Cassandra at least used to do disc cleanup as a side effect of
garbage collection through finalizers. (This is a mistake for the
reason outlined below.)
It is important to understand that you can *never* force* a gc in java.
Even calling System.gc() is merely a hint to the VM. What you are doing
I get this error:
bin/cassandra: syntax error at line 29: `system_memory_in_mb=$' unexpected
Thanks
JK
--
It's always darkest just before you are eaten by a grue.
Ah. That solved it. ty.
On Mon, May 9, 2011 at 11:29 AM, Roland Gude roland.g...@yoochoose.com wrote:
Use bash as a shell
#bash bin/cassandra -f
-Ursprüngliche Nachricht-
Von: Jeffrey Kesselman [mailto:jef...@gmail.com]
Gesendet: Montag, 9. Mai 2011 17:12
An: user
If this a 64bit VM?
A 32bit Java VM with default c-heap settings can only actually use
about 2GB of Java Heap.
On Thu, May 12, 2011 at 8:08 PM, James Cipar jci...@cmu.edu wrote:
Oh, forgot this detail: I have no swap configured, so swapping is not the
cause of the crash. Could it be that
I believe coherence is their name for the TimesTen technology they bought.
TT is an in memory SQL database that can run as a cache for Oracle.
Its totally different from Cassandra. On the one hand it supports
trad SQL whereas Cassandra does not. On the other hand Cassandra is
truly
What consistency are you asking for?
On Fri, May 20, 2011 at 7:42 AM, Dikang Gu dikan...@gmail.com wrote:
Hi All,
I'm running three cassandra 0.7.4 nodes in a cluster, and I give 2G memory
to each node.
Now, I get the cfstats here:
Keyspace: UserMap
Read Count: 38411
Read Latency:
TCP/IP byte over-head v. UDP really isnt that much if your packets are
of any significant size (its 30 bytes).
And as others have pointed out you can easily get more over-head with
worse results trying to reinvent reliable transport on top of UDP.
Remember that TCP/IP has had 30 years of
scalable across LAN and WAN.
In terms of comparing Cassandra and Coherence, I wouldn't. Coherence
is a data grid and most often used as a fault tolerant distributed
cache, though it does a lot more than that. Oracle bought Tangosol a
few years back.
On Fri, May 20, 2011 at 4:23 AM, Jeffrey
Actually this is no gaurantee. Its a common misunderstanding that
System.gc forces gc. It does not. It is a suggestion only. The vm always
has the option as to when and how much it gcs
On May 26, 2011 2:51 PM, Jonathan Ellis jbel...@gmail.com wrote:
misunderstanding that system.gc is only a suggestion; on
any VM you're likely to run Cassandra on, System.gc will actually
invoke a full collection.
On Thu, May 26, 2011 at 2:18 PM, Jeffrey Kesselman jef...@gmail.com wrote:
Actually this is no gaurantee. Its a common misunderstanding
, Jeffrey Kesselman jef...@gmail.com wrote:
Actually this is no gaurantee. Its a common misunderstanding that
System.gc forces gc. It does not. It is a suggestion only. The vm always
has the option as to when and how much it gcs
On May 26, 2011 2:51 PM, Jonathan Ellis jbel...@gmail.com wrote
is
simply good engineering.
On Thu, May 26, 2011 at 4:51 PM, Jonathan Ellis jbel...@gmail.com wrote:
I've read the relevant source. While you're pedantically correct re
the spec, you're wrong as to what the JVM actually does.
On Thu, May 26, 2011 at 3:14 PM, Jeffrey Kesselman jef...@gmail.com wrote
Cassandra
to get rid of all of the extra space it is using on disk?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector
?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number
. While you're pedantically correct re
the spec, you're wrong as to what the JVM actually does.
On Thu, May 26, 2011 at 3:14 PM, Jeffrey Kesselman jef...@gmail.com wrote:
Some references...
An object enters an unreachable state when no more strong references
to it exist. When an object
Well, my information is old...
But back in the heyday of VMs, JRockit really only had one specific
area of performance advantage, which was in message passing, and all
their benchmarks were tweaked to play to that.
Id say its not coincidence that oracle has made this free shortly
after they
, 2011-06-05 at 00:51 -0400, Jeffrey Kesselman wrote:
Is CQL really the path for the future for Cassandra?
CQL is no more or less official than the Thrift interface, and TTBMK,
there is no secret cabal that met to decide it would be The Way. People
will use what works best for them, and if a de
While I agree the Thrift API sucks, Id love to see that sovled on a
binary level, and CQl on top of that.
