Sorry, the line "I still don't see it in jconsole" is ambiguous. I mean that I don't find a change of rowcache size in jconsole and neither performance gain. cfstats gives either 0 or NaN.
It's part of the CF definition.I still don't see it in jconsole.Check the docs for CLI or CQL which ever you are using.Assuming you are talking about the client side timing for reading 150,000 rows with several columns each this does not sound too crazy.how long would you expect to cost to read a column family of 150000 rows if it fits into row cache entirely? It takes me around 7s nowCheck the server side timing by calling nodetool cfstats before and after the query, the recent stats will be be since the last time cfstats was called.CheersOn 27/09/2012, at 2:32 PM, Manu Zhang <firstname.lastname@example.org> wrote:I still don't see it in jconsole. BTW, how long would you expect to cost to read a column family of 150000 rows if it fits into row cache entirely? It takes me around 7s now. My experiment is done on a single node.
On Thu, Sep 27, 2012 at 6:00 AM, aaron morton <email@example.com> wrote:Set the caching strategy for the CF to be ROWS_ONLY.CheersOn 26/09/2012, at 2:18 PM, Manu Zhang <firstname.lastname@example.org> wrote:The DEFAULT_CACHING_STRATEGY is Caching.KEYS_ONLY but even configuring row cache size to be greater zero
won't enable row cache. Why?On Wed, Sep 26, 2012 at 9:44 AM, Manu Zhang <email@example.com> wrote:
I wonder now if "get_range_slices" call will ever look for data in row cache. I don't see it in the codebase. Only the "get" call will check row cache?On Wed, Sep 26, 2012 at 12:11 AM, Charles Brophy <firstname.lastname@example.org> wrote:
There are settings in cassandra.yaml that will _gradually_ reduce the available cache to zero if you are under constant memory pressure:# Set to 1.0 to disable. <snip>reduce_cache_sizes_at: *reduce_cache_capacity_to: *My experience is that the cache size will not return to the configured size until a service restart if you leave this enabled. The text of this setting is not explicit about the long-term cache shrinkage, so it's easy to think that it will restore the cache to its configured size after the pressures have subsided. It won't.CharlesOn Tue, Sep 25, 2012 at 8:14 AM, Manu Zhang <email@example.com> wrote:
I've enabled row cache and set its capacity to 10MB but when I check its size in jconsole it's always 0. Isn't it that a row will be written to row cache if it isn't there when I read the row? I've bulk loaded the data into disk so row cache is crucial to the performance.