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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/StatsDev" by ahmedaly
Date Thu, 29 Jul 2010 00:36:30 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/StatsDev" page has been changed by ahmedaly.
http://wiki.apache.org/hadoop/Hive/StatsDev?action=diff&rev1=43&rev2=44

--------------------------------------------------

  set hive.stats.dbclass=hbase;
  }}}
  
- In case of JDBC implementations of temporary stored statistics (ex. Derby or MySQL), the
user should specify the appropriate connection string to the database by setting the variable
'''hive.stats.dbconnectionstring'''. Also the user should specify the appropriate JDBC driver
by setting the variable '''hive.stats.jdbcdriver'''
+ In case of JDBC implementations of temporary stored statistics (ex. Derby or MySQL), the
user should specify the appropriate connection string to the database by setting the variable
'''hive.stats.dbconnectionstring'''. Also the user should specify the appropriate JDBC driver
by setting the variable '''hive.stats.jdbcdriver'''.
  {{{
  set hive.stats.dbclass=jdbc;
  set hive.stats.dbconnectionstring="jdbc:derby:;databaseName=TempStatsStore;create=true"
@@ -126, +126 @@

  ANALYZE TABLE tablename [PARTITION(partcol1[=val1], partcol2[=val2], ...)] COMPUTE STATISTICS;
  }}}
  For the analyze command the user may or may not specify the partition specs. If the user
doesn't specify any partition specs, statistics are gathered for the table as well as all
the partitions (if any). If certain partition specs are specified, then statistics are gathered
for only those partitions.
+ 
+ == Examples ==
- For example, if table Table1 has 4 partitions with the following specs:
+ Suppose table Table1 has 4 partitions with the following specs:
- Partition1: ds='',hr=11
+  Partition1: ds='',hr=11
- Partition2: ds='',hr=12
+  Partition2: ds='',hr=12
- Partition3: ds='',hr=11
+  Partition3: ds='',hr=11
- Partition4: ds='',hr=12
+  Partition4: ds='',hr=12
  and the user issues the following command:
  {{{
  ANALYZE TABLE Table1 PARTITION(ds='', hr) COMPUTE STATISTICS;
  }}}
  then the 
  
- == Examples ==
- 

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