Re: Inter node communication over UDP
I am working on version 0.7.6 of cassandra. I have been looking into the code to identify communication between nodes. it seems to me that both inter-node and servernode-client communication happens using thrift protocol, is my understanding correct? and the gossiper communication takes place using tcp and message queue? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Inter-node-communication-over-UDP-tp6358459p6384978.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
How to reduce the Read Latency.
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: 123.54214613001484 ms. Write Count: 44155 Write Latency: 0.02341093873853471 ms. Pending Tasks: 0 Column Family: Map SSTable count: 3 Space used (live): 32704387 Space used (total): 32704387 Memtable Columns Count: 49 Memtable Data Size: 3348 Memtable Switch Count: 56 Read Count: 38411 Read Latency: 123.542 ms. Write Count: 44155 Write Latency: 0.023 ms. Pending Tasks: 0 Key cache capacity: 20 Key cache size: 611 Key cache hit rate: 0.9294361241314483 Row cache: disabled Compacted row minimum size: 125 Compacted row maximum size: 17436917 Compacted row mean size: 147647 You can find that the Read Latency is really high here, so what can I do to reduce the latency? Give more memory to the three nodes? Any other options? Thanks. -- Dikang Gu 0086 - 18611140205
CQL: Select for multiple ranges
In order to fully implement the functionality of super columns using compound columns I need to be able to select multiple column ranges - this would be functionally equivalent to selecting multiple super columns (and more!). I would like to request the following CQL syntax: SELECT [FIRST N] [REVERSED] name1..nameN1, name2..nameN2... FROM ... I am heading into my weekend here. If no one has created a JIRA ticket for this by Sunday, and I am not talked out of it, I will create one myself.
[RELEASE] Apache Cassandra 0.7.6-2 released
Apache Cassandra 0.7.6 is just 2 days old, but it shipped with a bug in the debian packaging code that prevents the package from being successfully installed. Since debian packaging is an integral part of the project, 0.7.6-2 comes to fix this issue. This is the only change[1] that separate 0.7.6-2 from 0.7.6, so if you don't use debian and have already upgraded to 0.7.6, you can safely upgrade 0.7.6-2 or simply skip that version. For the debian users, this will fix the error you may have seen during the upgrade to 0.7.6. As always, all relevant details are in the release notes[2] and please let us know if you encounter any problem[3]. And sorry for the inconvenience. The Cassandra Team. [1]: http://goo.gl/BfuBh (CHANGES.txt) [2]: http://goo.gl/y8gGF (NEWS.txt) [3]: https://issues.apache.org/jira/browse/CASSANDRA
Re: Cassandra Vs. Oracle Coherence
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 distributed and fault tolerant, whereas TT is not. I suggest getting and reading the Oriely Cassandra book. JK On Tue, May 17, 2011 at 10:44 PM, Karamel, Raghu raghu_kara...@intuit.com wrote: Hi, I am new to Cassandra and very excited with the technology. I am evaluating it and trying to understand the difference between Cassandra and Oracle Coherence. Precisely , looking for reasons why would some select Cassandra over Oracle Coherence. Does anyone did the exercise of comparing them? Appreciate if you can share some information on that. Regrads -RK -- It's always darkest just before you are eaten by a grue.
Re: How to reduce the Read Latency.
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: 123.54214613001484 ms. Write Count: 44155 Write Latency: 0.02341093873853471 ms. Pending Tasks: 0 Column Family: Map SSTable count: 3 Space used (live): 32704387 Space used (total): 32704387 Memtable Columns Count: 49 Memtable Data Size: 3348 Memtable Switch Count: 56 Read Count: 38411 Read Latency: 123.542 ms. Write Count: 44155 Write Latency: 0.023 ms. Pending Tasks: 0 Key cache capacity: 20 Key cache size: 611 Key cache hit rate: 0.9294361241314483 Row cache: disabled Compacted row minimum size: 125 Compacted row maximum size: 17436917 Compacted row mean size: 147647 You can find that the Read Latency is really high here, so what can I do to reduce the latency? Give more memory to the three nodes? Any other options? Thanks. -- Dikang Gu 0086 - 18611140205 -- It's always darkest just before you are eaten by a grue.
