snapshot issue

[Adeel Akbar]

Hi,

I am trying to taking snapshot of my data but faced following error. 
Please help me to resolve this issue.


[root@cassandra1 bin]# ./nodetool -h localhost snapshot 20120711
Exception in thread "main" java.io.IOError: java.io.IOException: Cannot 
run program "ln": java.io.IOException: error=12, Cannot allocate memory
at 
org.apache.cassandra.db.ColumnFamilyStore.snapshotWithoutFlush(ColumnFamilyStore.java:1660)
at 
org.apache.cassandra.db.ColumnFamilyStore.snapshot(ColumnFamilyStore.java:1686)

at org.apache.cassandra.db.Table.snapshot(Table.java:198)
at 
org.apache.cassandra.service.StorageService.takeSnapshot(StorageService.java:1393)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:616)
at 
com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:111)
at 
com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:45)
at 
com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:226)
at 
com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)
at 
com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:251)
at 
com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:857)
at 
com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:795)
at 
javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1450)
at 
javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:90)
at 
javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1285)
at 
javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1383)
at 
javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:807)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:616)
at 
sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)

at sun.rmi.transport.Transport$1.run(Transport.java:177)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
at 
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:553)
at 
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:808)
at 
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:667)
at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)

at java.lang.Thread.run(Thread.java:636)
Caused by: java.io.IOException: Cannot run program "ln": 
java.io.IOException: error=12, Cannot allocate memory

at java.lang.ProcessBuilder.start(ProcessBuilder.java:475)
at 
org.apache.cassandra.utils.CLibrary.createHardLinkWithExec(CLibrary.java:181)
at 
org.apache.cassandra.utils.CLibrary.createHardLink(CLibrary.java:147)
at 
org.apache.cassandra.io.sstable.SSTableReader.createLinks(SSTableReader.java:730)
at 
org.apache.cassandra.db.ColumnFamilyStore.snapshotWithoutFlush(ColumnFamilyStore.java:1653)

... 33 more
Caused by: java.io.IOException: java.io.IOException: error=12, Cannot 
allocate memory

at java.lang.UNIXProcess.(UNIXProcess.java:164)
at java.lang.ProcessImpl.start(ProcessImpl.java:81)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:468)
... 37 more

--


Thanks & Regards

*Adeel**Akbar*

RE snapshot issue

[Samuel CARRIERE]

Hello,

The problem is described here : 
http://wiki.apache.org/cassandra/Operations
The recommended way to avoit it is to use jna.

Cheers,
Samuel


> Adeel Akbar  
> 11/07/2012 11:38
> 
> 
> Hi,
> 
> I am trying to taking snapshot of my data but faced following error.
> Please help me to resolve this issue.
> 
> [root@cassandra1 bin]# ./nodetool -h localhost snapshot 20120711
> Exception in thread "main" java.io.IOError: java.io.IOException: 
> Cannot run program "ln": java.io.IOException: error=12, Cannot allocate 
memory

Reduced key-cache due to memory pressure and cache size estimate

[Omid Aladini]

Hi,

I'm trying to tune, memtable size, key cache size and heap size on
Cassandra 1.1.0 but I keep having memory pressure and reduced cache size.
With the following settings:

heap size: 10GB (had the same issue with 8GB so I'm testing with increased
heap size)
memtable_total_space_in_mb: 2GB
key_cache_size_in_mb: 2GB   (global key cache capacity)

Still, heap usage hits flush_largest_memtables_at (= 0.75) many times in a
short period of time before hitting reduce_cache_sizes_at (= 0.85) that
reduces the cache size and resolves memory pressure.

In one instance, cache size is reported to be 1450MB before reduction and
~870MB after reduction, but the gain in heap space due to reduction in
cache size is about 3GB.

Could it be that the cache size estimate in megabytes isn't accurate?

Thanks,
Omid

rounded timestamp ?

[Marco Matarazzo]

Greetings.

Running (CQL 3) queries like:

   update users set admin = 1 where corporation_id = 
'7a55bc4c-84e7-479c-9ac6-43f7836705b5';

… I see in logs a row like:

StorageProxy.java (line 175) Mutations/ConsistencyLevel are 
[RowMutation(keyspace='goh_test', 
key='37613535626334632d383465372d343739632d396163362d343366373833363730356235', 
modifications=[ColumnFamily(users [admin:false:1@1342006844093000,])])]/ONE

If I understand it correctly, that 1342006844093000 is the timestamp in 
microseconds, getting rounded to milliseconds.

If I modify queries in this way:

   update users using timestamp 1342006844106123 set admin = 1 where 
corporation_id = '7a55bc4c-84e7-479c-9ac6-43f7836705b5';

… the log row becomes:

StorageProxy.java (line 175) Mutations/ConsistencyLevel are 
[RowMutation(keyspace='goh_test', 
key='37613535626334632d383465372d343739632d396163362d343366373833363730356235', 
modifications=[ColumnFamily(users [admin:false:1@1342006844106123,])])]/ONE

…and what I see is that the timestamp get through NOT rounded, with 
microseconds precision.


We see this behavior using cqlsh, C++ thrift bindings and phpcassa. I guess 
they all use thrift, and so the rounding happens there.

One of the "problems" is that sometimes it gets rounded up, so it's in the 
future. But that's just a side effect of rounding, and I can't understand why 
in the first place there is a rounding. I guess that the second case is just 
Cassandra "correcting" the timestamp with data found in the CQL, and maybe 
thrift is still sending a milliseconds-rounded timestamp, but I still can't see 
a reason for thrift doing this.

Could someone enlighten me a bit on this matter ?

--
Marco Matarazzo
== Hex Keep ==

"You can learn more about a man
  in one hour of play
  than in one year of conversation.” - Plato

RE: help using org.apache.cassandra.cql3

[Leonid Ilyevsky]

I see.
The reason I looked at that package was, I need to use the batch feature, and I 
could not make it work using thrift with the CF having composite key. It worked 
fine with the simple key, but not composite, I was getting an error while 
trying to do the update.
Sylvain suggested (in reply to my other posting) that I use cql3 batch 
statement, but I am not sure how to do it efficiently from Java. Can batch 
statement be prepared? Is it OK to put 1 of update statements in one batch, 
with 5 question marks in it? The set that many variables?
Maybe I can try small example first, just to see if it works at all.


