Upgrade at least to 0.8.1 as your version has broken compaction...
Reagards
Wojtek Meler
----- Reply message -----
Od: "myreasoner" <myreaso...@gmail.com>
Data: pon., sie 1, 2011 04:23
Temat: Read latency is over 1 minute on a column family with 400,000 rows
Do: "cassandra-u...@incubator.apache.org" <cassandra-u...@incubator.apache.org>
Hi, my read latency is really horrible and I can't figure out what went
wrong. I'm running cassandra 0.8.0 on a 5 machine cluster. The Fingerprint
ColumnFamily has 400,000 rows, each row has about 4,000 Super columns, and
each super column has 1 to 4 columns. One row looks like:
RowKey: 00c26f
=> (super_column=008002c161f008566a4931d6efeab128ef,
(column=183e9d10-b5f0-11e0-b0f4-0025901867fb, value=,
timestamp=1311510352604000))
=> (super_column=008004c34cafa12e22acbf3c2aab9b15ef,
(column=e6371bf6-b72c-11e0-b201-0025901867fb, value=,
timestamp=1311646419206000)
(column=e6371c00-b72c-11e0-b201-0025901867fb, value=,
timestamp=1311646419206000))
=> (super_column=0080097ac5154a96ea8620784ea3b5b56f,
(column=7691b846-b6fc-11e0-a703-003048f330bb, value=,
timestamp=1311625615955000))
...
On cassandra-cli doing *get Fingerprint[rowkey][SuperColumnName]* usually
takes over 60 seconds to return, which almost make the read un-useable. Is
there anything I can tune?
Here are the stats for a column family Fingerprint.
Column Family: Fingerprint
SSTable count: 2056
Space used (live): 164074936666
Space used (total): 164074936666
Memtable Columns Count: 177451
Memtable Data Size: 119948171
Memtable Switch Count: 366
Read Count: 5
*Read Latency: 74487.252 ms.*
Write Count: 30023
Write Latency: 1.602 ms.
Pending Tasks: 0
Key cache capacity: 200000
Key cache size: 8157
Key cache hit rate: 0.01322228263555929
Row cache: disabled
Compacted row minimum size: 104
Compacted row maximum size: 315852
Compacted row mean size: 33709
--
View this message in context:
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Read-latency-is-over-1-minute-on-a-column-family-with-400-000-rows-tp6639649p6639649.html
Sent from the cassandra-u...@incubator.apache.org mailing list archive at
Nabble.com.
"WIRTUALNA POLSKA" Spolka Akcyjna z siedziba w Gdansku przy ul. Traugutta 115
C, wpisana do Krajowego Rejestru Sadowego - Rejestru Przedsiebiorcow
prowadzonego przez Sad Rejonowy Gdansk - Polnoc w Gdansku pod numerem KRS
0000068548, o kapitale zakladowym 67.980.024,00 zlotych oplaconym w calosci
oraz Numerze Identyfikacji Podatkowej 957-07-51-216.
