Optimizer should allow search for global patterns
-------------------------------------------------
Key: PIG-873
URL: https://issues.apache.org/jira/browse/PIG-873
Project: Pig
Issue Type: Improvement
Affects Versions: 0.3.1
Reporter: Santhosh Srinivasan
Fix For: 0.4.0
Currently, the optimizer works on the following mechanism:
1. Specify the pattern to be searched
2. For each occurrence of the pattern, check and then apply a transformation
With this approach, the search for a pattern is localized. An example will
illustrate the problem.
If the pattern to be searched for is foreach (with flatten) connected to any
operator and if the graph has more than one foreach (with flatten) connected to
an operator (cross, join, union, etc), then each instance of foreach connected
to the operator is returned as a match. While this is fine for a localized view
(per match), at a global view the pattern to be searched for is any number of
foreach connected to an operator.
The implication of not having a globalized view is more rules. There will be
one rule for one foreach connected to an opeator, one rule for two foreachs
connected to an operators, etc.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
