Cassandra JDBC
Hi, I downloaded the cassandra-jdbc and built with maven. And when I am trying to use it in my application I get an exception on the following code: java.sql.Connection conn = DriverManager.getConnection(jdbc:cassandra://localhost:9160/MyKeyspace); java.lang.IncompatibleClassChangeError: Implementing class at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631) … Does anyone have an idea what it might be? Best regards, Jone
Re: memory problems still post- CASSANDRA-3492
Dne 15.11.2011 22:04, Mick Semb Wever napsal(a): But another node (on the same machine but different cluster), even after an upgrade to the staging 1.0.3 and a `nodetool scrub`, always soaks all available memory (up to and plateau at 30G). In fact no cf there use compression anymore. I had similar problem yesterday with running nodetool scrub on 1.0.3 while i was trying to convert -g- tables to current format. There is memory leak in scrub. I do not use compression either. HintedHandoff (active)1(pending)2 and it just seems to stay like that. Is there a way to more closely monitor that active hinted handoff? you can count columns in system table holding hints but i got OOM everytime i tried. Can one hinted handoff be responsible for such heap? no. it is scrub because heap increases after each sstable is processed.
Re: Cassandra JDBC
Try this it should work..
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class InsertData {
public static void main(String[] args) throws ClassNotFoundException,
SQLException{
Class.forName(org.apache.cassandra.cql.jdbc.CassandraDriver);
Connection jdbcConn = DriverManager
.getConnection(jdbc:cassandra:/@localhost:9160/test);
Statement stmt = jdbcConn.createStatement();
ResultSet reset = stmt.executeQuery(select * from users);
jdbcConn.close();
}
}
On 16 November 2011 13:55, Jone Lura jone.l...@ecc.no wrote:
Hi,
I downloaded the cassandra-jdbc and built with maven.
And when I am trying to use it in my application I get an exception on the
following code:
java.sql.Connection conn = DriverManager.getConnection(
jdbc:cassandra://localhost:9160/MyKeyspace);
java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
…
Does anyone have an idea what it might be?
Best regards,
Jone
Re: Fast lookups for userId to username and vice versa
Or just have two column families to do it: A CF idToName that has the userIds as keys and the userName as the only column and a CF nameToId that has the userNames as keys and the userId as the only column On Mon, Nov 14, 2011 at 03:50, chovatia jaydeep chovatia_jayd...@yahoo.co.in wrote: Check if Cassandra secondary index meets your requirement. Thank you, Jaydeep From: Aklin_81 asdk...@gmail.com To: user user@cassandra.apache.org Sent: Sunday, 13 November 2011 12:32 PM Subject: Fast lookups for userId to username and vice versa I need to create mapping from userId(s) to username(s) which need to provide for fast lookups service ? Also I need to provide a mapping from username to userId inorder to implement search functionality in my application. What could be a good strategy to implement this ? (I would welcome suggestions to use any new technologies if they are really worth for my case.)
Re: Fast lookups for userId to username and vice versa
I think secondary index could do the trick. However, if you need to provide the pagination function, I will go for Konstantin's solution. On Wed, Nov 16, 2011 at 10:27 PM, Konstantin Naryshkin konstant...@a-bb.net wrote: Or just have two column families to do it: A CF idToName that has the userIds as keys and the userName as the only column and a CF nameToId that has the userNames as keys and the userId as the only column On Mon, Nov 14, 2011 at 03:50, chovatia jaydeep chovatia_jayd...@yahoo.co.in wrote: Check if Cassandra secondary index meets your requirement. Thank you, Jaydeep From: Aklin_81 asdk...@gmail.com To: user user@cassandra.apache.org Sent: Sunday, 13 November 2011 12:32 PM Subject: Fast lookups for userId to username and vice versa I need to create mapping from userId(s) to username(s) which need to provide for fast lookups service ? Also I need to provide a mapping from username to userId inorder to implement search functionality in my application. What could be a good strategy to implement this ? (I would welcome suggestions to use any new technologies if they are really worth for my case.)
