Re: Speed of user-defined aggregates using array_append as transfn - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: Speed of user-defined aggregates using array_append as transfn
Date
Msg-id c6cdc5e1-d0a1-08bd-e531-8162a678afcd@dunslane.net
Whole thread Raw
In response to Re: Speed of user-defined aggregates using array_append as transfn  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

On 10/28/2016 03:14 PM, Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> My initial admittedly ugly thought was why not have a second append
>> function that doesn't use expanded arrays?
> That won't get us out of the O(N^2) behavior.  Also I don't see what's
> better about it than my suggestion of making array_append itself do
> that when called as an aggregate function.
>
>             



Probably nothing, I was just thinking out loud. That suggestion seems 
like the most obviously back-patchable solution.

cheers

andrew



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