Re: Basic question on a write operation immediately followed by a read

2011/1/25 Wangpei (Peter) > What is the ConsistencyLevel value? Is it ConsistencyLevel.ANY? > > I am using Hector 0.7.0-22 and getting keyspace as * HFactory.createKeyspace()*, which seems to be defaulting the consistency level to QUORAM for both reads and writes. Nowhere else, it is explicitly

Re: Basic question on a write operation immediately followed by a read

> Is there a possibility that my read operation may miss the data that just got inserted? If write operation did not resulted in exception and there was no other clients writing to the same row/column concurrently - you will read exactly what you just written. > > Since there are no DB transactio

Re: Basic question on a write operation immediately followed by a read

What is the ConsistencyLevel value? Is it ConsistencyLevel.ANY? Javadoc: * Write consistency levels make the following guarantees before reporting success to the client: * ANY Ensure that the write has been written once somewhere, including possibly being hinted in a non-target node.

Re: client threads locked up - JIRA ISSUE 1594

I'm using Cassandra 0.6.8. I'm not using Hector - it's just raw thrift APIs. Arijit On 21 January 2011 22:13, Nate McCall wrote: > What versions of Cassandra and Hector? The versions mentioned on this > ticket are both several releases behind. > > On Fri, Jan 21, 2011 at 3:53 AM, Arijit Mukherje

Re: Basic question on a write operation immediately followed by a read

2011/1/25 Patricio Echagüe > Roshan, when a client invoke a write, the write goes first to commit log > and later to memtable. After that it returns to the client. > > After it reaches the memtable, that data is ready to be read. > > The reads consolidates de data from the memtables and sstables

Re: Basic question on a write operation immediately followed by a read

Roshan, when a client invoke a write, the write goes first to commit log and later to memtable. After that it returns to the client. After it reaches the memtable, that data is ready to be read. The reads consolidates de data from the memtables and sstables unless there is a hit in the row cache.

Re: Basic question on a write operation immediately followed by a read

Thanks for your inputs, Victor. In my app, it's a bit event driven. We do writes and fire events and listeners then read - so we can't predict how soon the reads will come. Sometimes they came too fast, which is better for our app, if we can have a Cassandra DB level understanding that they won't

Re: Basic question on a write operation immediately followed by a read

On Tue, Jan 25, 2011 at 9:57 AM, Victor Kabdebon wrote: > As far as I remember, please correct me if I am wrong, on a one node > cluster : > First Commitlog is updated then almost immediatly after order is send to > the memtable to add this new insert. You might have a very short delay > between t

Re: Basic question on a write operation immediately followed by a read

2011/1/25 Patricio Echagüe > Roshan, for specifics have a look at > http://wiki.apache.org/cassandra/ArchitectureOverview specially where it > says "Write path". I went through the "Write path" section and have a small follow-up question, please - again assuming a 1-node setup for now. How muc

Re: Basic question on a write operation immediately followed by a read

On Tue, Jan 25, 2011 at 9:32 AM, Victor Kabdebon wrote: > Roshan, just remember, what you do on a one node cluster might not be valid > on a 5 node cluster. Depending on the way your insert and query (QUORUM, > ALL, ... ) your data might not be available to get, yet it will be in your > cluster. I

Re: Basic question on a write operation immediately followed by a read

Thanks, Victor. Even in our application, it will be an advantage if the data can be immediately read and reads don't miss it for even the smallest amount of time after write queries have been executed at the app level. I am in the middle of migrating an app to Cassandra and observing some small a

Stress test inconsistencies

Hi All, I am struggling to make sense of a simple stress test I ran against the latest Cassandra 0.7. My server performs very poorly compared to a desktop and even a notebook. Here is the command I execute - a single threaded insert that runs on the same host as Cassnadra does (I am using new con

Re: Does Major Compaction work on dropped CFs? Doesn't seem so.

Thanks Aaron. As I remarked earlier (and it seems it not uncommon) none of the nodes have X11 installed (I think I could arrange this, but it's a bit of a hassle). So if I understand correctly, jconsole is a X11 app, and I'm out of luck with that. I would agree with you that having a proper nodet

Basic question on a write operation immediately followed by a read

Hi, I have a basic question - maybe silly too. Say, I have a 1-node Cassandra setup (no replication, eventual consistency, etc) and I do an insert into a column family and then very close in time to the insert, I do a read on it for the same data. Is there a possibility that my read operation ma

Re: Does Major Compaction work on dropped CFs? Doesn't seem so.

