On Thu, Mar 23, 2017 at 1:54 PM, Ashutosh Sharma <ashu.coe...@gmail.com> wrote: >> Yeah, but I think "unused" might be better. Because a page could be >> in use (as an overflow page or primary bucket page) and still be >> empty. > > 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. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
pgstathashindex-empty.patch
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