Is field specification faster?

[lilleman]

Hi,

Let us assume that I have a table with three fields called id, name and email. I want to retrieve all the fields. Which one of the following queries is best to use regarding execution speed?

SELECT * FROM table

SELECT id, name, email FROM table

Yours, Erik.

[r937]

the second will be marginally faster based on speed, because in the first, the optimizer must first go get the column names out of the system table

always using the second style as a matter of coding hygiene on all queries is better for other reasons, too

[lilleman]

Hi,

Thanks for the explanation. I will use the second style from now on.

Yours, Erik.

[swampBoogie]

the second will be marginally faster based on speed, because in the first, the optimizer must first go get the column names out of the system table

The DBMS needs to get the names in any case so the cost for dictionary lookup will be the same.