From: Derek Williams [mailto:de...@fyrie.net]
Sent: Tuesday, July 10, 2012 7:19 PM
To: user@cassandra.apache.org
Subject: Re: help using org.apache.cassandra.cql3

On Tue, Jul 10, 2012 at 3:04 PM, Leonid Ilyevsky 
mailto:lilyev...@mooncapital.com>> wrote:
I am trying to use the org.apache.cassandra.cql3 package. Having problem 
connecting to the server using ClientState.
I was not sure what to put in the credentials map (I did not set any 
users/passwords on my server), so I tried setting empty strings for “username” 
and “password”, setting them to bogus values, passing null to the login method 
– there was no difference.
It does not complain at the login(), but then it complains about 
setKeyspace(), saying that the specified keyspace does not exist 
(it obviously does exist).
The configuration was loaded from cassandra.yaml used by the server.

I did not have any problem like this when I used 
org.apache.cassandra.thrift.Cassandra.Client .

What am I doing wrong?

I think that package just contains server classes. Everything you need should 
be in org.apache.cassandra.thrift.

To use cql3 I just use the client methods 'execute_cql_query', 
'prepare_cql_query' and 'execute_prepared_cql_query', after setting cql version 
to '3.0.0'.


--
Derek Williams



This email, along with any attachments, is confidential and may be legally 
privileged or otherwise protected from disclosure. Any unauthorized 
dissemination, copying or use of the contents of this email is strictly 
prohibited and may be in violation of law. If you are not the intended 
recipient, any disclosure, copying, forwarding or distribution of this email is 
strictly prohibited and this email and any attachments should be deleted 
immediately. This email and any attachments do not constitute an offer to sell 
or a solicitation of an offer to purchase any interest in any investment 
vehicle sponsored by Moon Capital Management LP (“Moon Capital”). Moon Capital 
does not provide legal, accounting or tax advice. Any statement regarding 
legal, accounting or tax matters was not intended or written to be relied upon 
by any person as advice. Moon Capital does not waive confidentiality or 
privilege as a result of this email.

Re: rounded timestamp ?

[Sylvain Lebresne]

There is no rounding or correction whatsoever. It just happens that if
you don't give a timestamp in CQL, the timestamp is generated server
side using that Java System.currentTimeMillis() that only provide
milliseconds precision. If you provide your own timestamp however we
use it without doing anything with it.

--
Sylvain

On Wed, Jul 11, 2012 at 1:56 PM, Marco Matarazzo
 wrote:
> Greetings.
>
> Running (CQL 3) queries like:
>
>update users set admin = 1 where corporation_id = 
> '7a55bc4c-84e7-479c-9ac6-43f7836705b5';
>
> … I see in logs a row like:
>
> StorageProxy.java (line 175) Mutations/ConsistencyLevel are 
> [RowMutation(keyspace='goh_test', 
> key='37613535626334632d383465372d343739632d396163362d343366373833363730356235',
>  modifications=[ColumnFamily(users [admin:false:1@1342006844093000,])])]/ONE
>
> If I understand it correctly, that 1342006844093000 is the timestamp in 
> microseconds, getting rounded to milliseconds.
>
> If I modify queries in this way:
>
>update users using timestamp 1342006844106123 set admin = 1 where 
> corporation_id = '7a55bc4c-84e7-479c-9ac6-43f7836705b5';
>
> … the log row becomes:
>
> StorageProxy.java (line 175) Mutations/ConsistencyLevel are 
> [RowMutation(keyspace='goh_test', 
> key='37613535626334632d383465372d343739632d396163362d343366373833363730356235',
>  modifications=[ColumnFamily(users [admin:false:1@1342006844106123,])])]/ONE
>
> …and what I see is that the timestamp get through NOT rounded, with 
> microseconds precision.
>
>
> We see this behavior using cqlsh, C++ thrift bindings and phpcassa. I guess 
> they all use thrift, and so the rounding happens there.
>
> One of the "problems" is that sometimes it gets rounded up, so it's in the 
> future. But that's just a side effect of rounding, and I can't understand why 
> in the first place there is a rounding. I guess that the second case is just 
> Cassandra "correcting" the timestamp with data found in the CQL, and maybe 
> thrift is still sending a milliseconds-rounded timestamp, but I still can't 
> see a reason for thrift doing this.
>
> Could someone enlighten me a bit on this matter ?
>
> --
> Marco Matarazzo
> == Hex Keep ==
>
> "You can learn more about a man
>   in one hour of play
>   than in one year of conversation.” - Plato
>
>
>
>

Re: help using org.apache.cassandra.cql3

[Sylvain Lebresne]

When I said to use the BATCH statement I mean't using a query that is
a BATCH statement, so something like:
  BEGIN BATCH
INSERT ...;
INSERT ...;
...
  APPLY BATCH;

If you want to that from java, you will want to look at the jdbc
driver (http://code.google.com/a/apache-extras.org/p/cassandra-jdbc/),
though I don't know what is the status of the support for CQL3.

On Wed, Jul 11, 2012 at 2:18 PM, Leonid Ilyevsky
 wrote:
> Is it OK to put 1 of update statements in one
> batch, with 5 question marks in it? The set that many variables?

Yes batch statement can be prepared and in theory there isn't much
limit on the number of update statement (nor question marks) you can
put in one batch. However, the way C* work best is if you do
reasonably sized batches. It's even more true for CQL in the sense
that by using a huge batch statement you'll pay the parsing. So you
probably want to prepare one batch statement with a reasonable number
of statement in it (you'll have to test to find number that give the
best performances, but I would typically start with say 50-100 and see
if the performance are good enough) and reuse that to insert the data.

The other reason why breaking the insert into smallish batches is a
good idea is that it allows you to parallelize the insert using
multiple threads. And you need to parallelize if you want to get the
best out of C*.

