On 6 Feb 2002 at 8:38, Mensing, Joerg wrote: > > Hmm, so having multiple connections (one per thread) really > > serves no useful function > > other than to allow each thread to operate as a different user. > > > Who talked about a different user? I just said different connection. It is > possible and allowed to connected several times from within a single client > using the same user.
I think we're having a language breakdown, I'm not explaining myself here. Lets use a real example. Zope on Python on Linux or Windows. Zope spawns multiple threads. Each thread can share a single database connection, in which case requests are serialized by Zope so threads will block if there is already a db request in progress. Or, each thread can have it's own database connection. Typically it's the same userid that is used, but that's not important in our example. Each thread has it's own database connection and Zope will not serialize access since each connection is independent. What I need to know is, will the underlying client DLL/library serialize access from multiple connections within the same process space. I'm not concerned about multiple processes being serialized since a) hope that doesn't happen, and b) I'm using Zope mostly. Earlier it was said that the ODBC driver will serialize multiple requests, but it's not clear if that happens when multiple ODBC connections are made from a single process, one connection per thread. I understand that you're using a simple request/reply client-server method, and only one-outstanding-request is allowed per connection. That's okay. Coming from Interbase, I do have this problem where both under Windows and Linux the gds32 library/dll is unreliable if multiple threads are used, even when each thread instatiates it's own connection. > As i said, you just have to open more than one connection. The restriction > is on a single connection you have to wait for a reply to your request, > before you can issue another request. And again be carefull not to > establish connections in parallel. CU jrg Ok, so you're saying that I can have multiple connections from a single process. Typically one connection per thread in my case. Each thread can send a request to the server and it won't be blocked by other thread's pending requests because each thread has it's own connection.. Right? However I have to be sure to not call "open connection (whatever you call it)" from two threads simultaneously because there's no semaphore to control the connection list? Brad Clements, [EMAIL PROTECTED] (315)268-1000 http://www.murkworks.com (315)268-9812 Fax netmeeting: ils://ils.murkworks.com AOL-IM: BKClements _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
