Re: [Exim] speed of lookup types

On Mon, 15 Mar 2004, Avleen Vig wrote:

> On Sun, Mar 14, 2004 at 11:05:20PM -0800, Tom wrote:
> > > Different expenses. Better to use PostgreSQL (or at least INNODB on
> > > mysql) which isn't locking.
> > > You're competing with two problems on flat file DB's:
> > > Locking
> > > Linear search speeds
> >
> > A dbm style lookup (BDB) will not lock or require a linear search. dbm
> > files are indexed. And usually you just rebuild the entire file and
> > rename it over the old file with exim_dbmbuild, so locking is not an
> > issue.
>
> Incorrect. In Berkley DB (at least before 4.x) you need to lock the
> entire file in order to write to it. I don't know the case after 4.x it
> may have changed.

Yes, but you are never going to write it, as exim_dbmbuild just builds a
totally new dbm file.

Tom