Re: Informix vs. Sybase vs. Oracle vs. (gasp) MS SQL Server

Anthony Mandic wrote:
>
> David Williams wrote:
>
> > Imagine 1 page with 2 rows one it.
> >
> > 1. Page level locking
> >
> > User A updates row 1
> > At the same time user B updates row 2. User B has to wait for
> > User B to commit.
>
> You're forgetting latency. There's no way that you'd ever
> get immediate concurrency as in your second scenario below.

How about a multi-processor system with a multi-threaded db server?

> > Lock granularity is still a problem. Why do UNIX kernels lock
> > individual files and data structures rather than having one large
> > kernel lock? Try reading
>
> Hey but they don't lock rows of text in a file do they?

There is no such thing as a row of text in a UNIX file. They are nothing by streams of bytes. Received on Fri Jan 01 1999 - 00:00:00 CET