[DRILL-1651] Allow Filter to push past Project with ITEM operator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.7.0
• Fix Version/s: 1.2.0
• Component/s: Query Planning & Optimization, Storage - HBase
• Assignee: Chun Chang
• Reporter: Chun Chang
• Created: 07/Nov/14 01:06
• Updated: 16/Sep/15 18:23
• Resolved: 22/Jul/15 21:51

Description

#Tue Nov 04 16:58:08 UTC 2014
git.commit.id.abbrev=129cb9c

I noticed that the following query did not cause a pushdown:

select cast(row_key as integer) student_id, (cast(twocf['age'] as integer)/cast(threecf['gpa'] as float)) from student where row_key < '800' and row_key > '750';

plan:

00-01      Project(student_id=[CAST($0):INTEGER NOT NULL], EXPR$1=[/(CAST($1):INTEGER, CAST($2):FLOAT)])
00-02        SelectionVectorRemover
00-03          Filter(condition=[AND(<($0, '800'), >($0, '750'))])
00-04            Project(row_key=[$1], ITEM=[ITEM($2, 'age')], ITEM2=[ITEM($0, 'gpa')])
00-05              Scan(groupscan=[HBaseGroupScan [HBaseScanSpec=HBaseScanSpec [tableName=student, startRow=null, stopRow=null, filter=null], columns=[SchemaPath [`row_key`], SchemaPath [`twocf`.`age`], SchemaPath [`threecf`.`gpa`]]]])

But the following query did:

select cast(row_key as integer) student_id, cast(onecf['name'] as varchar(30)) name, cast(twocf['age'] as integer) age, cast(threecf['gpa'] as decimal(4,2)) gpa, cast(fourcf['studentnum'] as bigint) student_num, cast(fivecf['create_date'] as timestamp) create_date from student where row_key > '750' and row_key < '800';

plan:

00-01      Project(student_id=[CAST($0):INTEGER NOT NULL], name=[CAST(ITEM($3, 'name')):VARCHAR(30) CHARACTER SET "ISO-8859-1" COLLATE "ISO-8859-1$en_US$primary"], age=[CAST(ITEM($5, 'age')):INTEGER], gpa=[CAST(ITEM($4, 'gpa')):DECIMAL(4, 2)], student_num=[CAST(ITEM($2, 'studentnum')):BIGINT], create_date=[CAST(ITEM($1, 'create_date')):TIMESTAMP(0)])
00-02        Scan(groupscan=[HBaseGroupScan [HBaseScanSpec=HBaseScanSpec [tableName=student, startRow=750\x00, stopRow=800, filter=FilterList AND (2/2): [RowFilter (GREATER, 750), RowFilter (LESS, 800)]], columns=[SchemaPath [`*`]]]])

Select * caused triggered pushdown:

0: jdbc:drill:schema=hbase> explain plan for select *  from student where row_key < '800' and row_key > '750';
+------------+------------+
|    text    |    json    |
+------------+------------+
| 00-00    Screen
00-01      Project(row_key=[$0], fivecf=[$1], fourcf=[$2], onecf=[$3], threecf=[$4], twocf=[$5])
00-02        Scan(groupscan=[HBaseGroupScan [HBaseScanSpec=HBaseScanSpec [tableName=student, startRow=750\x00, stopRow=800, filter=FilterList AND (2/2): [RowFilter (LESS, 800), RowFilter (GREATER, 750)]], columns=[SchemaPath [`*`]]]])