On Tue, Jul 26, 2016 at 8:27 PM, Stephen Frost <sfrost@snowman.net> wrote:
> * Joshua D. Drake (jd@commandprompt.com) wrote:
>> Hello,
>>
>> The following article is a very good look at some of our limitations
>> and highlights some of the pains many of us have been working
>> "around" since we started using the software.
>>
>> https://eng.uber.com/mysql-migration/
>>
>> Specifically:
>>
>> * Inefficient architecture for writes
>> * Inefficient data replication
>
> The above are related and there are serious downsides to having an extra
> mapping in the middle between the indexes and the heap.
>
> What makes me doubt just how well they understood the issues or what is
> happening is the lack of any mention of hint bits of tuple freezing
> (requiring additional writes).
Yeah. A surprising amount of that post seemed to be devoted to
describing how our MVCC architecture works rather than what problem
they had with it. I'm not saying we shouldn't take their bad
experience seriously - we clearly should - but I don't feel like it's
as clear as it could be about exactly where the breakdowns happened.
That's why I found Josh's restatement useful - I am assuming without
proof that his restatement is accurate....
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company