--
Sylvain

>
> Maybe I can try small example first, just to see if it works at all.
>
>
>
>
>
> From: Derek Williams [mailto:de...@fyrie.net]
> Sent: Tuesday, July 10, 2012 7:19 PM
> To: user@cassandra.apache.org
> Subject: Re: help using org.apache.cassandra.cql3
>
>
>
> On Tue, Jul 10, 2012 at 3:04 PM, Leonid Ilyevsky 
> wrote:
>
> I am trying to use the org.apache.cassandra.cql3 package. Having problem
> connecting to the server using ClientState.
>
> I was not sure what to put in the credentials map (I did not set any
> users/passwords on my server), so I tried setting empty strings for
> “username” and “password”, setting them to bogus values, passing null to the
> login method – there was no difference.
>
> It does not complain at the login(), but then it complains about
> setKeyspace(), saying that the specified keyspace does not
> exist (it obviously does exist).
>
> The configuration was loaded from cassandra.yaml used by the server.
>
>
>
> I did not have any problem like this when I used
> org.apache.cassandra.thrift.Cassandra.Client .
>
>
>
> What am I doing wrong?
>
>
>
> I think that package just contains server classes. Everything you need
> should be in org.apache.cassandra.thrift.
>
>
>
> To use cql3 I just use the client methods 'execute_cql_query',
> 'prepare_cql_query' and 'execute_prepared_cql_query', after setting cql
> version to '3.0.0'.
>
>
>
>
>
> --
>
> Derek Williams
>
>
>
>
> 
> This email, along with any attachments, is confidential and may be legally
> privileged or otherwise protected from disclosure. Any unauthorized
> dissemination, copying or use of the contents of this email is strictly
> prohibited and may be in violation of law. If you are not the intended
> recipient, any disclosure, copying, forwarding or distribution of this email
> is strictly prohibited and this email and any attachments should be deleted
> immediately. This email and any attachments do not constitute an offer to
> sell or a solicitation of an offer to purchase any interest in any
> investment vehicle sponsored by Moon Capital Management LP (“Moon Capital”).
> Moon Capital does not provide legal, accounting or tax advice. Any statement
> regarding legal, accounting or tax matters was not intended or written to be
> relied upon by any person as advice. Moon Capital does not waive
> confidentiality or privilege as a result of this email.

RE: help using org.apache.cassandra.cql3

[Leonid Ilyevsky]

Thanks Sylvain, I actually tried the prepared batch, works fine. I did the 1000 
rows in one batch, 20 columns each, and it was good. Then I tried 1, and it 
still works, I am going to measure which way it is faster overall.

-Original Message-
From: Sylvain Lebresne [mailto:sylv...@datastax.com]
Sent: Wednesday, July 11, 2012 9:32 AM
To: user@cassandra.apache.org
Subject: Re: help using org.apache.cassandra.cql3

When I said to use the BATCH statement I mean't using a query that is
a BATCH statement, so something like:
  BEGIN BATCH
INSERT ...;
INSERT ...;
...
  APPLY BATCH;

If you want to that from java, you will want to look at the jdbc
driver (http://code.google.com/a/apache-extras.org/p/cassandra-jdbc/),
though I don't know what is the status of the support for CQL3.

On Wed, Jul 11, 2012 at 2:18 PM, Leonid Ilyevsky
 wrote:
> Is it OK to put 1 of update statements in one
> batch, with 5 question marks in it? The set that many variables?

Yes batch statement can be prepared and in theory there isn't much
limit on the number of update statement (nor question marks) you can
put in one batch. However, the way C* work best is if you do
reasonably sized batches. It's even more true for CQL in the sense
that by using a huge batch statement you'll pay the parsing. So you
probably want to prepare one batch statement with a reasonable number
of statement in it (you'll have to test to find number that give the
best performances, but I would typically start with say 50-100 and see
if the performance are good enough) and reuse that to insert the data.

The other reason why breaking the insert into smallish batches is a
good idea is that it allows you to parallelize the insert using
multiple threads. And you need to parallelize if you want to get the
best out of C*.

--
Sylvain

>
> Maybe I can try small example first, just to see if it works at all.
>
>
>
>
>
> From: Derek Williams [mailto:de...@fyrie.net]
> Sent: Tuesday, July 10, 2012 7:19 PM
> To: user@cassandra.apache.org
> Subject: Re: help using org.apache.cassandra.cql3
>
>
>
> On Tue, Jul 10, 2012 at 3:04 PM, Leonid Ilyevsky 
> wrote:
>
> I am trying to use the org.apache.cassandra.cql3 package. Having problem
> connecting to the server using ClientState.
>
> I was not sure what to put in the credentials map (I did not set any
> users/passwords on my server), so I tried setting empty strings for
> "username" and "password", setting them to bogus values, passing null to the
> login method - there was no difference.
>
> It does not complain at the login(), but then it complains about
> setKeyspace(), saying that the specified keyspace does not
> exist (it obviously does exist).
>
> The configuration was loaded from cassandra.yaml used by the server.
>
>
>
> I did not have any problem like this when I used
> org.apache.cassandra.thrift.Cassandra.Client .
>
>
>
> What am I doing wrong?
>
>
>
> I think that package just contains server classes. Everything you need
> should be in org.apache.cassandra.thrift.
>
>
>
> To use cql3 I just use the client methods 'execute_cql_query',
> 'prepare_cql_query' and 'execute_prepared_cql_query', after setting cql
> version to '3.0.0'.
>
>
>
>
>
> --
>
> Derek Williams
>
>
>
>
> 
> This email, along with any attachments, is confidential and may be legally
> privileged or otherwise protected from disclosure. Any unauthorized
> dissemination, copying or use of the contents of this email is strictly
> prohibited and may be in violation of law. If you are not the intended
> recipient, any disclosure, copying, forwarding or distribution of this email
> is strictly prohibited and this email and any attachments should be deleted
> immediately. This email and any attachments do not constitute an offer to
> sell or a solicitation of an offer to purchase any interest in any
> investment vehicle sponsored by Moon Capital Management LP ("Moon Capital").
> Moon Capital does not provide legal, accounting or tax advice. Any statement
> regarding legal, accounting or tax matters was not intended or written to be
> relied upon by any person as advice. Moon Capital does not waive
> confidentiality or privilege as a result of this email.

This email, along with any attachments, is confidential and may be legally 
privileged or otherwise protected from disclosure. Any unauthorized 
dissemination, copying or use of the contents of this email is strictly 
prohibited and may be in violation of law. If you are not the intended 
recipient, any disclosure, copying, forwarding or distribution of this email is 
strictly prohibited and this email and any attachments should be deleted 
immediately.  This email and any attachments do not constitute an offer to sell 
or a solicitation of an offer to purchase any interest in any investment 
vehicle sponsored by Moon Capital Management LP ("Moon Capital"). Moon Capital 
does not provide legal, accounting or tax advice. Any statement regarding 
l

Re: Zurich / Swiss / Alps meetup

[Benoit Perroud]

Coming back on this thread, we are proud to announce we opened a Swiss
BigData UserGroup.

http://www.bigdata-usergroup.ch/

Next meetup is July 16, with topic "NoSQL Storage: War Stories and
Best Practices".

