Re: Basic question on a write operation immediately followed by a read
2011/1/25 Wangpei (Peter) peter.wang...@huawei.com for your 1-node cluster, ANY is the only consistency level that client may returns BEFORE node write to memory table. And read op on the node read both the memory table and SSTable. It real puzzle me. :( Please don't be puzzled just yet. :-) As I said from the beginning, I wasn't confirming yet that reads were in fact missing the writes. I have just observed that kind of behavior at my app level and I wanted to understand what was the possibility of it happening from the Cassdandra side. If reads were sure to read what was written (with QUORAM level, let's say), then I can look at other causes inside the app.
Re: Schema Question
Aaron,
A question about one of your general points, "do not create CF's on
the fly" - what, exactly, does this mean? Do you mean named column
families, like "BlogEntries" from Sam's example, or do you mean
column family keys, like "i-got-a-new-guitar"? If it's the latter,
then could you please explain why not to do this? My application is
based around creating row keys on the fly, so I'd like to know ahead
of time if I'm creating potential trouble for myself.
To be honest, if you do mean specifically column families and not
column family keys, then I don't even understand how you would go
about creating those on-the-fly anyway. Don't they have to be
pre-configured in storage-conf.xml?
Thanks,
Andy.
On 25/01/11 00:39, Aaron Morton wrote:
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 denormalise to
support these, the writes will be fast enough.
- try to get each read request to be resolved by reading from
a single CF (not a rule, just a guideline)
- avoid big super columns.
- this may also be interestinghttp://www.rackspacecloud.com/blog/2010/05/12/cassandra-by-example/
If you are happy with the one in the article start with that
and see how it works with you app. See how it works for your
read activities.
Hope that helps.
Aaron
On 25 Jan, 2011,at 12:47 PM, Sam Hodgson
hodgson_...@hotmail.com wrote:
Hi all,
Im brand new to Cassandra - im migrating from MySql for a
large forum site and would be grateful if anyone can give me
some basic pointers on schema design, or any recommended
documentation.
The example used in
http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model
is very close if not exactly what I need for my main CF:
!--
ColumnFamily: BlogEntries
This is where all the blog entries will go:
Row Key + post's slug (the seo friendly portion of the uri)
Column Name: an attribute for the entry (title, body, etc)
Column Value: value of the associated attribute
Access: grab an entry by slug (always fetch all Columns for Row)
fyi: tags is a denormalization... its a comma separated list of tags.
im not using json in order to not interfere with our
notation but obviously you could use anything as long as your app
knows how to deal w/ it
BlogEntries : { // CF
i-got-a-new-guitar : { // row key - the unique "slug" of the entry.
title: This is a blog entry about my new, awesome guitar,
body: this is a cool entry. etc etc yada yada
author: Arin Sarkissian // a row key into the Authors CF
tags: life,guitar,music // comma sep list of tags (basic denormalization)
pubDate: 1250558004 // unixtime for publish date
slug: i-got-a-new-guitar
},
// all other entries
another-cool-guitar : {
...
tags: guitar,
slug: another-cool-guitar
},
scream-is-the-best-movie-ever : {
..
tags: movie,horror,
slug: scream-is-the-best-movie-ever
}
}
--
ColumnFamily CompareWith="BytesType" Name="BlogEntries"/
How well would this scale? Say you are storing 5 million posts and looking to scale that up
would it be better to segment them into several column families and if so to what extent?
I could create column families to store posts for each category however i'd end up with thousands of CF's.
Saying that the data would then be stored in a very sorted manner for querying/presenting.
My db is very write heavy and growing fast, Cassandra sounds like the best solution.
Any advice is greatly appreciated!!
Thanks
Sam
--
Andy Burgess
Principal Development Engineer
Application Delivery
WorldPay Ltd.
270-289 Science Park, Milton Road
Cambridge, CB4 0WE, United Kingdom (Depot Code: 024)
Office: +44 (0)1223 706 779| Mobile: +44 (0)7909 534 940
andy.burg...@worldpay.com
WorldPay (UK) Limited, Company No. 07316500. Registered Office: 55 Mansell
Street, London E1 8AN
Authorised and regulated by the Financial Services Authority.
‘WorldPay Group’ means WorldPay (UK) Limited and its affiliates from time to
time. A reference to an “affiliate”
Re: Upgrading from 0.6 to 0.7.0
Yes, it should be possible to try. We have not yet quite decided which way to go, think operations won't be happy with upgrading both server and client at the same time. Either we upgrade to 0.7.0 (currently does not look very likely), or we go to 0.6.9 and patch with TTL. I'm not too sure what a possible future upgrade would look like if we use the TTL patch, though. /Daniel 2011/1/21 Aaron Morton aa...@thelastpickle.com Yup, you can use diff ports and you can give them different cluster names and different seed lists. After you upgrade the second cluster partition the data should repair across, either via RR or the HHs that were stored while the first partition was down. Easiest thing would be to run node tool repair. Then a clean up to remove any leftover data. AFAIK file formats are compatible. But drain the nodes before upgrading to clear the log. Can you test this on a non production system? Aaron (we really need to write some upgrade docs:)) On 21/01/2011, at 10:42 PM, Dave Gardner dave.gard...@imagini.net wrote: What about executing writes against both clusters during the changeover? Interested in this topic because we're currently thinking about the same thing - how to upgrade to 0.7 without any interruption. Dave On 21 January 2011 09:20, Daniel Josefsson jid...@gmail.com jid...@gmail.com wrote: No, what I'm thinking of is having two clusters (0.6 and 0.7) running on different ports so they can't find each other. Or isn't that configurable? Then, when I have the two clusters, I could upgrade all of the clients to run against the new cluster, and finally upgrade the rest of the Cassandra nodes. I don't know how the new cluster would cope with having new data in the old cluster when they are upgraded though. /Daniel 2011/1/20 Aaron Morton aa...@thelastpickle.comaa...@thelastpickle.com I'm not sure if your suggesting running a mixed mode cluster there, but AFAIK the changes to the internode protocol prohibit this. The nodes will probable see each either via gossip, but the way the messages define their purpose (their verb handler) has been changed. Out of interest which is more painful, stopping the cluster and upgrading it or upgrading your client code? Aaron On 21/01/2011, at 12:35 AM, Daniel Josefsson jid...@gmail.com jid...@gmail.com wrote: In our case our replication factor is more than half the number of nodes in the cluster. Would it be possible to do the following: - Upgrade half of them - Change Thrift Port and inter-server port (is this the storage_port?) - Start them up - Upgrade clients one by one - Upgrade the the rest of the servers Or might we get some kind of data collision when still writing to the old cluster as the new storage is being used? /Daniel
Re: [mapreduce] ColumnFamilyRecordWriter hidden reuse
On Tue, 2011-01-25 at 09:37 +0100, Patrik Modesto wrote: While developing really simple MR task, I've found that a combiantion of Hadoop optimalization and Cassandra ColumnFamilyRecordWriter queue creates wrong keys to send to batch_mutate(). I've seen similar behaviour (junk rows being written), although my keys are always a result from LongSerializer.get().toByteBuffer(key) i'm interested in looking into it - but can you provide a code example? From what i can see TextOutputFormat.LineRecordWriter.write(..) doesn't clone anything, but it does write it out immediately. While ColumnFamilyRecordWriter does batch the mutations up as you say, it takes a ByteBuffer as a key, why/how are you re-using this client-side (arn't you creating a new ByteBuffer each call to write(..))? ~mck -- Never let your sense of morals get in the way of doing what's right. Isaac Asimov | http://semb.wever.org | http://sesat.no | http://finn.no | Java XSS Filter signature.asc Description: This is a digitally signed message part
Re: [mapreduce] ColumnFamilyRecordWriter hidden reuse
Hi Mick,
attached is the very simple MR job, that deletes expired URL from my
test Cassandra DB. The keyspace looks like this:
Keyspace: Test:
Replication Strategy: org.apache.cassandra.locator.SimpleStrategy
Replication Factor: 2
Column Families:
ColumnFamily: Url2
Columns sorted by: org.apache.cassandra.db.marshal.UTF8Type
Row cache size / save period: 0.0/0
Key cache size / save period: 20.0/3600
Memtable thresholds: 4.7015625/1003/60
GC grace seconds: 864000
Compaction min/max thresholds: 4/32
Read repair chance: 1.0
Built indexes: []
In the CF the key is URL and inside there are some data. My MR job
needs just expire_date which is int64 timestamp. For now I store it
as a string because I use Python and C++ to manipulate the data as
well.
