Re: [PATCH] Don't block HOT update by BRIN index

On 7/12/21 10:55 PM, Alvaro Herrera wrote:
> On 2021-Jul-12, Tomas Vondra wrote:
> 
>> Well, one of us is confused and it might be me ;-)
> 
> :-)
> 
>> The point is that BRIN is the only index type with amhotblocking=false,
>> so it would return NULL (and thus it does not block HOT). All other
>> indexes AMs have amblocking=true and so should return rd_indexattr (I
>> forgot to change that in the code chunk).
> 
> But RelationGetIndexAttrBitmap is called for the table that contains the
> index (and probably contains some other indexes too), not for one
> specific index.  So the bitmap is about the columns involved in *all*
> indexes of the table ...
> 

D'oh! Well, I did say I might be confused ...

Yeah, that optimization is not possible, unfortunately.


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company