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ORC File reading same amount of data as Sequence File even after sorting the column in where clause.

Explorer

I have a table A, with age a column in it.
I created a table B in orc with age column sorted.
Now,
select * from A where age=60;
select * from B where age=60;
Both reads same amount of data and no difference in time was observed.
Please help me with this.

3 REPLIES 3

ORC is columnar format, you will see the advantage if and only if you select selective columns.

The SQL query does a Select * hence the complete row is read and then where cause is applied.
Please try reading selective columns to see the difference.

Explorer

Hey @kgautam,

I didn't understand what you said. I think row groups should be skipped based on max and min stored for them. And also I tried for one selecting one column too. It didn't work. Maybe I'm wrong in my understanding.

Explorer

And also by mistake I wrote that data read is same, actually I wanted to say that data read from B is actually equal to size of B. No predicate pushdown.

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