[CASSANDRA-2552] ReadResponseResolver Race

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 0.7.6, 0.8.0 beta 2
• Severity: Normal
• Assignee: Jonathan Ellis
• Reporter: Stu Hood

Authors

Jonathan Ellis

Reviewers

Stu Hood

• Created: 25/Apr/11 01:21
• Updated: 16/Apr/19 09:33
• Resolved: 28/Apr/11 13:26

Description

When receiving a response, ReadResponseResolver uses a 3 step process to decide whether to trigger the condition that enough responses have arrived:

1. Add new response
2. Check response set size
3. Check that data is present

I think that these steps must have been reordered by the compiler in some cases, because I was able to reproduce a case for a QUORUM read where the condition is not properly triggered:

INFO [RequestResponseStage:15] 2011-04-25 00:26:53,514 ReadResponseResolver.java (line 87) post append for 1087367065: hasData=false in 2 messages
INFO [RequestResponseStage:8] 2011-04-25 00:26:53,514 ReadResponseResolver.java (line 87) post append for 1087367065: hasData=true in 1 messages
INFO [pool-1-thread-54] 2011-04-25 00:27:03,516 StorageProxy.java (line 623) Read timeout: java.util.concurrent.TimeoutException: ReadResponseResolver@1087367065(/10.34.131.109=false,/10.34.132.122=true,)

The last line shows that both results were present, and that one of them was holding data.