Re: WIP: Fast GiST index build

On 15.06.2011 10:24, Alexander Korotkov wrote:
> On Wed, Jun 15, 2011 at 11:21 AM, Alexander Korotkov
> <aekorotkov(at)gmail(dot)com>wrote:
>
>> I've tried index tuples sorting on penalty function before buffer
>> relocation on split. But it was without any success. Index quality becomes
>> even worse than without sorting.
>> The next thing I've tried is buffer relocation between all neighbor
>> buffers. Results of first tests is much more promising. Number of page
>> accesses during index scan is similar to those without fast index build. I'm
>> going to hold on this approach.
>>
>> test=# create index test_idx on test using gist(v);
>> NOTICE: Level step = 1, pagesPerBuffer = 406
>> CREATE INDEX
>> Time: 10002590,469 ms
>>
> I forget to say that build time increases in about 40%, but it is still
> faster than ordinal build in about 10 times.

Is this relocation mechanism something that can be tuned, for different
tradeoffs between index quality and build time? In any case, it seems
that we're going to need a lot of testing with different data sets to
get a better picture of how this performs. But at least for now, it
looks like this approach is going to be acceptable.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com