Hi Aaron, Here it is.
Keyspace: XXXX Read Count: 1123637972 Read Latency: 5.757938114343114 ms. Write Count: 128201833 Write Latency: 0.0682576607387509 ms. Pending Tasks: 0 Column Family: YY SSTable count: 18 Space used (live): 103318720685 Space used (total): 103318720685 Number of Keys (estimate): 92404992 Memtable Columns Count: 1425580 Memtable Data Size: 359655747 Memtable Switch Count: 2522 Read Count: 1123637972 Read Latency: 14.731 ms. Write Count: 128201833 Write Latency: NaN ms. Pending Tasks: 0 Bloom Filter False Postives: 1488 Bloom Filter False Ratio: 0.00000 Bloom Filter Space Used: 331522920 Key cache capacity: 16637958 Key cache size: 16637958 Key cache hit rate: 0.2708333333333333 Row cache: disabled Compacted row minimum size: 51 Compacted row maximum size: 6866 Compacted row mean size: 2560 Thanks, Eran Chinthaka Withana On Thu, Feb 16, 2012 at 12:30 AM, aaron morton <aa...@thelastpickle.com>wrote: > Its in the order of 261 to 8000 and the ratio is 0.00. But i guess 8000 is > bit high. Is there a way to fix/improve it? > > Sorry I don't understand what you mean. But if the ratio is 0.0 all is > good. > > Could you include the full output from cfstats for the CF you are looking > at ? > > Cheers > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 15/02/2012, at 1:00 PM, Eran Chinthaka Withana wrote: > > Its in the order of 261 to 8000 and the ratio is 0.00. But i guess 8000 is > bit high. Is there a way to fix/improve it? > > Thanks, > Eran Chinthaka Withana > > > On Tue, Feb 14, 2012 at 3:42 PM, aaron morton <aa...@thelastpickle.com>wrote: > >> Out of interest what does cfstats say about the bloom filter stats ? A >> high false positive could lead to a low key cache hit rate. >> >> Also, is there a way to warm start the key cache, meaning pre-load the >> amount of keys I set as keys_cached? >> >> See key_cache_save_period when creating the CF. >> >> Cheers >> >> >> ----------------- >> Aaron Morton >> Freelance Developer >> @aaronmorton >> http://www.thelastpickle.com >> >> On 15/02/2012, at 5:54 AM, Eran Chinthaka Withana wrote: >> >> Hi, >> >> I'm using Cassandra 1.0.7 and I've set the keys_cached to about 80% >> (using the numerical values). This is visible in cfstats too. But I'm >> getting less than 20% (or sometimes even 0%) key cache hit rate. Well, the >> data access pattern is not the issue here as I know they are retrieving the >> same row multiple times. I'm using hector client with dynamic load >> balancing policy with consistency ONE for both reads and writes. Any ideas >> on how to find the issue and fix this? >> >> Here is what I see on cfstats. >> >> Key cache capacity: 16637958 >> Key cache size: 16637958 >> Key cache hit rate: 0.045454545454545456 >> >> Also, is there a way to warm start the key cache, meaning pre-load the >> amount of keys I set as keys_cached? >> >> Thanks, >> Eran >> >> >> > >
