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
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
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
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
ON-STAGE0 0 293735704
>>> MESSAGE-STREAMING-POOL0 0 6
>>> LOAD-BALANCER-STAGE 0 0 0
>>> FLUSH-SORTER-POOL 0 0 0
>>> MEMTABLE-PO
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,
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
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 :
> >
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
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
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
>
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
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
>
}
> 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
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
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
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
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
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'
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
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,"
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
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
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
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