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Posted to dev@lens.apache.org by "Rajat Khandelwal (JIRA)" <ji...@apache.org> on 2015/06/24 08:35:42 UTC
[jira] [Commented] (LENS-630) Using Duration and Fact Weight Based
Query Cost Calculator for Hive Driver
[ https://issues.apache.org/jira/browse/LENS-630?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14598955#comment-14598955 ]
Rajat Khandelwal commented on LENS-630:
---------------------------------------
HiveDriver's estimate:
{noformat}
@Override
public QueryCost estimate(AbstractQueryContext qctx) throws LensException {
log.info("Estimate: " + qctx.getDriverQuery(this));
if (qctx.getDriverQuery(this) == null) {
throw new NullPointerException("Null driver query for " + qctx.getUserQuery());
}
if (qctx.getDriverContext().getDriverQueryCost(this) != null) {
// estimate called again and again
return qctx.getDriverContext().getDriverQueryCost(this);
}
if (qctx.isOlapQuery()) {
// if query is olap query and rewriting takes care of semantic validation
// estimate is not doing anything as of now
return HiveQueryPlan.HIVE_DRIVER_COST;
} else {
// its native table query. Do explain and return cost
return explain(qctx).getCost();
}
}
{noformat}
Question is, what normalized cost should we return for native table queries?
> Using Duration and Fact Weight Based Query Cost Calculator for Hive Driver
> --------------------------------------------------------------------------
>
> Key: LENS-630
> URL: https://issues.apache.org/jira/browse/LENS-630
> Project: Apache Lens
> Issue Type: Improvement
> Reporter: Himanshu Gahlaut
> Assignee: Rajat Khandelwal
>
> Along with this, we can add a new field in QueryCost to return the query cost calculated by the implementation. normalizedQueryCost could be one name for that field.
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