cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jonathan Ellis (JIRA)" <>
Subject [jira] Updated: (CASSANDRA-724) Insert/Get Contention
Date Wed, 20 Jan 2010 23:26:54 GMT


Jonathan Ellis updated CASSANDRA-724:

    Attachment: debug.patch

patch to add debug timing info if you want to investigate further.

there does seem to be occasional latency spikes inside ColumnFamilyStore.apply that I do not
yet understand.

when cpus are busy w/ compaction latency increases.  no real surprise there.

thrift sometimes adds 10s of ms of latency according to the differences b/t what my python
client sees and what CassandraServer sees.  the java side of thrift does call setTcpNoDelay(true),
but the python side does not -- the equivalent would be, setsockopt(SOL_TCP, TCP_NODELAY,
1).  that is probably the culprit.

> Insert/Get Contention
> ---------------------
>                 Key: CASSANDRA-724
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Chris Goffinet
>            Assignee: Jonathan Ellis
>             Fix For: 0.6
>         Attachments: 724.patch, debug.patch,
> We tried out the socket io patch in CASSANDRA-705, tested the latest JVM of b18 for 1.6.
Still seeing very strange insert times. We see this with get_slices as well but it's easy
to reproduce with batch_insert. I wonder if its related to Memtable contention, it's pretty
easy to see the slow times when you restart the test script attached. We are running this
on a 7 node cluster, <1% cpu. Consistency Level of 1.
> Results
> ---------------------
> Slow insert test.10882 0.203548192978
> Slow insert test.18005 0.203876972198
> Slow insert test.21154 0.204496860504
> Slow insert test.22054 0.0444049835205
> Slow insert test.26445 0.201545000076

This message is automatically generated by JIRA.
You can reply to this email to add a comment to the issue online.

View raw message