ANNOUNCE: xsdb -- the eXtremely Simple Database goes alpha

Wolfgang Lipp lipp at
Mon Dec 29 16:37:41 CET 2003


thanks for some great ideas and implementations. i'm in the course of 
testing out whether xsdb could be useful for my present project, 
and i like it! one minor thing i've found is that when i create 
a database, populate it, commit, and then re-open it, i get a nasty
xsdb.xsdbExceptions.RollBackError: write attempt after younger read
exception. this turned out to be avoidable by placing time.sleep(1) 
between the commit and the re-open. i guess the culprit might be 
on line 34 of xsdb\ self.startTime = int(time()). 
maybe this should be changed to sth like int(time()*TIME_GRANULARITY), 
with the constant being a number in the hundreds or thousands?


Aaron Watters <aaron at> wrote in message news:<mailman.25.1071054806.9307.python-list at>...
> ANNOUNCE: xsdb -- the eXtremely Simple Database goes alpha
> Links:
>     Home page with docs and other links:
>     Sourceforge project with download links
> Executive Summary:
> The xsdb package is an open source database implementation implemented 
> in Python
> and hosted on SourceForge.
> The xsdb package provides fundamental concurrent database functionality 
> with
> concurrency control and recovery. Fundamental characteristics include:
>  - Extreme portability and ease of installation and use.
>  - A simple semantics of objects with associated descriptions
>    compatible with the relational model, object modelling methods,
>    and other data organizations such as OLAP.
>  - Multiple access paths and indices.
>  - Timestamp based concurrency control for safe concurrent database access.
>  - Commit/Rollback and recovery support.
>  - A variety of underlying storage implementations with configurable 
> features and
>    performance characteristics.
>  - No intrinsic database size limitations.
> The package is intended to provide what you really need from a database 
> for most applications,
> without the other stuff (among other goals).
> General Technical Notes:
> The xsdb package is implemented in Python, and the server mode requires 
> stackless python.
> An xsdb database (not in server mode) will run using standard C Python 
> or Java Python (Jython).
> Please have a look and give it a try.  Thanks very much!
>     -- Aaron Watters  [attempt 2]
> ===
> Even in a perfect world where everyone is equal
> I'd still own the movie rights and be working on the sequel
>    -- Elvis Costello "Every day I write the book"

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