[ZOOKEEPER-2249] CRC check failed when preAllocSize smaller than node data

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.5.3, 3.4.11, 3.6.0
• Fix Version/s: 3.5.4, 3.6.0, 3.4.12
• Labels: server
• Assignee: Abraham Fine
• Reporter: Benjamin Jaton
• Created: 17/Aug/15 16:24
• Updated: 08/Mar/18 17:40
• Resolved: 18/Jan/18 23:48

Description

Unexpected exception, exiting abnormally
java.io.IOException: CRC check failed
org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.next(FileTxnLog.java:612)
org.apache.zookeeper.server.persistence.FileTxnSnapLog.restore(FileTxnSnapLog.java:157)
org.apache.zookeeper.server.ZKDatabase.loadDataBase(ZKDatabase.java:223)
org.apache.zookeeper.server.ZooKeeperServer.loadData(ZooKeeperServer.java:272)
org.apache.zookeeper.server.ZooKeeperServer.startdata(ZooKeeperServer.java:399)

To reproduce, set the preAllocSize to 8MB, the jute.maxbuffer to 20MB and try saving a 15MB node several times.
In my case the erroneous CRC appears after the second save. I use the LogFormatter class to detect it.
I suspect that the CRC error happens when the new transaction log is created, the code probably expects to have enough room to save the transaction when creating a new file, but it's too small.

Issue Links

• relates to: ZOOKEEPER-2994 Tool required to recover log and snapshot entries with CRC errors
• links to: GitHub Pull Request #436