"Heikki Linnakangas" <[EMAIL PROTECTED]> writes: "Heikki Linnakangas" <[EMAIL PROTECTED]> writes:
> Gregory Stark wrote: >> "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. > > Return type of hash* functions is just 32 bits. I wonder if that's wide enough > to avoid accidental collisions? Depends on the application of course... Oh, I missed that you were suggesting a UNIQUE index. That seems unsafe to me even for md5 or its ilk. But that would depend on the application too. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services! ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
