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Robert Brewer wrote:
> Eric S. Johansson wrote:
>
>>I have an application where I need a very simple database,
>>effectively a very large dictionary. The very large
>>dictionary must be accessed from multiple processes
>>simultaneously. I need to be able to lock records within
>>the very large dictionary when records are written to.
>
>
> Just to clarify, you want shared-read until a write, at which point you
> want to lock just the item being written? Or would page or table locking
> be acceptable at that point?

just the item/record. I'm doing arrival rate calculations. each record
contains a set of arrival times and I am rewriting the record every time
a new entry arrives. complete page or table locking will work in the
sense that it will prevent collisions but it will have an increasing
impact as load and simultaneous table but not record accesses increase.

---eric

On Tue, 18 Jan 2005 12:57:21 -0500, Eric S. Johansson <>
wrote:

> Robert Brewer wrote:
>> Eric S. Johansson wrote:
>>
>>> I have an application where I need a very simple database, effectively
>>> a very large dictionary. The very large
>>> dictionary must be accessed from multiple processes
>>> simultaneously. I need to be able to lock records within
>>> the very large dictionary when records are written to.
>> Just to clarify, you want shared-read until a write, at which point
>> you
>> want to lock just the item being written? Or would page or table locking
>> be acceptable at that point?
>
> just the item/record. I'm doing arrival rate calculations. each record
> contains a set of arrival times and I am rewriting the record every time
> a new entry arrives. complete page or table locking will work in the
> sense that it will prevent collisions but it will have an increasing
> impact as load and simultaneous table but not record accesses increase.
>
> ---eric
>

Use Firebird as sql backend. Is designed as you request (readers not lock
writers and writers not lock readers). Google for "firebird optimistic
lock".

Off course, you have python driver: http://kinterbasdb.sf.net and can
deploy on windows and linux with a very little footprint.

--
Olaf Zetanien

Olaf Zetanien wrote:

<snip>
>
> Use Firebird as sql backend. Is designed as you request (readers not lock
> writers and writers not lock readers). Google for "firebird optimistic
> lock".
>
> Off course, you have python driver: http://kinterbasdb.sf.net and can
> deploy on windows and linux with a very little footprint.
>

And OS X. But it fails the OP's "no SQL" test.

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