Performance scalability was the main concern people had when I first
described Prevayler, an object
persistence layer for Java, in an Advogato article last
Christmas.
People have run some tests since then. Guess what the results were.

Performance scalability was the main concern people had when I first
described Prevayler, an object
persistence layer for Java, in an Advogato article last
Christmas.
People have run some tests since then. Guess what the results were.
I'd like to suggest that you set up a testing database instance for advogato users. I shall call it the DeliTalk Global Food Services database. All advogato users can enter their local grocery shopping prices, their favorite local restaurant menus, their own home cooking recipes and ingredients etc ...
Yes. That is a good idea.
Another option is to write a JSP/Servlets face for the Prevayler Bank Demo.
We might consider something with a much greater volume of data to illustrate Prevayler's robustness and scalability. Any ideas?
If anyone writes any of the above, I shall put it up on the prevayler.org server.
Here's a few more ideas:
A good database design is to attract more people willing to go through raw data so they are able to form true knowledge of their own from those raw data and to make a better living for themselves.
fields: owner, media_type:media_code:title, owner_note ....
(media_type: book, CD, DVD, newspaper clip, internet ...
media_code: ISBN, ?, ? , ?, URL, ... )
I have one record for input today:
owner="sye";
media_type:media_code:title="book:0-486-26375-4:the works of mencius";
owner_note=
This edition of Mencius' works contains the complete texts of his
writings in Chinese, printed in large, clear characters. It also
contains the revised version of the English translation prepared by the
great Sinologist James Legge. Published in Canada by General Publishing
Company ltd. This Dover edition, first published in 1970, is an
unabridged and unaltered republication of the second, revised edition as
published by the Clarendon Press, Oxford, in 1895 as Volume II in "The
Chinese Classics Series.
When cross-pollinating databases, we find what eaters read. I know certain publishers in my neighborhood who would want to see results based on ISBN and DeliTalk Global ID. A grid display would work fine, printable and crease lines for placing in envelopes. Incorporate with ideas from sye, her word is absolute currency.
The marketing department of prevayler has to offer a lot of literature targeting at current SQL programmers. Something like "how Java class object can be seen through the eyes of SQL statements" and how to interpret the coding restrictions that my business classes have to be serializable and deterministic. Can you give us some real life examples?
Serialization is a fundamental service in Java and other languages. To be serializable, a Java class needs only to indicate that it wants to be serializable (for security reasons) and must use only other serializable classes. All collections included in the Java API are serializable.
99.9% of all source code is deterministic. There are a few ugly things, though, that you have to avoid.
People forget that there's a reason why web applications are faster to write and more reliable than desktop applications. It's the fact that requests are typically handled with nonpersistant processes so that the total state of the system is in the filesystem, a relational db or some other kind of specialized store.
Desktop applications have a way of going bad the same way cheese goes bad. Every other line of code adds state to the system, and eventually the system is going to make a transition into a degraded or nonfunctioning state... This includes memory leaks.
Web apps based on a relational database have an engineered state space... Abstractions in OO programming often hide the fact that programming decisions have consequences -- once you start throwing arbitrary objects into a persistant store, sooner or later somebody is going to make a mistake which gradually corrupts the store.
I have heard of relational databases go bad due to bad DDL, so I don't think this is an issue.
I have heard of relational databases go bad due to bad DDL and DML programming, so I don't think this is an issue.
New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.
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