How do I find the number of regions for an HTable? In a quick lookup I did on the actual machines, it seems that all the machine had new data in them once I load the table.
Thanks -Yair -----Original Message----- From: Bryan Duxbury [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 09, 2008 11:13 AM To: [email protected] Subject: Re: Slow mapreduce using Hbase , regardless on number of machines How many regions are there in your table? If your 200k regions fits inside a single region, adding more region servers isn't going to make anything faster because only one server will be participating. -Bryan On Jul 9, 2008, at 7:36 AM, yair even-zohar wrote: > I am testing HBase 0.1.2 and am getting the following performance > using RowCounter class (I had to modify the main() method of the > original class because it contains some hardcoded parameters :-) > > Single regionserver - counting 200,000 lines in 60 or 61 seconds > 5 regieonservers - counting 200,000 lines in 55 or 58 seconds > > Clearly, one expects better performance, so I assume I'm doing > something wrong. By the way, I'm getting about the same performance > when I'm iterating through a scanner without the mapreduce. > > Here is my hadoop-site.xml > > <configuration> > <property> > <name>fs.default.name</name> > <value>hdfs://sb-centercluster01:9100</value> > </property> > <property> > <name>mapred.job.tracker</name> > <value>hdfs://sb-centercluster01:9101</value> > </property> > <property> > <name>mapred.map.tasks</name> > <value>13</value> > </property> > <property> > <name>mapred.reduce.tasks</name> > <value>5</value> > </property> > <property> > <name>dfs.replication</name> > <value>3</value> > </property> > <property> > <name>dfs.name.dir</name> > <value>/home/hadoop/dfs16,/tmp/hadoop/dfs16</value> > </property> > <property> > <name>dfs.data.dir</name> > <value>/state/partition1/hadoop/dfs16</value> > </property> > </configuration> > > Increasing "io.bytes.per.checksum" and "io.file.buffer.size" didn't > help. Neither decreasing "dfs.replication" > > Here is my hbase-site.xml > > <configuration> > <property> > <name>hbase.master</name> > <value>sb-centercluster01:60002</value> > <description>The host and port that the HBase master runs at. > </description> > </property> > <property> > <name>hbase.rootdir</name> > <value>hdfs://sb-centercluster01:9100/hbase</value> > <description>The directory shared by region servers. > </description> > </property> > <property> > <name>hbase.io.index.interval</name> > <value>8</value> > </property> > </configuration> > > > Any help will be appreciated. > > Thanks > -Yair > > >
