incubator-blur-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Aaron McCurry <amccu...@gmail.com>
Subject Re: enable/disable bug, caching, and stuff
Date Tue, 12 Aug 2014 17:56:31 GMT
On Tue, Aug 12, 2014 at 1:21 PM, Tim Williams <williamstw@gmail.com> wrote:

> We have a bug where you disable the table and it doesn't show as
> disabled - I suspect the other way is problematic too but don't know
> for sure.  Looking into this brings up a few questions:
>
> 1) Based on the usage, I'm not so sure the tableDescriptor even needs
> to be cached, so instead of fixing, perhaps the easy route of just
> don't cache it should be taken?
>

Perhaps, we will need to review all calls to get the tableDesc.


>
> 2) If we do keep the cache, I think we should move to a proper cache
> (e.g. Guava LoadingCache or somesuch) that has proper
> evictions/invalidation.  Anyone have strong feelings on that?
>

The evictions will have to occur with ZooKeeper changes/updates not based
on timeouts as long as we stick with that restriction we could use any lib
to implement.


>
> 3) It feels weird/wrong to have useCache in the calling method - it
> seems like that should be an internal decision not one of the caller.
>  Thoughts on this?
>

The issue is that at certain times the cache is OK to use even if it's a
second or two out of sync with ZK.  Other times we have to know the correct
answer, and basically make a ZK call.  The whole point of the cache is to
remove ZK calls because of the performance impacts both on Blur and the
extra load on ZK.

Aaron


>
> Thanks,
> --tim
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message