For the MR Job to run you need a patch I did. You can find it here:
https://issues.apache.org/jira/browse/CASSANDRA-2014
The atttached file contains the working version with cloned key in
reduce() method. My other aproache was:
[code]
context.write(ByteBuffer.wrap(key.getBytes(), 0, key.getLength()),
Collections.singletonList(getMutation(key)));
[/code]
Which produce junk keys.
Best regards,
Patrik
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.LongBuffer;
import java.util.*;
import org.apache.cassandra.avro.Mutation;
import org.apache.cassandra.avro.Deletion;
import org.apache.cassandra.avro.SliceRange;
import org.apache.cassandra.hadoop.ColumnFamilyOutputFormat;
import org.apache.cassandra.db.IColumn;
import org.apache.cassandra.hadoop.ColumnFamilyInputFormat;
import org.apache.cassandra.hadoop.ConfigHelper;
import org.apache.cassandra.thrift.SlicePredicate;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
public class ContextExpirator extends Configured implements Tool
{
static final String KEYSPACE = Test;
static final String COLUMN_FAMILY = Url2;
static final String OUTPUT_COLUMN_FAMILY = Url2;
static final String COLUMN_VALUE = expire_date;
public static void main(String[] args) throws Exception
{
// Let ToolRunner handle generic command-line options
ToolRunner.run(new Configuration(), new ContextExpirator(), args);
System.exit(0);
}
public static class UrlFilterMapper
extends MapperByteBuffer, SortedMapByteBuffer, IColumn, Text, NullWritable
{
private final static NullWritable nic = NullWritable.get();
private ByteBuffer sourceColumn;
private static long now;
protected void setup(org.apache.hadoop.mapreduce.Mapper.Context context)
throws IOException, InterruptedException
{
sourceColumn = ByteBuffer.wrap(COLUMN_VALUE.getBytes());
now = System.currentTimeMillis() / 1000; // convert from ms
}
public void map(ByteBuffer key, SortedMapByteBuffer, IColumn columns, Context context)
throws IOException, InterruptedException
{
IColumn column = columns.get(sourceColumn);
if (column == null) {
return;
}
Text tKey = new Text(ByteBufferUtil.string(key));
Long value = Long.decode(ByteBufferUtil.string(column.value()));
if(now value) {
context.write(tKey, nic);
}
}
}
public static class RemoveUrlReducer
extends ReducerText, NullWritable, ByteBuffer, ListMutation
{
public void reduce(Text key, IterableNullWritable values, Context context)
throws IOException, InterruptedException
{
ByteBuffer bbKey = ByteBufferUtil.clone(ByteBuffer.wrap(key.getBytes(), 0, key.getLength()));
context.write(bbKey, Collections.singletonList(getMutation()));
}
private static Mutation getMutation()
{
Deletion d = new Deletion();
d.timestamp = System.currentTimeMillis();
Mutation m = new Mutation();
m.deletion = d;
return m;
}
}
public int run(String[] args) throws Exception
{
Job job = new Job(getConf(), context_expitator);
job.setJarByClass(ContextExpirator.class);
job.setInputFormatClass(ColumnFamilyInputFormat.class);
ConfigHelper.setInputColumnFamily(job.getConfiguration(), KEYSPACE, COLUMN_FAMILY);
job.setMapperClass(UrlFilterMapper.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(NullWritable.class);
Re: Schema Question
I'm fairly certain Aaron is referring to named families like BlogEntries,
not named columns (i-got-a-new-guitar).
On Tue, Jan 25, 2011 at 4:37 AM, Andy Burgess
andy.burg...@rbsworldpay.comwrote:
Aaron,
A question about one of your general points, do not create CF's on the
fly - what, exactly, does this mean? Do you mean named column families,
like BlogEntries from Sam's example, or do you mean column family keys,
like i-got-a-new-guitar? If it's the latter, then could you please explain
why not to do this? My application is based around creating row keys on the
fly, so I'd like to know ahead of time if I'm creating potential trouble for
myself.
To be honest, if you do mean specifically column families and not column
family keys, then I don't even understand how you would go about creating
those on-the-fly anyway. Don't they have to be pre-configured in
storage-conf.xml?
Thanks,
Andy.
On 25/01/11 00:39, Aaron Morton wrote:
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 denormalise to support these, the
writes will be fast enough.
- try to get each read request to be resolved by reading from a single CF
(not a rule, just a guideline)
- avoid big super columns.
- this may also be interesting
http://www.rackspacecloud.com/blog/2010/05/12/cassandra-by-example/
If you are happy with the one in the article start with that and see how
it works with you app. See how it works for your read activities.
Hope that helps.
Aaron
On 25 Jan, 2011,at 12:47 PM, Sam Hodgson
hodgson_...@hotmail.comhodgson_...@hotmail.comwrote:
Hi all,
Im brand new to Cassandra - im migrating from MySql for a large forum site
and would be grateful if anyone can give me some basic pointers on schema
design, or any recommended documentation.
