Performance LOAD; SQL SELECT

[#1]

Hello everyone,

Is there a difference in terms of performance in doing :

LOAD

A,

B;

SQL SELECT *

FROM ..

or

LOAD

A,

B;

SQL SELECT A,B

FROM...

Let's say the table has a lot of fields.

Thank you.

Have a good day.

Laura

[jerrysvensson]

Yes there could be a huge difference if your table has like 100 fields.

[datanibbler]

Hi Laura,

I'd say the performance should logically be bettter if, out of a lot of fields in the database_table, you SELECT only the fields that you need. The difference is probably not too much, though, as the preceding LOAD takes only those two fields ...

[giakoum]

especially if large text fields are included

[jerrysvensson]

I have seen data loads go from one hour (Select *) to five minutes (Select A,B). We had a table with 170 fields.

[Anonymous]

Hi,

There will be huge difference between Getting  two fields and 100's of fields from database in terms of performance.

As SQL SELECT statement does Implicit LOAD.

Regards

Neetha

[Anonymous]

additionally to existing answers there is another aspect

Select * requires a full table scan which takes time

select a,b might take use of an index which is much faster

in our case we dropped the load time from 1hour to 5 minutes (select * got 6 fields, later we used select with 2 fields)!