Re: Speeding up HBase read response

2012-04-12 Thread Michael Segel
Uhm, Lets take a look back at the original post : I'm confused with a read latency I got, comparing to what YCSB team achieved and showed in their YCSB paper. They achieved throughput of up to 7000 ops/sec with a latency of 15 ms (page 10, read latency chart). I can't get throughput higher than

Re: Speeding up HBase read response

2012-04-12 Thread Andrew Purtell
Pardon yes that is probably true. I hijacked this thread anyway. /eot Best regards, - Andy On Apr 11, 2012, at 11:04 PM, Michael Segel michael_se...@hotmail.com wrote: Uhm, Lets take a look back at the original post : I'm confused with a read latency I got, comparing to what YCSB team

Re: Speeding up HBase read response

2012-04-12 Thread Michael Segel
No need for pardon. I mean its good to hear about the changes to help improve performance. :-) I just wanted to try and answer the OPs question and set a realistic expectation. -Mike On Apr 12, 2012, at 1:14 AM, Andrew Purtell wrote: Pardon yes that is probably true. I hijacked this thread

unable to start regionservers on slaves in hbase

2012-04-12 Thread amsal
i have a problem starting regionservers on slave pc,s. when i enlist only master pc in conf/regionservers every thing works fine but when i add two more slaves to it the hbase does not start . if i delete all hbase folders in the tmp folder from all pc,s and then start regionserver (with 3

RE: Not a host:port issue

2012-04-12 Thread Tom Wilcox
Thanks Stack, We have successfully restored our Hadoop/HBase cluster to a healthy state. It seems that moving the pig and zookeeper references to the back of the HADOOP_CLASSPATH so that the backticked `hbase classpath` came first in the HADOOP_CLASSPATH resolved the issue. I have not

Re: Performance Optimization techniques HBase

2012-04-12 Thread Alex Baranau
In case you haven't checked yet: * http://hbase.apache.org/bulk-loads.html * http://hbase.apache.org/book.html Alex Baranau -- Sematext :: http://blog.sematext.com/ :: Solr - Lucene - Hadoop - HBase On Wed, Apr 11, 2012 at 10:06 PM, Neha justn...@in.com wrote: I am a newbie in HBase. I am

Re: Performance Optimization techniques HBase

2012-04-12 Thread Marcos Ortiz
And the HBase: THe Definitive Guide book from Lars George http://shop.oreilly.com/product/0636920014348.do On 04/12/2012 08:14 AM, Alex Baranau wrote: In case you haven't checked yet: * http://hbase.apache.org/bulk-loads.html * http://hbase.apache.org/book.html Alex Baranau -- Sematext

Re: Not a host:port issue

2012-04-12 Thread Stack
On Thu, Apr 12, 2012 at 2:52 AM, Tom Wilcox tom.wil...@cse.org.uk wrote: I have not confirmed this, but I have suspicions that the old hbase client references were coming from the pig contributions to the classpath. I am wondering if perhaps the current hbase and zookeeper libs would have

Re: unable to start regionservers on slaves in hbase

2012-04-12 Thread Stack
On Thu, Apr 12, 2012 at 12:50 AM, amsal amsal_na...@yahoo.com wrote: i have a problem starting regionservers on slave pc,s. when i enlist only master pc in conf/regionservers every thing works fine but when i add two more slaves to it the hbase does not start . if i delete all hbase

Re: Schema Updates: what do you do today?

2012-04-12 Thread Jean-Daniel Cryans
Still doing it old school unless I have to alter a bunch of tables for the same reason, like enabling replication. J-D On Mon, Apr 9, 2012 at 9:08 AM, Ian Varley ivar...@salesforce.com wrote: All: I'm doing a little research into various ways to apply schema modifications to an HBase

Re: Not a host:port issue

2012-04-12 Thread Royston Sellman
On 12 Apr 2012, at 15:49, Stack wrote: On Thu, Apr 12, 2012 at 2:52 AM, Tom Wilcox tom.wil...@cse.org.uk wrote: I have not confirmed this, but I have suspicions that the old hbase client references were coming from the pig contributions to the classpath. I am wondering if perhaps the

Re: Is HBase Thread-Safety?

2012-04-12 Thread Sean Bigdatafun
There only 'transaction' HBase provides is row-level transaction. On Thu, Apr 12, 2012 at 3:10 PM, Bing Li lbl...@gmail.com wrote: Dear all, Is HBase thread-safety? Do I need to consider the consistency issue when manipulating HBase? Thanks so much! Best regards, Bing -- --Sean

Re: Is HBase Thread-Safety?

2012-04-12 Thread Doug Meil
re: Is HBase thread-safety? HTable instances are not thread safe, though. http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html On 4/12/12 6:10 PM, Bing Li lbl...@gmail.com wrote: Dear all, Is HBase thread-safety? Do I need to consider the consistency issue when

Re: Is HBase Thread-Safety?

2012-04-12 Thread lars hofhansl
Hi Bing, Which part? The server certainly is thread safe. The client is not, at least not all the way through. The main consideration is HTable, which is not thread safe, you need to create one instance for each thread (HBASE-4805 makes that much cheaper), store the HTable in a ThreadLocal

Re: Is HBase Thread-Safety?

2012-04-12 Thread Bing Li
Dear Iars, Thanks so much for your reply! In my case, I need to overwrite or update a HTable. If reading during the process of updating or overwriting, any exceptions will be thrown by HBase? If multiple instances for a HTable are used by multiple threads, there must be inconsistency among

Zookeeper available but no active master location found

2012-04-12 Thread Henri Pipe
client.HConnectionManager$HConnectionImplementation: ZooKeeper available but no active master location found Having a problem with master startup that I have not seen before. running the following packages: hadoop-hbase-0.90.4+49.137-1 hadoop-0.20-secondarynamenode-0.20.2+923.197-1

Re: Is HBase Thread-Safety?

2012-04-12 Thread NNever
1. A pre-row lock is here during the update, so other clients will block whild on client performs an update.(see HRegion.put 's annotaion), no exception. In the client side, while a process is updating, it may not reach the buffersize so the other process may read the original value, I think. 2.