Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Chris Burroughs
On 2011-01-11 15:41, Chris Burroughs wrote: > On 01/11/2011 02:56 PM, Peter Schuller wrote: >>> But now I need two knobs: "Max size of row cache" (best optimal steady >>> state hit rate) and "number of row cache items to read in on startup" >>> (so that the ROW-READ-STAGE does not need to drop pac

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Chris Burroughs
On 01/11/2011 02:56 PM, Peter Schuller wrote: >> But now I need two knobs: "Max size of row cache" (best optimal steady >> state hit rate) and "number of row cache items to read in on startup" >> (so that the ROW-READ-STAGE does not need to drop packets and node can >> be restarted in a reasonable

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Peter Schuller
> This makes total sense and is obvious in hindsight.  But wouldn't such a > hypothetical "stale" row cache on be corrected by read repair (in other > words useless for write heavy workloads, not a problem for read heavy)? It's not quite that simple. For example, suppose you write to the cluster a

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Peter Schuller
> But now I need two knobs:  "Max size of row cache" (best optimal steady > state hit rate) and "number of row cache items to read in on startup" > (so that the ROW-READ-STAGE does not need to drop packets and node can > be restarted in a reasonable amount of time). Good idea IMO. File a jira tick

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Chris Burroughs
On 01/11/2011 12:23 PM, Peter Schuller wrote: >> Is this the intentional implementation? Are there any reason not to >> just the entire row to disk to allow for faster startup? > > Intentional (in the sense of "not a mistake"), but see: > >https://issues.apache.org/jira/browse/CASSANDRA-1625

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Chris Burroughs
On 01/11/2011 10:11 AM, Edward Capriolo wrote: > I think because the RowCache is only saved periodically it could be > out of sync. IE saved at 12:00 changed at 12:01 then the row cache > would consistently return the wrong results since it never looks at > the disk again. I guess saving the row ca

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Peter Schuller
> https://issues.apache.org/jira/browse/CASSANDRA-1417 [snip, row cache saving only keys] > Is this the intentional implementation?  Are there any reason not to > just the entire row to disk to allow for faster startup? Intentional (in the sense of "not a mistake"), but see: https://issues.a

Re: Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Edward Capriolo
On Tue, Jan 11, 2011 at 9:54 AM, Chris Burroughs wrote: > https://issues.apache.org/jira/browse/CASSANDRA-1417 > http://www.riptano.com/blog/whats-new-cassandra-066 > > My naive reading of CASSANDRA-1417 was that it could be used to save the > row cache to disk.  Empirically it appears to only sav

Confused about CASSANDRA-1417; saving row cache

2011-01-11 Thread Chris Burroughs
https://issues.apache.org/jira/browse/CASSANDRA-1417 http://www.riptano.com/blog/whats-new-cassandra-066 My naive reading of CASSANDRA-1417 was that it could be used to save the row cache to disk. Empirically it appears to only save the row keys, and then reads each row. In my case I set the row