An alternative is to force a full GC through JConsole. Am wondering out loud if we can add a JMX Operation to delete unneeded SSTables without needing to kick of GC.  AaronOn 25 Jan, 2011,at 02:41 PM, buddhasystem wrote: Thanks for the note, yes, I do know what files I don't need anymore. And, I

Re: Cassandra + Puppet

Thanks all.AOn 25 Jan, 2011,at 02:42 PM, Edward Capriolo wrote:On Mon, Jan 24, 2011 at 5:17 PM, Nate McCall wrote: > Might be a bit out of date, but this one is useful: > https://github.com/cmceniry/cassandrapuppet > > > > On Mon, Jan 24, 2011 at 3:51 PM, Aaron Morton

Re: Cassandra + Puppet

On Mon, Jan 24, 2011 at 5:17 PM, Nate McCall wrote: > Might be a bit out of date, but this one is useful: > https://github.com/cmceniry/cassandrapuppet > > > > On Mon, Jan 24, 2011 at 3:51 PM, Aaron Morton wrote: >> Is anyone using puppet http://www.puppetlabs.com/ to deploy / manage >> cassandra

Re: Does Major Compaction work on dropped CFs? Doesn't seem so.

Thanks for the note, yes, I do know what files I don't need anymore. And, I do realize the difference between grace period of CFs, and garbage collection (or at least I hope I do). On the face value, documentation wasn't precise enough about JVM GC taking care of dropped CFs. I understand this i

Re: Does Major Compaction work on dropped CFs? Doesn't seem so.

Do you have a list of the files you think are not been deleted ? The GC referred to here is deleting whole SSTables on disk that are no longer needed either due to compaction or dropping the CF. This is different to the GCGraceSeconds which refers to the minimum duration a deletion Tombstone should

Re: Does Major Compaction work on dropped CFs? Doesn't seem so.

OK, so I'm looking at this page: http://wiki.apache.org/cassandra/MemtableSSTable This looks promising: "A compaction marker is also added to obsolete sstables so they can be deleted on startup if the server does not perform a GC before being restarted." So it would seem that if I restart the s

Re: Schema Question

Sam, The best advice is to jump in and try any schema If you are just starting out, start simple you're going to re-write it several times. Worry about scale later, in most cases it's going to work. Some general points:- do not create CF's on the fly. - work out your common read requests and denorm

Re: Repair on single CF not working (0.7)

On Mon, Jan 24, 2011 at 4:15 PM, Dan Hendry wrote: > I am trying to repair a single CF using nodetool. It seems like the request > to limit the repair to one CF is not being respected. Here is my current > situation: > > - Run “nodetool repair *KEYSPACE* CF_A” on node 3 > > -

Re: Cassandra + Puppet

Might be a bit out of date, but this one is useful: https://github.com/cmceniry/cassandrapuppet On Mon, Jan 24, 2011 at 3:51 PM, Aaron Morton wrote: > Is anyone using puppet http://www.puppetlabs.com/ to deploy / manage > cassandra  ? > Has anyone used this > module https://github.com/plathrop/

Repair on single CF not working (0.7)

I am trying to repair a single CF using nodetool. It seems like the request to limit the repair to one CF is not being respected. Here is my current situation: - Run "nodetool repair KEYSPACE CF_A" on node 3 - Validation compaction runs on nodes 2,3,4 for CF_A only (expected)

Re: Lost MUTATIONS on several Cassandra nodes - no impact on the client

2011/1/24 Jonathan Ellis > Currently it does not. > > And it is planned to make? And when? Or it not an important feature?

