Hi Martin, On Saturday 15 September 2007 15:01, Martin Kersten wrote:
Hi,
Thanks for the feedback. We will certainly look at your results in detail, but a quick scan already raises a number of issues.
Great! :)
1) Given the DVD benchmark results we know that the MySQL/PHP coupling has been well-optimized. An area we haven't spent much time on. (MonetDB/JDBC was faster then MySQL/JDBC)
mmm. Any idea what sort of optimizations are needed/possible in Monet's PHP extension?
2) What are the transaction settings? It makes a huge difference if you run in auto-commit mode or without transaction control. Also the finalization of a transaction commit should not be forgotten in the equation.
It's all in the scripts I sent. There were no begin/commit statements, so the default mode of both DBs was used, which I assume to be auto-commit. I'll try wrapping the whole thing in a begin/commit.
3) Running such query sequences would benefit from prepare() calls and batching
Ok. I'll see if that changes the results as well.
4) Integrity checking is another major source of differences
Well, I am really only concerned with read performance. I wouldn't think integrity checking would come into play there...
5) Data distributions may lead to (hash) collisions, or are too regular to measure anything
So overall, comparing systems to understand their characteristics is a difficult job. Naive tests should be replaced by simple tests and a deed analysis. Their are a plethora of reasons why systems differ and there is certainly no single answer.
Can you give an example of a "simple test" that would be worth doing? I thought this was rather simple actually.
The database complexity you measure is covered by (old) benchmarks like the Wisconsin and AS3AP benchmarks.
Are those published, with results for MonetDB and MySQL? I don't see them linked on the monetdb site.
Success with your experiments. A clear application focus will help to determine which route to take is best.
Yes, I'd like to import all of our mysql data and run some real app tests. I haven't tackled that project yet. Do you know if there is a document anywhere that discusses mysql to monetdb migration? I did see that monet can handle the mysql auto_increment keyword, which should be helpful. -- Dan Libby Open Source Consulting San Jose, Costa Rica http://osc.co.cr phone: 011 506 223 7382 Fax: 011 506 223 7359