JK
On Wed, Jun 8, 2011 at 2:50 PM, Marcos Ortiz mlor...@uci.cu wrote:
On 06/08/2011 01:23 PM, SriSatish Ambati wrote:
Gotta love, Eric!
to something else underneath that's
more efficient and CQL itself wouldn't have to change at all.
On Jun 8, 2011, at 1:29 PM, Jeffrey Kesselman wrote:
While I agree the Thrift API sucks, Id love to see that sovled on a
binary level, and CQl on top of that.
JK
On Wed, Jun 8, 2011 at 2:50 PM
Correct me if I'm wrong, but AFAIK Hector is the only higher level
APi I would consider complete' right now, with support for things
like fail-over.
I notice in the latest Hector build he is starting to add CQL support,
so thats what I'm sticking with. When he has CQL support done I'll
decide
files stay more than 10 hours already. There is no guarantee that
gc will cleanup all compacted sstable files.
We have a great interest on the following ticket.
https://issues.apache.org/jira/browse/CASSANDRA-2521
Regards,
Shotaro
On Fri, May 27, 2011 at 11:27 AM, Jeffrey Kesselman jef
I'm using Hector. AFAIK its the only one that supports failover today.
On Fri, Jun 17, 2011 at 6:02 PM, Daniel Colchete d...@cloud3.tc wrote:
Good day everyone!
I'm getting started with a new project and I'm thinking about using
Cassandra because of its distributed quality and because of its
GetLong has to get it a byte at a time still to support endianess.
Id have to think about it, but what you really want is to get it all
into a byte array and then process it in 64bits. AIR there are some
new array recasting things in Java 5+. Ill need to go look at them
more closely...
On Fri,
I'd fetch it all at once into a single byte array and try Arrays.equals()
On Sat, Jul 2, 2011 at 12:45 PM, Jeffrey Kesselman jef...@gmail.com wrote:
GetLong has to get it a byte at a time still to support endianess.
Id have to think about it, but what you really want is to get it all
Hi Jonnathan,
This brings up an important question. I have been assuming that the
validation check is part of the atomic update operation. Is this NOT the
case? Which is to say, can the row be changed between the time the
validation method is executed and the validated data is written?
The
The old row is accessible and my validation requires a comparison of the
two.
JK
On Thu, Jul 7, 2011 at 3:23 PM, Yang tedd...@gmail.com wrote:
validation is on the new incoming column ,not the old row,right?
On Jul 7, 2011 8:25 AM, Jeffrey Kesselman jef...@gmail.com wrote:
Hi Jonnathan
insertion can happen in parallel
On Jul 7, 2011 9:24 AM, Jeffrey Kesselman jef...@gmail.com wrote:
This has me more confused.
Does this mean that ALL rows on a given node are only updated
sequentially,
never in parallel?
On Thu, Jul 7, 2011 at 3:21 PM, Yang tedd...@gmail.com wrote
not to change
underneath the validation call?
On Thu, Jul 7, 2011 at 3:43 PM, Yang tedd...@gmail.com wrote:
no , the memtable is a concurrentskiplistmap
insertion can happen in parallel
On Jul 7, 2011 9:24 AM, Jeffrey Kesselman jef...@gmail.com wrote:
This has me more confused.
Does
Not confusing, but assuming a few things.
I made a more detailed post in the Datatstax forums.
On Thu, Jul 7, 2011 at 10:27 PM, Jonathan Ellis jbel...@gmail.com wrote:
Sounds to me like you're confusing atomicity with isolation.
On Thu, Jul 7, 2011 at 2:54 PM, Jeffrey Kesselman jef
with isolation.
On Thu, Jul 7, 2011 at 2:54 PM, Jeffrey Kesselman jef...@gmail.com
wrote:
Yup, im even more confused.Lets talk about the model, not the
implementation.
AIUI updates to a row are atomic across all columns in that row at once,
true?
If true then the next question
Really, as i lay in the bath thinking nabout it, I concluded what I am
looking for is a very limited form of Consistency.
Its consistency over a single row on a single node just for the period of
update.
On Thu, Jul 7, 2011 at 10:34 PM, Jeffrey Kesselman jef...@gmail.com wrote:
Its not really
). But, if A' and B are
changes to a different set of columns, I believe that would interleave,
which itself could be inconsistent from your application's point of view.
will
On Thu, Jul 7, 2011 at 11:41 PM, Jeffrey Kesselman jef...@gmail.comwrote:
Really, as i lay in the bath thinking
I am confused by what you mean by Cassandra client code. Is this part of
the Cassnadra server?
My architecture is my user talks thrift to Cassandra.
, coordinator sends Am to the replica owners,
effectively creating A'.
Neither A nor A' is ever explicitly assembled on the write path.
