Re: Which is faster: md5() or hashtext()?

Timing is on.
psql (9.1devel)
Type "help" for help.

# select count(hashtext(a::text)) FROM generate_series(1,10000) a;
 count
-------
 10000
(1 row)

Time: 106.637 ms
# select count(hashtext(a::text)) FROM generate_series(1,1000000) a;
  count
---------
 1000000
(1 row)

Time: 770.823 ms
# select count(md5(a::text)) FROM generate_series(1,1000000) a;
  count
---------
 1000000
(1 row)

Time: 1238.453 ms
# select count(hashtext(a::text)) FROM generate_series(1,1000000) a;
  count
---------
 1000000
(1 row)

Time: 763.169 ms
# select count(md5(a::text)) FROM generate_series(1,1000000) a;
  count
---------
 1000000
(1 row)

Time: 1258.958 ms


I would say hashtext is consequently beating md5 in terms of performance here.

Just remember, that it returns integer, unlike md5 that returns text.