Using MyISAM - Have InnoDB reads etc.

[smacream]

Hi,

I have a database server full of MyISAM tables but I did not set the skip-innodb option. Accordingly the InnoDB storage engine system variables are set to their defaults.

Looking at the system status variables, I see that:
Innodb_buffer_pool_pages_data = 19
Innodb_buffer_pool_read_requests = 77
Innodb_buffer_pool_reads = 12
Innodb_data_read = 2494K
Innodb_data_Reads = 25
Innodb_data_writes = 3
Innodb_data_written = 1536
Innodb_log_writes = 1
Innodb_pages_read = 19

How can this be? Does MySQL use InnoDB for some internal stuff?

Also, I've restarted the database server a few times while make configuration changes. Do the status variables reset to zero after restart of server?

Thanks,

Seosamh

 

[ingresman]

I think whenm you install MYSQL you get a large default INNODB file (10mb I recall). There was a thread here within the last few months that talked about it. So I would imagine those figures are things like start up reads, consistency writes etc. They look pretty low so looks like no "real" work is going on.
I presume that these figures hardly change through the day ?

 

[smacream]

Thanks for the reply ingresman. There are three innodb files in the server's data directory: ibdata1 (10M), ib_logfile0 (5M) and ib_logfile1 (5M). It seems they are default Innodb files (according to this:

http://dev.mysql.com/doc/refman/5.0/en/innodb-configuration.html

).

The status variables seem pretty static so you must be right about them being due to start up reads etc. Is there any risk in restarting the server with skip-innodb on? Presumambly there's at least a small perforamnce gain by removing the innodb buffers, and a slightly quicker startup. We will not require Innodb for the foreseeable future. Thanks again.

 

[ingresman]

I woudn't think there would be any risk, to be honest I'd just leave it. Just out of interest is there any reason you don't user INNOdb ?

 

[smacream]

Ok. Thanks.

We use MyISAM tables - from what I've read and seen they suit our requirements better. Think they're much faster for the queries we use. Don't need the row locking or foreign key functionality of InnoDB as not really appropriate. We don't have many users accessing the database. Just have to be a bit more careful about backing up than you probably would with InnoDB. I'm not an expert - we just made this choice from what we've read and seen.

 

[ingresman]

No, that sounds good and well thought out. Mysql served us for years before the new fangled transactional Innodb came along !

 

[smacream]

Thanks!!