[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15545247#comment-15545247
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user asfgit closed the pull request at:

https://github.com/apache/flink/pull/2560


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15544993#comment-15544993
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2560
  
@wuchong I heavily tested this PR again as it could introduce difficult 
bugs. And I also found one issue that needs to be discussed. If you have an 
expression like `CAST(TRUE AS VARCHAR) || 'Test'` the result will be `TTest` 
not `trueTest`. So the expression reduction has a different string 
representation of boolean literals. The question is, do we wanna adapt our 
code, can this be configured, or is Calcite doing something wrong? What do you 
think @fhueske?


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15534886#comment-15534886
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2560
  
@twalthr  I add some Table API tests but skip some tests doesn't supported 
in Table API, such as `NULLIF`, `IN`, `EXTRACT`


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15534809#comment-15534809
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r81270921
  
--- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/FlinkPlannerImpl.scala
 ---
@@ -60,6 +60,7 @@ class FlinkPlannerImpl(
   var root: RelRoot = _
 
   private def ready() {
+planner.setExecutor(config.getExecutor)
--- End diff --

Yes you are right ! This is the reason why Table API not work.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15533076#comment-15533076
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r81163353
  
--- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/FlinkPlannerImpl.scala
 ---
@@ -60,6 +60,7 @@ class FlinkPlannerImpl(
   var root: RelRoot = _
 
   private def ready() {
+planner.setExecutor(config.getExecutor)
--- End diff --

I would not set the planner here as this class is only used by the SQL API. 
`FlinkRelBuilder.create()` is a better place.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15533067#comment-15533067
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2560
  
@wuchong it seems that the constant expression reduction does not work in 
the Table API . Could you convert your SQL tests also to additional Table tests 
and have a look at it? The SQL part seems to work fine.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15532959#comment-15532959
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2560
  
Thanks for updating the PR @wuchong. I found a little bug, but I will fix 
it myself and merge this.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15532576#comment-15532576
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2560
  
Hi @twalthr , I have updated this PR , could you have a look again ? 


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15529773#comment-15529773
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r80925547
  
--- Diff: 
flink-libraries/flink-table/src/test/scala/org/apache/flink/api/table/BatchTableEnvironmentTest.scala
 ---
@@ -0,0 +1,46 @@
+/*
+ * 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.flink.api.table
+
+import org.apache.flink.api.scala.ExecutionEnvironment
+import org.apache.flink.api.scala.table._
+import org.apache.flink.api.scala.util.CollectionDataSets
+import org.junit.Assert._
+import org.junit.Test
+
+
+class BatchTableEnvironmentTest {
--- End diff --

Could you add some additional expressions for better testing? Boolean 
expressions, something with `NULL`, `CASE`, strings and date/time types.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15529775#comment-15529775
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r80927113
  
--- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/BatchTableEnvironment.scala
 ---
@@ -228,19 +229,13 @@ abstract class BatchTableEnvironment(
   }
 
   /**
-* Translates a [[Table]] into a [[DataSet]].
-*
-* The transformation involves optimizing the relational expression 
tree as defined by
+* Generates the optimized [[RelNode]] tree from the relational 
expression tree as defined by
 * Table API calls and / or SQL queries and generating corresponding 
[[DataSet]] operators.
--- End diff --

The method does not generate a `DataSet` operators. Can you also add that 
it converts to DataSet/DataStream convertion?


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15529774#comment-15529774
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r80919671
  
--- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/BatchTableEnvironment.scala
 ---
@@ -228,19 +229,13 @@ abstract class BatchTableEnvironment(
   }
 
   /**
-* Translates a [[Table]] into a [[DataSet]].
-*
-* The transformation involves optimizing the relational expression 
tree as defined by
+* Generates the optimized [[RelNode]] tree from the relational 
expression tree as defined by
 * Table API calls and / or SQL queries and generating corresponding 
[[DataSet]] operators.
 *
 * @param table The root node of the relational expression tree.
-* @param tpe The [[TypeInformation]] of the resulting [[DataSet]].
-* @tparam A The type of the resulting [[DataSet]].
-* @return The [[DataSet]] that corresponds to the translated [[Table]].
+* @return The optimized [[RelNode]] tree
 */
-  protected def translate[A](table: Table)(implicit tpe: 
TypeInformation[A]): DataSet[A] = {
-
-validateType(tpe)
+  private[flink] def optimize(table: Table): RelNode = {
--- End diff --

