Re: proposal: prefix function - Mailing list pgsql-hackers

Hi

can we implement prefix function for fast test if substr is prefix of some string?

create or replace function prefix(str text, substr text)

returns boolean as $$
  select substr(str, 1, length(substr)) = substr
$$ language sql;

This function can be very effective in C language. Now it should be implemented with like or regexp, what is significantly more expensive.

Regards

Pavel