Re: Postfix + MySQL engine type

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Postfix + MySQL engine type
\ Justin Kim (10 Apr 2007)
. \ Magnus Bäck (11 Apr 2007)
. \ mouss (11 Apr 2007)
. \ mouss (11 Apr 2007)

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Subject:	Re: Postfix + MySQL engine type
Group:	Postfix-users
From:	mouss
Date:	11 Apr 2007

Eric Frazier wrote:
>
> On 11-Apr-07, at 3:09 PM, mouss wrote:
>
>> Justin Kim wrote:
>>> Hi all,
>>> I have a question that might be more related to MySQL.
>>> However, it is related to postfix using MySQL as a databse backend.
>>> I setup Postfix+Dovecot+MySQL+Postfixadmin on redhat box.
>>> And following postfixadmin guide to create database stucture, it is by
>>> default to create a tables using MyISAM engine.
>>> But I was told that InnoDB engine is better to use.
>>>
>>
>> better for what? unless you need innodb features (transactions,
>> references, ...), you can use whichever engine you want.
>>
>> Unless postfixadmin hardcodes the engine type, you can set a default
>> type in /etc/my.cnf. you may need to enable innodb.
>>
>
> For read only stuff, I can't think of a reason to use Innodb. When
> doing nothing but selects, Myisam is the only way to go(not counting
> in memory stuff)

there is no "only way to go". the speed of myisam is probably irrelevant
in postfix context. as Magnus said, the bottleneck is certainly elsewhere.

> The InnoDB thing you read, probably has to do with when you are doing
> lots of inserts/update and then can take adv of row level locks that
> Myisam can't do.

I guess the OP got his "better use innodb" from discussions about
bayesian spam filters (spamassassin, dspam, ...) which indeed need to
update their "dictionary".

for postfix, this is irrelevant.

> I think a lot of high vol severs use something to that effect, where
> you keep a disk cache of data, but use shared memory or at least heap
> tables to read from. I am not sure if you really get that much
> advantage with heap tables over just using they query cache though.
> What I would be curious about is if you would in fact end up doing
> better with BDB tables? Simple hashes don't exactly need an SQL
> database, and I would think that would end up being faster, but that
> is just guessing.

bdb will certainly be faster. cdb even faster. but there is no point in
tuning for the fun of tuning. ease of remote administration may be more
important than tuning, as far as the system can cope with the traffic.
many people start tuning a lot of thing, and end up tuning the faster
parts of the platform. the net gain is about 0. if you run spamassassin
with a huge ruleset, then don't even think of tuning mysql.