Re: Is the Halloween problem an issue in Postgres - Mailing list pgsql-general

From Adrian Klaver
Subject Re: Is the Halloween problem an issue in Postgres
Date
Msg-id 869172f6-9114-e759-79ba-eb17f1c5082c@aklaver.com
Whole thread Raw
In response to Re: Is the Halloween problem an issue in Postgres  (Thomas Kellerer <shammat@gmx.net>)
Responses Re: Is the Halloween problem an issue in Postgres
List pgsql-general
On 12/2/20 2:02 PM, Thomas Kellerer wrote:
> guyren@icloud.com schrieb am 02.12.2020 um 21:27:
>> The Halloween problem is that it is a challenge for the database if
>> you’re updating a field that is also in the WHERE clause of the same
>> query.
>>
>> I just saw a presentation from someone about how in SQL Server he
>> recommended writing changes to a temp table and then writing them to
>> the table as being much more efficient.
> 
> It sounds strange to me, that this _is_ actually a problem.
> 
> Why exactly is that a problem in SQL Server?

Yeah that was a new one to me. A quick search found:

https://www.sqlshack.com/the-halloween-problem-in-sql-server-and-suggested-solutions/

> And what are the consequences if you do it nevertheless.
> 
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com



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