Question

I have CF with 1280 rows.
Each row has 6 columns. Im trying to $cf->get_range(‘pq_questions’,”,”,1200) and it gets all rows but too slow(about 4-6 sec)

Column Family: pq_questions
                SSTable count: 1
                Space used (live): 668363
                Space used (total): 668363
                Number of Keys (estimate): 1280
                Memtable Columns Count: 0
                Memtable Data Size: 0
                Memtable Switch Count: 0
                Read Count: 0
                Read Latency: NaN ms.
                Write Count: 0
                Write Latency: NaN ms.
                Pending Tasks: 0
                Key cache capacity: 200000
                Key cache size: 1000
                Key cache hit rate: 0.10998439937597504
                Row cache capacity: 1000
                Row cache size: 1000
                Row cache hit rate: 0.0
                Compacted row minimum size: 373
                Compacted row maximum size: 1331
                Compacted row mean size: 574

It is strange but read latency in cfstats is NaN ms
When i calling htop on debian i see that the most load causes phpcassa
I has only one node and use consistency level ONE.
What can cause so slow quering?

Answer 1

I’m guessing you don’t have the C extension installed. Without it, a similar query takes 1-2 seconds for me. With it installed, the same query takes about 0.2 seconds.

Regarding the NaN read latency, latencies aren’t captured for get_range_slices (get_range in phpcassa).