`optimize` from `Table` to `RelNode` looks strange. I think 
`optimize(relNode: RelNode): RelNode` would be better.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15529776#comment-15529776
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2560#discussion_r80921875
  
--- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/FlinkRelBuilder.scala
 ---
@@ -38,7 +38,12 @@ class FlinkRelBuilder(
 cluster,
 relOptSchema) {
 
-  def getPlanner: RelOptPlanner = cluster.getPlanner
+  def getPlanner: RelOptPlanner = {
+val planner = cluster.getPlanner
+// set the executor to evaluate constant expressions
+planner.setExecutor(new 
RexExecutorImpl(Schemas.createDataContext(null)))
--- End diff --

Why don't you use `FrameworkConfig.executor()` in `TableEnvironment` to set 
the executor at the very beginning?


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15528968#comment-15528968
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2560
  
I will shepherd this PR.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15528157#comment-15528157
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

GitHub user wuchong opened a pull request:

https://github.com/apache/flink/pull/2560

[FLINK-4068] [table] Move constant computations out of code-generated

Thanks for contributing to Apache Flink. Before you open your pull request, 
please take the following check list into consideration.
If your changes take all of the items into account, feel free to open your 
pull request. For more information and/or questions please refer to the [How To 
Contribute guide](http://flink.apache.org/how-to-contribute.html).
In addition to going through the list, please provide a meaningful 
description of your changes.

- [x ] General
  - The pull request references the related JIRA issue ("[FLINK-XXX] Jira 
title text")
  - The pull request addresses only one issue
  - Each commit in the PR has a meaningful commit message (including the 
JIRA id)

- [x ] Documentation
  - Documentation has been added for new functionality
  - Old documentation affected by the pull request has been updated
  - JavaDoc for public methods has been added

- [x ] Tests & Build
  - Functionality added by the pull request is covered by tests
  - `mvn clean verify` has been executed successfully locally or a Travis 
build has passed


The origin PR is #2102. This PR makes `ReduceExpressionsRules` take effect. 
This rule can reduce constant expressions and replacing them with the 
corresponding constant.

And add some tests.

You can merge this pull request into a Git repository by running:

$ git pull https://github.com/wuchong/flink reduce-expression-FLINK-4068

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/flink/pull/2560.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

This closes #2560


commit 22a0f2e949e524e20151c11cc83bd6e1e4f2a1b2
Author: Jark Wu 
Date:   2016-09-28T02:31:59Z

[FLINK-4068] [table] Move constant computations out of code-generated




> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15526170#comment-15526170
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong closed the pull request at:

https://github.com/apache/flink/pull/2102


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15473300#comment-15473300
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2102
  
As I mentioned above, the `cannot translate call AS($t0, $t1)` error 
because of a Calcite bug. The 
[CALCITE-1297](https://issues.apache.org/jira/browse/CALCITE-1297) fixed it , 
but not yet released.  I will wait for Calcite 1.9 released and start working 
on it. 


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15447903#comment-15447903
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2102
  
Thanks @twalthr . This issue is more complex than I expected before. I will 
try to update this PR in next days. 


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15445974#comment-15445974
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2102
  
@wuchong I have added symbols recently. So functions like `TRIM` are now 
called correctly. If you like you could update this PR.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15335668#comment-15335668
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2102
  
@twalthr That sounds great ! Thank you . 


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15335636#comment-15335636
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user twalthr commented on the issue:

https://github.com/apache/flink/pull/2102
  
Regarding 3.: I already have some code in a branch that introduces symbols 
instead of the "Integer hack" we are currently using, but I haven't finished it 
so far. I can solve this issue for you.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API & SQL
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>Assignee: Jark Wu
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15333991#comment-15333991
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user wuchong commented on the issue:

https://github.com/apache/flink/pull/2102
  
After introducing `RexExecutor` which make `ReduceExpressionRules` taking 
effect ,  many errors occurred.  

