Re: How to make RDBMS ?

Hi!

I have also been interested in the relative complexity of an OS and a RDBMS.

I have written the InnoDB RDBMS, which is currently available as a transactional backend of MySQL.

For operating systems I have to rely on reading some academic material, and looking a bit at Linux source code.

My impression is that the two products are largely analogous. For example, the buffer pool of a database corresponds to the file cache of an operating system. Transactions can be seen analogous to operating system processes.

It is a tradition in database implementation that we try to bypass some functions of the operating system to get better performance. The buffer pool is one example, the tablespace concept of Oracle another. Thread pooling a third.

A database contains some functionality which is not available in typical operating systems: rollback, recovery, and query optimization.

An operating system on the other hand has to support interrupt handling, device drivers, and several ways of communication between processes.

InnoDB contains 120 000 lines of C, and the part of Linux kernel written by Linus Torvalds used to contain 50 000 lines of C.

Based on the above facts, my current impression is that an OS and a database are about equal in complexity. I do not know anybody who would have written both an OS and a database. Thus the comparison is difficult.

Regards,

Heikki Tuuri
Innobase Oy
http://www.innodb.com

David Cressey wrote in message <7zoZ7.49$Nq6.2808_at_petpeeve.ziplink.net>...
>D at B dot A,
>
>Correct me if I'm wrong, but I think there are three different positions
>here:
>
>Todd, who was saying that DB is inherently simpler than OS.
>You, who are saying DB is inherently more complex than OS, as current
>research is revealing.
>And I, who regard them as being of approximately the same order of
>complexity.
>
>The middle position isn't always the right position. But, in this case, I
>get certain comfort
>from knowing that there are opinions on both sides of mine here.
>
>Unless I've misunderstood you or Todd.
>
>
>
>--
>Regards,
> David Cressey
> www.dcressey.com
>
>
>
>
Received on Sat Jan 05 2002 - 00:10:54 CET