Hope to meet you there !

Benoit.


2012/5/17 Sasha Dolgy :
> All,
>
> A year ago I made a simple query to see if there were any users based in and
> around Zurich, Switzerland or the Alps region, interested in participating
> in some form of Cassandra User Group / Meetup.  At the time, 1-2 replies
> happened.  I didn't do much with that.
>
> Let's try this again.  Who all is interested?  I often am jealous about all
> the fun I miss out on with the regular meetups that happen stateside ...
>
> Regards,
> -sd
>
> --
> Sasha Dolgy
> sasha.do...@gmail.com

Connected file list in Cassandra

[Tomek Hankus]

Hi,
at the moment I'm doing research about keeping "linked/connected file list"
in Cassandra- e.g. PDF file cut into pages (multiple PDFs) where first page
is connected to second, second to third etc.
This "files connection/link" is not specified. Main goal is to be able to
get all "linked files" (the whole PDF/ all pages) while having only key to
first file (page).

Is there any Cassandra tool/feature which could help me to do that or the
only way is to create some wrapper holding keys relations?


Tom H

Re: Connected file list in Cassandra

[David McNelis]

I would use something other than the page itself as the key.  Maybe a
filename, something smaller.

Then you could use a LongType comparator for the columns and use the page
number for the column name, the value being the contents of the files.

On Wed, Jul 11, 2012 at 1:34 PM, Tomek Hankus  wrote:

> Hi,
> at the moment I'm doing research about keeping "linked/connected file
> list" in Cassandra- e.g. PDF file cut into pages (multiple PDFs) where
> first page is connected to second, second to third etc.
> This "files connection/link" is not specified. Main goal is to be able to
> get all "linked files" (the whole PDF/ all pages) while having only key to
> first file (page).
>
> Is there any Cassandra tool/feature which could help me to do that or the
> only way is to create some wrapper holding keys relations?
>
>
> Tom H
>
>
>

Re: Connected file list in Cassandra

[David Brosius]

 why not just hold the pages as different columns in the same row? columns are 
automatically sorted such that if the column name was associated with the page 
number it would automatically flow the way you wanted.  - Original Message 
-From: "Tomek Hankus" >;tom...@gmail.com 

Why is our range query failing in Cassandra 0.8.10 Client

[JohnB]

Hi: 

We are currently using Cassandra 0.8.10 and have run into some strange issues 
surrounding 
querying for a range of data


I ran a couple of get statements via the Cassandra client and found some 
interesting results:


Consider the following Column Family Definition:

ColumnFamily: events
  Key Validation Class: org.apache.cassandra.db.marshal.BytesType
  Default column value validator: org.apache.cassandra.db.marshal.BytesType
  Columns sorted by: org.apache.cassandra.db.marshal.UTF8Type
  Row cache size / save period in seconds: 0.0/0
  Row Cache Provider: 
org.apache.cassandra.cache.ConcurrentLinkedHashCacheProvider
  Key cache size / save period in seconds: 20.0/14400
  Memtable thresholds: 0.2953125/1440/63 (millions of ops/minutes/MB)
  GC grace seconds: 864000
  Compaction min/max thresholds: 4/32
  Read repair chance: 1.0
  Replicate on write: true
  Built indexes: [events.events_Firm_idx, events.events_OrdType_idx, 
events.events_OrderID_idx
 , events.events_OrderQty_idx, events.events_Price_idx, 
events.events_Symbol_idx, events.events_ds_timestamp_idx]
  Column Metadata:
Column Name: Firm
  Validation Class: org.apache.cassandra.db.marshal.BytesType
  Index Name: events_Firm_idx
  Index Type: KEYS
Column Name: OrdType
  Validation Class: org.apache.cassandra.db.marshal.BytesType
  Index Name: events_OrdType_idx
  Index Type: KEYS
Column Name: OrderID
  Validation Class: org.apache.cassandra.db.marshal.BytesType
  Index Name: events_OrderID_idx
  Index Type: KEYS
Column Name: OrderQty
  Validation Class: org.apache.cassandra.db.marshal.LongType
  Index Name: events_OrderQty_idx
  Index Type: KEYS
Column Name: Price
  Validation Class: org.apache.cassandra.db.marshal.LongType
  Index Name: events_Price_idx
  Index Type: KEYS
Column Name: Symbol
  Validation Class: org.apache.cassandra.db.marshal.BytesType
  Index Name: events_Symbol_idx
Column Name: ds_timestamp
  Validation Class: org.apache.cassandra.db.marshal.LongType
  Index Name: events_ds_timestamp_idx
  Index Type: KEYS
 

get events WHERE Firm=434550 AND ds_timestamp=1341955958200;


…and the results are pretty much instantaneous.

1 Row Returned.

[default@FIX] get events WHERE Firm=434550 AND ds_timestamp=1341955958200;

---

RowKey: 64326430363362302d636164362d313165312d626637622d333836303737306639303133
=> (column=ClOrdID, value=32323833, timestamp=1341955980651010)
=> (column=Firm, value=434550, timestamp=1341955980651026)
=> (column=OrdType, value=31, timestamp=1341955980651008)
=> (column=OrderQty, value=8200, timestamp=1341955980651013)
=> (column=Price, value=433561, timestamp=1341955980651019)
=> (column=Symbol, value=544e54, timestamp=1341955980651018)
=> (column=ds_timestamp, value=1341955958200, timestamp=1341955980651020)


If I run the following query:

get events WHERE Firm=434550 AND ds_timestamp>=1341955958200 AND 
ds_timestamp<=1341955958200;

(which in theory would should return the same 1 row result)

 

It runs for around 12 seconds,

 

And I get:

TimedOutException()

 


If I run:

get events WHERE Firm=434550 AND ds_timestamp>=1341955958200; 

or

get events WHERE Firm=434550 AND ds_timestamp<=1341955958200;

The results return quickly.



Curious, I also ran  a similar set of queries against the price field:

get events WHERE Firm=434550 AND Price=433561;
get events WHERE Firm=434550 AND Price>=433561;
get events WHERE Firm=434550 AND Price<=433561;

These all work  fine.


While, 

get events WHERE Firm=434550 AND Price=433561 AND Price <= 433561;

returns an IO Exception.



This feels like it’s attempting to do a full table scan here….

What is going on here?

Am I doing something incorrectly?

