On Oct 31, 2009, at 1:04 PM, Rob Stewart wrote:
2009/10/31 Santhosh Srinivasan <s...@yahoo-inc.com>
Misc question: Do you anticipate that Pig will be compatible with
Hadoop 0.20 ?
The Hadoop 0.20 compatible version, Pig 0.5.0, will be released
shortly. The release got the required votes.
thanks, I will watch out for that, and anticipate using 0.5 for my
study.
Finally, I am correct to assume that Pig is not Turing Complete? I
am
not clear on this. SQL is not Turing Complete, whereas Java is. So
does
that make, Hive or Pig, for example Turing complete, or not?
Short answer: Hive and Pig are not Turing complete. Turing
completeness
is for a particular language and not for the language implementing
the
language under question. Since Hive is SQL (like), its not Turing
complete. Till Pig supports loops and conditional statements, Pig
will
not be Turing complete.
OK, as I thought. Thanks. I assume therefore that, as Java is turing
complete, I would be able to illustrate this difference with a
certain query
design that requires turing completeness to execute?
The common case where we see users wanting Turing Completeness in Pig
is for iterative algorithms that need their answer to converge. You
can't do this in a single pass of MR either. You can write Java code
around either Pig or MR to iterate until your data reaches convergence.
Alan.