Re: Inter node communication over UDP
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 development and tuning. On Fri, May 20, 2011 at 7:39 AM, pankajsoni0126 pankajsoni0...@gmail.com wrote: I am working on version 0.7.6 of cassandra. I have been looking into the code to identify communication between nodes. it seems to me that both inter-node and servernode-client communication happens using thrift protocol, is my understanding correct? and the gossiper communication takes place using tcp and message queue? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Inter-node-communication-over-UDP-tp6358459p6384978.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com. -- It's always darkest just before you are eaten by a grue.
Re: How to reduce the Read Latency.
I use the default consistency level in the hector client, so it should be QUORUM. -- Dikang Gu 0086 - 18611140205 On Friday, May 20, 2011 at 4:25 PM, Jeffrey Kesselman wrote: 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: 123.54214613001484 ms. Write Count: 44155 Write Latency: 0.02341093873853471 ms. Pending Tasks: 0 Column Family: Map SSTable count: 3 Space used (live): 32704387 Space used (total): 32704387 Memtable Columns Count: 49 Memtable Data Size: 3348 Memtable Switch Count: 56 Read Count: 38411 Read Latency: 123.542 ms. Write Count: 44155 Write Latency: 0.023 ms. Pending Tasks: 0 Key cache capacity: 20 Key cache size: 611 Key cache hit rate: 0.9294361241314483 Row cache: disabled Compacted row minimum size: 125 Compacted row maximum size: 17436917 Compacted row mean size: 147647 You can find that the Read Latency is really high here, so what can I do to reduce the latency? Give more memory to the three nodes? Any other options? Thanks. -- Dikang Gu 0086 - 18611140205 -- It's always darkest just before you are eaten by a grue.
Re: Inter node communication over UDP
On Fri, May 20, 2011 at 9:39 AM, pankajsoni0126 pankajsoni0...@gmail.com wrote: I am working on version 0.7.6 of cassandra. I have been looking into the code to identify communication between nodes. it seems to me that both inter-node and servernode-client communication happens using thrift protocol, is my understanding correct? No. inter-node communication uses MessagingService that itself uses OutboundTcpConnection that just write serialized Message to a tcp socket (using a message queue). None of this uses thrift. and the gossiper communication takes place using tcp and message queue? Yes, but actually gossip uses MessagingService too. So gossip communication is really just one type of inter-node communication. -- Sylvain -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Inter-node-communication-over-UDP-tp6358459p6384978.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
simple implementation of counters
Hi,
I'm trying to play around with 0.8.0-rc1 and counters, and I'm a
little confused.
First question I have is about the definition. A column within a
standard column family cannot be a counter column type?
I had tried the following, with no success.
create column family urlcounts
with comparator = UTF8Type
and default_validation_class = LongType
and column_metadata=[
{ column_name:count,
validation_class:CounterColumnType
}
];
The only successful way was for me to create a new column family with
a default validation class of CounterColumnType:
create column family counters with default_validation_class = CounterColumnType;
Now I have a column family with counters:
Keyspace: sdo:
Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy
Options: [datacenter1:1]
Column Families:
ColumnFamily: counters
Key Validation Class: org.apache.cassandra.db.marshal.BytesType
Default column value validator:
org.apache.cassandra.db.marshal.CounterColumnType
Columns sorted by: org.apache.cassandra.db.marshal.BytesType
Row cache size / save period in seconds: 0.0/0
Key cache size / save period in seconds: 20.0/14400
Memtable thresholds: 0.2953125/63/1440 (millions of ops/MB/minutes)
GC grace seconds: 864000
Compaction min/max thresholds: 4/32
Read repair chance: 1.0
Replicate on write: false
Built indexes: []
From the CLI, I insert / increment a [key][column] in this column family:
incr counters[ascii('foo')][ascii('c1')];
Second question: If I want to implement counters, they have to exist
in a seperate column family from the rest of my data?