Cassandra + Puppet

Is anyone using puppet http://www.puppetlabs.com/ to deploy / manage cassandra  ? Has anyone used this module https://github.com/plathrop/puppet-module-cassandra or using it for backups http://www.edwardcapriolo.com/roller/edwardcapriolo/entry/cassandra_backup_is_a_snap or know of any other resourc

Re: Forcing GC w/o jconsole

> What port number do I actually need? 8080 (well, up until just very recently in trunk). Look at the VM options Cassandra is running with and you'll see the JMX agent port: -Dcom.sun.management.jmxremote.port=8080 -- / Peter Schuller

Forcing GC w/o jconsole

My situation is similar to one described at this link: http://stackoverflow.com/questions/4155696/how-to-trigger-manual-java-gc-from-linux-console-with-no-x11 I'm trying the following command but it fails (connection refused) java -jar cmdline-jmxclient-0.10.3.jar - localhost:8081 java.lang:type

Re: Range scan returns more results then expected (Using ByteOrderedPartitioner)

I see, now it makes perfect sense. Thank you. On Mon, Jan 24, 2011 at 11:05 PM, Aaron Morton wrote: > It's not pattern matching, it's comparing / ordering the byte values. You > are asking to return 100 keys in ascending order where the value of the key > (after the partitioner has been applied)

Re: Range scan returns more results then expected (Using ByteOrderedPartitioner)

It's not pattern matching, it's comparing / ordering the byte values. You are asking to return 100 keys in ascending order where the value of the key (after the partitioner has been applied) is greater than "1_265_8_12" If you want to do a seek and partial scan, you could use an end value in the li

Re: Does Cassandra support range queries on keys ?

I found this on the wiki, may be useful http://wiki.apache.org/cassandra/LargeDataSetConsiderationsAaronOn 24 Jan, 2011,at 09:26 PM, Peter Schuller wrote:> Following your suggestions, of using key of super column as range token > won't I have a storage problem? You won't get me to proclaim that y

Re: Multiple indexes - how does Cassandra handle these internally?

Timo, Below is a test I did via the CLI, it worked as expected for me. If you're still experiencing the problem could you try to repro it like this ?Paste this into the CLI to setup the schema and data create keyspace index_test     with replication_factor = 1;use index_test;create column family In

Re: Multiple indexes - how does Cassandra handle these internally?

Maxim, Off the top of my head I'm not aware of any limitations in the indexes (other than the operators). This will give me a reason to dig into the code further and do some more reading Can you provide some more info on the system (in another thread) and the group may be able to help with the desi

Range scan returns more results then expected (Using ByteOrderedPartitioner)

Hello, Cassandra is configure as following: conf/cassandra.yaml | grep 'partitioner:' partitioner: org.apache.cassandra.dht.ByteOrderedPartitioner Why yet doing range query on part of the key return more results then expected (column, CF and keyspace names masked): [default@KEYSPACE] list CF1

Re: How does Bootstrapping work in 0.7 ??

Thanks very much Patrick for the good words and suggestions. Those are important points about initial_token and nodetool move. Definitely, keep us informed about any and all doc issues you have, and we will do what we can to keep improving the docs. Eric On Sun, Jan 23, 2011 at 2:26 PM, Patrick

Re: Lost MUTATIONS on several Cassandra nodes - no impact on the client

Currently it does not. On Mon, Jan 24, 2011 at 10:35 AM, ruslan usifov wrote: > Thanks for very  useful explanations, i have a last question about > batch_mutate method, does it guarantee that if any mutation in mutations > list will throw UnavailableException, all batch will throw > UnavailableE

Re: Lost MUTATIONS on several Cassandra nodes - no impact on the client

2011/1/23 Edward Capriolo > On Sun, Jan 23, 2011 at 11:23 AM, ruslan usifov > wrote: > > > > > > > >> On Sun, Jan 23, 2011 at 6:30 AM, ruslan usifov > > >> wrote: > >> > >> Right. The difference is that the gossip process builds a topology of > >> UP/DOWN hosts so Unavailable is thrown quickly.

Re: Question re: the use of multiple ColumnFamilies

Yes, that's exactly so. I have no need for multiple DataFileDirectories, except that it was a convenient way to test the hypothesis that the performance bottleneck I was experiencing due to writing only one sstable to disk at once could be solved by increasing the queue size for the writer (the

Re: Does Cassandra support range queries on keys ?

> Following your suggestions, of using key of super column as range token > won't I have a storage problem? You won't get me to proclaim that you won't have a storage problem ;) If you're going to deploy this at scale, I'm sure you'll have problems whatever you do... > I couldn't find informatio

Re: about the partitioner type

The OrderPreservingPartitioner will treat the key byte array as a UTF8 string. Specifically it uses the nio Charset decoder http://download.oracle.com/javase/1.4.2/docs/api/java/nio/charset/Charset.html to turn the byte array into a string. The ByteOrderedPartitioner will treat the key as a sim