Re: [HACKERS] pageinspect and hash indexes - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: [HACKERS] pageinspect and hash indexes
Date
Msg-id CAA4eK1JbiOho++V8f3KrFA+iucRWb2HMYOY6VHM4xF6iAHv8Ug@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] pageinspect and hash indexes  (Ashutosh Sharma <ashu.coek88@gmail.com>)
Responses Re: [HACKERS] pageinspect and hash indexes  (Ashutosh Sharma <ashu.coek88@gmail.com>)
List pgsql-hackers
On Sat, Mar 18, 2017 at 12:12 AM, Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> On Fri, Mar 17, 2017 at 10:54 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
>> While trying to figure out some bloating in the newly logged hash indexes,
>> I'm looking into the type of each page in the index.  But I get an error:
>>
>> psql -p 9876 -c "select hash_page_type(get_raw_page('foo_index_idx',x)) from
>> generate_series(1650,1650) f(x)"
>>
>> ERROR:  page is not a hash page
>> DETAIL:  Expected 0000ff80, got 00000000.
>>
>> The contents of the page are:
>>
>> \xa4000000d8f203bf65c900001800f01ff01f0420...
>>
>> (where the elided characters at the end are all zero)
>>
>> What kind of page is that actually?
>
> it is basically either a newly allocated bucket page or a freed overflow page.
>

What makes you think that it can be a newly allocated page?
Basically, we always initialize the special space of newly allocated
page, so not sure what makes you deduce that it can be newly allocated
page.


-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com



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