At 9:01 am +0100 15/3/00, Ragnar Beer wrote:
Hello Zopistas out there!
I just stumbled about the threadsafety of different SQL-DAs. I'm coming from mod_perl + MySQL so it seemed a natural choice for me to also run Zope with MySQL in the background. I'm doing research (= low budget) in clinical psychology and have people fill in all kinds of questionnaires regularly which I have to store somewhere later. Looking at some past messages it seems to me that free and speedy MySQL is awfully bottlenecked by MySQLdb and financially-out-of-range Oracle rules. But how big is the difference? Does anybody know?
I could be talking out of a hole in the top of my head here, but here goes:
If you get Andy Dustmans' MySQLdb Module (http://www.zope.org/Members/adustman/MySQLdb). It's designed to be thread-safe. I've always taken that to mean that if a Zope request does a ZSQL query that uses this module, then if another ZSQL query comes along (in a different Zope thread) then it is *not* blocked until the first query is finished, but runs alongside the first query.
If I'm wrong on this I would *really* appreciate a correction here.
The Python DB API spec 2.0 talks about different levels of thread safety. MySQLdb has threadsafety level 1 (= threads my share the module but not connections), the ORACLE db has threadsafety level 3 (= threads may share the module, connections and cursors). I wonder what that means in % performance gain in high traffic situations. I have no idea where the different levels of threadsafety kick in. Any experienced users?
Can I access ZODB via TCP/IP socket to retrieve data for statistical calculations?
I'd reckon so. Look into XML-RPC as an example. Of course you can just construct URLs that obtain the data you need (eg have a folder with lots of properties of the form prop_n and get the values as http://server/path/to/folder/prop_125) and perhaps use something like urllib (Python library) to do some machinations at the client end).
I was rather thinking of connecting directly to ZODB (in a kind of server mode) via TCP/IP - not via Zope. But I guess that's an aberrant thought that would rather be applicable to connecting to ZEO. Still I feel like I'm only beginning to understand but in about two weeks the new production site must be ready running zope ;) Ragnar