We also see similar behavior when submit the query through our app via the 
Thrift API.

 
Thanks,
JohnB

Re: Java heap space on Cassandra start up version 1.0.10

[Jason Hill]

Thanks Jonathan that did the trick. I deleted the Statistics.db files
for the offending column family and was able to get Cassandra to
start.

Thank you,
Jason

RE: How to come up with a predefined topology

[Richard Lowe]

Using PropertyFileSnitch you can fine tune the topology of the cluster. 

What you tell Cassandra about your "DC" and "rack" doesn't have to match how 
they are in real life. You can create virtual DCs for Cassandra and even treat 
each node as a separate rack.

For example, in cassandra-topology.properties:

# Format is =:
192.168.0.11=DC1_realtime:node_1
192.168.0.12=DC1_realtime:node_2
192.168.0.13=DC1_analytics:node_3
192.168.1.11=DC2_realtime:node_1

If you then specify the parameters for the keyspace to use these, you can 
control exactly which set of nodes replicas end up on. 

For example, in cassandra-cli:

create keyspace ks1 with placement_strategy = 
'org.apache.cassandra.locator.NetworkTopologyStrategy' and strategy_options = { 
DC1_realtime: 2, DC1_analytics: 1, DC2_realtime: 1 };

As far as I know there isn't any way to use the rack name in the 
strategy_options for a keyspace. You might want to look at the code to dig into 
that, perhaps.

Whichever snitch you use, the nodes are sorted in order of proximity to the 
client node. How this is determined depends on the snitch that's used but most 
(the ones that ship with Cassandra) will use the default ordering of same-node 
< same-rack < same-datacenter < different-datacenter. Each snitch has methods 
to tell Cassandra which rack and DC a node is in, so it always knows which node 
is closest. Used with the Bloom filters this can tell us where the nearest 
replica is.



-Original Message-
From: prasenjit mukherjee [mailto:prasen@gmail.com] 
Sent: 11 July 2012 06:33
To: user
Subject: How to come up with a predefined topology

Quoting from 
http://www.datastax.com/docs/0.8/cluster_architecture/replication#networktopologystrategy
:

"Asymmetrical replication groupings are also possible depending on your use 
case. For example, you may want to have three replicas per data center to serve 
real-time application requests, and then have a single replica in a separate 
data center designated to running analytics."

Have 2 questions :
1. Any example how to configure a topology with 3 replicas in one DC ( with 2 
in 1 rack + 1 in another rack ) and one replica in another DC ?
 The default networktopologystrategy with rackinferringsnitch will only give me 
equal distribution ( 2+2 )

2. I am assuming the reads can go to any of the replicas. Is there a client 
which will send query to a node ( in cassandra ring ) which is closest to the 
client ?

-Thanks,
Prasenjit

Re: is this something to be concerned about - MUTATION message dropped

[Frank Hsueh]

out of curiosity, is there a way that Cassandra can communicate that it's
close to the being overloaded ?


On Sun, Jun 17, 2012 at 6:29 PM, aaron morton wrote:

> http://wiki.apache.org/cassandra/FAQ#dropped_messages
>
> https://www.google.com/#q=cassandra+dropped+messages
>
> Cheers
>
>
> -
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 15/06/2012, at 12:54 AM, Poziombka, Wade L wrote:
>
> INFO [ScheduledTasks:1] 2012-06-14 07:49:54,355 MessagingService.java
> (line 615) 15 MUTATION message dropped in last 5000ms
> ** **
> It is at INFO level so I’m inclined to think not but is seems like
> whenever messages are dropped there may be some issue?
>
>
>


-- 
Frank Hsueh | frank.hs...@gmail.com

Concerns about Cassandra upgrade from 1.0.6 to 1.1.X

[Roshan]

Hello

Currently we are using Cassandra 1.0.6 in our production system but suffer
with the CASSANDRA-3616 (it is already fixed in 1.0.7 version).

We thought to upgrade the Cassandra to 1.1.X versions, to get it's new
features, but having some concerns about the upgrade and expert advices are
mostly welcome.

1. Can Cassandra 1.1.X identify 1.0.X configurations like SSTables, commit
logs, etc without ant issue? And vise versa. Because if something happens to
1.1.X after deployed to production, we want to downgrade to 1.0.6 version
(because that's the versions we tested with our applications). 

2. How do we need to do upgrade process?  Currently we have 3 node 1.0.6
cluster in production. Can we upgrade node by node? If we upgrade node by
node, will the other 1.0.6 nodes identify 1.1.X nodes without any issue?

Appreciate experts comments on this. Many Thanks.

/Roshan 

--
View this message in context: 
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Concerns-about-Cassandra-upgrade-from-1-0-6-to-1-1-X-tp7581197.html
Sent from the cassandra-u...@incubator.apache.org mailing list archive at 
Nabble.com.

Re: How to come up with a predefined topology

[prasenjit mukherjee]

> As far as I know there isn't any way to use the rack name in the 
> strategy_options for a keyspace. You
> might want to look at the code to dig into that, perhaps.

Aha, I was wondering if I could do that as well ( specify rack options ) :)

Thanks for the pointer, I will dig into the code.

-Thanks,
Prasenjit

On Thu, Jul 12, 2012 at 5:33 AM, Richard Lowe  wrote:
> If you then specify the parameters for the keyspace to use these, you can 
> control exactly which set of nodes replicas end up on.
>
> For example, in cassandra-cli:
>
> create keyspace ks1 with placement_strategy = 
> 'org.apache.cassandra.locator.NetworkTopologyStrategy' and strategy_options = 
> { DC1_realtime: 2, DC1_analytics: 1, DC2_realtime: 1 };
>
> As far as I know there isn't any way to use the rack name in the 
> strategy_options for a keyspace. You might want to look at the code to dig 
> into that, perhaps.
>
> Whichever snitch you use, the nodes are sorted in order of proximity to the 
> client node. How this is determined depends on the snitch that's used but 
> most (the ones that ship with Cassandra) will use the default ordering of 
> same-node < same-rack < same-datacenter < different-datacenter. Each snitch 
> has methods to tell Cassandra which rack and DC a node is in, so it always 
> knows which node is closest. Used with the Bloom filters this can tell us 
> where the nearest replica is.
>
>
>
> -Original Message-
> From: prasenjit mukherjee [mailto:prasen@gmail.com]
> Sent: 11 July 2012 06:33
> To: user
> Subject: How to come up with a predefined topology
>
> Quoting from 
> http://www.datastax.com/docs/0.8/cluster_architecture/replication#networktopologystrategy
> :
>
> "Asymmetrical replication groupings are also possible depending on your use 
> case. For example, you may want to have three replicas per data center to 
> serve real-time application requests, and then have a single replica in a 
> separate data center designated to running analytics."
>
> Have 2 questions :
> 1. Any example how to configure a topology with 3 replicas in one DC ( with 2 
> in 1 rack + 1 in another rack ) and one replica in another DC ?
>  The default networktopologystrategy with rackinferringsnitch will only give 
> me equal distribution ( 2+2 )
>
> 2. I am assuming the reads can go to any of the replicas. Is there a client 
> which will send query to a node ( in cassandra ring ) which is closest to the 
> client ?
>
> -Thanks,
> Prasenjit
>
>

