I have a system where it would be very useful for the primary keys for a few tables to be UUIDs (actually MD5s of files, but UUID seems to be the best 128-bit type available). What is the expected performance of using a UUID as a primary key which will have numerous foreign references to it, versus using a 64-bit int (32-bit isn't big enough)?
>From the uuid.c in adt, it looks like a UUID is just stored as 8 consecutive bytes, and are compared using memcmp, whereas an int uses primitive CPU instructions for comparison. Is that a significant issue with foreign key performance, or is it mostly just the size that the key would take in all related tables? -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
