Make column timestamps optional- kidding me, right ?:) I do understand
that this wont be possible as then cassandra wont be able to distinguish
the latest among several copies of same column. I dont mean that. I just
want the while ordering the columns, Cassandra(in an optional mode per CF)
Hi!
Thanks for the response. My cluster is in a bad state those recent days.
I have 29 CFs, and my disk is 5% full... So I guess the VMs still have more
space to go, and I am not sure this is considered many CFs.
But maybe I have memory issues. I enlarge cassandra memory from about ~2G
to ~4G
Sylvain,
I've seen to the code. Yes, you right about local deletion time. But it
contradicts to the tests results.
Do you have any thoughts how to explain result of the second test after
patch applying?
Our patch:
diff --git a/src/java/org/apache/cassandra/db/DeletedColumn.java
Hi Ben,
I suggest you to compare amount of queries for each node. May be the
problem is on the client side.
Yoy can do that using JMX:
org.apache.cassandra.db:type=ColumnFamilies,keyspace=YOUR
KEYSPACE,columnfamily=YOUR CF,ReadCount
org.apache.cassandra.db:type=ColumnFamilies,keyspace=YOUR
Hi Rob,
What version of Cassandra? What JVM? Are JNA and Jamm working?
cassandra 1.0.8. Sun JDK 1.7.0_05-b06, JNA memlock enabled, jamm works.
It sounds like the two nodes that are pathological right now have
exhausted the perm gen with actual non-garbage, probably mostly the Bloom
filters and
Hi All,
For of my projects I want to buy a machine to host Casssandra database.
The options I am offered are machines with 16GB RAM with Quad-Core processor
and 6GB RAM with Hexa-Core processor.
Which one do you recommend, big RAM or high number of cores?
greetings
Ambes
Hi, Hagos,
I think it depends on your business case. Big RAM reduce latency and
improve responsibility, High number of cores increase concurrency of your
app. thanks.
On Fri, Oct 12, 2012 at 4:23 PM, Hagos, A.S. a.s.ha...@tue.nl wrote:
Hi All,
For of my projects I want to buy a machine to
Hi,
Sure it depends... but IMHO 6 GB is suboptimal for big data because it
means 1,5 GB or 2 GB for Cassandra.
Maybe you could elaborate your use case. You really want a one node
cluster ?
cheers,
Romain
wang liang wla...@gmail.com a écrit sur 12/10/2012 10:36:15 :
Hi, Hagos,
I think it
Hi there,
My application is uses Cassandra to store abstracted sensor data from a sensor
network in large building (up to 3000 sensors).
For now I am starting one node in one floor of the building, for the future it
will definitely be a cluster. Some of the sensors have up 16HZ sampling rate.
IMO, in most cases you'll be limited by the RAM first.
Take into account size of sstables, you will need to keep bloom filters and
indexes in RAM and if it will not fit, 4 cores, or 24 cores doesn't matter,
except you're on SSD.
You need to design first, stress test second, conclude last.
Hello,
I wonder if it's possible to specify an array of values as a value of a
super column... If it's not possible, is there another way to do that?
Thanks very much for your help.
Thierry
On Fri, 2012-10-12 at 10:20 +, Viktor Jevdokimov wrote:
IMO, in most cases you'll be limited by the RAM first.
+1 - I've seen our 8-core boxes limited by RAM and inter-rack
networking, but not by CPU (yet).
Tim
Also, take into account i/o since they are often a limiting factor.
struct SuperColumn {
1: required binary name,
2: required listColumn columns,
}
Best regards / Pagarbiai
Viktor Jevdokimov
Senior Developer
Email: viktor.jevdoki...@adform.com
Phone: +370 5 212 3063
Fax: +370 5 261 0453
J. Jasinskio 16C,
LT-01112 Vilnius,
Lithuania
Disclaimer: The
+1
I want to see how this plays out as well. Anyone know the answer?
Dean
From: Alexey Zotov azo...@griddynamics.commailto:azo...@griddynamics.com
Reply-To: user@cassandra.apache.orgmailto:user@cassandra.apache.org
user@cassandra.apache.orgmailto:user@cassandra.apache.org
Date: Friday,
I have a two node cluster hosting a 45 gig dataset. I periodically have to
read a high fraction (20% or so) of my 'rows', grabbing a few thousand at a
time and then processing them.
This used to result in about 300-500 reads a second which seemed quite
good. Recently that number has plummeted
You probably already know this but I'm pretty sure it wouldn't be a trivial
change, since to efficiently lookup a column by name requires the columns
to be ordered by name. A separate index would be needed in order to provide
lookup by column name if the row was sorted by timestamp (which is the
Jim,
Great idea - though it doesn't look like it's in 1.1.3 (which is what
I'm running).
My lame idea of the morning is that I'm going to just read the whole
keyspace with QUORUM reads to force read repairs - the unfortunate truth
is that this is about 2B reads...
--david
On 10/11/12
did the amount of data finally exceed your per machine RAM capacity?
is it the same 20% each time you read? or do your periodic reads
eventually work through the entire dataset?
if you are essentially table scanning your data set, and the size
exceeds available RAM, then a degradation like that
https://issues.apache.org/jira/browse/CASSANDRA-3483
Is directly on point for the use case in question, and introduces
rebuild concept..
https://issues.apache.org/jira/browse/CASSANDRA-3487
https://issues.apache.org/jira/browse/CASSANDRA-3112
Are for improvements in repair sessions..
On Fri, Oct 12, 2012 at 2:24 AM, Tamar Fraenkel ta...@tok-media.com wrote:
Thanks for the response. My cluster is in a bad state those recent days.
I have 29 CFs, and my disk is 5% full... So I guess the VMs still have
more space to go, and I am not sure this is considered many CFs.
That's
On Fri, Oct 12, 2012 at 3:26 AM, Daniel Woo daniel.y@gmail.com wrote:
Disable swap for cassandra node
I am gonna change swappiness to 20%
Dead nodes are better than crippled nodes. I'll echo Rob's suggestion that
you disable swap entirely.
--
Tyler Hobbs
DataStax http://datastax.com/
trying to think of a use case where you would want to order by
timestamp, and also have unique column names for direct access.
not really trying to challenge the use case, but you can get ordering
by timestamp and still maintain a name for the column using
composites. if the first component of
On Fri, Oct 12, 2012 at 1:26 AM, Daniel Woo daniel.y@gmail.com wrote:
What version of Cassandra? What JVM? Are JNA and Jamm working?
cassandra 1.0.8. Sun JDK 1.7.0_05-b06, JNA memlock enabled, jamm works.
The unusual aspect here is Sun JDK 1.7. Can you use 1.6 on an affected
node and see if
We instrumented the Cassandra and Hector code adding more logs to check where
the time was being spent.
We found the Cassandra read times to be very low, eg.
CassandraServer.getSlice() is only 3ms.
However, on Hector's side, creating a ColumnFamilyTemplateString, Composite,
and doing
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