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https://issues.apache.org/jira/browse/PHOENIX-4288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16252831#comment-16252831
]
ASF GitHub Bot commented on PHOENIX-4288:
-----------------------------------------
Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/281#discussion_r151015329
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/execute/ClientAggregatePlan.java
---
@@ -87,6 +89,25 @@ public ClientAggregatePlan(StatementContext context,
FilterableStatement stateme
}
@Override
+ public Cost getCost() throws SQLException {
+ Long byteCount = getEstimatedBytesToScan();
+ if (byteCount == null) {
+ return Cost.ZERO;
+ }
+
+ int parallelLevel = 1;
--- End diff --
So parallelLevel is 1 because aggregation is done client-side instead of
pushed to the cluster, right? Would be good to doc the thinking behind
calculating the cost throughout.
> Indexes not used when ordering by primary key
> ---------------------------------------------
>
> Key: PHOENIX-4288
> URL: https://issues.apache.org/jira/browse/PHOENIX-4288
> Project: Phoenix
> Issue Type: Sub-task
> Reporter: Marcin Januszkiewicz
> Assignee: Maryann Xue
> Labels: CostBasedOptimization
>
> We have a table
> CREATE TABLE t (
> rowkey VARCHAR PRIMARY KEY,
> c1 VARCHAR,
> c2 VARCHAR
> )
> which we want to query by doing partial matches on c1, and keep the ordering
> of the source table:
> SELECT rowkey, c1, c2 FROM t where c1 LIKE 'X0%' ORDER BY rowkey;
> We expect most queries to select a small subset of the table, so we create an
> index to speed up searches:
> CREATE LOCAL INDEX t_c1_ix ON t (c1);
> However, this index will not be used since Phoenix will always choose not to
> resort the data.
> In our actual use case, adding index hints is not a practical solution.
> See also discussion at:
> https://lists.apache.org/thread.html/26ab58288eb811d2f074c3f89067163d341e5531fb581f3b2486cf43@%3Cuser.phoenix.apache.org%3E
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