[TYPO3-dev] Typo3 4.1 - Server crashes

[Dmitry Dulepov]

Elmar HInz wrote:
> Am Mon, 26 Mar 2007 15:04:39 +0300 schrieb Dmitry Dulepov:
> 
>> You forget that innodb works much better with locks, which is esential 
>> for index tables...
> 
> That is one point, but is it that relevant for TYPO3 usage at all?

Yes. Verified in real life.

> a) Locks work in the moment of writing. 99.9% of use of index tables -
> in all TYPO3 tables - is reading. They need to be optimized for that,
> rarely for secure transactions.

No. typo3 also executes many UODATE queries on index tables. It is also 
writing.

> b) In high load indexing there is only one user at one time writing to the
> index table. That is the indexing engine, so there is no concurrent access
> to the tables.

Wrong. In high load there are many users coming to the site. All of them 
execute UPDATE query and all rquest to indexing table will wait in the 
queue if table is myisam.

> If indexing happens in concurrent way -- that is triggered
> by human editors -- that is rather low load. Updates by editors happen
> comparingly seldom within one TYPO3 DB.

Updates happen whan user comes to page. At least, this is what I see in 
query log.

> c) MyIsam Tables are written in timly order, so that the bits and bytes
> don't need to be moved around. InnoDB are written in order of the primary
> key, wich requires additional mechanism to reorder the data. Also a
> resource eater.

Source of this information about InnoDB, please? I know that InnoDB 
contains keys together with data to minimize seeks but I never heard 
about data rearrangement with InnoDB.

By the way, mysql uses innodb as default type starting from version 4.0 
at least on Windows platform. I wonder why...

-- 
Dmitry Dulepov

Web: http://typo3bloke.net/
Skype: callto:liels_bugs

"It is our choices, that show what we truly are,
far more than our abilities." (A.P.W.B.D.)