Well, how big is a single line? On Jul 9, 2008, at 9:30 AM, Yair Even-Zohar wrote:
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
