Re: WIP: extensible enums

On 10/24/2010 09:20 PM, Tom Lane wrote:
> Andrew Dunstan<andrew@dunslane.net>  writes:
>> On 10/24/2010 08:12 PM, Tom Lane wrote:
>>> This shows that the bitmapset optimization really is quite effective,
>>> at least for cases where all the enum labels are sorted by OID after
>>> all.  That motivated me to change the bitmapset setup code to what's
>>> attached.  This is potentially a little slower at initializing the
>>> cache, but it makes up for that by still marking most enum members
>>> as sorted even when a few out-of-order members have been inserted.
>> That's nice. It's a tradeoff though. Bumping up the cost of setting up
>> the cache won't have much effect on a creating a large index, but could
>> affect to performance of retail comparisons significantly. But this is
>> probably worth it. You'd have to work hard to create the perverse case
>> that could result in seriously worse cache setup cost.
> Well, notice that I moved the caching into typcache.c, rather than
> having it be associated with query startup.  So unless you're actively
> frobbing the enum definition, that's going to be paid only once per
> session.

Oh, yes. Good. I'm just starting to look at this in detail.

cheers

andrew