Re: need help from the list admin

Reindl Harald <[email protected]>
Newsgroups gmane.comp.db.mysql.general
Organization the lounge interactive design
Message-ID <[email protected]>

Am 28.03.2016 um 21:36 schrieb Lentes, Bernd:
> ----- On Mar 27, 2016, at 2:49 PM, Reindl Harald [email protected] wrote:
>
>> Am 27.03.2016 um 14:34 schrieb Lentes, Bernd:
>>>> You would be better served by first converting your MyISAM tables to
>>>> InnoDB to stop mixing storage engine behaviors (transactional and
>>>> non-transactional) within the scope of a single transaction. But if you
>>>> cannot convert them, using MIXED will be a good compromise.
>>>
>>> Is this a big problem ? Something to take care of ? Currently we have a mix.
>>> I will ask the girl who developed it why we have both kinds. I hope i can
>>> convert
>>
>> surely - when you have non-transactional tables involved in
>> updates/inserts you can go and forget using transactions at all since
>> interruption or rollback would not rollback already written changes in
>> MyISAM tables
>>
>> transactions are all about consistency - impossible with a mix of InnoDB
>> and MyISAM tables
>
> I read that the converting is not difficult. But has the code of our webapp to be changed ? It's written in php and perl.
> What i understand is that inserts/updates/deletions in InnoDB tables have to be commited. Yes ?

first please stop place a space before "?" - it hurts :-)

NO - it only has to be commited if you START A TRANSACTION at the begin

> This has to be done in the code ? Or can we use the system variable autocommit ?

if you are using automcommit you lose any purpose of having transactions

> That means that everything is commited immediately ? Is this a good solution ?

if you don't care about consistency yes

> What means "By default, client connections begin with autocommit set to 1" in the doc ?

that nobody is starting a transaction automatically because nobody can 
tell when it is finished automatically end hence you need to tell it the 
db server

> That every client connection established via perl/php is started with autocommit=1 ?

surely

> And when does the commit happen ? When the connection is closed ? Is that helpful ?

depends - maybe you should start to read what transactions in the 
database world are because than you can answer all of your questions 
above at your own
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