CQL and subcolumns
Hi, I am trying to find out how to use CQL to be able to use cassandra-jdbc in my application, and I have some questions. I have tried to find the answers int the documentation of Cassandra Query Language (CQL) v2.0, but I did not find the answers to my following questions. How do I create a column family with a sub column? How do I insert values to a column with a sub column? I am using cassandra 1.0.2. Best regards Jone
Thanks for CQL
I just wanted to say thanks to the entire Cassandra Team and Hector client team for CQL. I've been using it this week and it makes life easier. At first I had mixed feelings on CQL, but after using it the last few days, the user friendly factor makes a huge difference. peter
Re: Thanks for CQL
+1 Sent from my iPhone On Nov 16, 2011, at 8:09 AM, Peter Lin wool...@gmail.com wrote: I just wanted to say thanks to the entire Cassandra Team and Hector client team for CQL. I've been using it this week and it makes life easier. At first I had mixed feelings on CQL, but after using it the last few days, the user friendly factor makes a huge difference. peter
sstableloader issue
Hello , I need to load an external SSTABLEs to a cluster with 4 nodes. So I shutdown one of the node , and created a separate folder on this node as a temporary staging place for the external sstables, and run the sstableloader command like: ./bin/sstableloader /cassandra/bulk_load/Timeseries Starting client (and waiting 30 seconds for gossip) ... org.apache.thrift.transport.TTransportException: java.net.ConnectException: Connection refused Did anyone have the same issue before? How to get around it? Thank you, Mike This email was sent to you by Thomson Reuters, the global news and information company. Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Thomson Reuters.
Re: BulkLoader
On Mon, Nov 14, 2011 at 2:49 PM, Giannis Neokleous gian...@generalsentiment.com wrote: Hello everyone, We're using the bulk loader to load data every day to Cassandra. The machines that use the bulkloader are diferent every day so their IP addresses change. When I do describe cluster i see all the unreachable nodes that keep piling up for the past few days. Is there a way to remove those IP addresses without terminating the whole cluster at the same time and restarting it? The unreachable nodes cause issues when we want to make schema changes to all the nodes or when we want to truncate a CF. Any suggestions? It sounds like you're running into https://issues.apache.org/jira/browse/CASSANDRA-3351 so the first step would be to upgrade to a version that has it fixed. Unfortunately, this won't solve the problem, just prevent it from happening in the future. To remove the old nodes, you can apply https://issues.apache.org/jira/browse/CASSANDRA-3337 on one node and call the JMX method for the unreachable endpoints. -Brandon
Efficiency of Cross Data Center Replication...?
Hi All, I have a question about inter-data centre replication : if you have 2 Data Centers, each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is the replication to DC2 - i.e. is that data : - replicated over to a single node in DC2 once and internally replicated or - replicated explicitly to two separate nodes? Obviously from a LAN resource utilisation perspective, the former would be preferable. Many thanks, Brian
Re: Efficiency of Cross Data Center Replication...?
To be complete, https://issues.apache.org/jira/browse/CASSANDRA-3472 is relevant. -- Sylvain On Wed, Nov 16, 2011 at 9:40 PM, Jake Luciani jak...@gmail.com wrote: the former On Wed, Nov 16, 2011 at 3:33 PM, Brian Fleming bigbrianflem...@gmail.com wrote: Hi All, I have a question about inter-data centre replication : if you have 2 Data Centers, each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is the replication to DC2 - i.e. is that data : - replicated over to a single node in DC2 once and internally replicated or - replicated explicitly to two separate nodes? Obviously from a LAN resource utilisation perspective, the former would be preferable. Many thanks, Brian -- http://twitter.com/tjake
Re: Efficiency of Cross Data Center Replication...?
Great - thanks Jake B. On Wed, Nov 16, 2011 at 8:40 PM, Jake Luciani jak...@gmail.com wrote: the former On Wed, Nov 16, 2011 at 3:33 PM, Brian Fleming bigbrianflem...@gmail.comwrote: Hi All, I have a question about inter-data centre replication : if you have 2 Data Centers, each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is the replication to DC2 - i.e. is that data : - replicated over to a single node in DC2 once and internally replicated or - replicated explicitly to two separate nodes? Obviously from a LAN resource utilisation perspective, the former would be preferable. Many thanks, Brian -- http://twitter.com/tjake
Re: Efficiency of Cross Data Center Replication...?
