[Zope] RE: [Zope-dev] RE: ZODBC problem
Philipp Auersperg
zope@philosoft.at
Wed, 07 Mar 2001 22:23:23 +0100
Yes, ZmxODBC solves many problems (I also had locking problems with=
ZODBCDA), it is level 3 compliant,
ZmXODBC uses mxODBC as low-level driver. The new release that fixes many=
problems, especially
with proprietary datatypes can be found at:
http://www.lemburg.com/files/python/mxODBC.html
it is a source-distribution but you have to pay some (but not too much) $=
for it, but it's worth.
I tested the beta two months ago and will buy the 2.0 release too.
regards
phil
phil@bluedynamics.com
*********** REPLY SEPARATOR ***********
On 07.03.2001 at 14:07 Bryan Baszczewski wrote:
>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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