Renato, slides 20-23 on this presentation describe the implementations of the joins: http://squarecog.wordpress.com/2009/11/03/apache-pig-apittsburgh-hadoop-user-group/
You can also search the pig wiki for design docs for each join. D On Tue, Apr 12, 2011 at 9:48 PM, Renato Marroquín Mogrovejo < [email protected]> wrote: > Hi there, > > I have some questions about how PIG performs joins. The site says there are > three types of specialized joins: Replicated, skew, and merge joins. I > wanted to know these implementations. For instance, what about the regular > type of join? Is there a difference between the repartition join > (org.apache.hadoop.contrib.utils.join) and the regular join implemented in > PIG? Is the merge join what is called a map-side join (where input is > sorted > and just regular scans are done)? > And about PIG join framework[1], are there other specific implementation > done? e.g. Semi-joins? > Thanks in advance. > > > Renato M. >