On a related note - assuming there are available resources across the board (cpu and memory on every node, low network latency, non-saturated nics/circuits/disks), what's a reasonable expectation for timing on replication? Sub-second? Less than five seconds? Ernie On Wed, Nov 16, 2011 at 4:00 PM, Brian Fleming bigbrianflem...@gmail.comwrote: Great - thanks Jake B. On Wed, Nov 16, 2011 at 8:40 PM, Jake Luciani jak...@gmail.com wrote: the former On Wed, Nov 16, 2011 at 3:33 PM, Brian Fleming bigbrianflem...@gmail.com wrote: Hi All, I have a question about inter-data centre replication : if you have 2 Data Centers, each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is the replication to DC2 - i.e. is that data : - replicated over to a single node in DC2 once and internally replicated or - replicated explicitly to two separate nodes? Obviously from a LAN resource utilisation perspective, the former would be preferable. Many thanks, Brian -- http://twitter.com/tjake
Re: Seeking advice on Schema and Caching
Thanks to samal who pointed to look at the composite columns. I am now
using composite columns names containing username+userId valueless
column. Thus column names are now unique even for users with same name as
userId is also attached to the same composite col name. Thus the
supercolumn issue is resolved.
But I am still seeking advice some on the caching strategy for these rows.
Since while a user is doing the search, the DB will be queried multiple
times because I 'm not keeping the retrieved columns in the application
layer. Thus I am thinking of caching this row so that the further queries
be served through the cache. However the important point here is that I am
using very fewer resources for this cache so that the rows remain in cache
for a very short time so as to serve the needs only for a single search
time interval like max 30 seconds. Is this approach correct.? That way I
wont be putting unneccessary data in cache for a long time thus saving
resources for other needs.
On Wed, Nov 16, 2011 at 11:20 AM, samal samalgo...@gmail.com wrote:
I think you can but I am not sure, I haven't tried that yet, Nothing harm
in keeping value also it will be read in single query only.
In 2nd case, yes 2 or more query required to get specific user details. As
username is map to user_id's key(unique like UUID) and user_id key store
actual details.
On Wed, Nov 16, 2011 at 11:10 AM, Aditya Narayan ady...@gmail.com wrote:
Regarding the first option that you suggested through composite columns,
can I store the username id both in the column name and keep the column
valueless?
Will I be able to retrieve both the username and id from the composite
col name ?
Thanks a lot
On Wed, Nov 16, 2011 at 10:56 AM, Aditya Narayan ady...@gmail.comwrote:
Got the first option that you suggested.
However, In the second one, are you suggested to use, for e.g,
key='Marcos' store cols, for all users of that name, containing userId
inside that row. That way it would have to read multiple rows while user is
doing a single search.
On Wed, Nov 16, 2011 at 10:47 AM, samal samalgo...@gmail.com wrote:
I need to add 'search users' functionality to my application. (The
trigger for fetching searched items(like google instant search) is made
when 3 letters have been typed in).
For this, I make a CF with String type keys. Each such key is made
of first 3 letters of a user's name.
Thus all names starting with 'Mar-' are stored in single row (with
key=Mar).
The column names are framed as remaining letters of the names.
Thus, a name 'Marcos' will be stored within rowkey Mar col name
cos.
The id will be stored as column value. Since there could be many users
with
same name. Thus I would have multple userIds(of users named Marcos) to
be
stored inside columnname cos under key Mar. Thus,
1. Supercolumn seems to be a better fit for my use case(so that ids
of users with same name may fit as sub-columns inside a super-column) but
since supercolumns are not encouraged thus I want to use an alternative
schema for this usecase if possible. Could you suggest some ideas on
this ?
Aditya,
Have you any given thought on Composite columns [1]. I think it can
help you solve your problem of multiple user with same name.
