UUID GENERATOR POSTGRES UPGRADE

The code doesn't depend any random numbers, so it's good enough to use in production. SHA-1 is preferred by the RFC, but PostgreSQL only has a built-in function for MD5, so the decision for us was easy. There are two options for hashing, either MD5 (version 3) or SHA-1 (version 5). The idea is to concatenate a namespace and a name, calculate a cryptographic hash of the result, and use it's bits to generate the UUID. The next idea was to create the URL on which the new rows will be server and generate name-based UUIDs using the URL namespace. That was good, because we would need a better PNRG for the final version. It turned out that we need deterministic IDs to be generated from the script, so V4 was out of question. Messing with bits in high-level languages is always fun :) Here is the result ( because of the use of the random() function, don't use the code for anything serious): CREATE OR REPLACE FUNCTION generate_uuid_v4() RETURNS uuid I know I can't use this code in the end, because I need a good pseudo-random number generator, but I couldn't resist to write it anyway.

MusicBrainz uses random-based UUIDs (version 4) for all it's new IDs, so the first idea was to implement the same.

I had this idea to write PL/pgSQL functions to generate UUIDs, so I skimmer over the RFC 4122 that documents them and found out that it isn't actually that hard. PostgreSQL has a native UUID data type and a contrib module for generating UUIDs since version 8.3, but this wouldn't help me, because I needed it to work with at least version 8.1.

UUID GENERATOR POSTGRES UPGRADE

While writing an SQL script to upgrade the MusicBrainz database for the last release, I needed a way to generate new UUIDs from SQL.

Uuid generator postgres