01/Oct/19 22:07
• Resolved: 29/Feb/16 19:34

Description

There are still a few operations in TxnHandler that run at Serializable isolation.
Most or all of them can be dropped to READ_COMMITTED now that we have SELECT ... FOR UPDATE support. This will reduce number of deadlocks in the DBs.

Issue Links

• is blocked by: HIVE-11948 Investigate TxnHandler and CompactionTxnHandler to see where we improve concurrency
• is blocked by: HIVE-11388 Allow ACID Compactor components to run in multiple metastores