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https://issues.apache.org/jira/browse/TAJO-1658?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14604443#comment-14604443
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ASF GitHub Bot commented on TAJO-1658:
--------------------------------------
Github user jihoonson commented on a diff in the pull request:
https://github.com/apache/tajo/pull/613#discussion_r33417668
--- Diff:
tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/SeqScanExec.java
---
@@ -167,23 +162,55 @@ public void init() throws IOException {
projected = outSchema;
}
- initScanner(projected);
- super.init();
-
- if (plan.hasQual()) {
- if (scanner.isProjectable()) {
- qual.bind(context.getEvalContext(), projected);
- } else {
- qual.bind(context.getEvalContext(), inSchema);
- }
+ return projected;
+ }
+ private void initScanIterator() {
+ // We should use FilterScanIterator only if underlying storage does
not support filter push down.
--- End diff --
We currently have two kinds of scan operator, sequential scan
(```SeqScanExec``` and ```PartitionMergeScanExec```) and index scan
(```BSTIndexScanExec```).
In the case of when an index exists for a HDFS table, index scan will do
the same operation of ```FullScanIterator```. So, there seems an unified
interface for index scan and ```FullScanIterator```.
Maybe, we design a new scanner for HDFS like ```IndexedScanner```. If so,
we can also handle index scan in the below code block.
What do you think? Do you have any plans for this?
> Filter push down to underlying storages
> ---------------------------------------
>
> Key: TAJO-1658
> URL: https://issues.apache.org/jira/browse/TAJO-1658
> Project: Tajo
> Issue Type: Sub-task
> Components: physical operator, storage
> Reporter: Hyunsik Choi
> Assignee: Hyunsik Choi
> Fix For: 0.11.0
>
>
> Some storages can filter unqualified rows. For it, SeqScanner should support
> the filter push down to underlying scanners.
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