[jira] [Work logged] (BEAM-8664) [SQL] MongoDb should use project push-down

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/BEAM-8664?focusedWorklogId=352226&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-352226 ]

ASF GitHub Bot logged work on BEAM-8664:
----------------------------------------

                Author: ASF GitHub Bot
            Created on: 02/Dec/19 21:24
            Start Date: 02/Dec/19 21:24
    Worklog Time Spent: 10m 
      Work Description: 11moon11 commented on pull request #10095: [BEAM-8664] [SQL] MongoDb project push down
URL: https://github.com/apache/beam/pull/10095#discussion_r351538013
 
 

 ##########
 File path: sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/meta/provider/mongodb/MongoDbReadWriteIT.java
 ##########
 @@ -187,7 +199,68 @@ public void testWriteAndRead() {
     PCollection<Row> output =
         BeamSqlRelUtils.toPCollection(readPipeline, sqlEnv.parseQuery("select * from TEST"));
 
-    assertEquals(output.getSchema(), SOURCE_SCHEMA);
+    assertEquals(SOURCE_SCHEMA, output.getSchema());
+
+    PAssert.that(output).containsInAnyOrder(testRow);
+
+    readPipeline.run().waitUntilFinish();
+  }
+
+  @Test
+  public void testProjectPushDown() {
+    final Schema expectedSchema =
+        Schema.builder()
+            .addNullableField("c_varchar", STRING)
+            .addNullableField("c_boolean", BOOLEAN)
+            .addNullableField("c_integer", INT32)
+            .build();
+    Row testRow = row(expectedSchema, "varchar", true, 2147483647);
+
+    String createTableStatement =
+        "CREATE EXTERNAL TABLE TEST( \n"
+            + "   c_bigint BIGINT, \n "
+            + "   c_tinyint TINYINT, \n"
+            + "   c_smallint SMALLINT, \n"
+            + "   c_integer INTEGER, \n"
+            + "   c_float FLOAT, \n"
+            + "   c_double DOUBLE, \n"
+            + "   c_boolean BOOLEAN, \n"
+            + "   c_varchar VARCHAR, \n "
+            + "   c_arr ARRAY<VARCHAR> \n"
+            + ") \n"
+            + "TYPE 'mongodb' \n"
+            + "LOCATION '"
+            + mongoSqlUrl
+            + "'";
+    sqlEnv.executeDdl(createTableStatement);
+
+    String insertStatement =
+        "INSERT INTO TEST VALUES ("
+            + "9223372036854775807, "
+            + "127, "
+            + "32767, "
+            + "2147483647, "
+            + "1.0, "
+            + "1.0, "
+            + "TRUE, "
+            + "'varchar', "
+            + "ARRAY['123', '456']"
+            + ")";
+
+    BeamRelNode insertRelNode = sqlEnv.parseQuery(insertStatement);
+    BeamSqlRelUtils.toPCollection(writePipeline, insertRelNode);
+    writePipeline.run().waitUntilFinish();
+
+    BeamRelNode node = sqlEnv.parseQuery("select c_varchar, c_boolean, c_integer from TEST");
+    // Calc should be dropped, since MongoDb supports project push-down and field reordering.
+    assertThat(node, instanceOf(BeamPushDownIOSourceRel.class));
 
 Review comment:
   Fields retrieved from MongoDB are returned as a `PCollection<Document>` from `MongoDBIO.expand()`, which is called by `MongoDbTable.buildIOReader(...)`.
   An `IOSourceRel` does not do any data manipulations (just wraps an IO and does type conversion).
   I am not exactly sure that checking values returned by `MongoDBIO.expand()` would be much different, unless I am misunderstanding something.
   
   I also [looked](https://stackoverflow.com/questions/41550450/mongodb-list-previous-queries) into retrieving some sort of log (from the embedded database) to check what query actually got executed, but I am not sure that we can easily retrieve that data.
   
   Alternatively, we could validate that `withQueryFn` on `MongoDbIO.Read` does indeed have projected fields set. But that would require somehow exposing `MongoDbIO.Read` to the tests.
   
   What do you think?
 
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Issue Time Tracking
-------------------

    Worklog Id:     (was: 352226)
    Time Spent: 4h  (was: 3h 50m)

> [SQL] MongoDb should use project push-down
> ------------------------------------------
>
>                 Key: BEAM-8664
>                 URL: https://issues.apache.org/jira/browse/BEAM-8664
>             Project: Beam
>          Issue Type: Improvement
>          Components: dsl-sql
>            Reporter: Kirill Kozlov
>            Assignee: Kirill Kozlov
>            Priority: Major
>          Time Spent: 4h
>  Remaining Estimate: 0h
>
> MongoDbTable should implement the following methods:
> {code:java}
> public PCollection<Row> buildIOReader(
>     PBegin begin, BeamSqlTableFilter filters, List<String> fieldNames);
> public ProjectSupport supportsProjects();
> {code}
>  



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