From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
---|---|
To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
Cc: | Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pageinspect: Hash index support |
Date: | 2016-09-23 12:41:38 |
Message-ID: | 05d0b6f8-4254-e2b5-5602-aa140783c81c@2ndquadrant.com |
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Lists: | pgsql-hackers |
On 9/23/16 1:56 AM, Amit Kapila wrote:
> On Fri, Sep 23, 2016 at 9:40 AM, Peter Eisentraut
>> - hash_metap result fields spares and mapp should be arrays of integer.
>>
>
> how would you like to see both those arrays in tuple, right now, I
> think Jesper's code is showing it as string.
I'm not sure what you are asking here.
>> (Incidentally, the comment in hash.h talks about bitmaps[] but I think
>> it means hashm_mapp[].)
>>
>
> which comment are you referring here? hashm_mapp contains block
> numbers of bitmap pages.
The comment I'm referring to says
The blknos of these bitmap pages are kept in bitmaps[]; nmaps is the
number of currently existing bitmaps.
But there is no "bitmaps" field anywhere.
> In the above code, it appears that you are trying to calculate
> max_avail space for all pages in same way. Don't you need to
> calculate it differently for bitmap page or meta page as they don't
> share the same format as other type of pages?
Is this even useful for hash indexes? This idea came from btrees.
Neither the gin nor the brin code have this.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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