1. The `cannot translate call AS($t0, $t1)` is a Calcite bug I think, and I 
created a related issue : 
[CALCITE-1295](https://issues.apache.org/jira/browse/CALCITE-1295).

2. We should replace 
[L69](https://github.com/apache/flink/blob/master/flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/expressions/arithmetic.scala#L69-L73)
 to `relBuilder.call(SqlStdOperatorTable.CONCAT, l, cast)` otherwise will throw 
the following exception. Because calcite have no plus(String, String) method. 

```
java.lang.RuntimeException: while resolving method 'plus[class 
java.lang.String, class java.lang.String]' in class class 
org.apache.calcite.runtime.SqlFunctions

at org.apache.calcite.linq4j.tree.Types.lookupMethod(Types.java:345)
at org.apache.calcite.linq4j.tree.Expressions.call(Expressions.java:442)
at 
org.apache.calcite.adapter.enumerable.RexImpTable$BinaryImplementor.implement(RexImpTable.java:1640)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementCall(RexImpTable.java:854)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementNullSemantics(RexImpTable.java:843)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementNullSemantics0(RexImpTable.java:756)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.access$900(RexImpTable.java:181)
at 
org.apache.calcite.adapter.enumerable.RexImpTable$3.implement(RexImpTable.java:411)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translateCall(RexToLixTranslator.java:535)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate0(RexToLixTranslator.java:507)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate(RexToLixTranslator.java:222)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate0(RexToLixTranslator.java:472)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate(RexToLixTranslator.java:222)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate(RexToLixTranslator.java:217)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translateList(RexToLixTranslator.java:700)
at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translateProjects(RexToLixTranslator.java:192)
at 
org.apache.calcite.rex.RexExecutorImpl.compile(RexExecutorImpl.java:80)
at 
org.apache.calcite.rex.RexExecutorImpl.compile(RexExecutorImpl.java:59)
at 
org.apache.calcite.rex.RexExecutorImpl.reduce(RexExecutorImpl.java:118)
at 
org.apache.calcite.rel.rules.ReduceExpressionsRule.reduceExpressionsInternal(ReduceExpressionsRule.java:544)
at 
org.apache.calcite.rel.rules.ReduceExpressionsRule.reduceExpressions(ReduceExpressionsRule.java:455)
at 
org.apache.calcite.rel.rules.ReduceExpressionsRule.reduceExpressions(ReduceExpressionsRule.java:438)
at 
org.apache.calcite.rel.rules.ReduceExpressionsRule$CalcReduceExpressionsRule.onMatch(ReduceExpressionsRule.java:350)
at 
org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:213)
at 
org.apache.calcite.plan.volcano.VolcanoPlanner.findBestExp(VolcanoPlanner.java:838)
at 
org.apache.calcite.tools.Programs$RuleSetProgram.run(Programs.java:334)
at 
org.apache.flink.api.table.BatchTableEnvironment.translate(BatchTableEnvironment.scala:250)
at 
org.apache.flink.api.java.table.BatchTableEnvironment.toDataSet(BatchTableEnvironment.scala:146)
at org.apache.flink.api.java.batch.table.ExpressionsITCase.testCom


3. The following error is when we convert `Trim` to `RexNode`, we use a 
Integer to represent "LEADING", "TRAILING", "BOTH". Instead we should use 
`SqlTrimFunction.Flag`. But I haven't found how to write SqlTrimFunction.Flag 
into a `RexNode`.