The example used in
http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model is very
close if not exactly what I need for my main CF:
!--ColumnFamily: BlogEntriesThis is where all the blog entries will
go:Row Key + post's slug (the seo friendly portion of the uri)Column
Name: an attribute for the entry (title, body, etc)Column Value: value of
the associated attributeAccess: grab an entry by slug (always fetch all
Columns for Row)fyi: tags is a denormalization... its a comma separated
list of tags.im not using json in order to not interfere with our
notation but obviously you could use anything as long as your appknows
how to deal w/ itBlogEntries : { // CFi-got-a-new-guitar : { //
row key - the unique slug of the entry.title: This is a blog
entry about my new, awesome guitar,body: this is a cool entry.
etc etc yada yadaauthor: Arin Sarkissian // a row key into the
Authors CFtags: life,guitar,music // comma sep list of tags
(basic denormalization)pubDate: 1250558004 // unixtime for
publish dateslug: i-got-a-new-guitar},// all
other entriesanother-cool-guitar : {...tags:
guitar,slug: another-cool-guitar},
scream-is-the-best-movie-ever : {..tags:
movie,horror,slug: scream-is-the-best-movie-ever}
}--ColumnFamily CompareWith=BytesType Name=BlogEntries/
How well would this scale? Say you are storing 5 million posts and looking to
scale that up
would it be better to segment them into several column families and if so to
what extent?
I could create column families to store posts for each category however i'd
end up with thousands of CF's.
Saying that the data would then be stored in a very sorted manner for
querying/presenting.
My db is very write heavy and growing fast, Cassandra sounds like the best
solution.Any advice is greatly appreciated!!
Thanks
Sam
--
Andy Burgess
Principal Development Engineer
Application Delivery
WorldPay Ltd.
270-289 Science Park, Milton Road
Cambridge, CB4 0WE, United Kingdom (Depot Code: 024)
Office: +44 (0)1223 706 779| Mobile: +44 (0)7909 534
940andy.burg...@worldpay.com
WorldPay (UK) Limited, Company No. 07316500. Registered Office: 55 Mansell
Street, London E1 8AN
Authorised and regulated by the Financial Services Authority.
‘WorldPay Group’ means WorldPay (UK) Limited and its affiliates from time
to time. A reference to an “affiliate” means any Subsidiary Undertaking,
any Parent Undertaking and any Subsidiary Undertaking of any such Parent
Undertaking and reference to a “Parent Undertaking” or a “Subsidiary
Undertaking” is to be construed in accordance with section 1162 of the
Companies Act 2006, as amended.
DISCLAIMER: This email and
Re: client threads locked up - JIRA ISSUE 1594
What version of the Thrift API are you using? (In general, you should use an existing client library rather than rolling your own - I recommend Hector: https://github.com/rantav/hector). On Tue, Jan 25, 2011 at 12:38 AM, Arijit Mukherjee ariji...@gmail.com wrote: 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 n...@riptano.com 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 Mukherjee ariji...@gmail.com wrote: Hi All I'm facing the same issue as this one mentioned here - https://issues.apache.org/jira/browse/CASSANDRA-1594 Is there any solution or work-around for this? Regards Arijit -- And when the night is cloudy, There is still a light that shines on me, Shine on until tomorrow, let it be. -- And when the night is cloudy, There is still a light that shines on me, Shine on until tomorrow, let it be.
Re: Stress test inconsistencies
Try using something higher than -t 1, like -t 100. - Tyler On Mon, Jan 24, 2011 at 9:38 PM, Oleg Proudnikov ol...@cloudorange.comwrote: 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 contrib/stress but old py_stress produces similar results): ./stress -t 1 -o INSERT -c 30 -n 1 -i 1 On a SUSE Linux server with a 4-core Intel XEON I get maximum 30 inserts a second with 40ms latency. But on a Windows desktop I get incredible 200-260 inserts a second with a 4ms latency!!! Even on the smallest MacBook Pro I get bursts of high throughput - 100+ inserts a second. Could you please help me figure out what is wrong with my server? I tried several servers actually with the same results. I would appreciate any help in tracing down the bottleneck. Configuration is the same in all tests with the server having the advantage of separate physical disks for commitlog and data. Could you also share with me what numbers you get or what is reasonable to expect from this test? Thank you very much, Oleg Here is the output for the Linux server, Windows desktop and MacBook Pro, one line per second: Linux server - INtel XEON X3330 @ 2.666Mhz, 4G RAM, 2G heap Created keyspaces. Sleeping 1s for propagation. total,interval_op_rate,interval_key_rate,avg_latency,elapsed_time 19,19,19,0.05947368421052632,1 46,27,27,0.04274074074074074,2 70,24,24,0.04733,3 95,25,25,0.04696,4 119,24,24,0.048208333,5 147,28,28,0.04189285714285714,7 177,30,30,0.03904,8 206,29,29,0.04006896551724138,9 235,29,29,0.03903448275862069,10 Windows desktop: Core2 Duo CPU E6550 @ 2.333Mhz, 2G RAM, 1G heap Keyspace already exists. total,interval_op_rate,interval_key_rate,avg_latency,elapsed_time 147,147,147,0.005292517006802721,1 351,204,204,0.0042009803921568625,2 527,176,176,0.006551136363636364,3 718,191,191,0.005617801047120419,4 980,262,262,0.00400763358778626,5 1206,226,226,0.004150442477876107,6 1416,210,210,0.005619047619047619,7 1678,262,262,0.0040038167938931295,8 MacBook Pro: Core2 Duo CPU @ 2.26Mhz, 2G RAM, 1G heap Created keyspaces. Sleeping 1s for propagation. total,interval_op_rate,interval_key_rate,avg_latency,elapsed_time 0,0,0,NaN,1 7,7,7,0.21185714285714285,2 47,40,40,0.026925,3 171,124,124,0.007967741935483871,4 258,87,87,0.01206896551724138,6 294,36,36,0.022444,7 303,9,9,0.14378,8 307,4,4,0.2455,9 313,6,6,0.128,10 508,195,195,0.007938461538461538,11 792,284,284,0.0035985915492957746,12 882,90,90,0.01219,13
Re: [mapreduce] ColumnFamilyRecordWriter hidden reuse
On Tue, 2011-01-25 at 14:16 +0100, Patrik Modesto wrote: The atttached file contains the working version with cloned key in reduce() method. My other aproache was: context.write(ByteBuffer.wrap(key.getBytes(), 0, key.getLength()), Collections.singletonList(getMutation(key))); Which produce junk keys. In fact i have another problem (trying to write an empty byte[], or something, as a key, which put one whole row out of whack, ((one row in 25 million...))). But i'm debugging along the same code. I don't quite understand how the byte[] in ByteBuffer.wrap(key.getBytes(),...) gets clobbered. Well your key is a mutable Text object, so i can see some possibility depending on how hadoop uses these objects. Is there something to ByteBuffer.allocate(..) i'm missing... btw. is d.timestamp = System.currentTimeMillis(); ok? shouldn't this be microseconds so that each mutation has a different timestamp? http://wiki.apache.org/cassandra/DataModel ~mck -- As you go the way of life, you will see a great chasm. Jump. It is not as wide as you think. Native American Initiation Rite | http://semb.wever.org | http://sesat.no | http://finn.no | Java XSS Filter -- Everything should be made as simple as possible, but not simpler. Albert Einstein (William of Ockham) | http://semb.wever.org | http://sesat.no | http://finn.no | Java XSS Filter signature.asc Description: This is a digitally signed message part
Re: Forcing GC w/o jconsole
