Re: GIN improvements part 1: additional information

On Fri, Oct  4, 2013 at 02:23:33AM +0400, Alexander Korotkov wrote:
> I came to idea that I like option #4 more than option #2.
> If we try to make new GIN work with old page formats we have to maintain 3 use
> cases:
> 1) old GIN with old page format (because of old releases)
> 2) new GIN with old page format
> 3) new GIN with new page format
> 
> If we create GIN2 we maintain only 2 use cases:
> 1) old GIN with old page format
> 2) new GIN with new page format
> The code of old GIN would be additional code in 9.4, but not additional code we
> maintain. Because we anyway maintain exactly same in old releases.
> 
> The problem I see is how to migrate users to GIN2. We can't expect they read
> release notes, create GIN2 indexes and drop GIN1 indexes. A lot of users will
> still use GIN1, because of they don't care :)
> Ideally any new GIN index should be GIN2 and reindex turns GIN1 into GIN2.

I am not sure I like the complexity of a GIN2, but we should give this
problem some serious thought as it will affect how we deal with other
on-disk index changes in the future.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +