[DBCP-330] Calling getMetaData() without closing the connection lead to a memory leak

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.4
• Fix Version/s: 1.4.1

Environment

Linux Mint 8 Helena - Universal Edition

Linux version 2.6.31-14-generic (buildd@rothera) (gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu8) ) #48-Ubuntu SMP Fri Oct 16 14:04:26 UTC 2009

java version "1.6.0_15"
Java(TM) SE Runtime Environment (build 1.6.0_15-b03)
Java HotSpot(TM) Client VM (build 14.1-b02, mixed mode, sharing)

• Assignee: Unassigned
• Reporter: Timothee Maret
• Created: 14/Apr/10 09:44
• Updated: 24/Feb/15 03:23
• Resolved: 23/Apr/11 23:56

Description

In my program, I am using a BasicDataSource to get my database connections. I have to keep one of the connection alive and thus never close it. On this connection, I have to periodically get the metadata (call the getMetaData() method) for my processing.
However, I have noticed that each call to this method create a new DelegatingDatabaseMetaData instance which can't be garbage collected until the connection is closed. This creation of DelegatingDatabaseMetaData will finally consume all the memory and generate a OutOfMemory error.

Actually, in it's constructor, the DelegatingDatabaseMetaData class calls its super constructor (from the AbandonedTrace class) which creates a reference (parent.addTrace(this) from the connection to the DelegatingDatabaseMetaData. This reference prevent the DelegatingDatabaseMetaData to be collected until the Connection is closed.

Issue Links

• blocks: DBCP-352 Repeated calls to getMetadata in a transaction leads to performance degredation