mar:{
{cos,unique_user_id}:unique_user_id,
{cos,1}:1,
{cos,2}:2,
{cos,3}:3,
// {utf8,timeUUID}:timeUUID,
}
OR
you can try wide rows indexing user name to ID's
marcos{
user1:' ',
user2:' ',
user3:' '
}
[1]http://www.slideshare.net/edanuff/indexing-in-cassandra
Re: Network traffic patterns
Are all of your machines equal hardware? Since those machines are sending data somewhere, maybe they are behind in replicating and are continuously catching up? Use a tool like tcpdump to find out where the data is going From: Philippe watche...@gmail.commailto:watche...@gmail.com Reply-To: user@cassandra.apache.orgmailto:user@cassandra.apache.org user@cassandra.apache.orgmailto:user@cassandra.apache.org Date: Tue, 15 Nov 2011 13:22:38 -0800 To: user user@cassandra.apache.orgmailto:user@cassandra.apache.org Subject: Re: Network traffic patterns Sorry about the previous message, I've enabled keyboard shortcuts on gmail...*sigh*... Hello, I'm trying to understand the network usage I am seeing in my cluster, can anyone shed some light? It's an RF=3, 12-node, cassandra 0.8.6 cluster. repair is performed on each node once a week, with a rolling schedule. The nodes are p13,p14,p15...p24 and are consecutive in that order on the ring. Each node is only a cassandra database. I am hitting the cluster from another server (p4). p4 is doing this with 20 threads in parallel 1. read a lot of data (some columns for hundreds to tens of thousands of keys, split into 512-key multigets) 2. process the data 3. write back a byte array to cassandra (average size is 400 bytes) 4. go back to 1 According to my munin graphs, network usage is about as follows. I am not surprised at the bias towards p13-p15 as p4 is getting storing data mainly for keys located on one of those nodes. * p4 : 1.5Mb/s in and out * p13-p15 : 15Mb/s in and 80Mb/s out * p16-p24 : 45Mb/s in and 5Mb/s out What I don't understand is why p4 is only seeing 1.5Mb/s while I see 80Mb/s on p13 p15. The way I understand this: * p4 makes a multiget to the cluster, electing to use any node in the cluster (IN traffic for describe the query) * coordinator node replays the query on all 3 replicas (so 3 servers each get the IN traffic, mostly p13-p15) * each server replies to coordinator * coordinator chooses matching values and sends back data to p4 So if p13-p15 are outputting 80Mb/s why am I not seeing 80Mb/s coming into p4 which is on the receiving end ? Thanks 2011/11/15 Philippe watche...@gmail.commailto:watche...@gmail.com Hello, I'm trying to understand the network usage I am seeing in my cluster, can anyone shed some light? It's an RF=3, 12-node, cassandra 0.8.6 cluster. The nodes are p13,p14,p15...p24 and are consecutive in that order on the ring. Each node is only a cassandra database. I am hitting the cluster from another server (p4). The pattern on p4 is the pattern is to 1. read a lot of data (some columns for hundreds to tens of thousands of keys, split into 512-key multigets) 2. process the data 3. write back a byte array to cassandra (average size is 400 bytes) p4 reads as
Re: Efficiency of Cross Data Center Replication...?
Pretty sure data is sent to the coordinating node in DC2 at the same time it is sent to replicas in DC1, so I would think 10's of milliseconds after the transport time to DC2. On Nov 16, 2011, at 3:48 PM, ehers...@gmail.com wrote: On a related note - assuming there are available resources across the board (cpu and memory on every node, low network latency, non-saturated nics/circuits/disks), what's a reasonable expectation for timing on replication? Sub-second? Less than five seconds? Ernie On Wed, Nov 16, 2011 at 4:00 PM, Brian Fleming bigbrianflem...@gmail.com wrote: Great - thanks Jake B. On Wed, Nov 16, 2011 at 8:40 PM, Jake Luciani jak...@gmail.com wrote: the former On Wed, Nov 16, 2011 at 3:33 PM, Brian Fleming bigbrianflem...@gmail.com wrote: Hi All, I have a question about inter-data centre replication : if you have 2 Data Centers, each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is the replication to DC2 - i.e. is that data : - replicated over to a single node in DC2 once and internally replicated or - replicated explicitly to two separate nodes? Obviously from a LAN resource utilisation perspective, the former would be preferable. Many thanks, Brian -- http://twitter.com/tjake
Re: Seeking advice on Schema and Caching
Edanuff + Beautiful People
I think row cache could be the best fit but it can take resource
depending on row size. It will only touch disk once (first time) in case of
SST, rest of the req for that row will be served from memory. Try
increasing row cache size and decreasing save period to appropriate value
*Row cache size / save period in seconds: *200/30
one catch this is only good for small size row, as your one row contain
all entry with first 3 similar char, this can happen that one row could
become very large while other remain very thin.
eg:
many ppl can have aditya name
adi{
{tya,1}
.
.
}
but only few ppl will have name with x or y.
On Thu, Nov 17, 2011 at 3:29 AM, Aditya ady...@gmail.com wrote:
Thanks to samal who pointed to look at the composite columns. I am now
using composite columns names containing username+userId valueless
column. Thus column names are now unique even for users with same name as
userId is also attached to the same composite col name. Thus the
supercolumn issue is resolved.
