Re: [exim] Tools for SQL export to CDB

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Συντάκτης: Jeff Garzik
Ημερομηνία:  
Προς: David Saez Padros
Υ/ο: exim users, W B Hacker
Αντικείμενο: Re: [exim] Tools for SQL export to CDB
David Saez Padros wrote:
> Hi !!
>
>>> we use here a cdb database for white/black listing that is rebuilt every
>>> 5 minutes from a mysql database (with more than 4 million ip addresses),
>>> in our case the cdb read speed compensates the databse rebuild every 5
>>> minutes. Of course this maybe even better using some dbm like database
>>> but we don't have tried it yet. For other purposes where data is updated
>>> from time to time is even better (username/passwords, etc ...)
>>
>> I agree cdb is a nice solution, but I would love to see a comparison
>> with SQlite.
>
> the problem with sqlite and also with dbm databases is that writing to
> the database locks all database (read/write) and only one process can
> update the database (only one write lock) and while the database is
> being updated no process can read it, so frequent updates make reading
> the database slower. As cdb is read only no locking is required.


Agreed, but have you actually measured it? SQLite updating is really
fast, even for hundreds of transactions per second (my usage test here).
That's why I mentioned a comparison... guesses aren't necessarily
worth much :)

    Jeff