Hi Everyone,
Starting to shift focus now to the NetworkTopology strategy and how it
works with Ec2Snitch. .. or how it can be complemented. A few
questions have come to mind:
- how can i validate and assure that if RF=3 and the topology is
designed such that 2 copies are kept in 1 DC and a 3rd
Hi all,
When defining a new column family, there is the possiblity to define
columns. I see the benefit in defining the columns when I want to
explicitly define that a secondary index will be created on that
column. I also see the benefit of predefining the type of that column
if it will differ
Hi all,
FYI: The next Cassandra London meetup is tonight at Skills Matter. The focus
is Cassandra internals and CQL.
http://www.meetup.com/Cassandra-London/events/15490573/
There will be three talks:
1. Lorenzo Alberton on Bloom Filters, Merkle Trees and some interesting
variants
2. Andrew Hyd
Schema updates in cassandra tickle through the cluster over time very much like
normal writes do.
But they keep some state indicating the "parent" schema and they will only be
applied to some node if the parent schema is correct thus asserting the correct
order of schema changes. This process is
That's what I thought was happening, yes. A careful reading of the
documentation suggests that this is correct behavior.
Tyler says this can also occur because of a TimedOutException on the writes.
This worries me because TimedOutExceptions are so frequent (at least for my
test cluster), ther
> Does anyone have any intuition about whether this will happen with
> consistency_level=ALL? I will try it today, but I'd like to know what the
> expected behavior is. It seems like it would not happen in this case.
Assuming my understanding is correct (see my comment in the JIRA
ticket), then
> Schema changes should not be seen as something that can be done regularly. It
> should not be done programmatically. There should always be some operator
> looking at the cluster verifying that all nodes are reachable and ring is ok.
> And then issue schema changes one at a time using the cli.
Sharing an useful article on Cassandra Monitoring through Hyperic HQ-
http://www.theserverside.com/news/thread.tss?thread_id=62185
Regards,
Sanjay Sharma
Impetus
Are you exploring a Big Data Strategy ? Listen to this recorded webinar on
Planning your Hadoop/ No
Separate commitlog matters the most when you are
(a) doing mixed read/write workload (i.e. most real-world scenarios) and
(b) using full CL durability (batch mode rather than default periodic sync)
If your hot data set fits in memory, reads are about as fast as
writes. Otherwise they will be subs
No.
But, it is not recommended to mix default_validation_class and column
definitions. If you have a relatively static set of columns, column
definitions are recommended.
On Mon, Apr 18, 2011 at 2:23 AM, Sasha Dolgy wrote:
> Hi all,
>
> When defining a new column family, there is the possiblity
So, in the instance of a simple CF for user data:
username
fullname
birthdate
If birthdate is unix timestamp, it wont need the UTF8 validator. The
other 2 columns could. Does this then mean that a default should
-not- be set for the column family?
-sd
On Mon, Apr 18, 2011 at 3:27 PM, Jonathan
We are pleased to announce the release of Apache Cassandra 0.6.13.
This maintenance release contains fixes for a couple of recent bugs[1]
and should be an easy upgrade.
As usual, links to source and binary archives are available from the
Downloads page[2], and packages for Debian-based systems a
We are planning to deploy Cassandra on two data centers. Let us say that we
went with three replicas with 2 being in one data center and last replica in
2nd Data center.
What will happen to Quorum Reads and Writes when DC1 goes down (2 of 3 replicas
are unreachable)? Will they timeout?
R
unsubscribe
Ok, I made the changes and tried again. Here is the before modifying my
method using a simple get, confirmed the same output in the cli:
DEBUG [pool-1-thread-2] 2011-04-18 09:37:23,910 CassandraServer.java (line
279) get
DEBUG [pool-1-thread-2] 2011-04-18 09:37:23,911 StorageProxy.java (line 322)
Incidentally, if you haven't been clicking on those CHANGES links,
there hasn't been a whole lot to fix since 0.6.9 (3, 1, 5, and 2 fixes
in .10, .11, .12, and .13, respectively). It's possible that this
will be the last 0.6 release; currently, there is no 0.6.14 open in
Jira.
On Mon, Apr 18, 201
They will timeout until failure detector realizes the DC1 nodes are
down (~10 seconds). After that they will immediately return
UnavailableException until DC1 comes back up.
On Mon, Apr 18, 2011 at 10:43 AM, Baskar Duraikannu
wrote:
> We are planning to deploy Cassandra on two data centers. Let
In my case all hosts were reachable and I ran nodetool ring before running
the schema update. I don't think it was because of node being down. I tihnk
for some reason it just took over 10 secs because I was reducing key_cache
from 1M to 1000. I think it might be taking long to trim the keys hence 1
if it's not set it will be the BytesTypes where validation is a no-op.
IMHO best to keep that validation in your app.
