Re: extensible enum types - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: extensible enum types
Date
Msg-id 4C229915.3080803@dunslane.net
Whole thread Raw
In response to Re: extensible enum types  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
>   
>> Well, we don't need the enum value to map into the entire oid range. 
>> Can't we just add one to the top-most value and see if there is a
>> conflict?
>>     
>
> If you don't use the OID counter to generate the new value, you're going
> to have problems with race conditions.  There's also that small chance
> that there is no free value before 2^32.
>
> The bottom line here is not wanting a feature that "usually" works but
> fails once in awhile on the basis of conditions the user can't control.
>
>   

Yeah, what I'm now hoping to be able to do, following good suggestions 
from Tom, is to provide a way to get virtually no degradation in bulk 
comparison performance in the common case where any additions have been 
made at the end of the list with no oid wraparound, and acceptable 
performance otherwise, but provide for an ability to add new values at 
arbitrary places in the ordering, with no limit.

If we can do that why would we want less?

cheers

andrew


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