Hi,
I have an application that consists of multiple (possible 1000's) of
measurement series, and each measurement series generates a small amount of
data output (only about 500 bytes) every 10 seconds. This time series of
data should be stored in Cassandra in a fashion that both read access is
pos
Does a call to
list get_slice(binary key, ColumnParent
column_parent, SlicePredicate predicate, ConsistencyLevel
consistency_level)
give us any guarantees on the order of the returned list? I understand that
when the predicate actually contains a sliceRange, then the order _is_
guaranteed to be i
Hi,
First of all, thanks all of you guys who are contributing to this amazing
project. I've been looking at Cassandra for a couple of days now, and I'm
still impressed by the whole thing.
However, it wasn't all that straight-forward getting my first "hello world"
programs to run with Cassandra. A
now (however, also doesn't throw
an exception).
Please don't shoot me, I came up with this code just grep'ing the
source and doing something that seemed to make a little sense... ;-)
Greetings,
Roland
2010/3/24 Eric Evans
> On Wed, 2010-03-24 at 14:15 +0100, Roland Hä
Jonathan,
I agree with your idea about a tool that could 'propose' good token choices
for optimal load-balancing.
If I was going to write such a tool: do you think the thrift API provides
the necessary information? I think with the RandomPartitioner you cannot
scan all your rows to actually find
But this
26.03.2010 22:29 schrieb am "Rob Coli" :
On 3/26/10 1:36 PM, Roland Hänel wrote:
>
> If I was going to write such a tool: do you think the th...
The JMX interface exposes an Attribute which seems appropriate to this use.
It is called "TotalDiskSpaceUsed,"
oland
26.03.2010 22:29 schrieb am "Rob Coli" :
On 3/26/10 1:36 PM, Roland Hänel wrote:
>
> If I was going to write such a tool: do you think the th...
The JMX interface exposes an Attribute which seems appropriate to this use.
It is called "TotalDiskSpaceUsed," and is availa
ig deal to integrate in
JMX if not already there.
Roland
26.03.2010 22:36 schrieb am "Mike Malone" :
2010/3/26 Roland Hänel
>
> Jonathan,
>
> I agree with your idea about a tool that could 'propose' good token
choices for op...
With the random partitioner there'
Is there any effort ongoing to make the row key a binary (byte[]) instead of
a string? In the current cassandra.thrift file (0.6.0), I find:
const string VERSION = "2.1.0"
[...]
struct KeySlice {
1: required *string* key,
2: required list columns,
}
while on the current (?) SVN
https://sv
I have a configuration like this:
/storage01/cassandra/data
/storage02/cassandra/data
/storage03/cassandra/data
After loading a big chunk of data into cassandra, I end up wich some 70GB in
the first directory, and only about 10GB in the second and third one. All
rows are q
1) you can re-balance a node with
bin/nodetool -h token []
specify a new token manually or let the system guess one.
2) take a look into your system.log to find out why your nodes are dying.
2010/4/26 刘兵兵
> i do some INSERT ,because i will do some scan operations, i use the
> OrderPres
sorry, if specifying the token manually, use:
bin/nodetool -h move
2010/4/26 Roland Hänel
> 1) you can re-balance a node with
>
> bin/nodetool -h token []
>
> specify a new token manually or let the system guess one.
>
> 2) take a look into your system.log to fi
}
> else
> {
> currentIndex = maxDiskIndex;
> }
> return dataFileDirectory;
> }
>
> So, DataFileDirectories means multiple disks or disk-partitions.
> I think your storage01, storage02 and storage03 are in same disk or disk
> partit
t; I would recommend using RAID-0 rather that multiple data directories.
> >>
> >> -ryan
> >>
> >> 2010/4/26 Roland Hänel :
> >>> I have a configuration like this:
> >>>
> >>>
> >>> /storage01/cassandra/data
>
I have a cluster of 5 machines building a Cassandra datastore, and I load
bulk data into this using the Java Thrift API. The first ~250GB runs fine,
then, one of the nodes starts to throw OutOfMemory exceptions. I'm not using
and row or index caches, and since I only have 5 CF's and some 2,5 GB of
Ryan King
> 2010/4/26 Roland Hänel :
> > Hm... I understand that RAID0 would help to create a bigger pool for
> > compactions. However, it might impact read performance: if I have several
> > CF's (with their SSTables), random read requests for the CF files that
>
time.
Thanks,
Roland
2010/4/26 Chris Goffinet
> Which version of Cassandra?
> Which version of Java JVM are you using?
> What do your I/O stats look like when bulk importing?
> When you run `nodeprobe -host tpstats` is any thread pool backing up
> during the import?
>
> -Ch
Thanks Chris
2010/4/26 Chris Goffinet
> Upgrade to b20 of Sun's version of JVM. This OOM might be related to
> LinkedBlockQueue issues that were fixed.
>
> -Chris
>
>
> 2010/4/26 Roland Hänel
>
>> Cassandra Version 0.6.1
>> OpenJDK Server VM (build
completely blocked for 8ms. If you handle the disks independently, only the
disk containing the file is blocked.
RAID0 has its advantages of course. Streaming reads/writes (e.g. during a
compaction) will be extremely fast.
-Roland
2010/4/26 Paul Prescod
> 2010/4/26 Roland Hänel :
> >
Typically, in the SQL world we use things like AUTO_INCREMENT columns that
let us create a unique key automatically if a row is inserted into a table.
What do you guys usually do to create identifiers for use in Cassandra?
Do we only rely on "currentTimeMills() + random()" to create something tha
Does Cassandra make any guarantees on the outcome of a scenario like this:
Two clients insert the same key/colum with different values at the same
time:
client A does insert(keyspace, key_1,
column_name_1, value_A, timestamp_1, consistency_level.QUORUM)
client B does insert(keyspace, key_1,
ON-STAGE0 0 293735704
>>> MESSAGE-STREAMING-POOL0 0 6
>>> LOAD-BALANCER-STAGE 0 0 0
>>> FLUSH-SORTER-POOL 0 0 0
>>> MEMTABLE-PO
imestamps, what value
is elected for repair? The first one that the node got in the read request?
If we make that deterministic, we could avoid this scenario, right?
-Roland
2010/4/28 Jonathan Ellis
> 2010/4/28 Roland Hänel :
> > Two clients insert the same key/colum with different val
only turned upside down. This could be prevented by introduction of a
tie-breaker.
Imagine the following rule: if we are in doubt whether to repair a column
with timestamp T (because two values X and Y are present within the cluster,
both at timestamp T), then we always repair towards X if md
Here is the ticket: https://issues.apache.org/jira/browse/CASSANDRA-1039
Thanks, Roland
2010/4/29 Jonathan Ellis
> 2010/4/29 Roland Hänel :
> > Imagine the following rule: if we are in doubt whether to repair a column
> > with timestamp T (because two values X and Y are pre
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