My experience (running C* 1.2.2):
1. I also observe that this occurs during compaction.
2. I have never yet seen a node recover from this state. Once it starts
complaining about heap, it starts a death spiral, i.e., futile attempts to fix
the situation. Eventually the node starts running GC fo
Hi Sorin,
Thanks very much for your response. From the sounds of it I think I can
share the prepared statements as long as I handle the case when they
disappear (out of LSU cache or due to server restart). To identify this I
think I need to catch InvalidRequestException and look at the message (
On 2013-04-19 13:57, Stuart Broad wrote:
Hi,
I am using Cassandra.Client
prepare_cql3_query/execute_prepared_cql3_query to create and run some
prepared statements. It is working well but I am unclear as to how long
the server side 'caches' the prepared statements. Should a prepared
statement b
The CMS compaction threshold is usually set to 75% as well, it might help
to set it lower to 70% to see if that resolves these warnings as Cassandra
will start CMS GC before it hits the 75% warning.
There is also a setting to lower the max amount of memory used for
compacting each row. This may ca
> So I guess we have to switch to Ec2MultiRegionSnitch.
It depends on how you are connecting the regions.
If the nodes can directly communicate with each other, say through a VPN, you
may not need to change it.
If they are behind a NAT you will need to use it.
When you change the snitch test f
> You are suggesting to go back to STCS and increase the compaction_throughput
> step by step to see if compaction catch up with write traffic?
As a personal approach, when so many config settings are changed it becomes
impossible to understand cause and effect. So I try to return to a known ba
> Write performance decreases.
>
Check the logs for WARN messages from the GCInspector. With 2Gb and only 2
Cores you may be seeing ParNew compaction which pauses the server.
> Sometimes I have to wait 3-4 seconds to get a count even though there're only
> couple of thousand small entries in
Use nodetool cfhistograms to get a better understanding of the latency. It will
also tell you the number of SSTables involved in the read, if it's above 3 it
may indicate the data model needs changes. If you have rows written to for a
long time they can become very fragmented.
Also check the d
I have inserted 1000 rows in Cassandra database. Now I am trying to find
out how many rows have been inserted in Cassandra database using the CLI
mode.
In rdbms, I can do this sql-
* SELECT count(*) from TABLE;*
And this will give me total count for that table;
How to do the same thing i
>> [default@production] describe Users;
show schema; is the cli equivalent of describe in cqlsh.
There was a schema related issue in 1.1 CASSANDRA-4561 that was fixed.
This is a tricky one to diagnose remotely. I could try using nodetool
resetlocalschema on each node, it's just wild guess incas
Sorry i do not understand you question. What are the two solutions ?
Cheers
-
Aaron Morton
Freelance Cassandra Consultant
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 20/04/2013, at 3:43 AM, Kais Ahmed wrote:
> Hello and thank you for your answers.
>
> The first
> There are many more such CFs all with prefixes of "grpId". By hashing grpId
> to cassandra's token, I thought we can co-locate all the group's data into
> one set of replicated nodes.
>
> Is there a way to achieve this?
No.
Rows with the same row key are stored on the same nodes. Rows with d
Using cqlsh you can do:
SELECT COUNT(*) FROM columnfamily LIMIT 5000;
Does that help?
Read more: http://www.datastax.com/docs/1.0/references/cql/SELECT
Thanks,
-Utkarsh
On Sun, Apr 21, 2013 at 1:04 PM, Techy Teck wrote:
> I have inserted 1000 rows in Cassandra database. Now I am trying to
> This is very acceptable but wanted to get everyone's take as I have seen
> messages about this "starving" the request pool.
The issue with sending large mutli gets or batch mutations is that it can
reduce overall request throughput. Every row in your 10K multi becomes RF
number of tasks that
In 1.2 there is also a -Sample file which contains a sample of -Index at the
last index_interval. This is done to (dramatically) improve startup time.
Cheers
-
Aaron Morton
Freelance Cassandra Consultant
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 20/04/2013, at 7
Yeah it helps a lot. I always have this doubt with me. What is the
difference between CLI and CQL?
On Sun, Apr 21, 2013 at 1:30 PM, Utkarsh Sengar wrote:
> Using cqlsh you can do:
>
> SELECT COUNT(*) FROM columnfamily LIMIT 5000;
>
> Does that help?
>
> Read more: http://www.datastax.com/docs/1
https://www.getpantheon.com/news/inside-pantheon-valhalla-filesystem
http://weblog.leapster.org/archives/250-cassafs-a-fuse-based-filesystem-using-apache-cassandra-as-a-backend.html
Cheers
-
Aaron Morton
Freelance Cassandra Consultant
New Zealand
@aaronmorton
http://www.thelastpi
Make sure that the server rpc_address is set to 127.0.0.1
Cheers
-
Aaron Morton
Freelance Cassandra Consultant
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 20/04/2013, at 1:47 PM, Techy Teck wrote:
> I am also running into this problem. I have already enabled
> st
The key to your problem is likely the row key.
Take a look in at the table schema / sample data in the cassandra-cli to see
how CQL uses composites also
http://thelastpickle.com/2013/01/11/primary-keys-in-cql/
The simple thing to do is use COMPACT STORAGE but that may not suite all use
cases
I believe the two solutions that are being referred to is the "lift and shift"
vs. upgrading by replacing a node and letting it restore from the cluster.
I don't think there are any more "risks" per-say on the upgrading by replacing,
as long as you can make sure your new node is configured prope
Can anyone help me out here?
The thing that I wanted to know is whether I can insert into Column Family
(that I created from CLI mode) using Datastax Java driver or not? As soon
as I am trying to insert into Column Family which I have created in CLI
mode, I always get the above exception.
But If I
Difference b/w cqlsh and cli is documented by the datastax guys here
nicely: http://www.datastax.com/support-forums/topic/cli-vs-cql
Thanks,
-Utkarsh
On Sun, Apr 21, 2013 at 1:39 PM, Techy Teck wrote:
> Yeah it helps a lot. I always have this doubt with me. What is the
> difference between CLI
I figured that the primary key and how to define it was the issue.
What I don't get is how to structure my
SSTableSimpleUnsortedWriter.newRow() call to support the CQL3 style
composite primary keys. It takes only a ByteBuffer as an argument...
I guess I'm looking for some kind of example of a ne
If you're using Cassandra 1.2.3, and new Hadoop interface, that would make
a call to next(), you'll have an eternal loop reading same things all over
again from your cassandra nodes (you may see it if you enable Debug output).
next() is clearing key() which is required for Wide Row iteration.
Set
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