February 2009 - cl-prevalence-devel@common-lisp.net

[cl-prevalence-devel] CLISP patch
by Leslie P. Polzer 08 Feb '09

08 Feb '09

Anton, could you merge your patch with Tomas Zellerin's? His patch should also be separated into CLISP-specific and other parts. Leslie

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[cl-prevalence-devel] what concurrency approach you use with cl-prevalence
by Anton Vodonosov 06 Feb '09

06 Feb '09

Hello everyone, Could you share your approach to concurrency in combination with cl-prevalence? As far as I understand, simultaneous transactions (IOW modifications) of the database are impossible, because all transactions use the same transaction log file and therefore must happen sequentially to avoid the transaction log corruption caused by concurrent writes. What about reading operations for persistent data? Has anyone implemented multiple-read/single write locking? Or you don't care and just user one global lock for all your database? Best regards, - Anton

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[cl-prevalence-devel] clisp patch
by Anton Vodonosov 06 Feb '09

06 Feb '09

Hello. Attached is the patch (against CVS HEAD) for SERIALIZABLE-SLOTS methods for CLISP. I've just tried cl-prevalece. With this patch I can presist/load objects. Is porting of cl-prevalence as trivial as implementing these two methods? BTW, why these methods have #+sbcl conditionals two times? Best regards, - Anton

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Re: [cl-prevalence-devel] Extending the serializer
by Leslie P. Polzer 03 Feb '09

03 Feb '09

> Is your branch going to be integrated with the mainline (perhaps you > should get commit permissions) or are you likely to maintain a > parallel branch that deals with weblocks integration issues? This branch contains changes that I'd like to see in the main repository. I intend to contribute more to cl-prevalence since it's a central component of some of my applications. I have asked Sven for commit access but he hasn't responded yet. He's probably not reading mail right now. In the meantime all my contributions will go into the hg branch, which is also easier to work with than CVS.

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[cl-prevalence-devel] Extending the serializer
by Ian Eslick 03 Feb '09

03 Feb '09

I've extended cl-prevalence slightly to support some custom serialization and deserialization of user data types. The attached diff contains a patch that allows users to hook into the serialization protocol at the appropriate places. Here is an example of how to hook into the protocol. The last two functions (of 3) were added in the diff. ;; Serializer support for persistent objects (defmethod s-serialization::serialize-xml-internal ((object persistent) stream serialization-state) (declare (ignore serialization-state)) (write-string "<PERSISTENT ID=\"" stream) (prin1 (oid object) stream) (write-string "\"/>" stream)) (defmethod s-serialization::deserialize-xml-new-element-aux ((name (eql :persistent)) attributes) (elephant::controller-recreate-instance *store-controller* (parse-integer (s-serialization::get-attribute-value :id attributes)))) ;; Not needed in this app: ;; (defgeneric deserialize-xml-finish-element-aux ((name (eql :persistent)) attributes parent-seed seed) ;; seed) Regards, Ian

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