But I am still seeking advice some on the caching strategy for these rows.
Since while a user is doing the search, the DB will be queried multiple
times because I 'm not keeping the retrieved columns in the application
layer. Thus I am thinking of caching this row so that the further queries
be served through the cache. However the important point here is that I am
using very fewer resources for this cache so that the rows remain in cache
for a very short time so as to serve the needs only for a single search
time interval like max 30 seconds. Is this approach correct.? That way I
wont be putting unneccessary data in cache for a long time thus saving
resources for other needs.
On Wed, Nov 16, 2011 at 11:20 AM, samal samalgo...@gmail.com wrote:
I think you can but I am not sure, I haven't tried that yet, Nothing harm
in keeping value also it will be read in single query only.
In 2nd case, yes 2 or more query required to get specific user details.
As username is map to user_id's key(unique like UUID) and user_id key store
actual details.
On Wed, Nov 16, 2011 at 11:10 AM, Aditya Narayan ady...@gmail.comwrote:
Regarding the first option that you suggested through composite columns,
can I store the username id both in the column name and keep the column
valueless?
Will I be able to retrieve both the username and id from the composite
col name ?
Thanks a lot
On Wed, Nov 16, 2011 at 10:56 AM, Aditya Narayan ady...@gmail.comwrote:
Got the first option that you suggested.
However, In the second one, are you suggested to use, for e.g,
key='Marcos' store cols, for all users of that name, containing userId
inside that row. That way it would have to read multiple rows while user is
doing a single search.
On Wed, Nov 16, 2011 at 10:47 AM, samal samalgo...@gmail.com wrote:
I need to add 'search users' functionality to my application. (The
trigger for fetching searched items(like google instant search) is made
when 3 letters have been typed in).
For this, I make a CF with String type keys. Each such key is made
of first 3 letters of a user's name.
Thus all names starting with 'Mar-' are stored in single row (with
key=Mar).
The column names are framed as remaining letters of the names.
Thus, a name 'Marcos' will be stored within rowkey Mar col name
cos.
The id will be stored as column value. Since there could be many users
with
same name. Thus I would have multple userIds(of users named Marcos)
to be
stored inside columnname cos under key Mar. Thus,
1. Supercolumn seems to be a better fit for my use case(so that
ids of users with same name may fit as sub-columns inside a
super-column)
but since supercolumns are not encouraged thus I want to use an
alternative
schema for this usecase if possible. Could you suggest some ideas on
this ?
Aditya,
Have you any given thought on Composite columns [1]. I think it can
help you solve your problem of multiple user with same name.
mar:{
{cos,unique_user_id}:unique_user_id,
{cos,1}:1,
{cos,2}:2,
{cos,3}:3,
// {utf8,timeUUID}:timeUUID,
}
OR
you can try wide rows indexing user name to ID's
marcos{
user1:' ',
user2:' ',
user3:' '
}
[1]http://www.slideshare.net/edanuff/indexing-in-cassandra
Re: Seeking advice on Schema and Caching
On Thu, Nov 17, 2011 at 10:25 AM, samal samalgo...@gmail.com wrote:
Edanuff + Beautiful People
I think row cache could be the best fit but it can take resource
depending on row size. It will only touch disk once (first time) in case of
SST, rest of the req for that row will be served from memory. Try
increasing row cache size and decreasing save period to appropriate value
*Row cache size / save period in seconds: *200/30
Very nice . I didn't knew that we could even have the save period setting
as well. This makes the job easier. Now can reduce the period to 30 sec
put the row cache size to a good enough limit. Thanks :)
Yes there may be rows that will be very wide, I'll need to figure if I can
do something better for that, but even this wont be problematic until my
cache period is reasonable and cache size is set to a good limit, right ?
one catch this is only good for small size row, as your one row contain
all entry with first 3 similar char, this can happen that one row could
become very large while other remain very thin.
eg:
many ppl can have aditya name
adi{
{tya,1}
.
.
}
but only few ppl will have name with x or y.
On Thu, Nov 17, 2011 at 3:29 AM, Aditya ady...@gmail.com wrote:
Thanks to samal who pointed to look at the composite columns. I am now
using composite columns names containing username+userId valueless
column. Thus column names are now unique even for users with same name as
userId is also attached to the same composite col name. Thus the
supercolumn issue is resolved.
