Hi!
----- Original Message -----
From: "Balteo" <balteo@stripped>
To: "Heikki Tuuri" <Heikki.Tuuri@stripped>
Sent: Wednesday, May 01, 2002 8:02 AM
Subject: Re: Innodb's inner workings and checkpoints
> Heikki,
>
> Thanks for your prompt reply.
>
> If I understand:
>
> 1. In order for data to make it to the (disk)-log, it needs to be
commited.
No, the data can be in the log on disk long before the transaction is
committed. Consider, for example, a large table import run inside a single
transaction. The InnoDB log buffer is typically set to 8 MB, but we can
easily import gigabytes of data inside a single transaction.
> 2. In order for data to make it to the (disk)-tablespace it needs to be
> on the (disk)-log.
This is correct.
> I can infer from the above that:
>
> Data that is not commited can never make it to the disk. Then if I am
> right what is the "disk-bound rollback" that is referred to in the
> "performance tuning tips" paragraph 8 of the innodb documentation?
A disk-bound rollback is a danger in large table imports inside a single
transaction. Since inserts use the insert buffer, but deletes do not, the
rollback can take much longer than the inserts lasted.
> Balteo.
Best regards,
Heikki Tuuri
Innobase Oy
---
InnoDB - transactions, row level locking, and foreign key support for MySQL
See http://www.innodb.com, download MySQL-Max from http://www.mysql.com
