[GitHub] [drill] vvysotskyi commented on a change in pull request #2092: DRILL-7763: Add Limit Pushdown to File Based Storage Plugins

[GitBox <gi...@apache.org>]

vvysotskyi commented on a change in pull request #2092:
URL: https://github.com/apache/drill/pull/2092#discussion_r457178768



##########
File path: exec/java-exec/src/test/java/org/apache/drill/exec/metastore/TestMetastoreWithEasyFormatPlugin.java
##########
@@ -1079,14 +1079,14 @@ public void testFilesPruningWithLimit() throws Exception {
       queryBuilder()
           .sql("select * from dfs.tmp.`%s` limit 1", tableName)
           .planMatcher()
-          .include("Limit", "numFiles=1,")
+          .include("Limit", "numFiles=12,")

Review comment:
       This is the regression I mentioned in the previous comment. It is non-optimal to read all 12 files instead of the single one.

##########
File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/dfs/easy/EasyGroupScan.java
##########
@@ -172,6 +175,26 @@ private EasyGroupScan(final EasyGroupScan that) {
     mappings = that.mappings;
     partitionDepth = that.partitionDepth;
     metadataProvider = that.metadataProvider;
+    maxRecords = that.maxRecords;
+    supportsLimitPushdown = that.formatPlugin.easyConfig().supportsLimitPushdown;
+  }
+
+  // Constructor to get the limit pushed down
+  private EasyGroupScan(final EasyGroupScan that, int maxRecords) {

Review comment:
       Please do not introduce the new constructor. `maxRecords` is not final, so it is possible to assign its value after using the existing copy constructor.

##########
File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/dfs/easy/EasyGroupScan.java
##########
@@ -17,31 +17,30 @@
  */
 package org.apache.drill.exec.store.dfs.easy;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
+import com.fasterxml.jackson.annotation.JacksonInject;

Review comment:
       Please keep the original imports order.




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