Just confirming. Thanks for the clarification.
On Tue, Jul 12, 2011 at 10:53 AM, Peter Schuller <peter.schul...@infidyne.com> wrote: >> From "Cassandra the definitive guide" - Basic Maintenance - Repair >> "Running nodetool repair causes Cassandra to execute a major compaction..... >> During a major compaction (see “Compaction” in the Glossary), the >> server initiates a >> TreeRequest/TreeReponse conversation to exchange Merkle trees with >> neighboring >> nodes." >> >> So is this text from the book misleading ? > > It's just being a bit less specific (I suppose maybe misleading can be > claimed). If you repair everything on a node, that will imply a > validating compaction (i.e., do the read part of the compaction stage > but don't merge to and write new sstables) which is expensive for the > usual reasons with disk I/O; it's "major" since it covers all data. > The data read is in fact used to calculate a merkle tree for > comparison with neighbors, as claimed. > > -- > / Peter Schuller >