Re: BulkLoading sstables from v1.0.3 to v1.1.1

[aaron morton]

Do you have the full error logs ? Their should be a couple of caused by: errors 
that will help track it down where the original Assertion is thrown.

The second error is probably the result of the first. Something has upset the 
SSTable tracking. 

If you can get the full error stack, and some steps to reproduce, can you raise 
a ticket on https://issues.apache.org/jira/browse/CASSANDRA ? 

Thanks


-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 10/07/2012, at 7:43 PM, rubbish me wrote:

> Thanks Ivo. 
> 
> We are quite close to releasing so we'd hope to understand what causing the 
> error and may try to avoid it where possible. As said, it seems to work ok 
> the first time round. 
> 
> The problem you referring in the last mail, was it restricted to bulk loading 
> or otherwise?
> 
> Thanks
> 
> -A
> 
> Ivo Meißner  於 10 Jul 2012 07:20 寫道：
> 
>> Hi,
>> 
>> there are some problems in version 1.1.1 with secondary indexes and key 
>> caches that are fixed in 1.1.2. 
>> I would try to upgrade to 1.1.2 and see if the error still occurs. 
>> 
>> Ivo
>> 
>> 
>> 
>>> 
>>> 
>>> Hi 
>>> 
>>> As part of a continuous development of a system migration, we have a test 
>>> build to take a snapshot of a keyspace from cassandra v 1.0.3 and bulk load 
>>> it to a cluster of 1.1.1 using the sstableloader.sh.  Not sure if relevant, 
>>> but one of the cf contains a secondary index. 
>>> 
>>> The build basically does: 
>>> Drop the destination keyspace if exist 
>>> Add the destination keyspace, wait for schema to agree 
>>> run sstableLoader 
>>> Do some validation of the streamed data 
>>> 
>>> Keyspace / column families schema are basically the same, apart from in the 
>>> one of v1.1.1, we had compression and key cache switched on. 
>>> 
>>> On a clean cluster, (empty data, commit log, saved-cache dirs) the sstables 
>>> loaded beautifully. 
>>> 
>>> But subsequent build failed with 
>>> -- 
>>> [21:02:02][exec] progress: []... [total: 0 - 0MB/s (avg: 
>>> 0MB/s)]ERROR 21:02:02,811 Error in 
>>> ThreadPoolExecutorjava.lang.RuntimeException: java.net.SocketException: 
>>> Connection reset 

Re: Using a node in separate cluster without decommissioning.

[aaron morton]

> Since replication factor is 2 in first cluster, I
> won't lose any data.
Assuming you have been running repair or working at CL QUORUM (which is the 
same as CL ALL for RF 2)

> Is it advisable and safe to go ahead?
um, so the plan is to turn off 2 nodes in the first cluster, restask them into 
the new cluster and then reverse the process ?

If you simply turn two nodes off in the first cluster you will have reduce the 
availability for a portion of the ring. 25% of the keys will now have at best 1 
node they can be stored on. If a node is having any sort of problems, and it's 
is a replica for one of the down nodes, the cluster will appear down for 12.5% 
of the keyspace.

If you work at QUORUM you will not have enough nodes available to write / read 
25% of the keys. 

If you decomission the nodes, you will still have 2 replicas available for each 
key range. This is the path I would recommend.

If you _really_ need to do it what you suggest will probably work. Some tips:

* do safe shutdowns - nodetool disablegossip, disablethrift, drain
* don't forget to copy the yaml file. 
* in the first cluster the other nodes will collect hints for the first hour 
the nodes are down. You are not going to want these so disable HH. 
* get the nodes back into the first cluster before gc_grace_seconds expires. 
* bring them back and repair them.
* when you bring them back, reading at CL ONE will give inconsistent results. 
Reading at QUOURM may result in a lot of repair activity.

Hope that helps. 
 
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 11/07/2012, at 6:35 AM, rohit bhatia wrote:

> Hi
> 
> I want to take out 2 nodes from a 8 node cluster and use in another
> cluster, but can't afford the overhead of streaming the data and
> rebalance cluster. Since replication factor is 2 in first cluster, I
> won't lose any data.
> 
> I'm planning to save my commit_log and data directories and
> bootstrapping the node in the second cluster. Afterwards I'll just
> replace both the directories and join the node back to the original
> cluster.  This should work since cassandra saves all the cluster and
> schema info in the system keyspace.
> 
> Is it advisable and safe to go ahead?
> 
> Thanks
> Rohit

Re: failed to delete commitlog, cassandra can't accept writes

[aaron morton]

I don't think it's related to 4337. 

There is an explicit close call just before the deletion attempt. 

Can you create a ticket on https://issues.apache.org/jira/browse/CASSANDRA with 
all of the information you've got here (including the full JVM vendor, version, 
build). Can you also check if the file it tries to delete exists ? (I assume it 
does, otherwise it would be a different error). 

Thanks for digging into this. 

