Alan, I am having a similar lock-out problem while performing a complex query on SQL Server 2K. All other hits cannot connect until the query returns the results. My research has so far taken me here: http://www.zope.org/Members/petrilli/DARoadmap Which is telling me I am probably using at most a Level-2 DA with my ZODBC. And then here: http://www.zope.org/Members/djay/ZmxODBC/ZmxODBC_0_0_2.tgz/README Which is a Level-3 mxZODBC DA (multithreaded). If anyone sees a problem with what I am about to do, let me know. What do you think? -----Original Message----- From: zope-dev-admin@zope.org [mailto:zope-dev-admin@zope.org]On Behalf Of Capesius, Alan Sent: Wednesday, March 07, 2001 12:31 PM To: zope@zope.org Cc: zope-dev@zope.org Subject: [Zope-dev] RE: ZODBC problem Thanks Dieter, I was kinda looking for a solution, I reviewed the mailing lists but do not see any solutions. I've done some more testing here: Summary: The user selects an involved financial report. The report takes about 55 seconds for Zope to prepare. The first second is the SQL server request and reply. The remaining time is Zope processing (dual 200mhz NT box). My queries are SELECT JOINS. No tables are modified at the server. The problem I see here is that Zope/ZODBCDA is holding the connection to SQL open via ODBC until all processing is complete and then issuing an SQL statement: IF @@TRANCOUNT>0 COMMIT TRAN Zope could free up this connection after one second. (at least in this case) Until Zope does the commit, other users are locked out. For read only queries, there is no need to have the request under transaction control. In any case, Zope should be able to early release the SQL connection and then process on the results. Certainly increasing processor speed will mask this problem and provide better response to users, but I'm hoping for a real fix. Thanks, Alan Network Monitor trace Wed 03/07/01 10:51:50 c:\cap1.TXT Frame Time Src MAC Addr Dst MAC Addr Protocol 1 4.413 006008F6062B COMPAQ851F04 TCP 2 4.413 006008F6062B COMPAQ851F04 TCP 3 4.413 006008F6062B COMPAQ851F04 TCP [....] 193 5.072 006008F6062B COMPAQ851F04 TCP 194 5.073 COMPAQ851F04 006008F6062B TCP 195 5.090 COMPAQ851F04 006008F6062B TCP 196 5.090 006008F6062B COMPAQ851F04 TCP 197 5.090 006008F6062B COMPAQ851F04 TCP 198 5.091 COMPAQ851F04 006008F6062B TCP 199 5.109 COMPAQ851F04 006008F6062B TCP 200 5.127 COMPAQ851F04 006008F6062B TCP // SQL server goes idle after this // python DTML processing occurs here 201 10.834 006008F6062B COMPAQ851F04 TCP // not sure what this is, Data is 0xA8 202 10.834 COMPAQ851F04 006008F6062B TCP // reply, data is empty // page returns to user at 60 second mark // then Zope closes the connection 203 60.385 COMPAQ851F04 006008F6062B TCP SQL: IF @@TRANCOUNT>0 COMMIT TRAN 204 60.386 006008F6062B COMPAQ851F04 TCP 205 60.601 COMPAQ851F04 006008F6062B TCP
Capesius, Alan writes:
... with further testing I have determined that the Zope server itself is not locking up, but rather requests to the database (MS SQL7 via ZODBCDA) seem to be queueing up.
My memory tells me faintly that such an issue has already been discussed in the mailing lists (zope, zope-dev). When I remember right, ZODBCDA synchronizes all database requests --> searchable list archives...
Dieter
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