| From: | Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com> | 
|---|---|
| To: | "Henry C(dot)" <henka(at)cityweb(dot)co(dot)za> | 
| Cc: | pgsql-general(at)postgresql(dot)org | 
| Subject: | Re: Which is faster: md5() or hashtext()? | 
| Date: | 2010-11-05 07:52:49 | 
| Message-ID: | AANLkTimM0HtHrmujgngNPSmGFZPwnHE+XSwqSr6N5-4M@mail.gmail.com | 
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| Thread: | |
| Lists: | pgsql-general | 
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.
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