--
Sasha Dolgy
sasha.do...@gmail.com
Re : selecting data
is there a way to set for a column of the same key a set of value ? De : Watanabe Maki watanabe.m...@gmail.com À : user@cassandra.apache.org user@cassandra.apache.org Envoyé le : Jeu 19 mai 2011, 17h 38min 39s Objet : Re: selecting data Cassandra is not a RDBMS. Only you can do is search on a key, or you need full scan. You need to design your schema carefully as your application needs. On 2011/05/20, at 1:11, karim abbouh karim_...@yahoo.fr wrote: i'm new using cassandra database, i want to get data as in relationnel database: select * from table where field=value; i see using CLI we have just the followings commands : get ksp.cf['key'] Get a slice of columns. get ksp.cf['key']['super'] Get a slice of sub columns. get ksp.cf['key']['col'] Get a column value. get ksp.cf['key']['super']['col'] Get a sub column value. is there a way for that. i think using java API is possible. cassandra version : 6.0.12 thanks for help
Re: Cassandra Vs. Oracle Coherence
That's completely wrong. TimesTen and Coherence are 2 separate products sold by Oracle. Coherence is a data grid that takes a key/value approach. It is massively 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 Kesselman jef...@gmail.com wrote: 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 distributed and fault tolerant, whereas TT is not. I suggest getting and reading the Oriely Cassandra book. JK On Tue, May 17, 2011 at 10:44 PM, Karamel, Raghu raghu_kara...@intuit.com wrote: Hi, I am new to Cassandra and very excited with the technology. I am evaluating it and trying to understand the difference between Cassandra and Oracle Coherence. Precisely , looking for reasons why would some select Cassandra over Oracle Coherence. Does anyone did the exercise of comparing them? Appreciate if you can share some information on that. Regrads -RK -- It's always darkest just before you are eaten by a grue.
DatabaseMetadata
Any thoughts on building something like separate DatabaseMetadata api for CQL? -Original Message- From: Peter Lin [mailto:wool...@gmail.com] Sent: Friday, May 20, 2011 5:28 PM To: user@cassandra.apache.org Subject: Re: Cassandra Vs. Oracle Coherence That's completely wrong. TimesTen and Coherence are 2 separate products sold by Oracle. Coherence is a data grid that takes a key/value approach. It is massively 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 Kesselman jef...@gmail.com wrote: 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 distributed and fault tolerant, whereas TT is not. I suggest getting and reading the Oriely Cassandra book. JK On Tue, May 17, 2011 at 10:44 PM, Karamel, Raghu raghu_kara...@intuit.com wrote: Hi, I am new to Cassandra and very excited with the technology. I am evaluating it and trying to understand the difference between Cassandra and Oracle Coherence. Precisely , looking for reasons why would some select Cassandra over Oracle Coherence. Does anyone did the exercise of comparing them? Appreciate if you can share some information on that. Regrads -RK -- It's always darkest just before you are eaten by a grue. Write to us for a Free Gold Pass to the Cloud Computing Expo, NYC to attend a live session by Head of Impetus Labs on ‘Secrets of Building a Cloud Vendor Agnostic PetaByte Scale Real-time Secure Web Application on the Cloud ‘. Looking to leverage the Cloud for your Big Data Strategy ? Attend Impetus webinar on May 27 by registering at http://www.impetus.com/webinar?eventid=42 . NOTE: This message may contain information that is confidential, proprietary, privileged or otherwise protected by law. The message is intended solely for the named addressee. If received in error, please destroy and notify the sender. Any use of this email is prohibited when received in error. Impetus does not represent, warrant and/or guarantee, that the integrity of this communication has been maintained nor that the communication is free of errors, virus, interception or interference.
