Re: Add pgstathashindex() to get hash index table statistics.

Hi,

>>
>> Based on the earlier discussions, I have prepared a patch that would
>> allow pgstathashindex() to show the number of unused pages in hash
>> index. Please find the attached patch for the same. Thanks.
>
> My idea is that we shouldn't end up with both a zero_pages column and
> an unused_pages column.  Instead, we should end up with just an
> unused_pages column, which will include both pages that are all-zeroes
> and pages that have a valid special space marked as LH_UNUSED.
>
> Also, I don't see why it's correct to test PageIsEmpty() here instead
> of just testing the page type as we do in pageinspect.
>
> Attached is a revised patch that shows what I have in mind; please
> review.  Along the way I made the code for examining the page type
> more similar to what pageinspect does, because I see no reason for
> those things to be different, and I think the pageinspect code is
> better.

I have reviewed the patch and it looks good to me. Also, the idea of
including both zero and unused pages in a single 'unused' column looks
better. Thanks.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com