Thanks! It doesn't seem to have any effect on GCing dropped CFs, though. Maxim -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Forcing-GC-w-o-jconsole-tp5956747p5960100.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Stress test inconsistencies
Tyler Hobbs tyler at riptano.com writes: Try using something higher than -t 1, like -t 100.- Tyler Thank you, Tyler! When I run contrib/stress with a higher thread count, the server does scale to 200 inserts a second with latency of 200ms. At the same time Windows desktop scales to 900 inserts a second and latency of 120ms. There is a huge difference that I am trying to understand and eliminate. In my real life bulk load I have to stay with a single threaded client for the POC I am doing. The only option I have is to run several client processes... My real life load is heavier than what contrib/stress does. It takes several days to bulk load 4 million batch mutations !!! It is really painful :-( Something is just not right... Oleg
Re: Stress test inconsistencies
Oleg, I'm a novice at this, but for what it's worth I can't imagine you can have a _sustained_ 1kHz insertion rate on a single machine which also does some reads. If I'm wrong, I'll be glad to learn that I was. It just doesn't seem to square with a typical seek time on a hard drive. Maxim -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Stress-test-inconsistencies-tp5957467p5960182.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Stress test inconsistencies
On Tue, Jan 25, 2011 at 1:23 PM, Oleg Proudnikov ol...@cloudorange.comwrote: When I run contrib/stress with a higher thread count, the server does scale to 200 inserts a second with latency of 200ms. At the same time Windows desktop scales to 900 inserts a second and latency of 120ms. There is a huge difference that I am trying to understand and eliminate. Those are really low numbers, are you still testing with 10k rows? That's not enough, try 1M to give both JVMs enough time to warm up. -Brandon
Files not deleted after compaction and GCed
Using cassandra 0.7.0 The class org.apache.cassandra.io.sstable.SSTableDeletingReference only remove the -Data.db file, but leave the xxx-Compacted, xxx-Filter.db, xxx-Index.db and xxx-Statistics.db intact. And that's the behavior I saw.I ran manual compact then trigger a GC from jconsole. The Data.db file got removed but not the others. Is this the expected behavior? Regards, Chen
Re: Stress test inconsistencies
Brandon Williams driftx at gmail.com writes: On Tue, Jan 25, 2011 at 1:23 PM, Oleg Proudnikov olegp at cloudorange.com wrote: When I run contrib/stress with a higher thread count, the server does scale to 200 inserts a second with latency of 200ms. At the same time Windows desktop scales to 900 inserts a second and latency of 120ms. There is a huge difference that I am trying to understand and eliminate. Those are really low numbers, are you still testing with 10k rows? That's not enough, try 1M to give both JVMs enough time to warm up. -Brandon I agree, Brandon, the numbers are very low! The warm up does not seem to make any difference though... There is something that is holding the server back because the CPU is very low. I am trying to understand where this bottleneck is on the Linux server. I do not think it is Cassandra's config as I use the same config on Windows and get much higher numbers as I described. Oleg
Re: Errors During Compaction
Dan how did you go with this? More joy, less joy or a continuation of the current level of joy? Aaron On 24/01/2011, at 9:38 AM, Dan Hendry dan.hendry.j...@gmail.com wrote: I have run into a strange problem and was hoping for suggestions on how to fix it (0.7.0). When compaction occurs on one node for what appears to be one specific column family, the following error pops up the Cassandra log. Compaction apparently fails and temp files don’t get cleaned up. After a while and what seems to be multiple failed compactions on the CF, the node runs out of disk space and crashes. Not sure if it is a related problem or a function of this being a heavily used column family but after failing to compact, compaction restarts on the same CF exacerbating the issue. Problems with this specific node started earlier this weekend when it crashed with and OOM error. This is quite surprising since my memtable thresholds and GC settings have been tuned to run with quite a bit of overhead during normal operation (max heap usage usually = 10 GB on a 12 GB heap, average usage of 6-8 GB). I could not find anything abnormal in the logs which would prompt an OOM. I will look things over tomorrow and try to provide a bit more information on the problem but as a solution, I was going to wipe out all SSTables for this CF on this node and then run a repair. Far from ideal, is this a reasonable solution? ERROR [CompactionExecutor:1] 2011-01-23 14:10:29,855 AbstractCassandraDaemon.java (line 91) Fatal exception in thread Thread[CompactionExecutor:1,1,RMI Runtime] java.io.IOError: java.io.EOFException: attempted to skip -1983579368 bytes but only skipped 0 at org.apache.cassandra.io.sstable.SSTableIdentityIterator.init(SSTableIdentityIterator.java:78) at org.apache.cassandra.io.sstable.SSTableScanner$KeyScanningIterator.next(SSTableScanner.java:178) at org.apache.cassandra.io.sstable.SSTableScanner$KeyScanningIterator.next(SSTableScanner.java:143) at org.apache.cassandra.io.sstable.SSTableScanner.next(SSTableScanner.java:135) at org.apache.cassandra.io.sstable.SSTableScanner.next(SSTableScanner.java:38) at org.apache.commons.collections.iterators.CollatingIterator.set(CollatingIterator.java:284) at org.apache.commons.collections.iterators.CollatingIterator.least(CollatingIterator.java:326) at org.apache.commons.collections.iterators.CollatingIterator.next(CollatingIterator.java:230) at org.apache.cassandra.utils.ReducingIterator.computeNext(ReducingIterator.java:68) at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:136) at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:131) at org.apache.commons.collections.iterators.FilterIterator.setNextObject(FilterIterator.java:183) at org.apache.commons.collections.iterators.FilterIterator.hasNext(FilterIterator.java:94) at org.apache.cassandra.db.CompactionManager.doCompaction(CompactionManager.java:323) at org.apache.cassandra.db.CompactionManager$1.call(CompactionManager.java:122) at org.apache.cassandra.db.CompactionManager$1.call(CompactionManager.java:92) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) Caused by: java.io.EOFException: attempted to skip -1983579368 bytes but only skipped 0 at org.apache.cassandra.io.sstable.IndexHelper.skipBloomFilter(IndexHelper.java:52) at org.apache.cassandra.io.sstable.SSTableIdentityIterator.init(SSTableIdentityIterator.java:69) ... 20 more Dan Hendry (403) 660-2297
Re: Files not deleted after compaction and GCed
No, that is not expected. All the sstable components are removed in the same method; did you check the log for exceptions? On Tue, Jan 25, 2011 at 2:58 PM, Ching-Cheng Chen cc...@evidentsoftware.com wrote: Using cassandra 0.7.0 The class org.apache.cassandra.io.sstable.SSTableDeletingReference only remove the -Data.db file, but leave the xxx-Compacted, xxx-Filter.db, xxx-Index.db and xxx-Statistics.db intact. And that's the behavior I saw. I ran manual compact then trigger a GC from jconsole. The Data.db file got removed but not the others. Is this the expected behavior? Regards, Chen -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Does Major Compaction work on dropped CFs? Doesn't seem so.