how to use indexed column for this case
Hi, I have a SCF, Key is string, super column is TimeUUID, and several columns with one column named type, I create secondary index on this column. I want to have the foliowing query to fetch all super columns along with all columns. 1. given a specific key 2. given a range of super column (start time to end time) 3. given specific type value. Is such query possible? I could not figure out how to use getIndexedSlice to achieve this. Any idea? Thanks. Hou
cannot parse as hex bytes
The following sample: http://www.datastax.com/dev/blog/whats-new-cassandra-07-secondary-indexes No longer works with 0.8.0-rc1 I get cannot parse as hex bytes when doing the Next we add some users: [default@demo] set users[bsanderson][full_name] = 'Brandon Sanderson'; section I can confirm that CASSANDRA-2497 does work
Re : Re : selecting data
a storage-conf.xml is read just at the starting of cassandra? is there a way to add a column family dynamically? BR De : karim abbouh karim_...@yahoo.fr À : user@cassandra.apache.org Envoyé le : Ven 20 mai 2011, 12h 48min 54s Objet : Re : selecting data is there a way to set for a column of the same key a set of value ? De : Watanabe Maki watanabe.m...@gmail.com À : user@cassandra.apache.org user@cassandra.apache.org Envoyé le : Jeu 19 mai 2011, 17h 38min 39s Objet : Re: selecting data Cassandra is not a RDBMS. Only you can do is search on a key, or you need full scan. You need to design your schema carefully as your application needs. On 2011/05/20, at 1:11, karim abbouh karim_...@yahoo.fr wrote: i'm new using cassandra database, i want to get data as in relationnel database: select * from table where field=value; i see using CLI we have just the followings commands : get ksp.cf['key'] Get a slice of columns. get ksp.cf['key']['super'] Get a slice of sub columns. get ksp.cf['key']['col'] Get a column value. get ksp.cf['key']['super']['col'] Get a sub column value. is there a way for that. i think using java API is possible. cassandra version : 6.0.12 thanks for help
Re: Cassandra Vs. Oracle Coherence
AH, I stand corrected. Hard to follow Larry's acquisitions without a scorecard. On 5/20/11, Peter Lin wool...@gmail.com wrote: That's completely wrong. TimesTen and Coherence are 2 separate products sold by Oracle. Coherence is a data grid that takes a key/value approach. It is massively 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 Kesselman jef...@gmail.com wrote: 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 distributed and fault tolerant, whereas TT is not. I suggest getting and reading the Oriely Cassandra book. JK On Tue, May 17, 2011 at 10:44 PM, Karamel, Raghu raghu_kara...@intuit.com wrote: Hi, I am new to Cassandra and very excited with the technology. I am evaluating it and trying to understand the difference between Cassandra and Oracle Coherence. Precisely , looking for reasons why would some select Cassandra over Oracle Coherence. Does anyone did the exercise of comparing them? Appreciate if you can share some information on that. Regrads -RK -- It's always darkest just before you are eaten by a grue. -- It's always darkest just before you are eaten by a grue.
RE: Re : Re : selecting data
This is how you create it dynamically: KsDef ksdef = new KsDef(); ksdef.name = ProgKS; ksdef.replication_factor = 1; ksdef.strategy_class = org.apache.cassandra.locator.RackUnawareStrategy; ListCfDef cfdefs = new ArrayListCfDef(); CfDef cfdef1 = new CfDef(); cfdef1.name = ProgCF1; cfdef1.keyspace = ksdef.name; cfdefs.add(cfdef1); ksdef.cf_defs = cfdefs; client.system_add_keyspace(ksdef); CfDef cfdef2 = new CfDef(); cfdef2.keyspace = ksdef.name; cfdef2.column_type = Standard; cfdef2.name = ProgCF; client.system_add_column_family(cfdef2); From: karim abbouh [mailto:karim_...@yahoo.fr] Sent: Friday, May 20, 2011 8:03 AM To: user@cassandra.apache.org Subject: Re : Re : selecting data a storage-conf.xml is read just at the starting of cassandra? is there a way to add a column family dynamically? BR De : karim abbouh karim_...@yahoo.fr À : user@cassandra.apache.org Envoyé le : Ven 20 mai 2011, 12h 48min 54s Objet : Re : selecting data is there a way to set for a column of the same key a set of value ? De : Watanabe Maki watanabe.m...@gmail.com À : user@cassandra.apache.org user@cassandra.apache.org Envoyé le : Jeu 19 mai 2011, 17h 38min 39s Objet : Re: selecting data Cassandra is not a RDBMS. Only you can do is search on a key, or you need full scan. You need to design your schema carefully as your application needs. On 2011/05/20, at 1:11, karim abbouh karim_...@yahoo.fr wrote: i'm new using cassandra database, i want to get data as in relationnel database: select * from table where field=value; i see using CLI we have just the followings commands : get ksp.cf['key'] Get a slice of columns. get ksp.cf['key']['super'] Get a slice of sub columns. get ksp.cf['key']['col'] Get a column value. get ksp.cf['key']['super']['col'] Get a sub column value. is there a way for that. i think using java API is possible. cassandra version : 6.0.12 thanks for help
