cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Brice Figureau <brice+cassan...@daysofwonder.com>
Subject Re: Read query taking a long time
Date Tue, 20 Oct 2015 12:59:31 GMT
Hi,

Thanks for your answer. Unfortunately since I wrote my e-mail, things
are a bit better.

This might be because I moved from openjdk 7 to oracle jdk 8 after
having seen a warning in the C* log about openjdk, and I also added a
node (for other reasons).

Now the query itself takes only 1.5s~2s instead of the 5s~6s it was
taking before.

On Mon, 2015-10-19 at 14:38 +0100, Carlos Alonso wrote:
> Could you send cfhistograms and cfstats relevant to the read column
> family?

Here are the requested informatrion
% nodetool proxyhistograms
proxy histograms
Percentile      Read Latency     Write Latency     Range Latency
                    (micros)          (micros)          (micros)
50%                  1109.00            372.00           1916.00
75%                 14237.00            535.00           2759.00
95%                105778.00            642.00           4768.00
98%                545791.00            770.00          11864.00
99%                785939.00            924.00          14237.00
Min                    73.00              0.00            373.00
Max               5839588.00          88148.00          73457.00

% nodetool cfstats akka.messages
Keyspace: akka
        Read Count: 3334784
        Read Latency: 9.98472696792356 ms.
        Write Count: 7124
        Write Latency: 0.572256457046603 ms.
        Pending Flushes: 0
                Table: messages
                SSTable count: 1
                Space used (live): 4680841
                Space used (total): 4680841
                Space used by snapshots (total): 23615746
                Off heap memory used (total): 4051
                SSTable Compression Ratio: 0.17318784636027024
                Number of keys (estimate): 478
                Memtable cell count: 317
                Memtable data size: 42293
                Memtable off heap memory used: 0
                Memtable switch count: 10
                Local read count: 3334784
                Local read latency: 9.985 ms
                Local write count: 7124
                Local write latency: 0.573 ms
                Pending flushes: 0
                Bloom filter false positives: 0
                Bloom filter false ratio: 0.00000
                Bloom filter space used: 592
                Bloom filter off heap memory used: 584
                Index summary off heap memory used: 203
                Compression metadata off heap memory used: 3264
                Compacted partition minimum bytes: 73
                Compacted partition maximum bytes: 17436917
                Compacted partition mean bytes: 63810
                Average live cells per slice (last five minutes):
0.6693421039216356
                Maximum live cells per slice (last five minutes): 1033.0
                Average tombstones per slice (last five minutes): 0.0
                Maximum tombstones per slice (last five minutes): 0.0

----------------

If I read correctly this, there's a huge read latency while proxying,
but local read latency, or even all node latency on this table is
correct.

Would that mean this is a network issue?
-- 
Brice Figureau <brice+cassandra@daysofwonder.com>


Mime
View raw message