[HIVE-25483] TxnHandler::acquireLock should close the DB conn to avoid connection leaks

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: KIRTI RUGE
• Reporter: Rajesh Balamohan
• Created: 26/Aug/21 09:54
• Updated: 10/Nov/22 06:58
• Resolved: 10/Nov/22 06:58

Description

TxnHandler::acquireLock should close DB connection on exiting the function.

https://github.com/apache/hive/blob/master/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java#L5688

https://github.com/apache/hive/blob/master/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java#L5726

https://github.com/apache/hive/blob/master/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java#L5737-L5740

 If there are any exceptions downstream, this connection isn't closed cleanly. In a corner case, hikari connection leak detector reported the following

2021-08-26 09:19:18,102 WARN  com.zaxxer.hikari.pool.ProxyLeakTask: [HikariPool-4 housekeeper]: Connection leak detection triggered for org.postgresql.jdbc.PgConnection@77f76747, stack trace follows
java.lang.Exception: Apparent connection leak detected
        at org.apache.hadoop.hive.metastore.txn.TxnHandler.getDbConn(TxnHandler.java:3843)
        at org.apache.hadoop.hive.metastore.txn.TxnHandler.acquireLock(TxnHandler.java:5135) 
        at org.apache.hadoop.hive.ql.txn.compactor.Initiator.run(Initiator.java:107) 

Issue Links

• duplicates: HIVE-24236 Connection leak in TxnHandler