Documentation of Known Issues
Hi all I was wondering if there might be some way to better communicate known issues. We do try to track jira issues but at times some slip through or we miss implications. Things like the broken repair of specific CFs. (https://issues.apache.org/jira/browse/CASSANDRA-2670). I know that this potentially dups jira but maybe tasks could get tagged and some magic filter could show a list. Or something like a simple wiki page that lists the known issues that might not be critical such as the mentioned bug but still are a pain if it happens to you. Cheers, Daniel
Re: Exception when starting
Whenever I hear someone say data is corrupted I panic :) I have seen few people have reported that but have not seen the real reason for it. Is it a manual error, config error, bug etc. It will be good to identify why these things happen so that it can be fixed before it happens in PROD :( -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6386809.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: how to use indexed column for this case
From what I know you cannot create secondary indexes on SCF. You should have gotten this = https://issues.apache.org/jira/browse/CASSANDRA-1813 on index creation. On Fri, May 20, 2011 at 6:56 AM, Monkey me monkey1024.pub...@gmail.comwrote: Hi, I have a SCF, Key is string, super column is TimeUUID, and several columns with one column named type, I create secondary index on this column. I want to have the foliowing query to fetch all super columns along with all columns. 1. given a specific key 2. given a range of super column (start time to end time) 3. given specific type value. Is such query possible? I could not figure out how to use getIndexedSlice to achieve this. Any idea? Thanks. Hou
Re: How to reduce the Read Latency.
What's your avg column size and row size? Your read latency in most case will directly be related to how much you are trying to read. In my experience you will see high read latency if you have big column size. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/How-to-reduce-the-Read-Latency-tp6385107p6386817.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Can I use secondary index with any partitioner
Yes. On Thu, May 19, 2011 at 7:24 PM, Dave Rav daver...@yahoo.com wrote: Can I use secondary index with any partitioner 1) RandomPartitioner 2) ByteOrderedPartitioner -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: simple implementation of counters
On Fri, May 20, 2011 at 5:55 AM, Sasha Dolgy sdo...@gmail.com wrote: First question I have is about the definition. A column within a standard column family cannot be a counter column type? Right. https://issues.apache.org/jira/browse/CASSANDRA-2614 is open to address this but that's going to be post-0.8.0. Second question: If I want to implement counters, they have to exist in a seperate column family from the rest of my data? Isn't that the same as the first question? :) -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: cannot parse as hex bytes
You'd need to add a key validation type for 0.8. On Fri, May 20, 2011 at 9:28 AM, Patrick Julien pjul...@gmail.com wrote: The following sample: http://www.datastax.com/dev/blog/whats-new-cassandra-07-secondary-indexes No longer works with 0.8.0-rc1 I get cannot parse as hex bytes when doing the Next we add some users: [default@demo] set users[bsanderson][full_name] = 'Brandon Sanderson'; section I can confirm that CASSANDRA-2497 does work -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Cassandra Vs. Oracle Coherence
Coherence is similar to memcachd (free). It's in memory cache layer on top of the DB. You as a user need to keep that cache in sync with the DB. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-Vs-Oracle-Coherence-tp6375561p6386847.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Exception when starting
There was a bug, it is fixed. It's just a cache, chill. On May 20, 2011 11:50 AM, mcasandra mohitanch...@gmail.com wrote: Whenever I hear someone say data is corrupted I panic :) I have seen few people have reported that but have not seen the real reason for it. Is it a manual error, config error, bug etc. It will be good to identify why these things happen so that it can be fixed before it happens in PROD :( -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6386809.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Cassandra Vs. Oracle Coherence
