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https://issues.apache.org/jira/browse/DRILL-1328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15290142#comment-15290142
 ] 

ASF GitHub Bot commented on DRILL-1328:
---------------------------------------

Github user sudheeshkatkam commented on a diff in the pull request:

    https://github.com/apache/drill/pull/425#discussion_r63805232
  
    --- Diff: 
exec/java-exec/src/main/java/org/apache/drill/exec/physical/config/UnpivotMaps.java
 ---
    @@ -0,0 +1,59 @@
    +/**
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + * <p/>
    + * http://www.apache.org/licenses/LICENSE-2.0
    + * <p/>
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +package org.apache.drill.exec.physical.config;
    +
    +import java.util.List;
    +
    +import org.apache.drill.exec.physical.base.AbstractSingle;
    +import org.apache.drill.exec.physical.base.PhysicalOperator;
    +import org.apache.drill.exec.physical.base.PhysicalVisitor;
    +import org.apache.drill.exec.proto.UserBitShared.CoreOperatorType;
    +
    +import com.fasterxml.jackson.annotation.JsonCreator;
    +import com.fasterxml.jackson.annotation.JsonProperty;
    +import com.fasterxml.jackson.annotation.JsonTypeName;
    +
    +@JsonTypeName("unpivot-maps")
    +public class UnpivotMaps extends AbstractSingle {
    --- End diff --
    
    Can this be exposed as a function too, might be useful function in general?


> Support table statistics
> ------------------------
>
>                 Key: DRILL-1328
>                 URL: https://issues.apache.org/jira/browse/DRILL-1328
>             Project: Apache Drill
>          Issue Type: Improvement
>            Reporter: Cliff Buchanan
>             Fix For: Future
>
>         Attachments: 0001-PRE-Set-value-count-in-splitAndTransfer.patch
>
>
> This consists of several subtasks
> * implement operators to generate statistics
> * add "analyze table" support to parser/planner
> * create a metadata provider to allow statistics to be used by optiq in 
> planning optimization
> * implement statistics functions
> Right now, the bulk of this functionality is implemented, but it hasn't been 
> rigorously tested and needs to have some definite answers for some of the 
> parts "around the edges" (how analyze table figures out where the table 
> statistics are located, how a table "append" should work in a read only file 
> system)
> Also, here are a few known caveats:
> * table statistics are collected by creating a sql query based on the string 
> path of the table. This should probably be done with a Table reference.
> * Case sensitivity for column statistics is probably iffy
> * Math for combining two column NDVs into a joint NDV should be checked.
> * Schema changes aren't really being considered yet.
> * adding getDrillTable is probably unnecessary; it might be better to do 
> getTable().unwrap(DrillTable.class)



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