The infamous to-do list

Heath Kehoe heath.kehoe at intermec.com
Thu Jun 29 14:27:11 UTC 2000


>
>> Good. :-) Hopefully we can finally do away with dbz and the text file
>> (which today really is only a bloated-by-hex-conversion binary file
>> anyway). I expect to test a Berkeley DB based history as soon as I
>> can...
>
>I'll be glad to see that tested, but I'll be really surprised if it beats
>a hand-tuned database format in performance.  There are a couple of minor
>tweaks that I plan to make to the current history format to create a new
>default one, and of course the current text file will become binary by
>default (part of the plan is to be able to read any older history format
>too, though), but I think the layout of the index and so forth is actually
>fundamentally sound.
>

This is from my server, which uses ovdb:

Code region              Time    Pct    Invoked   Min(ms)    Avg(ms)    Max(ms)
history write    01:37:50.997   6.8%     578895     4.943     10.142     25.791
overview write   01:02:17.445   4.3%     365013     4.704     10.239     34.359

The average times are nearly the same... and an overview store operation does
more than a history store.  So at least, storing would be at least as fast.
I'm not sure about lookups, but I bet they'd be comparable, too.

Another advantage of using BerkeleyDB is that you can delete history
entries on the fly, which would allow you to have an expire-daemon of some
kind that runs continuously.

-heath




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