Re: > Subject: Re: Detailed explanation why uber move from postgress to mysql

On 12/25/2016 12:43 AM, Tim Gorman wrote:
> >> Explaining those features is the least I could do for an Oracle ACE.
>
> Actually, the least you could do is explain them correctly.
>
> You started off OK in describing the Oracle in-memory implementation
> as a column store, which is easy enough since it is. And you should
> have stopped there.
>
> Instead, you veered into the weeds with an odd analogy to bitmap
> indexes, which indicates either unfamiliarity with in-memory column
> stores, or with bitmap indexes, or both. There is nothing to suggest
> the method, the manner, the usage, or the impact of bitmap indexes in
> any in-memory column store implementation.
>
Actually, I didn't come up with that analogy. The credit goes to another Oracle ACE, soon to be retired:

https://jonathanlewis.wordpress.com/2013/11/06/12c-in-memory/ /
///With the in-memory columnar copy you should be able to drop many “DSS indexes”, thus improving OLTP response times – in effect the in-memory stuff behaves a bit like non-persistent bitmap indexing./ /
I can see that you disagree with such a description, but I cannot claim the authorship. I am glad you recognized that as a falsehood from a mile away and I am sure you will be able to correct the author.

Last but certainly not least, I wish you a merry Christmas.

-- 
Mladen Gogala
Oracle DBA
http://mgogala.freehostia.com


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