-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 11/07/2012, at 9:36 AM, Frank Hsueh wrote:

> oops; I missed log line:
> 
> 
> ERROR [COMMIT-LOG-ALLOCATOR] 2012-07-10 14:19:39,776 
> AbstractCassandraDaemon.java (line 134) Exception in thread 
> Thread[COMMIT-LOG-ALLOCATOR,5,main]
> java.io.IOError: java.io.IOException: Failed to delete 
> C:\var\lib\cassandra\commitlog\CommitLog-948695923996466.log
>   at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.discard(CommitLogSegment.java:176)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$4.run(CommitLogAllocator.java:223)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$1.runMayThrow(CommitLogAllocator.java:95)
>   at 
> org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:30)
>   at java.lang.Thread.run(Thread.java:662)
> Caused by: java.io.IOException: Failed to delete 
> C:\var\lib\cassandra\commitlog\CommitLog-948695923996466.log
>   at 
> org.apache.cassandra.io.util.FileUtils.deleteWithConfirm(FileUtils.java:54)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.discard(CommitLogSegment.java:172)
>   ... 4 more
> 
> 
> 
> On Tue, Jul 10, 2012 at 2:35 PM, Frank Hsueh  wrote:
> after reading the JIRA, I decided to use Java 6.
> 
> with Casandra 1.1.2 on Java 6 x64 on Win7 sp1 x64 (all latest versions), 
> after a several minutes of sustained writes, I see:
> 
> from system.log:
> 
> java.io.IOError: java.io.IOException: Failed to delete 
> C:\var\lib\cassandra\commitlog\CommitLog-948695923996466.log
>   at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.discard(CommitLogSegment.java:176)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$4.run(CommitLogAllocator.java:223)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$1.runMayThrow(CommitLogAllocator.java:95)
>   at 
> org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:30)
>   at java.lang.Thread.run(Thread.java:662)
> Caused by: java.io.IOException: Failed to delete 
> C:\var\lib\cassandra\commitlog\CommitLog-948695923996466.log
>   at 
> org.apache.cassandra.io.util.FileUtils.deleteWithConfirm(FileUtils.java:54)
>   at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.discard(CommitLogSegment.java:172)
>   ... 4 more
> 
> 
> anybody seen this before?  is this related to 4337 ?
> 
> 
> 
> 
> On Sat, Jul 7, 2012 at 6:36 PM, Frank Hsueh  wrote:
> bug already reported:
> 
> https://issues.apache.org/jira/browse/CASSANDRA-4337
> 
> 
> 
> On Sat, Jul 7, 2012 at 6:26 PM, Frank Hsueh  wrote:
> Hi,
> 
> I'm running Casandra 1.1.2 on Java 7 x64 on Win7 sp1 x64 (all latest 
> versions).  If it matters, I'm using a late version of Astyanax as my client.
> 
> I'm using 4 threads to write a lot of data into a single CF.
> 
> After several minutes of load (~ 30m at last incident), Cassandra stops 
> accepting writes (client reports an OperationTimeoutException).  I looked at 
> the logs and I see on the Cassandra server:
> 
> 
> ERROR 18:00:42,807 Exception in thread Thread[COMMIT-LOG-ALLOCATOR,5,main]
> java.io.IOError: java.io.IOException: Rename from 
> \var\lib\cassandra\commitlog\CommitLog-701533048437587.log to 703272597990002 
> failed
> at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.(CommitLogSegment.java:127)
> at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.recycle(CommitLogSegment.java:204)
> at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$2.run(CommitLogAllocator.java:166)
> at 
> org.apache.cassandra.db.commitlog.CommitLogAllocator$1.runMayThrow(CommitLogAllocator.java:95)
> at 
> org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:30)
> at java.lang.Thread.run(Thread.java:722)
> Caused by: java.io.IOException: Rename from 
> \var\lib\cassandra\commitlog\CommitLog-701533048437587.log to 703272597990002 
> failed
> at 
> org.apache.cassandra.db.commitlog.CommitLogSegment.(CommitLogSegment.java:105)
> ... 5 more
> 
> 
> Anybody else seen this before ?
> 
> 
> -- 
> Frank Hsueh | frank.hs...@gmail.com
> 
> 
> 
> -- 
> Frank Hsueh | frank.hs...@gmail.com
> 
> 
> 
> -- 
> Frank Hsueh | frank.hs...@gmail.com
> 
> 
> 
> -- 
> Frank Hsueh | frank.hs...@gmail.com

Re: snapshot issue

[aaron morton]

Make sure JNA is in the class path http://wiki.apache.org/cassandra/FAQ#jna

Cheers

-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 11/07/2012, at 9:38 PM, Adeel Akbar wrote:

> Hi,
> 
> I am trying to taking snapshot of my data but faced following error. Please 
> help me to resolve this issue.
> 
> [root@cassandra1 bin]# ./nodetool -h localhost snapshot 20120711
> Exception in thread "main" java.io.IOError: java.io.IOException: Cannot run 
> program "ln": java.io.IOException: error=12, Cannot allocate memory
>at 
> org.apache.cassandra.db.ColumnFamilyStore.snapshotWithoutFlush(ColumnFamilyStore.java:1660)
>at 
> org.apache.cassandra.db.ColumnFamilyStore.snapshot(ColumnFamilyStore.java:1686)
>at org.apache.cassandra.db.Table.snapshot(Table.java:198)
>at 
> org.apache.cassandra.service.StorageService.takeSnapshot(StorageService.java:1393)
>at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>at 
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
>at 
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>at java.lang.reflect.Method.invoke(Method.java:616)
>at 
> com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:111)
>at 
> com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:45)
>at 
> com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:226)
>at com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)
>at com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:251)
>at 
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:857)
>at 
> com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:795)
>at 
> javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1450)
>at 
> javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:90)
>at 
> javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1285)
>at 
> javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1383)
>at 
> javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:807)
>at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>at 
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
>at 
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>at java.lang.reflect.Method.invoke(Method.java:616)
>at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
>at sun.rmi.transport.Transport$1.run(Transport.java:177)
>at java.security.AccessController.doPrivileged(Native Method)
>at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
>at 
> sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:553)
>at 
> sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:808)
>at 
> sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:667)
>at 
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
>at 
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
>at java.lang.Thread.run(Thread.java:636)
> Caused by: java.io.IOException: Cannot run program "ln": java.io.IOException: 
> error=12, Cannot allocate memory
>at java.lang.ProcessBuilder.start(ProcessBuilder.java:475)
>at 
> org.apache.cassandra.utils.CLibrary.createHardLinkWithExec(CLibrary.java:181)
>at 
> org.apache.cassandra.utils.CLibrary.createHardLink(CLibrary.java:147)
>at 
> org.apache.cassandra.io.sstable.SSTableReader.createLinks(SSTableReader.java:730)
>at 
> org.apache.cassandra.db.ColumnFamilyStore.snapshotWithoutFlush(ColumnFamilyStore.java:1653)
>... 33 more
> Caused by: java.io.IOException: java.io.IOException: error=12, Cannot 
> allocate memory
>at java.lang.UNIXProcess.(UNIXProcess.java:164)
>at java.lang.ProcessImpl.start(ProcessImpl.java:81)
>at java.lang.ProcessBuilder.start(ProcessBuilder.java:468)
>... 37 more
> 
> -- 
> 
> 
> Thanks & Regards
> 
> *Adeel**Akbar*
> 
> 
> 

Re: is this something to be concerned about - MUTATION message dropped

[Tyler Hobbs]

JMX is really the only way it exposes that kind of information.  I
recommend setting up mx4j if you want to check on the server stats
programmatically.

