On 19 October 2010 05:21, Andrew Dunstan <and...@dunslane.net> wrote: > > > On 10/18/2010 10:52 AM, Tom Lane wrote: >> >> We could possibly deal with enum types that follow the existing >> convention if we made the cache entry hold a list of all the original, >> known-to-be-sorted OIDs. (This could be reasonably compact and cheap to >> probe if it were represented as a starting OID and a Bitmapset of delta >> values, since we can assume that the initial set of OIDs is pretty close >> together.) But we have to have that cache entry, and we have to consult >> it on every single comparison, so it's definitely going to be slower >> than before. >> >> So I'm thinking the comparison procedure goes like this: >> >> 1. Both OIDs even? >> If so, just compare them numerically, and we're done. >> >> 2. Lookup cache entry for enum type. >> >> 3. Both OIDs in list of known-sorted OIDs? >> If so, just compare them numerically, and we're done. >> >> 4. Search the part of the cache entry that lists sort positions. >> If not both present, refresh the cache entry. >> If still not present, throw error. >> >> 5. Compare by sort positions. >> >> Step 4 is the slowest part but would be avoided in most cases. >> However, step 2 is none too speedy either, and would usually >> be required when dealing with pre-existing enums. > > OK, I've made adjustments that I think do what you're suggesting. > > Patch is attached. > > Alternatively this can be pulled from > <g...@github.com:adunstan/postgresql-dev.git>
Andrew, can't you get your own repo at git.postgresql.org? -- Thom Brown Twitter: @darkixion IRC (freenode): dark_ixion Registered Linux user: #516935 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
