Hello
Every time when we do truncate, cassandra automatically create snapshots.
How can we prevent this?
Took me a while to figure out that // == parallel :)
Sorry, that's left over from Math classes :)
I'm pretty sure (but not entirely, I'd have to check the code) that
the request is forwarded as one request to the necessary node(s); what
Humm... hadn't even thought of that forwarding
Ah, I keep always assuming random partitions since it is a very common
case (just to be sure: unless you specifically want the ordering
despite the downsides, you generally want to default to the random
partitioner).
Yes, I'm working on geographical data so everything is keyed by a
Hi guys, just thought I'd chip in...
Fight My Monster is still using Cages, which is working fine, but...
I'm looking at using Cassandra to replace Cages/ZooKeeper(!) There are 2
main reasons:-
1. Although a fast ZooKeeper cluster can handle a lot of load (we aren't
getting anywhere near to
Hello everyone!
I have a strange problem with Cassandra (v1.0.5, one node, 8GB, 2xCPU):
a query asking for each key from a certain (super) CF results in timeout
and almost dead cassandra after that (it's somewhat alive, but does not
return any data - has to be restarted).
CF details:
I've written a locking mechanism for Solandra (I refer to it as a
reservation system) which basically allows you to acquire a lock. This is
used to ensure a node is service unique sequential IDs for lucene.
It sounds a bit similar to Dominic's description but I'll explain how the
Solandra one
I'd like to second this. I've been working with Cassandra for a good while now,
but when I first started little things like this were confusing.
From: Don Smith [mailto:dsm...@likewise.com]
Sent: Friday, December 09, 2011 3:41 PM
To: user@cassandra.apache.org
Subject: Suggestion about syntax of
Hello everyone,
I seem to have came across rather weird (at least for me!) problem /
behaviour with Cassandra.
I am running a 4-nodes cluster on Cassandra 0.8.7. For the keyspace in
question, I have RF=3, SimpleStrategy with multiple ColumnFamilies inside
the KeySpace. On of the ColumnFamilies
You've got at least one row over 1GB, compacted !
Have you checked whether you are running out of heap ?
2011/12/12 Wojtek Kulik wojtek.ku...@futureful.com
Hello everyone!
I have a strange problem with Cassandra (v1.0.5, one node, 8GB, 2xCPU): a
query asking for each key from a certain
This is a tad annoying there are a few commands that snapshot for safety
reasons. truncate, scrub, and maybe cleanup. You have to keep mental note
to run nodetool clearsnapshot a few seconds after running these.
On Mon, Dec 12, 2011 at 3:29 AM, ruslan usifov ruslan.usi...@gmail.comwrote:
Hello
What java are you using? OpenJDK or Sun/Oracle
(http://www.oracle.com/technetwork/java/javase/downloads/index.html)?
If you are using OpenJDK you might try Sun. Have you run diagnostics on
the disk? It is more likely there is an issue with your disk, not with
Cassandra.
On 12/11/2011
- We are seeing DecoratedKey error during compaction. Looks like the
sha1sum of the data file doesn't match the digest file created by
cassandra. I dont have any clue where things are failing. It could be
either at OS level, ESXi HBA level, or the DotHill iSCSI raid layer.
- We are using sun JRE
Here's the situation. We're running a 2-node cluster on EC2 (v 0.8.6). Each
node writes data to a mounted EBS volume mounted on /mnt2.
On Dec. 9th, for some reason both instances were rebooted (not sure yet
what triggered the reboot). But the EBS volumes were not added to
/etc/fstab, and didn't
Dominic/Jake: very interesting. This is getting more into fundamentals on
locking/isolation rather than transactions/atomicity, but it is still
relevant as I was going to use ZooKeeper for that stuff, but it would
certainly nice to KISS and remove a component from my setup if I can do
without it.
Hi Dominic,
So I responded to your algorithm in another part of this thread (very
interesting) but this part of the paper caught my attention:
When client application code releases a lock, that lock must not actually
be
released for a period equal to one millisecond plus twice the maximum
Jake: The algorithm you've outlined is pretty similar to how Zookeeper
clients implement locking. The potential only issue that I see with it
implemented in Cassandra is that it uses the timestamps of the inserted
columns to determine the winner of the lock. The column timestamps are
What is the syntax for each_quorum in pycassa ?
Thanks.
pycassa.ConsistencyLevel.EACH_QUORUM
On Mon, Dec 12, 2011 at 2:51 PM, A J s5a...@gmail.com wrote:
What is the syntax for each_quorum in pycassa ?
Thanks.
--
Tyler Hobbs
DataStax http://datastax.com/
Hi,
We simulated a node 'failure' on one of our nodes by deleting the entire
Cassandra installation directory reconfiguring a fresh instance with the
same token. When we issued a 'repair' it started streaming data back onto
the node as expected.
However after the repair completed, we had over
Hey Jake,
So I guess my problem is that I've never really relied on NTP before to try
to guarantee consistency in my application. Does it tend to work really
well in practice? What's the maximum clock skew you can see even when
running NTP (especially if you're using more than one DC where you
If you don't want downtime, you can take the original data and use the
bulk sstable loader to send it back into the cluster. If you don't mind
downtime you can take all the files from both data folders and put them
together, make sure there aren't any with the same names (rename them if
there
On Mon, Dec 12, 2011 at 3:47 PM, Brian Fleming bigbrianflem...@gmail.comwrote:
However after the repair completed, we had over 2.5 times the original
load. Issuing a 'cleanup' reduced this to about 1.5 times the original
load. We observed an increase in the number of keys via 'cfstats'
On 12/12/2011 12:53 PM, Stephane Legay wrote:
On Dec. 9th, for some reason both instances were rebooted (not sure yet
what triggered the reboot).
You should have received an emailed reboot schedule - this has an example:
That's good to know, thanks. I'm looking through my inbox but can't find
the notification you're referring to.
Oh well. Looks like we'll survive the day. That wasn't much fun at all.
On Mon, Dec 12, 2011 at 4:50 PM, Michael Shuler mich...@pbandjelly.orgwrote:
On 12/12/2011 12:53 PM, Stephane
Hello,
I know that this problem used to exist in 0.8.1 --
I delete rows, run a repair and these rows are back with
a vengeance. I recall I was told that this was fixed in 0.8.6 --
is that the case? I still keep seeing that behavior.
Thanks
Maxim
Hi,
We are running 1.0.3. I tried to restart a node, but it won't come up.
Below is the error logged:
INFO [SSTableBatchOpen:1] 2011-12-13 04:14:52,095 SSTableReader.java (line
134) Opening /u01/cassandra/data/system/HintsColumnFamily-hb-114 (66 bytes)
INFO [main] 2011-12-13 04:14:52,145
Hi,
'threads' are nested in a 'forum', therefore, I decided to create a
column-family 'thread' with a column named 'parent'.
Is this idea matched with Cassandra philosophy? Because I feel that
extracting the data recursively is computational hungry for a site like
reddit.com.
Therefore one
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