On Wed, Jul 11, 2012 at 8:17 PM, Frank Hsueh  wrote:

> out of curiosity, is there a way that Cassandra can communicate that it's
> close to the being overloaded ?
>
>
> On Sun, Jun 17, 2012 at 6:29 PM, aaron morton wrote:
>
>> http://wiki.apache.org/cassandra/FAQ#dropped_messages
>>
>> https://www.google.com/#q=cassandra+dropped+messages
>>
>> Cheers
>>
>>
>>   -
>> Aaron Morton
>> Freelance Developer
>> @aaronmorton
>> http://www.thelastpickle.com
>>
>> On 15/06/2012, at 12:54 AM, Poziombka, Wade L wrote:
>>
>> INFO [ScheduledTasks:1] 2012-06-14 07:49:54,355 MessagingService.java
>> (line 615) 15 MUTATION message dropped in last 5000ms
>> ** **
>> It is at INFO level so I’m inclined to think not but is seems like
>> whenever messages are dropped there may be some issue?
>>
>>
>>
>
>
> --
> Frank Hsueh | frank.hs...@gmail.com
>



-- 
Tyler Hobbs
DataStax 

Re: Concerns about Cassandra upgrade from 1.0.6 to 1.1.X

[Tyler Hobbs]

On Wed, Jul 11, 2012 at 8:38 PM, Roshan  wrote:

>
>
> Currently we are using Cassandra 1.0.6 in our production system but suffer
> with the CASSANDRA-3616 (it is already fixed in 1.0.7 version).
>
> We thought to upgrade the Cassandra to 1.1.X versions, to get it's new
> features, but having some concerns about the upgrade and expert advices are
> mostly welcome.
>
> 1. Can Cassandra 1.1.X identify 1.0.X configurations like SSTables, commit
> logs, etc without ant issue? And vise versa. Because if something happens
> to
> 1.1.X after deployed to production, we want to downgrade to 1.0.6 version
> (because that's the versions we tested with our applications).
>

1.1 can handle 1.0 data/schemas/etc without a problem, but the reverse is
not necessarily true.  I don't know what in particular might break if you
downgrade from 1.1 to 1.0, but in general, Cassandra does not handle
downgrading gracefully; typically the SSTable formats have changed during
major releases.  If you snapshot prior to upgrading, you can always roll
back to that, but you will have lost anything written since the upgrade.


>
> 2. How do we need to do upgrade process?  Currently we have 3 node 1.0.6
> cluster in production. Can we upgrade node by node? If we upgrade node by
> node, will the other 1.0.6 nodes identify 1.1.X nodes without any issue?


Yes, you can do a rolling upgrade to 1.1, one node at a time.  It's usually
fine to leave the cluster in a mixed state for a short while as long as you
don't do things like repairs, decommissions, or bootstraps, but I wouldn't
stay in a mixed state any longer than you have to.

It's best to test major upgrades with a second, non-production cluster if
that's an option.

-- 
Tyler Hobbs
DataStax 

Re: How to come up with a predefined topology

[Tyler Hobbs]

I highly recommend specifying the same rack for all nodes (using
cassandra-topology.properties) unless you really have a good reason not too
(and you probably don't).  The way that replicas are chosen when multiple
racks are in play can be fairly confusing and lead to a data imbalance if
you don't catch it.

On Wed, Jul 11, 2012 at 10:53 PM, prasenjit mukherjee
wrote:

> > As far as I know there isn't any way to use the rack name in the
> strategy_options for a keyspace. You
> > might want to look at the code to dig into that, perhaps.
>
> Aha, I was wondering if I could do that as well ( specify rack options ) :)
>
> Thanks for the pointer, I will dig into the code.
>
> -Thanks,
> Prasenjit
>
> On Thu, Jul 12, 2012 at 5:33 AM, Richard Lowe 
> wrote:
> > If you then specify the parameters for the keyspace to use these, you
> can control exactly which set of nodes replicas end up on.
> >
> > For example, in cassandra-cli:
> >
> > create keyspace ks1 with placement_strategy =
> 'org.apache.cassandra.locator.NetworkTopologyStrategy' and strategy_options
> = { DC1_realtime: 2, DC1_analytics: 1, DC2_realtime: 1 };
> >
> > As far as I know there isn't any way to use the rack name in the
> strategy_options for a keyspace. You might want to look at the code to dig
> into that, perhaps.
> >
> > Whichever snitch you use, the nodes are sorted in order of proximity to
> the client node. How this is determined depends on the snitch that's used
> but most (the ones that ship with Cassandra) will use the default ordering
> of same-node < same-rack < same-datacenter < different-datacenter. Each
> snitch has methods to tell Cassandra which rack and DC a node is in, so it
> always knows which node is closest. Used with the Bloom filters this can
> tell us where the nearest replica is.
> >
> >
> >
> > -Original Message-
> > From: prasenjit mukherjee [mailto:prasen@gmail.com]
> > Sent: 11 July 2012 06:33
> > To: user
> > Subject: How to come up with a predefined topology
> >
> > Quoting from
> http://www.datastax.com/docs/0.8/cluster_architecture/replication#networktopologystrategy
> > :
> >
> > "Asymmetrical replication groupings are also possible depending on your
> use case. For example, you may want to have three replicas per data center
> to serve real-time application requests, and then have a single replica in
> a separate data center designated to running analytics."
> >
> > Have 2 questions :
> > 1. Any example how to configure a topology with 3 replicas in one DC (
> with 2 in 1 rack + 1 in another rack ) and one replica in another DC ?
> >  The default networktopologystrategy with rackinferringsnitch will only
> give me equal distribution ( 2+2 )
> >
> > 2. I am assuming the reads can go to any of the replicas. Is there a
> client which will send query to a node ( in cassandra ring ) which is
> closest to the client ?
> >
> > -Thanks,
> > Prasenjit
> >
> >
>



-- 
Tyler Hobbs
DataStax