Re: SSTable compression ratio… percentage or 0.0 -> 1.0???

[Jack Krupansky]

It’s sloppy language in the doc. It is indeed a “ratio” – scroll down to the 
example.

See:
http://www.datastax.com/documentation/cassandra/2.0/cassandra/tools/toolsCFstats.html

-- Jack Krupansky

From: Kevin Burton 
Sent: Sunday, June 29, 2014 12:33 AM
To: user@cassandra.apache.org 
Subject: SSTable compression ratio… percentage or 0.0 -> 1.0???

I can't find documentation on this...

SSTable Compression Ratio: 0.31685324166491696


One entry on the datastax site says that it's the "percentage"

but is it 0.31% or 31% ?

I think it's 31% … but I don't see where this is specified..

-- 


Founder/CEO Spinn3r.com

Location: San Francisco, CA

blog: http://burtonator.wordpress.com
… or check out my Google+ profile

Does 'tracing on' always write to the system tracing table?

[Kevin Burton]

I couldn't figure this out in the documentation…

If I enable per request tracing, does this always make it into the system
traces table?

I'd like our customers to be able to selectively enable tracing and capture
the output.

The datastax driver allows me to enable tracing but I think it's just on
the request and I would have to send the data back to us…

Kevin

-- 

Founder/CEO Spinn3r.com
Location: *San Francisco, CA*
blog: http://burtonator.wordpress.com
… or check out my Google+ profile

tracing thrift queries?

[Kevin Burton]

Is it possible to trace thrift queries?

We're using KairosDB and *most* of the queries are amazingly slow… even
repeated queries which should be in cache.

Tracing them should help iron down whats happening.

Kevin

-- 

Founder/CEO Spinn3r.com
Location: *San Francisco, CA*
blog: http://burtonator.wordpress.com
… or check out my Google+ profile

How to deal with SSTable FileNotFoundException?

[Philo Yang]

Hi all,

I have a Cassandra 2.0.6 cluster with 12 nodes. I find in some nodes'
system.log, there are many RuntimeException such like:

java.lang.RuntimeException: java.io.FileNotFoundException:
/disk4/cassandra/data/{keyspace}/{cfname}/{keyspace}-{cfname}-jb-87-Data.db
(No such file or directory)
I think the reason is I have dropped this table and recreated it later. And
I find this Exception blocks the stream from these nodes to others so
bootstrap or rebuild can't finish and is stuck in 100% forever.

What should I do to refresh the SSTable list in these nodes?

-- 
Regards,
Zhe Yang

Any better solution to avoid TombstoneOverwhelmingException?

[Jason Tang]

Our application will use Cassandra to persistent for asynchronous tasks, so
in one time period, lots of records will be created in Cassandra (more then
10M). Later it will be executed.

Due to disk space limitation, the executed records will be deleted.
After gc_grace_seconds, it is expected to be auto removed from the disk.

So for the next round of execution, the deleted records, should not be
queried out.

In this traffic, it will be generated lots of tombstones.

To avoid TombstoneOverwhelmingException, One way is to larger
tombstone_failure_threshold, but is there any impact for the system's
performance on my traffic model, or is there any better solution for this
traffic?


BRs
//Tang