On Fri, Jul 8, 2011 at 9:22 AM, Jeffrey Kesselman jef...@gmail.com
wrote:
Not quite, its more limited and specific
The order of operations is all within
.
will
On Fri, Jul 8, 2011 at 11:08 AM, Jeffrey Kesselman jef...@gmail.comwrote:
I am confused by what you mean by Cassandra client code. Is this part
of the Cassnadra server?
My architecture is my user talks thrift to Cassandra.
--
It's always darkest just before you are eaten by a grue.
sequence for the type we are supposed to be comparing,
which sounds like a local operation to me (e.g. it shouldn't fetch remote
data, it's just saying yep, this is a valid member of type T).
will
On Fri, Jul 8, 2011 at 11:17 AM, Jeffrey Kesselman jef...@gmail.com
wrote:
Alright,
So
,
which sounds like a local operation to me (e.g. it shouldn't fetch remote
data, it's just saying yep, this is a valid member of type T).
will
On Fri, Jul 8, 2011 at 11:17 AM, Jeffrey Kesselman jef...@gmail.com
wrote:
Alright,
So are you saying the column validator, as specified
Are you on a 64 bit VM? A 32 bit vm will basically ignore any setting over
2GB
On Mon, Jul 11, 2011 at 4:55 PM, Anurag Gujral anurag.guj...@gmail.comwrote:
Hi All,
I am getting following error from cassandra:
ERROR [ReadStage:23] 2011-07-10 17:19:18,300
Im not sure if I have an answer for you, anyway, but I'm curious
A b-tree and a binary tree are not the same thing. A binary tree is a
basic fundamental data structure, A b-tree is an approach to storing and
indexing data on disc for a database.
Which do you mean?
On Wed, Jul 20, 2011 at
Technically, by the VM spec, you can never *force* a java VM to garbage
collect. You can request, but thats it.
Rather then open that whole debate again if anyone doubts this, i suggets
they look back in the archives.
JK
On Thu, Aug 4, 2011 at 6:35 PM, Teijo Holzer thol...@wetafx.co.nz
, so we doesn't need patch cassandra or thrift
code.
I found this article
https://wiki.cs.columbia.edu:8443/pages/viewpage.action?pageId=12585536,
where упоминается mentioned coreTransport.TcpClient.NoDelay, but what is
this i misunderstand
2012/1/26 Jeffrey Kesselman jef...@gmail.com
It should be noted that, in a distributed storage environment, scripting
*at the node of storage* is much more powerful then higher up at some
broker. Its easy to do this wrong.
2012/4/27 Data Craftsman database.crafts...@gmail.com
Howdy,
Some Polyglot Persistence(NoSQL) products started
Btw. I suggest you spin up JConsole as it will give you much more detai
kon what your VM is actually doing.
On Mon, Jun 11, 2012 at 9:14 PM, Jason Tang ares.t...@gmail.com wrote:
Hi
We have some problem with Cassandra memory usage, we configure the JVM
HEAP 6G, but after runing Cassandra
: Jeffrey Kesselman jef...@gmail.commailto:jef...@gmail.com
Reply-To: user@cassandra.apache.orgmailto:user@cassandra.apache.org
user@cassandra.apache.orgmailto:user@cassandra.apache.org
To: user@cassandra.apache.orgmailto:user@cassandra.apache.org
user@cassandra.apache.orgmailto:user
True consistancy, btw, pretty much is only possible in a transactional
environment.
On Thu, Aug 2, 2012 at 12:56 AM, Jeffrey Kesselman jef...@gmail.com wrote:
Roshni,
Thats not what consistancy in ACID means. Its not consistancy of reading
the ame data, its referntial integrity between
I haven't run Cassandra in production myself, but for other high load Java
based servers I've had really good scaling success with OpenSolaris. In
particular I've used Joyent's SmartOS which has the additional advantage
of bursting to cover brief periods of exceptional load.
On Tue, Feb 11,
I've built.
On Wed, Feb 12, 2014 at 1:52 PM, Robert Coli rc...@eventbrite.com wrote:
On Wed, Feb 12, 2014 at 8:55 AM, Jeffrey Kesselman jef...@gmail.comwrote:
I haven't run Cassandra in production myself, but for other high load
Java based servers I've had really good scaling success
why do you call it an ORM when Cassandra is not relational?
On Wed, Feb 19, 2014 at 11:39 AM, Matthew A. Brown mat.a.br...@gmail.comwrote:
Hi all,
I recently released version 1.0 of Cequelhttps://github.com/cequel/cequel,
a high-level Ruby library for Cassandra using CQL3. Version 1.0
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