Although one can use Coherence as a memory cache layer on top of a DB, many customer use it in the financial sector as a in-memory key/value store. Think of transient data that doesn't need to be saved, but needs to scale out across hundreds or thousands of nodes. memcached is making progress, but it is not comparable to coherence today. Eventually it will probably get there. On Fri, May 20, 2011 at 1:00 PM, mcasandra mohitanch...@gmail.com wrote: Coherence is similar to memcachd (free). It's in memory cache layer on top of the DB. You as a user need to keep that cache in sync with the DB. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-Vs-Oracle-Coherence-tp6375561p6386847.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Exception when starting
In my case I started cassandra after sometime with the newer version of it. I think this occurred because there were some files remained belongs to the previous version of cassandra and overwritten with the new one. This is just my thought. Thanks Eranda
Re: simple implementation of counters
uh. yeah ... was a bad morning ... cheers On Fri, May 20, 2011 at 6:57 PM, Jonathan Ellis jbel...@gmail.com wrote: On Fri, May 20, 2011 at 5:55 AM, Sasha Dolgy sdo...@gmail.com wrote: First question I have is about the definition. A column within a standard column family cannot be a counter column type? Right. https://issues.apache.org/jira/browse/CASSANDRA-2614 is open to address this but that's going to be post-0.8.0. Second question: If I want to implement counters, they have to exist in a seperate column family from the rest of my data? Isn't that the same as the first question? :)
Re: Cassandra Vs. Oracle Coherence
Other interesting flavors in a distributed cache terracotta, gemfire.together with a complex event processing engine. like OCEP drives a lot of low latency, high freq trading where nano seconds matter /*** sent from my android...please pardon occasional typos as I respond @ the speed of thought / On May 20, 2011 10:05 AM, Peter Lin wool...@gmail.com wrote: Although one can use Coherence as a memory cache layer on top of a DB, many customer use it in the financial sector as a in-memory key/value store. Think of transient data that doesn't need to be saved, but needs to scale out across hundreds or thousands of nodes. memcached is making progress, but it is not comparable to coherence today. Eventually it will probably get there. On Fri, May 20, 2011 at 1:00 PM, mcasandra mohitanch...@gmail.com wrote: Coherence is similar t...
Re: Cassandra Vs. Oracle Coherence
another product in the same area is gigaspaces. On Fri, May 20, 2011 at 1:12 PM, Milind Parikh milindpar...@gmail.com wrote: Other interesting flavors in a distributed cache terracotta, gemfire.together with a complex event processing engine. like OCEP drives a lot of low latency, high freq trading where nano seconds matter /*** sent from my android...please pardon occasional typos as I respond @ the speed of thought / On May 20, 2011 10:05 AM, Peter Lin wool...@gmail.com wrote: Although one can use Coherence as a memory cache layer on top of a DB, many customer use it in the financial sector as a in-memory key/value store. Think of transient data that doesn't need to be saved, but needs to scale out across hundreds or thousands of nodes. memcached is making progress, but it is not comparable to coherence today. Eventually it will probably get there. On Fri, May 20, 2011 at 1:00 PM, mcasandra mohitanch...@gmail.com wrote: Coherence is similar t...
Re: Exception when starting
Brandon Williams wrote: There was a bug, it is fixed. It's just a cache, chill. There is no time to chill when fighting it in production :) It's good to know it's fixed. Another question, when this happens are we able to restore data from replica nodes? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6386925.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Exception when starting
No data gets lost - * only * thing corrupted is key-cache On Fri, May 20, 2011 at 10:17 AM, mcasandra mohitanch...@gmail.com wrote: Brandon Williams wrote: There was a bug, it is fixed. It's just a cache, chill. There is no time to chill when fighting it in production :) It's good to know it's fixed. Another question, when this happens are we able to restore data from replica nodes? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6386925.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Can I use secondary index with any partitioner
if I use 'RandomPartitioner' and call 'get_indexed_slices'
what do I do with 'start_key'
struct IndexClause { 1: required listIndexExpression expressions 2:
required binary start_key, 3: required i32 count=100, }
Yes.