 ```
java.lang.ClassCastException: java.lang.Integer cannot be cast to 
org.apache.calcite.sql.fun.SqlTrimFunction$Flag

at 
org.apache.calcite.adapter.enumerable.RexImpTable$TrimImplementor.implement(RexImpTable.java:1448)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementCall(RexImpTable.java:854)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementNullSemantics(RexImpTable.java:843)
at 
org.apache.calcite.adapter.enumerable.RexImpTable.implementNullSemantics0(RexImpTable.java:756)
at 

[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15332427#comment-15332427
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

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

https://github.com/apache/flink/pull/2102#discussion_r67233943
  
--- Diff: 
flink-libraries/flink-table/src/test/scala/org/apache/flink/api/scala/batch/sql/SelectITCase.scala
 ---
@@ -146,4 +148,21 @@ class SelectITCase(
 tEnv.sql(sqlQuery)
   }
 
+  @Test
+  def testConstantReduce(): Unit = {
--- End diff --

I think the assertion of this this test should not check the name of the 
generate Flink operator.
Instead I propose the following:
- split the `translate()` method into an `optimize()` method that generates 
the optimized `RelNode` tree and a `translate()` method that translates into a 
`DataSet` / `DataStream` program.
- make the `optimize()` method `private[flink]` and therefore accessible 
from a unit test
- add a `BatchTableEnvironmentTest` and a `StreamTableEnvironmentTest` 
which check that the optimized `RelNode` tree contains reduced expressions.


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15331460#comment-15331460
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

Github user fhueske commented on the issue:

https://github.com/apache/flink/pull/2102
  
Thanks for the PR @wuchong! I will have a look at it soon :-)


> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[Jark Wu (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15331446#comment-15331446
 ] 

Jark Wu commented on FLINK-4068:


I tested some cases and find that tableAPI will automatically evaluate the 
constant expression , e.g.  {{select('a + (2+3))}} is  {{select('a+5}} actually 
.  But sql will not do this automatically. However , we can use optimize rule 
to do this (this should be done so). 

The {{ReduceExpressionsRule.CALC_INSTANCE}} can do this,  and it has been in 
FlinkRuleSet, but it doesn't work. I further study it and find that we miss the 
executor in planner. This is the PR: https://github.com/apache/flink/pull/2102, 
just one line changed.

> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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[jira] [Commented] (FLINK-4068) Move constant computations out of code-generated `flatMap` functions.

[ASF GitHub Bot (JIRA)]

[ 
https://issues.apache.org/jira/browse/FLINK-4068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15331443#comment-15331443
 ] 

ASF GitHub Bot commented on FLINK-4068:
---

GitHub user wuchong opened a pull request:

https://github.com/apache/flink/pull/2102

[FLINK-4068] [tableAPI] Move constant computations out of code-generated

The `ReduceExpressionsRule` rule can reduce constant expressions and 
replacing them with the corresponding constant.  We have 
`ReduceExpressionsRule.CALC_INSTANCE` in both `DATASET_OPT_RULES` and 
`DATASET_OPT_RULES`, but it dose not take effect. Because it require the 
planner have an executor to evaluate the constant expressions. This PR does 
this, and resolve FLINK-4068.

And some tests added.

You can merge this pull request into a Git repository by running:

$ git pull https://github.com/wuchong/flink FLINK-4068

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/flink/pull/2102.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

This closes #2102


commit 786653b7be085c1e80481137fed3d47c5da2357a
Author: Jark Wu 
Date:   2016-06-15T09:19:35Z

[FLINK-4068] [tableAPI] Move constant computations out of code-generated  
functions.




> Move constant computations out of code-generated `flatMap` functions.
> -
>
> Key: FLINK-4068
> URL: https://issues.apache.org/jira/browse/FLINK-4068
> Project: Flink
>  Issue Type: Improvement
>  Components: Table API
>Affects Versions: 1.1.0
>Reporter: Fabian Hueske
>
> The generated functions for expressions of the Table API or SQL include 
> constant computations.
> For instance the code generated for a predicate like:
> {code}
> myInt < (10 + 20)
> {code}
> looks roughly like:
> {code}
> public void flatMap(Row in, Collector out) {
>   Integer in1 = in.productElement(1);
>   int temp = 10 + 20;  
>   if (in1 < temp) {
> out.collect(in)
>   }
> }
> {code}
> In this example the computation of {{temp}} is constant and could be moved 
> out of the {{flatMap()}} method.
> The same might apply for generated function other than {{FlatMap}} as well.



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