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https://issues.apache.org/jira/browse/DRILL-4905?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15524920#comment-15524920
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ASF GitHub Bot commented on DRILL-4905:
---------------------------------------
Github user gparai commented on a diff in the pull request:
https://github.com/apache/drill/pull/597#discussion_r80612914
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/ParquetGroupScan.java
---
@@ -899,6 +907,16 @@ public FileGroupScan clone(FileSelection selection)
throws IOException {
return newScan;
}
+ // clone to create new groupscan with new file selection and batchSize.
+ public ParquetGroupScan clone(FileSelection selection, int batchSize)
throws IOException {
+ ParquetGroupScan newScan = new ParquetGroupScan(this);
+ newScan.modifyFileSelection(selection);
+ newScan.cacheFileRoot = selection.cacheFileRoot;
--- End diff --
Should we have a setter method for this?
> Push down the LIMIT to the parquet reader scan to limit the numbers of
> records read
> -----------------------------------------------------------------------------------
>
> Key: DRILL-4905
> URL: https://issues.apache.org/jira/browse/DRILL-4905
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Parquet
> Affects Versions: 1.8.0
> Reporter: Padma Penumarthy
> Assignee: Padma Penumarthy
> Fix For: 1.9.0
>
>
> Limit the number of records read from disk by pushing down the limit to
> parquet reader.
> For queries like
> select * from <table> limit N;
> where N < size of Parquet row group, we are reading 32K/64k rows or entire
> row group. This needs to be optimized to read only N rows.
>
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