You can run JConsole on your workstation and connect remotely to the nodes, it does not need to be run on the node itself. Connecting is discussed herehttp://wiki.apache.org/cassandra/MemtableThresholdsand some help for connecting is herehttp://wiki.apache.org/cassandra/JmxGotchasThere is also a Web front end for the JMX servicehttp://wiki.apache.org/cassandra/Operations#Monitoring_with_MX4JAnd a recent discussion on different way to monitor a nodehttp://www.mail-archive.com/user@cassandra.apache.org/msg08100.htmlIf you did through there is some talk about a JMXREST bridge.Hope that helps.AaronOn 25 Jan, 2011,at 04:17 PM, buddhasystem potek...@bnl.gov wrote: 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 nodetool command to zap the data you know you don't need, would be quite ideal. The reason I'm so retentive about it is that I plan to test scaling up to 250 million rows, and disk space matters. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Does-Major-Compaction-work-on-dropped-CFs-Doesn-t-seem-so-tp5946031p5957426.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Files not deleted after compaction and GCed
the other component types are deleted by this line: SSTable.delete(desc, components); On Tue, Jan 25, 2011 at 3:11 PM, Ching-Cheng Chen cc...@evidentsoftware.com wrote: Nope, no exception at all. But if the same class (org.apache.cassandra.io.sstable.SSTableDeletingReference) is responsible for delete other files, then that's not right. I checked the source code for SSTableDeletingReference, doesn't looks like it will delete other files type. Regards, Chen On Tue, Jan 25, 2011 at 4:05 PM, Jonathan Ellis jbel...@gmail.com wrote: No, that is not expected. All the sstable components are removed in the same method; did you check the log for exceptions? On Tue, Jan 25, 2011 at 2:58 PM, Ching-Cheng Chen cc...@evidentsoftware.com wrote: Using cassandra 0.7.0 The class org.apache.cassandra.io.sstable.SSTableDeletingReference only remove the -Data.db file, but leave the xxx-Compacted, xxx-Filter.db, xxx-Index.db and xxx-Statistics.db intact. And that's the behavior I saw. I ran manual compact then trigger a GC from jconsole. The Data.db file got removed but not the others. Is this the expected behavior? Regards, Chen -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: Schema Question
Yeah, I was talking about create a ColumnFamily definition via the API. Not inserting data into an already defined column family.The recommened approach to creating your schema is via the build in bin/cassandra-cli command line tool. It has loads of build in help and here is an example of how to create a keyspacehttp://www.mail-archive.com/user@cassandra.apache.org/msg09146.htmlLet me know how you get on.AaronOn 26 Jan, 2011,at 02:28 AM, David McNelis dmcne...@agentisenergy.com wrote:I'm fairly certain Aaron is referring to named families like BlogEntries, not named columns (i-got-a-new-guitar). On Tue, Jan 25, 2011 at 4:37 AM, Andy Burgess andy.burg...@rbsworldpay.com wrote:
Aaron,
A question about one of your general points, "do not create CF's on
the fly" - what, exactly, does this mean? Do you mean named column
families, like "BlogEntries" from Sam's example, or do you mean
column family keys, like "i-got-a-new-guitar"? If it's the latter,
then could you please explain why not to do this? My application is
based around creating row keys on the fly, so I'd like to know ahead
of time if I'm creating potential trouble for myself.
To be honest, if you do mean specifically column families and not
column family keys, then I don't even understand how you would go
about creating those on-the-fly anyway. Don't they have to be
pre-configured in storage-conf.xml?
Thanks,
Andy.
On 25/01/11 00:39, Aaron Morton wrote:
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 denormalise to
support these, the writes will be fast enough.
- try to get each read request to be resolved by reading from
a single CF (not a rule, just a guideline)
- avoid big super columns.
- this may also be interestinghttp://www.rackspacecloud.com/blog/2010/05/12/cassandra-by-example/
If you are happy with the one in the article start with that
and see how it works with you app. See how it works for your
read activities.
Hope that helps.
Aaron
On 25 Jan, 2011,at 12:47 PM, Sam Hodgson
hodgson_...@hotmail.com wrote:
Hi all,
Im brand new to Cassandra - im migrating from MySql for a
large forum site and would be grateful if anyone can give me
some basic pointers on schema design, or any recommended
documentation.
The example used in
http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model
is very close if not exactly what I need for my main CF:
!--
ColumnFamily: BlogEntries
This is where all the blog entries will go:
Row Key + post's slug (the seo friendly portion of the uri)
Column Name: an attribute for the entry (title, body, etc)
Column Value: value of the associated attribute
Access: grab an entry by slug (always fetch all Columns for Row)
fyi: tags is a denormalization... its a comma separated list of tags.
im not using json in order to not interfere with our
notation but obviously you could use anything as long as your app
knows how to deal w/ it
BlogEntries : { // CF
i-got-a-new-guitar : { // row key - the unique "slug" of the entry.
title: This is a blog entry about my new, awesome guitar,
body: this is a cool entry. etc etc yada yada
author: Arin Sarkissian // a row key into the Authors CF
tags: life,guitar,music // comma sep list of tags (basic denormalization)
pubDate: 1250558004 // unixtime for publish date
slug: i-got-a-new-guitar
},
// all other entries
another-cool-guitar : {
...
tags: guitar,
slug: another-cool-guitar
},
scream-is-the-best-movie-ever : {
..
tags: movie,horror,
slug: scream-is-the-best-movie-ever
}
}
--
ColumnFamily CompareWith="BytesType" Name="BlogEntries"/
How well would this scale? Say you are storing 5 million posts and looking to scale that up
would it be better to segment them into several column families and if so to what extent?
I could create column families to store posts for each category however i'd end up with thousands of CF's.
