Why are replicated (slave) vBuckets not used for read-only access?


#1

Hi,

Reading the technical whitepaper (http://www.couchbase.com/sites/default/files/uploads/all/whitepapers/Couchbase-Server-Technical-Whitepaper.pdf) I stumbled about the following sentence:
“only one server can service reads and writes for
any given vBucket, at any point in time”.
So if there are replicated vBuckets, there is one master node, that handles all reads and writes for that vBucket. But why are the replicated slave vBuckets not used for read-only access? Ok, this would mean that reading from a vBucket may eventually result in stale data (one could make this configurable, if stale data is allowed or not), but shouldn’t this come with a considerable performance improvement?

Thanks!


#2

If you want to fetch data from your replica nodes you can do so by explicitly calling the “get replica” command.


#3

Ah, many thanks for the hint!