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https://issues.apache.org/jira/browse/TAJO-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14740824#comment-14740824
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ASF GitHub Bot commented on TAJO-1493:
--------------------------------------

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

    https://github.com/apache/tajo/pull/624#discussion_r39271781
  
    --- Diff: 
tajo-plan/src/main/java/org/apache/tajo/plan/util/ScanQualConverter.java ---
    @@ -0,0 +1,297 @@
    +/**
    + * 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
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * 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.tajo.plan.util;
    +
    +import org.apache.tajo.algebra.*;
    +import org.apache.tajo.datum.DateDatum;
    +import org.apache.tajo.datum.Datum;
    +import org.apache.tajo.datum.TimeDatum;
    +import org.apache.tajo.datum.TimestampDatum;
    +import org.apache.tajo.plan.expr.*;
    +
    +import java.util.Stack;
    +
    +/**
    + * This converts Quals of ScanNode to Algebra expressions.
    + *
    + */
    +public class ScanQualConverter extends SimpleEvalNodeVisitor<Object> {
    --- End diff --
    
    I'd like to recommend renaming it to ``EvalNodeToExprConverter``. It 
appears to be more general in terms of converting any EvalNode tree into Expr 
tree.


> Make partition pruning based on catalog informations
> ----------------------------------------------------
>
>                 Key: TAJO-1493
>                 URL: https://issues.apache.org/jira/browse/TAJO-1493
>             Project: Tajo
>          Issue Type: Sub-task
>          Components: Catalog, Planner/Optimizer
>            Reporter: Jaehwa Jung
>            Assignee: Jaehwa Jung
>             Fix For: 0.11.0, 0.12.0
>
>         Attachments: TAJO-1493.patch, TAJO-1493_2.patch, TAJO-1493_3.patch, 
> TAJO-1493_4.patch
>
>
> Currently, PartitionedTableRewriter take a look into partition directories 
> for rewriting filter conditions. It get all sub directories of table path 
> because catalog doesn’t provide partition directories. But if there are lots 
> of sub directories on HDFS, such as, more than 10,000 directories, it might 
> be cause overload to NameNode. Thus, CatalogStore need to provide partition 
> directories for specified filter conditions. I designed new method to 
> CatalogStore as follows:
> * method name: getPartitionsWithConditionFilters
> * first parameter: database name
> * second parameter: table name
> * third parameter: where clause (included target column name and partition 
> value)
> * return values: 
> List<org.apache.tajo.catalog.proto.CatalogProtos.TablePartitionProto>
> * description: It scan right partition directories on CatalogStore with where 
> caluse. 
>   For examples, users set parameters as following:
> ** first parameter: default
> ** second parameter: table1
> ** third parameter: COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3
> In the previous cases, this method will create select clause as follows.
> {code:xml}
> SELECT DISTINCT A.PATH
> FROM PARTITIONS A, (
>   SELECT B.PARTITION_ID
>   FROM PARTITION_KEYS B
>   WHERE B.PARTITION_ID > 0 
>   AND (
>     COLUMN_NAME = 'col1' AND PARTITION_VALUE = '3'
>   )
> ) B
> WHERE A.PARTITION_ID > 0
> AND A.TID = ${table_id}
> AND A.PARTITION_ID = B.PARTITION_ID
> {code}
> At the first time, I considered to use EvalNode instead of where clause. But 
> I can’t use it because of recursive related problems between tajo-catalog 
> module and tajo-plan module. So, I’ll implement utility class to convert 
> EvalNode to SQL.



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