Aaron
On 19 Apr 2011, at 01:30, Sasha Dolgy wrote:
> So, in the instance of a simple CF for user data:
>
> username
> fullname
> birthdate
>
> If birthdate is unix timestamp
If I am currently only running with one data center, can I change the
replica_placement_strategy from
org.apache.cassandra.locator.RackUnawareStrategy to
org.apache.cassandra.locator.NetworkTopologyStrategy without issue? We
are planning to add another data center in the near future and want to
be
> If I am currently only running with one data center, can I change the
> replica_placement_strategy from
> org.apache.cassandra.locator.RackUnawareStrategy to
> org.apache.cassandra.locator.NetworkTopologyStrategy without issue? We
> are planning to add another data center in the near future and
When you run the get_slice which columns are returned ?
Aaron
On 19 Apr 2011, at 04:12, Abraham Sanderson wrote:
> Ok, I made the changes and tried again. Here is the before modifying my
> method using a simple get, confirmed the same output in the cli:
>
> DEBUG [pool-1-thread-2] 2011-04-1
I wish it were consistent enough that the answer were simple... It varies
between just the requested subcolumn to all subcolumns. It always does
return the columns in order, and the requested column is always one of the
columns returned. However, the slice start is not consistently in the same
Hi all,
The problem:
Map is maintained as a simple Cassandra CF and there is a
stream of put/deletes from clients. For newly inserted rows, I need to
update solr/lucene index, by pooling from cassandra. (I know for
solandra, not asking about this)
I am to use cassandra as a classical write ahead l
Cool... Okay, the plan is to eventually not use thrift underneath, for the
CQL stuff right?
Once this is done and the new transport is in place, or evening while
designing the new transport,
is this not something that's worth looking into again? I think it'd be a
nice feature.
-Original Me
It turns out that once a TProtocolException is thrown from Cassandra the
connection is useless for future operations. Pelops was closing connections
when it detected TimedOutException, TTransportException and
UnavailableException but not TProtocolException. We have now changed Pelops to
close c
Can you could provide an example of a get_slice request that failed and the
columns that were returned, so we can see the actual bytes for the super column
and column names.
Aaron
On 19 Apr 2011, at 09:26, Abraham Sanderson wrote:
> I wish it were consistent enough that the answer were simple
Hi All,
Can you please point me to the code where cassandra is iterating
over all the sstables for a key when doing read operation on a
key.
Thanks a ton,
Regards,
Anurag
Any idea what's causing the original TPE?
On Mon, Apr 18, 2011 at 6:22 PM, Dan Washusen wrote:
> It turns out that once a TProtocolException is thrown from Cassandra the
> connection is useless for future operations. Pelops was closing connections
> when it detected TimedOutException, TTransportE
Transport isn't the problem.
On Mon, Apr 18, 2011 at 6:21 PM, Courtney Robinson wrote:
> Cool... Okay, the plan is to eventually not use thrift underneath, for the
> CQL stuff right?
> Once this is done and the new transport is in place, or evening while
> designing the new transport,
> is this n
ColumnFamilyStore.getColumnFamily
On Mon, Apr 18, 2011 at 7:15 PM, Anurag Gujral wrote:
> Hi All,
> Can you please point me to the code where cassandra is iterating
> over all the sstables for a key when doing read operation on a
> key.
> Thanks a ton,
> Regards,
> Anurag
>
--
Jon
https://github.com/facebook/flashcache/
"FlashCache is a general purpose writeback block cache for Linux."
We have a case where:
- Access to data is not uniformly random (let's say Zipfian).
- The "hot" set > RAM.
- Size of disk is such that buying enough SSDs, fast drives, multiple
drives, et
An example scenario (that is now fixed in Pelops):
Attempt to write a column with a null value
Cassandra throws a TProtocolException which renders the connection useless for
future operations
Pelops returns the corrupt connection to the pool
A second read operation is attempted with the corrupt co
I'd say that following below steps, you'll the whole logic for 'READ' path :
org.apache.cassandra.thrift.CassandraServer.get(ByteBuffer, ColumnPath,
ConsistencyLevel) ->
'org.apache.cassandra.service.StorageProxy.read(List,
ConsistencyLevel)' -> essagingService.instance().sendRR (*ReadCommand
Messa
Thanks Dan for fixing that! Is the change integrated in the latest maven
snapshot?
El mar, 19-04-2011 a las 10:48 +1000, Dan Washusen escribió:
> An example scenario (that is now fixed in Pelops):
> 1. Attempt to write a column with a null value
> 2. Cassandra throws a TProtocolException
Sure is: scale7-pelops-1.1-0.7.x-20110418.225848-3.jar
Cheers,
--
Dan Washusen
On Tuesday, 19 April 2011 at 3:58 PM, Héctor Izquierdo Seliva wrote:
> Thanks Dan for fixing that! Is the change integrated in the latest maven
> snapshot?
>
> El mar, 19-04-2011 a las 10:48 +1000, Dan Washusen escri
Hum...
Seems like it could be an idea in a case like this with a mode where result
is always returned (if possible), but where a flay saying if the consistency
level was met, or to what level it was met (number of nodes answering for
instance).?
Terje
On Tue, Apr 19, 2011 at 1:13 AM, Jonathan El
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