On Thu, May 19, 2011 at 7:24 PM, Dave Rav daver...@yahoo.com wrote:
Can I use secondary index with any partitioner
1) RandomPartitioner
2) ByteOrderedPartitioner
Re: Exception when starting
In this case, yes. I was asking for the cases where commit log corruption was reported. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6387101.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: cannot parse as hex bytes
thanks On Fri, May 20, 2011 at 12:58 PM, Jonathan Ellis jbel...@gmail.com wrote: You'd need to add a key validation type for 0.8. On Fri, May 20, 2011 at 9:28 AM, Patrick Julien pjul...@gmail.com wrote: The following sample: http://www.datastax.com/dev/blog/whats-new-cassandra-07-secondary-indexes No longer works with 0.8.0-rc1 I get cannot parse as hex bytes when doing the Next we add some users: [default@demo] set users[bsanderson][full_name] = 'Brandon Sanderson'; section I can confirm that CASSANDRA-2497 does work -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Inconsistent results using secondary indexes between two DC
Has this cluster always been on 0.7.5 or was it upgraded from an earlier version? On Thu, May 19, 2011 at 3:26 AM, Wojciech Pietrzok kosci...@gmail.com wrote: Just checked. Seems to be present in CF on all nodes (in both datacenters), but are not indexed correctly On each node I've used sstablekeys for all CF_NAME-f-XX-Data.db files. In cassandra-cli I've (using node that behaves correctly) made query get CF_NAME where foo = bar, got correct number of results. Checked using grep if all the keys are present in the lists returned by sstablekeys - none was missing, so it seems that the rows are present on all nodes. When doing the same query on the nodes in the second DC (using ConsistencyLevel.ONE) the results are invalid. Sometimes I got 15 rows (expected, correct number of rows), 3 rows, or 10 rows. What's interesting every time I get only 3 rows it's the same list of 3 rows on both affected nodes. 2011/5/17 Jonathan Ellis jbel...@gmail.com: Nothing comes to mind. I'd start by using sstable2json to see if the missing rows are in the main data CF -- i.e., are they just unindexed, or are they missing completely? On Sun, May 15, 2011 at 4:33 PM, Wojciech Pietrzok kosci...@gmail.com wrote: Hello, I've noticed strange behaviour of Cassandra when using secondary indexes. There are 2 Data Centers, each with 2 nodes, RF=4, on all nodes Cassandra 0.7.5 is installed. When I connect to one of the nodes in DC1 and perform query using secondary indexes (get ColumnFamily where column = 'foo' in cassandra-cli) I always get correct number of rows returned, no matter which ConsistencyLevel is set. When I connect to one of the nodes in DC2 and perform same query using ConsistencyLevel LOCAL_QUORUM the results are correct. But using ConsistencyLevel ONE Cassandra doesn't return correct number of rows (it seems that most of the times there some of the rows are missing). Tried running nodetool repair, and nodetool scrub but this doesn't seem to help. What might the cause of such behaviour? -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- KosciaK mail: kosci...@gmail.com www : http://kosciak.net/ -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Can I use secondary index with any partitioner
empty byte array for the first call, last key from the previous
resultset afterwards
On Fri, May 20, 2011 at 12:53 PM, Dave Rav daver...@yahoo.com wrote:
if I use 'RandomPartitioner' and call 'get_indexed_slices'
what do I do with 'start_key'
struct IndexClause {
1: required listIndexExpression expressions
2: required binary start_key,
3: required i32 count=100,
}
Yes.