Saying that the data would then be stored in a very sorted manner for querying/presenting.
My db is very write heavy and growing fast, Cassandra sounds like
Re: Stress test inconsistencies
Look at iostat -x 10 10 when he active par tof your test is running. there should be something called svc_t - that should be in the 10ms range, and await should be low. Will tell you if IO is slow, or if IO is not being issued. Also, ensure that you ain't swapping with something like swapon -s On Tue, Jan 25, 2011 at 3:04 PM, Oleg Proudnikov ol...@cloudorange.comwrote: buddhasystem potekhin at bnl.gov writes: Oleg, I'm a novice at this, but for what it's worth I can't imagine you can have a _sustained_ 1kHz insertion rate on a single machine which also does some reads. If I'm wrong, I'll be glad to learn that I was. It just doesn't seem to square with a typical seek time on a hard drive. Maxim Maxim, As I understand during inserts Cassandra should not be constrained by random seek time as it uses sequential writes. I do get high numbers on Windows but there is something that is holding back my Linux server. I am trying to understand what it is. Oleg
Re-partitioning the cluster with nodetool: what's happening?
I'm trying re-partition my 4-node cluster to make the load exactly 25% on each node. As per recipes found in documentation, I calculate: for x in xrange(4): ... print 2**127/4*x ... 0 42535295865117307932921825928971026432 85070591730234615865843651857942052864 127605887595351923798765477786913079296 And I need to move the first one to 0, then the second one to 42535295865117307932921825928971026432 etc. Once I start the procedure, I see no progress when I look at nodetool netstats. Nothing's happening. What am I doing wrong? Thanks, Maxim -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-partitioning-the-cluster-with-nodetool-what-s-happening-tp5960843p5960843.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
Re: Re-partitioning the cluster with nodetool: what's happening?
Correction -- what I meant to say that I do see announcements about streaming in the output, but these are stuck at 0%. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-partitioning-the-cluster-with-nodetool-what-s-happening-tp5960843p5960851.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
get_range_slices getting deleted rows
Hi, I'm trying a test scenario where I create 100 rows in a CF, then use get_range_slices to get all the rows, and I get 100 rows, so far so good then after the test I delete the rows using remove but without a column or super column, this deletes the row, I can confirm that cos if I try to get it with get_slice using the key I get nothing but then if I do get_range_slice again, where the range goes between new byte[0] and new byte[0] (therefore returning everything), I still get the 100 row keys is that expected to be? thanks Nicolas Santini
Re: get_range_slices getting deleted rows
Yes. See this http://wiki.apache.org/cassandra/FAQ#range_ghosts -Naren On Tue, Jan 25, 2011 at 2:59 PM, Nick Santini nick.sant...@kaseya.comwrote: Hi, I'm trying a test scenario where I create 100 rows in a CF, then use get_range_slices to get all the rows, and I get 100 rows, so far so good then after the test I delete the rows using remove but without a column or super column, this deletes the row, I can confirm that cos if I try to get it with get_slice using the key I get nothing but then if I do get_range_slice again, where the range goes between new byte[0] and new byte[0] (therefore returning everything), I still get the 100 row keys is that expected to be? thanks Nicolas Santini
Fwd: CFP - Berlin Buzzwords 2011 - Search, Score, Scale
This might interest the Cassandra community. - Sincerely, David G. Boney dbon...@semanticartifacts.com http://www.semanticartifacts.com Begin forwarded message: From: Isabel Drost isa...@apache.org Date: January 25, 2011 2:53:28 PM CST To: u...@mahout.apache.org Cc: gene...@lucene.apache.org, gene...@hadoop.apache.org, u...@hbase.apache.org, solr-u...@lucene.apache.org, java-u...@lucene.apache.org, u...@nutch.apache.org Subject: CFP - Berlin Buzzwords 2011 - Search, Score, Scale Reply-To: u...@mahout.apache.org Reply-To: isa...@apache.org This is to announce the Berlin Buzzwords 2011. The second edition of the successful conference on scalable and open search, data processing and data storage in Germany, taking place in Berlin. Call for Presentations Berlin Buzzwords http://berlinbuzzwords.de Berlin Buzzwords 2011 - Search, Store, Scale 6/7 June 2011 The event will comprise presentations on scalable data processing. We invite you to submit talks on the topics: * IR / Search - Lucene, Solr, katta or comparable solutions * NoSQL - like CouchDB, MongoDB, Jackrabbit, HBase and others * Hadoop - Hadoop itself, MapReduce, Cascading or Pig and relatives * Closely related topics not explicitly listed above are welcome. We are looking for presentations on the implementation of the systems themselves, real world applications and case studies. Important Dates (all dates in GMT +2) * Submission deadline: March 1st 2011, 23:59 MEZ * Notification of accepted speakers: March 22th, 2011, MEZ. * Publication of final schedule: April 5th, 2011. * Conference: June 6/7. 2011 High quality, technical submissions are called for, ranging from principles to practice. We are looking for real world use cases, background on the architecture of specific projects and a deep dive into architectures built on top of e.g. Hadoop clusters. Proposals should be submitted at http://berlinbuzzwords.de/content/cfp-0 no later than March 1st, 2011. Acceptance notifications will be sent out soon after the submission deadline. Please include your name, bio and email, the title of the talk, a brief abstract in English language. Please indicate whether you want to give a lightning (10min), short (20min) or long (40min) presentation and indicate the level of experience with the topic your audience should have (e.g. whether your talk will be suitable for newbies or is targeted for experienced users.) If you'd like to pitch your brand new product in your talk, please let us know as well - there will be extra space for presenting new ideas, awesome products and great new projects. The presentation format is short. We will be enforcing the schedule rigorously. If you are interested in sponsoring the event (e.g. we would be happy to provide videos after the event, free drinks for attendees as well as an after-show party), please contact us. Follow @hadoopberlin on Twitter for updates. Tickets, news on the conference, and the final schedule are be published at http://berlinbuzzwords.de. Program Chairs: Isabel Drost, Jan Lehnardt, and Simon Willnauer. Please re-distribute this CfP to people who might be interested. If you are local and wish to meet us earlier, please note that this Thursday evening there will be an Apache Hadoop Get Together (videos kindly sponsored by Cloudera, venue kindly provided for free by Zanox) featuring talks on Apache Hadoop in production as well as news on current Apache Lucene developments. Contact us at: newthinking communications GmbH Schönhauser Allee 6/7 10119 Berlin, Germany Julia Gemählich Isabel Drost +49(0)30-9210 596
