| Subject | Re: [Firebird-Architect] "Write Committed" transaction mode |
|---|---|
| Author | Ann W. Harrison |
| Post date | 2010-11-30T19:55:28Z |
On 11/30/2010 12:23 PM, Dmitry Yemanov wrote:
longer find the article I read previously that made me think PostgreSQL
worked like InnoDB.
When executing a select for update, update, or delete with a where
clause that affects records other than the direct target, InnoDB
takes a record lock on all records it reads. So, if for example you
have a delete that looks like this
delete from employees
where salary < select avg(x.price) from x in cars
the statement blocks updates to some employees and all cars.
Best regards,
Ann
> Ann,You are absolutely right. I read that item too quickly and can no
>>
>> http://www.postgresql.org/docs/7.4/interactive/transaction-iso.html
>
> Sorry, but I cannot find a confirmation there. Exactly the opposite:
>
>
longer find the article I read previously that made me think PostgreSQL
worked like InnoDB.
When executing a select for update, update, or delete with a where
clause that affects records other than the direct target, InnoDB
takes a record lock on all records it reads. So, if for example you
have a delete that looks like this
delete from employees
where salary < select avg(x.price) from x in cars
the statement blocks updates to some employees and all cars.
Best regards,
Ann