"That cache retains at least 50 entries " This means The Cache retains 50 entries totally, or The Cache retains at least 50 entries per Channel?
On Thursday, February 11, 2016 at 2:30:58 AM UTC+8, Adam Fraser wrote: > > Jens is correct that channels are fairly lightweight, but there are a few > additional details you may want to take into consideration while evaluating > your design: > > 1. Adding/removing users to/from channels is a more computationally > expensive operation than adding/removing documents to/from a channel. When > a user is added to a channel, a Couchbase view call is required to > recalculate that user's channel access. When a document is added to a > channel, it's just an in-memory operation to add that to the cache for that > channel. Frequency subscription/unsubscription from a channel is going to > be a relatively expensive operation. > 2. Sync Gateway maintains an in-memory cache of recent changes to a > channel. That cache retains at least 50 entries (entries beyond 50 will be > expire out of the cache). If most of your channels are shallow (<50 docs), > it means that Sync Gateway will be attempting to cache a large fraction of > your total docs in memory. This will probably need to be considered when > sizing your SG node(s). > 3. Although channels are lightweight, I'd still expect you to see some > increase in CPU requirements as you increase the number of channels per > user, particularly as you get into thousands of channels per user. Each > replication is making a _changes request that's going to need to check each > of those channels for changes. > > I don't think any of these are barriers to your design as described, but I > wanted to share the details as additional context. > > Thanks, > Adam > -- You received this message because you are subscribed to the Google Groups "Couchbase Mobile" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/mobile-couchbase/08268a35-ba37-449f-8947-4ed53b0a3d21%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
