[HIVE-13527] Using deprecated APIs in HBase client causes zookeeper connection leaks.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.1.0
• Fix Version/s: 2.1.0
• Component/s: HiveServer2
• Assignee: Naveen Gangam
• Reporter: Naveen Gangam
• Created: 15/Apr/16 19:05
• Updated: 21/Jun/16 15:12
• Resolved: 24/Apr/16 00:52

Description

When running queries against hbase-backed hive tables, the following log messages are seen in the HS2 log.

2016-04-11 07:25:23,657 WARN org.apache.hadoop.hbase.mapreduce.TableInputFormatBase: You are using an HTable instance that relies on an HBase-managed Connection. This is usually due to directly creating an HTable, which is deprecated. Instead, you should create a Connection object and then request a Table instance from it. If you don't need the Table instance for your own use, you should instead use the TableInputFormatBase.initalizeTable method directly.
2016-04-11 07:25:23,658 INFO org.apache.hadoop.hbase.mapreduce.TableInputFormatBase: Creating an additional unmanaged connection because user provided one can't be used for administrative actions. We'll close it when we close out the table.

In a HS2 log file, there are 1366 zookeeper connections established but only a small fraction of them were closed. So lsof would show 1300+ open TCP connections to Zookeeper.
grep "org.apache.zookeeper.ClientCnxn: Session establishment complete on server" * |wc -l
1366
grep "INFO org.apache.zookeeper.ZooKeeper: Session:" * |grep closed |wc -l
54

According to the comments in TableInputFormatBase, the recommended means for subclasses like HiveHBaseTableInputFormat is to call initializeTable() instead of setHTable() that it currently uses.
"
Subclasses MUST ensure initializeTable(Connection, TableName) is called for an instance to function properly. Each of the entry points to this class used by the MapReduce framework,

{@link #createRecordReader(InputSplit, TaskAttemptContext)}

and

{@link #getSplits(JobContext)}

, will call

{@link #initialize(JobContext)}

as a convenient centralized location to handle retrieving the necessary configuration information. If your subclass overrides either of these methods, either call the parent version or call initialize yourself.
"

Currently setHTable() also creates an additional Admin connection, even though it is not needed.

So the use of deprecated APIs are to be replaced.

Issue Links

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