Re: get_range_slices getting deleted rows
thanks, so I need to check the returned slice for the key to verify that is a valid row and not a deleted one? Nicolas Santini On Wed, Jan 26, 2011 at 12:16 PM, Narendra Sharma narendra.sha...@gmail.com wrote: Yes. See this http://wiki.apache.org/cassandra/FAQ#range_ghosts -Naren On Tue, Jan 25, 2011 at 2:59 PM, Nick Santini nick.sant...@kaseya.comwrote: Hi, I'm trying a test scenario where I create 100 rows in a CF, then use get_range_slices to get all the rows, and I get 100 rows, so far so good then after the test I delete the rows using remove but without a column or super column, this deletes the row, I can confirm that cos if I try to get it with get_slice using the key I get nothing but then if I do get_range_slice again, where the range goes between new byte[0] and new byte[0] (therefore returning everything), I still get the 100 row keys is that expected to be? thanks Nicolas Santini
RE: Errors During Compaction
Limited joy I would say :) No long term damage at least. I ended up deleting (moving to another disk) all the sstables which fixed the problem. I ran in to even more problems during repair (detailed in another recent email) but it seems to have worked regardless. Just to be safe, I am in the process of starting a ‘manual repair’ (copying SSTables from other nodes for this particular CF then restarting and running a cleanup + major compaction). Any thoughts on what the root cause of this problem could be? It is somewhat worrying that a CF can randomly become corrupt bringing down the whole node. Cassandras handling of a corrupt CF (regardless of how rare an occurrence) is less than elegant. Dan From: Aaron Morton [mailto:aa...@thelastpickle.com] Sent: January-25-11 16:03 To: user@cassandra.apache.org Subject: Re: Errors During Compaction Dan how did you go with this? More joy, less joy or a continuation of the current level of joy? Aaron On 24/01/2011, at 9:38 AM, Dan Hendry dan.hendry.j...@gmail.com wrote: I have run into a strange problem and was hoping for suggestions on how to fix it (0.7.0). When compaction occurs on one node for what appears to be one specific column family, the following error pops up the Cassandra log. Compaction apparently fails and temp files don’t get cleaned up. After a while and what seems to be multiple failed compactions on the CF, the node runs out of disk space and crashes. Not sure if it is a related problem or a function of this being a heavily used column family but after failing to compact, compaction restarts on the same CF exacerbating the issue. Problems with this specific node started earlier this weekend when it crashed with and OOM error. This is quite surprising since my memtable thresholds and GC settings have been tuned to run with quite a bit of overhead during normal operation (max heap usage usually = 10 GB on a 12 GB heap, average usage of 6-8 GB). I could not find anything abnormal in the logs which would prompt an OOM. I will look things over tomorrow and try to provide a bit more information on the problem but as a solution, I was going to wipe out all SSTables for this CF on this node and then run a repair. Far from ideal, is this a reasonable solution? ERROR [CompactionExecutor:1] 2011-01-23 14:10:29,855 AbstractCassandraDaemon.java (line 91) Fatal exception in thread Thread[CompactionExecutor:1,1,RMI Runtime] java.io.IOError: java.io.EOFException: attempted to skip -1983579368 bytes but only skipped 0 at org.apache.cassandra.io.sstable.SSTableIdentityIterator.init(SSTableIdentityIterator.java:78) at org.apache.cassandra.io.sstable.SSTableScanner$KeyScanningIterator.next(SSTableScanner.java:178) at org.apache.cassandra.io.sstable.SSTableScanner$KeyScanningIterator.next(SSTableScanner.java:143) at org.apache.cassandra.io.sstable.SSTableScanner.next(SSTableScanner.java:135) at org.apache.cassandra.io.sstable.SSTableScanner.next(SSTableScanner.java:38) at org.apache.commons.collections.iterators.CollatingIterator.set(CollatingIterator.java:284) at org.apache.commons.collections.iterators.CollatingIterator.least(CollatingIterator.java:326) at org.apache.commons.collections.iterators.CollatingIterator.next(CollatingIterator.java:230) at org.apache.cassandra.utils.ReducingIterator.computeNext(ReducingIterator.java:68) at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:136) at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:131) at org.apache.commons.collections.iterators.FilterIterator.setNextObject(FilterIterator.java:183) at org.apache.commons.collections.iterators.FilterIterator.hasNext(FilterIterator.java:94) at org.apache.cassandra.db.CompactionManager.doCompaction(CompactionManager.java:323) at org.apache.cassandra.db.CompactionManager$1.call(CompactionManager.java:122) at org.apache.cassandra.db.CompactionManager$1.call(CompactionManager.java:92) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) Caused by: java.io.EOFException: attempted to skip -1983579368 bytes but only skipped 0 at org.apache.cassandra.io.sstable.IndexHelper.skipBloomFilter(IndexHelper.java:52) at org.apache.cassandra.io.sstable.SSTableIdentityIterator.init(SSTableIdentityIterator.java:69) ... 20 more Dan Hendry (403) 660-2297 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.872 / Virus
Re: get_range_slices getting deleted rows
No, checking the key will not do. You will need to check if row.getColumnSlice().getColumns() is empty or not. That's what I do and it works for me. On Wed, Jan 26, 2011 at 4:53 AM, Nick Santini nick.sant...@kaseya.comwrote: thanks, so I need to check the returned slice for the key to verify that is a valid row and not a deleted one? Nicolas Santini On Wed, Jan 26, 2011 at 12:16 PM, Narendra Sharma narendra.sha...@gmail.com wrote: Yes. See this http://wiki.apache.org/cassandra/FAQ#range_ghosts -Naren On Tue, Jan 25, 2011 at 2:59 PM, Nick Santini nick.sant...@kaseya.comwrote: Hi, I'm trying a test scenario where I create 100 rows in a CF, then use get_range_slices to get all the rows, and I get 100 rows, so far so good then after the test I delete the rows using remove but without a column or super column, this deletes the row, I can confirm that cos if I try to get it with get_slice using the key I get nothing but then if I do get_range_slice again, where the range goes between new byte[0] and new byte[0] (therefore returning everything), I still get the 100 row keys is that expected to be? thanks Nicolas Santini
Re: Re-partitioning the cluster with nodetool: what's happening?
It can take a bit of thinking time for the nodes to work out what to stream, the bottom of this pagehttp://wiki.apache.org/cassandra/Streamingtalks about how to watch whats happening.If it does get stuck let us know.AaronOn 26 Jan, 2011,at 11:42 AM, buddhasystem potek...@bnl.gov wrote: Correction -- what I meant to say that I do see announcements about streaming in the output, but these are stuck at 0%. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-partitioning-the-cluster-with-nodetool-what-s-happening-tp5960843p5960851.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
RE: the java client problem
I had find the loasschemafrom yaml by jconsole,How to load the schema ?
