Space of NULL values?

Question

If I have a column CHAR(100) and is allowed to have NULL values, when the value is NULL, how much space will this take?

Also, will there be a performance hit, considering the column will be written only one, never updated and selected a lot of times?

Not enough information are provided there – We're All Mad Here Feb 14 '14 at 17:57 — We're All Mad Here, Feb 14 '14 at 17:57

score 2 · Answer 1 · answered Feb 14 '14 at 17:57

2

Before version 5.0.3, the default format is set to "REDUNDANT" : any fixed-length field will use the same space, even if it's value is NULL.

Starting with version 5.0.3, the value is set to "COMPACT" : NULL values will never use any space in your database.

answered Feb 14 '14 at 17:57

echo_Me

Can you please be more specific about case #2, seems like a fairy tail. They must use at least one bit. – We're All Mad Here Feb 14 '14 at 17:57

1 Answers1