[CASSANDRA-1179] split commitlog into header + mutations files

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 0.7 beta 1
• Severity: Normal
• Assignee: Matthew F. Dennis
• Reporter: Jonathan Ellis

Authors

Matthew F. Dennis

• Created: 10/Jun/10 23:02
• Updated: 16/Apr/19 09:33
• Resolved: 19/Jun/10 16:09

Description

As mentioned in CASSANDRA-1119, it seems possible that a commitlog header could be corrupted by a power loss during update of the header, post-flush. We could try to make it more robust (by writing the size of the commitlogheader first, and skipping to the end if we encounter corruption) but it seems to me that the most foolproof method would be to split the log into two files: the header, which we'll overwrite, and the data, which is truly append only. If If the header is corrupt on reply, we just reply the data from the beginning; the header allows us to avoid replaying data redundantly, but it's strictly an optimization and not required for correctness.