good database type choices

Ken Murchison ken at
Wed Jun 4 10:01:40 EDT 2003

Patrick Welche wrote:
> On Tue, Jun 03, 2003 at 02:16:14PM -0600, Carl P. Corliss wrote:
>>So I think I figured out the problem. 
>>What was happening was that db4 was having issues (don't know what in 
>>particular) but it was causing lmtp to hang because lmtp was waiting for the 
>>duplicate delivery check to complete and it never did because of whatever 
>>issues db4 was having. So I switched the db type for deliver.db to skiplist 
>>and now all seems to be working well...
>                           Default          Recommended?
>   --with-duplicate-db=DB  db3_nosync       skiplist
>   --with-mboxlist-db=DB   db3              skiplist
>   --with-seen-db=DB       flat             skiplist 
>   --with-subs-db=DB       flat
>   --with-tls-db=DB        db3_nosync
> Going through past emails, it seems now that skiplist is recommended
> essentially for everything. Is that plausible? Comments?

No, skiplist isn't recommended for everything.  Rob posted a message 
multiple times with the current recommendations (which are the defaults 
in 2.2), and the reasons why.

In a nutshell:

   --with-duplicate-db=DB  db3_nosync
   --with-mboxlist-db=DB   skiplist
   --with-seen-db=DB       skiplist
   --with-subs-db=DB       flat
   --with-tls-db=DB        db3_nosync

The simple reason for this setup is that skiplist performs very well for 
when enumerating a database and BDB works very well for random access.

Kenneth Murchison     Oceana Matrix Ltd.
Software Engineer     21 Princeton Place
716-662-8973 x26      Orchard Park, NY 14127
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