Re: [exim] High Perf server - was (exim allowed someone to s…

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Author: Tony Finch
Date:  
To: exim-users
Subject: Re: [exim] High Perf server - was (exim allowed someone to slam my mail server for 3 hours)
On Wed, 29 Jun 2005, Philip Hazel wrote:
> On Wed, 29 Jun 2005, Tony Finch wrote:
>
> > The long term solution is to use more sophisticated database APIs to store
> > the hints, but this may mean Berkeley DB or SQL only (no gdbm etc.) which
> > would make Exim harder to build and install.
>
> Or go to the other extreme and use a very simple db library. Berkeley DB
> is a huge overkill for what Exim needs. A very simple db library does
> exist
>      http://sourceforge.net/projects/tdb/
> and Exim supports it. But whether that would actually help in practice,
> I don't know.


The crucial feature is multiple symultaneous readers and writers (i.e. row
locking rather than table locking, to use RDBMS terminology). Since tdb
supports that then it should (hopefully) give us the improvement we want.
An extended version of Exim's DB abstraction layer could support
concurrent access with tdb and recent Berkeley DB.

Tony.
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