Re: [Exim] exim's databases and sql

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Author: Philip Hazel
Date:  
To: Avleen Vig
CC: Jerry Jorgenson, exim-users
Subject: Re: [Exim] exim's databases and sql
On Tue, 7 Oct 2003, Avleen Vig wrote:

> On Tue, Oct 07, 2003 at 05:54:35AM -0500, Jerry Jorgenson wrote:


> > Do I see an EximII.the.sequel here, with a separate code branch?


1. I do *not* want to go through another Exim3/Exim4 transition if I can
help it. Actually, since this is very internal, I doubt that such a big
change would be necessary. Anything this is done in this are could
almost certainly be done in a compatible manner.

2. This is a big item; I'm not going to be implementing anything big
very soon (away rather a lot and need to get documentation updated for
the next release). I also intend to initiate a discussion on the
long-term sometime next year (as I have posted a couple of times).

>   2) structure the db better.
>      the current current db uses a simple key/value pair, where the
>      key is the MX hostname and the value is a long string of message
>      ID's waiting for delivery. part of the blocking is here; when I
>      have multiple queue runners trying to write to the same key's
>      value.. :-)


Yes, this is where the assumption of "small queue, not many delayed"
really bites.

>   3) it can even be beneficial to *not* use a hints db. maybe have an
>      which defaults to having the db enabled?


I presume you mean not to use an smtp-wait hints db. I suspect not that
using a normal retry hints db would not be such a good idea.

An option not to use an smtp-wait db would be utterly trivial to
implement, so it would be easy to test. All that is needed is for a
couple of lines of code not to be obeyed.


--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book