You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@hive.apache.org by "Jesus Camacho Rodriguez (JIRA)" <ji...@apache.org> on 2019/06/11 01:58:00 UTC
[jira] [Updated] (HIVE-21857) Sort conditions in a filter predicate
to accelerate query processing
[ https://issues.apache.org/jira/browse/HIVE-21857?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jesus Camacho Rodriguez updated HIVE-21857:
-------------------------------------------
Description:
Following approach similar to http://db.cs.berkeley.edu/jmh/miscpapers/sigmod93.pdf .
To reorder predicates in AND conditions, we could rank each of elements in the clauses in increasing order based on following formula:
{code}
rank = (selectivity - 1) / cost per tuple
{code}
Similarly, for OR conditions:
{code}
rank = (-selectivity) / cost per tuple
{code}
Selectivity can be computed with FilterSelectivityEstimator. For cost per tuple, we will need to come up with some heuristic based on how expensive is the evaluation of the functions contained in that predicate. Custom UDFs could be annotated.
was:
To reorder predicates in AND conditions, we could rank each of elements in the clauses in increasing order based on following formula:
{code}
rank = (selectivity - 1) / cost per tuple
{code}
Similarly, for OR conditions:
{code}
rank = (-selectivity) / cost per tuple
{code}
Selectivity can be computed with FilterSelectivityEstimator. For cost per tuple, we will need to come up with some heuristic based on how expensive is the evaluation of the functions contained in that predicate. Custom UDFs could be annotated.
> Sort conditions in a filter predicate to accelerate query processing
> --------------------------------------------------------------------
>
> Key: HIVE-21857
> URL: https://issues.apache.org/jira/browse/HIVE-21857
> Project: Hive
> Issue Type: Bug
> Components: CBO
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Priority: Major
>
> Following approach similar to http://db.cs.berkeley.edu/jmh/miscpapers/sigmod93.pdf .
> To reorder predicates in AND conditions, we could rank each of elements in the clauses in increasing order based on following formula:
> {code}
> rank = (selectivity - 1) / cost per tuple
> {code}
> Similarly, for OR conditions:
> {code}
> rank = (-selectivity) / cost per tuple
> {code}
> Selectivity can be computed with FilterSelectivityEstimator. For cost per tuple, we will need to come up with some heuristic based on how expensive is the evaluation of the functions contained in that predicate. Custom UDFs could be annotated.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)