From: Ashish [mailto:paliwalash...@gmail.com]
Sent: Friday, January 21, 2011 8:10 PM
To: user@cassandra.apache.org
Subject: Re: the java client problem
check cassandra-install-dir/conf/cassandra.yaml
start cassandra
connect via jconsole
find MBeans - org.apache.cassandra.db -
StorageServicehttp://wiki.apache.org/cassandra/StorageService - Operations
- loadSchemaFromYAML
load the schema
and then try the example again.
HTH
ashish
2011/1/21 raoyixuan (Shandy) raoyix...@huawei.commailto:raoyix...@huawei.com
Which schema is it?
From: Ashish [mailto:paliwalash...@gmail.commailto:paliwalash...@gmail.com]
Sent: Friday, January 21, 2011 7:57 PM
To: user@cassandra.apache.orgmailto:user@cassandra.apache.org
Subject: Re: the java client problem
you are missing the column family in your keyspace.
If you are using the default definitions of schema shipped with cassandra,
ensure to load the schema from JMX.
thanks
ashish
2011/1/21 raoyixuan (Shandy) raoyix...@huawei.commailto:raoyix...@huawei.com
I exec the code as below by hector client:
package com.riptano.cassandra.hector.example;
import me.prettyprint.cassandra.serializers.StringSerializer;
import me.prettyprint.hector.api.Cluster;
import me.prettyprint.hector.api.Keyspace;
import me.prettyprint.hector.api.beans.HColumn;
import me.prettyprint.hector.api.exceptions.HectorException;
import me.prettyprint.hector.api.factory.HFactory;
import me.prettyprint.hector.api.mutation.Mutator;
import me.prettyprint.hector.api.query.ColumnQuery;
import me.prettyprint.hector.api.query.QueryResult;
public class InsertSingleColumn {
private static StringSerializer stringSerializer = StringSerializer.get();
public static void main(String[] args) throws Exception {
Cluster cluster = HFactory.getOrCreateCluster(TestCluster,
*.*.*.*:9160);
Keyspace keyspaceOperator = HFactory.createKeyspace(Shandy, cluster);
try {
MutatorString mutator = HFactory.createMutator(keyspaceOperator,
StringSerializer.get());
mutator.insert(jsmith, Standard1,
HFactory.createStringColumn(first, John));
ColumnQueryString, String, String columnQuery =
HFactory.createStringColumnQuery(keyspaceOperator);
columnQuery.setColumnFamily(Standard1).setKey(jsmith).setName(first);
QueryResultHColumnString, String result = columnQuery.execute();
System.out.println(Read HColumn from cassandra: + result.get());
System.out.println(Verify on CLI with: get
Keyspace1.Standard1['jsmith'] );
} catch (HectorException e) {
e.printStackTrace();
}
cluster.getConnectionManager().shutdown();
}
}
And it shows the error :
me.prettyprint.hector.api.exceptions.HInvalidRequestException:
InvalidRequestException(why:unconfigured columnfamily Standard1)
at
me.prettyprint.cassandra.service.ExceptionsTranslatorImpl.translate(ExceptionsTranslatorImpl.java:42)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl$1.execute(KeyspaceServiceImpl.java:95)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl$1.execute(KeyspaceServiceImpl.java:88)
at
me.prettyprint.cassandra.service.Operation.executeAndSetResult(Operation.java:89)
at
me.prettyprint.cassandra.connection.HConnectionManager.operateWithFailover(HConnectionManager.java:142)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl.operateWithFailover(KeyspaceServiceImpl.java:129)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl.batchMutate(KeyspaceServiceImpl.java:100)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl.batchMutate(KeyspaceServiceImpl.java:106)
at
me.prettyprint.cassandra.model.MutatorImpl$2.doInKeyspace(MutatorImpl.java:149)
at
me.prettyprint.cassandra.model.MutatorImpl$2.doInKeyspace(MutatorImpl.java:146)
at
me.prettyprint.cassandra.model.KeyspaceOperationCallback.doInKeyspaceAndMeasure(KeyspaceOperationCallback.java:20)
at
me.prettyprint.cassandra.model.ExecutingKeyspace.doExecute(ExecutingKeyspace.java:65)
at
me.prettyprint.cassandra.model.MutatorImpl.execute(MutatorImpl.java:146)
at me.prettyprint.cassandra.model.MutatorImpl.insert(MutatorImpl.java:55)
at
com.riptano.cassandra.hector.example.InsertSingleColumn.main(InsertSingleColumn.java:21)
Caused by: InvalidRequestException(why:unconfigured columnfamily Standard1)
at
org.apache.cassandra.thrift.Cassandra$batch_mutate_result.read(Cassandra.java:16477)
at
org.apache.cassandra.thrift.Cassandra$Client.recv_batch_mutate(Cassandra.java:916)
at
org.apache.cassandra.thrift.Cassandra$Client.batch_mutate(Cassandra.java:890)
at
me.prettyprint.cassandra.service.KeyspaceServiceImpl$1.execute(KeyspaceServiceImpl.java:93)
... 13 more
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Re: [mapreduce] ColumnFamilyRecordWriter hidden reuse
On Tue, Jan 25, 2011 at 19:09, Mick Semb Wever m...@apache.org wrote: In fact i have another problem (trying to write an empty byte[], or something, as a key, which put one whole row out of whack, ((one row in 25 million...))). But i'm debugging along the same code. I don't quite understand how the byte[] in ByteBuffer.wrap(key.getBytes(),...) gets clobbered. Code snippet would help here. Well your key is a mutable Text object, so i can see some possibility depending on how hadoop uses these objects. Is there something to ByteBuffer.allocate(..) i'm missing... I don't know, I'm quite new to Java (but with long C++ history). btw. is d.timestamp = System.currentTimeMillis(); ok? shouldn't this be microseconds so that each mutation has a different timestamp? http://wiki.apache.org/cassandra/DataModel You are correct that microseconds would be better but for the test it doesn't matter that much. Patrik
Re: [mapreduce] ColumnFamilyRecordWriter hidden reuse
is d.timestamp = System.currentTimeMillis(); ok? You are correct that microseconds would be better but for the test it doesn't matter that much. Have you tried. I'm very new to cassandra as well, and always uncertain as to what to expect... ByteBuffer bbKey = ByteBufferUtil.clone(ByteBuffer.wrap(key.getBytes(), 0, key.getLength())); An alternative approach to your client-side cloning is ByteBuffer bbKey = ByteBuffer.wrap(key.toString().getBytes(UTF_8)); Here at least it is obvious you are passing in the bytes from an immutable object. As far as moving the clone(..) into ColumnFamilyRecordWriter.write(..) won't this hurt performance? Normally i would _always_ agree that a defensive copy of an array/collection argument be stored, but has this intentionally not been done (or should it) because of large reduce jobs (millions of records) and the performance impact here. The key isn't the only potential live byte[]. You also have names and values in all the columns (and supercolumns) for all the mutations. ~mck