On Thu, May 19, 2011 at 7:24 PM, Dave Rav daver...@yahoo.com wrote:
Can I use secondary index with any partitioner
1) RandomPartitioner
2) ByteOrderedPartitioner
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com
CounterColumn
CASSANDRA-2614 - create Column and CounterColumn in the same column family when this will be in cassandra will this be in cassandra 0.8
Re: CounterColumn
Look for Fix version on the ticket: https://issues.apache.org/jira/browse/CASSANDRA-2614. On Fri, May 20, 2011 at 4:35 PM, Mark Emerson a202...@yahoo.com wrote: CASSANDRA-2614 - create Column and CounterColumn in the same column family when this will be in cassandra will this be in cassandra 0.8 -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: RTG/MRTG/Cricket replacement using Cassandra?
hi Ryan: Thanks for the link. I read the slides, could you please provide some more details on how the temporal aggregation is implemented? do you use time+granularity as the key ? or as column names ? Thanks Yang In reply to this post by Aaron Turner We have a solution for time series data on cassandra at Twitter that we'd like to open source, but it requires 0.8/trunk so we're not going to release it until that's stable. See http://www.slideshare.net/kevinweil/rainbird-realtime-analytics-at-twitter-strata-2011 -ryan On Thu, Mar 31, 2011 at 3:56 PM, Aaron Turner [hidden email] wrote: I've been looking at replacing our PostgreSQL backend for RTG (a SNMP based polling and graphing solution for network traffic/ports) with something using Cassandra in order to solve our scalability and redundancy requirements. Based on a lot of what I've read, Cassandra is an ideal data store for this time series data. In fact, Eric Evans in his presentation on the Cassandra home page suggests that this kind of use case is perfect for Cassandra. So this got me wondering if someone had already come up with a CF model for this kind of data, including daily/weekly/monthly/yearly rollups. Perhaps there's even an open source project or two implementing this sorta thing? I've found flewton (https://github.com/flewton/flewton), which is possibly relevant, but my Java skills are pretty non-existent so I'm having a hard time figuring it out. Thanks, Aaron -- Aaron Turner http://synfin.net/ http://synfin.net/ Twitter: @synfinatic http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix Windows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. -- Benjamin Franklin carpe diem quam minimum credula postero ... [show rest of quote] -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/RTG-MRTG-Cricket-replacement-using-Cassandra-tp6229322p6388192.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: RTG/MRTG/Cricket replacement using Cassandra?
The first love of my open life was cacti. I am going to discuss with them porting some of the system to cassandra. On Friday, May 20, 2011, yangyangyyy tedd...@gmail.com wrote: hi Ryan: Thanks for the link. I read the slides, could you please provide some more details on how the temporal aggregation is implemented? do you use time+granularity as the key ? or as column names ? Thanks Yang In reply to this post by Aaron Turner We have a solution for time series data on cassandra at Twitter that we'd like to open source, but it requires 0.8/trunk so we're not going to release it until that's stable. See http://www.slideshare.net/kevinweil/rainbird-realtime-analytics-at-twitter-strata-2011 -ryan On Thu, Mar 31, 2011 at 3:56 PM, Aaron Turner [hidden email] wrote: I've been looking at replacing our PostgreSQL backend for RTG (a SNMP based polling and graphing solution for network traffic/ports) with something using Cassandra in order to solve our scalability and redundancy requirements. Based on a lot of what I've read, Cassandra is an ideal data store for this time series data. In fact, Eric Evans in his presentation on the Cassandra home page suggests that this kind of use case is perfect for Cassandra. So this got me wondering if someone had already come up with a CF model for this kind of data, including daily/weekly/monthly/yearly rollups. Perhaps there's even an open source project or two implementing this sorta thing? I've found flewton (https://github.com/flewton/flewton), which is possibly relevant, but my Java skills are pretty non-existent so I'm having a hard time figuring it out. Thanks, Aaron -- Aaron Turner http://synfin.net/ http://synfin.net/ Twitter: @synfinatic http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix Windows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. -- Benjamin Franklin carpe diem quam minimum credula postero ... [show rest of quote] -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/RTG-MRTG-Cricket-replacement-using-Cassandra-tp6229322p6388192.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
