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Posted to dev@pig.apache.org by "Cheolsoo Park (JIRA)" <ji...@apache.org> on 2013/10/10 02:43:43 UTC
[jira] [Updated] (PIG-3510) New filter extractor fails with more
than one filter statement
[ https://issues.apache.org/jira/browse/PIG-3510?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Cheolsoo Park updated PIG-3510:
-------------------------------
Description:
This is a regression from PIG-3461 - rewrite of partition filter optimizer. Here is an example that demonstrates the problem:
{code:title=two filters}
b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001);
c = FILTER b BY (event_id == 419 OR event_id == 418);
{code}
{code:title=one filter}
b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001) AND (event_id == 419 OR event_id == 418);
{code}
Both dateint and event_id are partition columns. For the 1 filter case, the whole expression is pushed down whereas for the 2 filter case, only (event_id == 419 OR event_id == 418) is pushed down.
was:
This is a regression from PIG-3461 - rewrite of partition filter optimizer. Here is an example that demonstrates the problem:
{code:title=two filters}
b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001);
c = FILTER b BY (event_id == 419 OR event_id == 418);
{code}
{code:title=one filter}
b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001) AND (event_id == 419 OR event_id == 418);
{code}
Both dateint and event_id are partition columns. For the 1 filter case, the whole expression is pushed down whereas for the 2 filter case, only (event_id == 419 OR event_id == 418) is pushed down.
The reason is the filter extractor overwrites the pushdown expression that it extracted from the 1st statement while visiting the 2nd statement.
{code}
private Expression pushdownExpr = null;
{code}
The old filter extractor used to keep pushdown expressions in array and assemble them with AND at the end.
{code}
private ArrayList<Expression> pColConditions = new ArrayList<Expression>();
{code}
After debugging further, I found that the real problem is that the order of optimization rules being applied has changed by PIG-3461. In particular, MergeFilter is applied *after* NewPartitionFilterOptimizer resulting that only partial expressions are pushed down.
Old order:
# MergeFilter
# PartitionFilterOptimizer
New order:
# NewPartitionFilterOptimizer
# MergeFilter
> New filter extractor fails with more than one filter statement
> --------------------------------------------------------------
>
> Key: PIG-3510
> URL: https://issues.apache.org/jira/browse/PIG-3510
> Project: Pig
> Issue Type: Bug
> Components: impl
> Affects Versions: 0.12.0
> Reporter: Cheolsoo Park
> Assignee: Cheolsoo Park
> Fix For: 0.12.1
>
>
> This is a regression from PIG-3461 - rewrite of partition filter optimizer. Here is an example that demonstrates the problem:
> {code:title=two filters}
> b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001);
> c = FILTER b BY (event_id == 419 OR event_id == 418);
> {code}
> {code:title=one filter}
> b = FILTER a BY (dateint >= 20130901 AND dateint <= 20131001) AND (event_id == 419 OR event_id == 418);
> {code}
> Both dateint and event_id are partition columns. For the 1 filter case, the whole expression is pushed down whereas for the 2 filter case, only (event_id == 419 OR event_id == 418) is pushed down.
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