"Heikki Linnakangas" <[EMAIL PROTECTED]> writes: > As others have pointed out, CREATE UNIQUE INDEX i ON ((md5(column)) is a > pretty > good work-around.
Unless you need cryptographic security I would not suggest using MD5. MD5 is intentionally designed to take a substantial amount of CPU resources to calculate. Postgres's internal hash method is exposed for most data types as hashtext() hashfloat8(), hashint4(), etc. These functions were chosen for their lightweight design. Cryptographic security is important only if you're concerned with people being able to intentionally create collisions. In this scenario that's probably not a top threat. Conceivably someone could create a denial-of-service attack slowing down your server by causing your indexes to become unbalanced. But it would be fairly challenging to engineer. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services! ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