But I am still seeking advice some on the caching strategy for these
rows. Since while a user is doing the search, the DB will be
queried multiple times because I 'm not keeping the retrieved columns in
the application layer. Thus I am thinking of caching this row so that
the further queries be served through the cache. However the important
point here is that I am using very fewer resources for this cache so that
the rows remain in cache for a very short time so as to serve the needs
only for a single search time interval like max 30 seconds. Is this
approach correct.? That way I wont be putting unneccessary data in cache
for a long time thus saving resources for other needs.
On Wed, Nov 16, 2011 at 11:20 AM, samal samalgo...@gmail.com wrote:
I think you can but I am not sure, I haven't tried that yet, Nothing
harm in keeping value also it will be read in single query only.
In 2nd case, yes 2 or more query required to get specific user details.
As username is map to user_id's key(unique like UUID) and user_id key store
actual details.
On Wed, Nov 16, 2011 at 11:10 AM, Aditya Narayan ady...@gmail.comwrote:
Regarding the first option that you suggested through composite
columns, can I store the username id both in the column name and keep the
column valueless?
Will I be able to retrieve both the username and id from the composite
col name ?
Thanks a lot
On Wed, Nov 16, 2011 at 10:56 AM, Aditya Narayan ady...@gmail.comwrote:
Got the first option that you suggested.
However, In the second one, are you suggested to use, for e.g,
key='Marcos' store cols, for all users of that name, containing userId
inside that row. That way it would have to read multiple rows while user
is
doing a single search.
On Wed, Nov 16, 2011 at 10:47 AM, samal samalgo...@gmail.com wrote:
I need to add 'search users' functionality to my application. (The
trigger for fetching searched items(like google instant search) is made
when 3 letters have been typed in).
For this, I make a CF with String type keys. Each such key is
made of first 3 letters of a user's name.
Thus all names starting with 'Mar-' are stored in single row
(with key=Mar).
The column names are framed as remaining letters of the names.
Thus, a name 'Marcos' will be stored within rowkey Mar col name
cos.
The id will be stored as column value. Since there could be many users
with
same name. Thus I would have multple userIds(of users named Marcos)
to be
stored inside columnname cos under key Mar. Thus,
1. Supercolumn seems to be a better fit for my use case(so that
ids of users with same name may fit as sub-columns inside a
super-column)
but since supercolumns are not encouraged thus I want to use an
alternative
schema for this usecase if possible. Could you suggest some ideas on
this ?
Aditya,
Have you any given thought on Composite columns [1]. I think it can
help you solve your problem of multiple user with same name.
mar:{
{cos,unique_user_id}:unique_user_id,
{cos,1}:1,
{cos,2}:2,
{cos,3}:3,
// {utf8,timeUUID}:timeUUID,
}
OR
you can try wide rows indexing user name to ID's
marcos{
user1:' ',
user2:' ',
user3:' '
}
[1]http://www.slideshare.net/edanuff/indexing-in-cassandra
About compile YCSB with Cassandra 1.02
Hi, I want to have performance measurement of Cassandra 1.02 using YCSB. But YCSB only supports Cassandra 0.7. If someone have knowledge about how to compile Cassandra 1.02 with YCSB or tips, could please share it with me? Thank you very much. Regards Miki
mmap I/O and shared memory
I am running 7 nodes cassandra(v1.0.2) cluster. I am putting 20K rows per sec to the cluster. This cluster has 1 KS, 3CFs. Each CF has 4-5 secondary indices. After I'v run for 1 week, nodes use swap memory. I changed disk-access-mode to index_only or standard. I got strange memory results. using mmap: VIRT: 566g RES: 36g SHR:12g standard disk access mode VIRT:24.7g RES: 24g SHR:68m I allocated 24g memory for JVM heap. I have some questions about mmap. It is easy to analyze standard disk access mode's memory result. I know cassandra use huge virtual memory for mmap I/O and each mmaped addresses are mapped to indexed file not swap memory. But, I don't understand why cassandra use shared memory, if using mmap I/O. Are there some documents that explain this situation? -- Jaesung Lee Sent with Sparrow (http://www.sparrowmailapp.com/?sig)
Dropped request...
Hello. I'm using cassandra 0.8.6 with nodetool tpstats, dropped statistics are shown. when drop happens... what can I do? are there ways to turn on debug messages or to look into? thanks.
