Andre Reitz wrote: > > We have a big problem, > > We have a client-server Application running on sapdb with > a multithreaded python server as a middleware. > > This means: one Multithreaded program which has several > connections on the database (all under the same database user > account). > > > Our Problem: > > - Sometimes the System blocks > > The possible causes: (we think so) > > - We forgot a "commit" in our application > - Sapdb runs out of free locks or any other resources > > Our Questions: > > - Is Isolation Level 1 (or 10) the default of the python driver? > - Do selected rows also get locked in Isolation Level 1?
Usually they are not locked. But there exist kernel-versions in which a row is selected, but updated by another transaction. It then has to wait for the release of that update/insert/delete-lock, i.e. has to wait for the commit/rollback of the other transaction. Then it will have a lock afterwards. > - If they get locked, is there a limit (maximum of row locks) YES, the installation parameter MAXLOCKS, (default:2500) > which can lead > to the blocking because the system runs out of resources > (or something similar)? > (in other words:) No, should not block, should return an error Please check the output of the systemtable LOCKS in the case of blocking database. And please check the value of the parameter REQUEST_TIMEOUT. > - Our applications sends many many selects without a > following commit/rollback. > Only when data is inserted/updated/deleted, the clients > send a commit/rollback. > Is it possible that the selects will lead to a deadlock? Possible: yes Elke SAP Labs Berlin > > - What about the parameter DEADLOCK_DETECTION (my value currently: 4)? > does it use very much resources if i set it to a higher value? > does it make sense to set it highter? > > > > Thank you very much in advance, > Greetings and best regards, Andre' > > -- > _____________________________________________ > inworks GmbH Andre Reitz > H�rvelsinger Weg 39 Tel. 0731/93 80 7-21 > 89081 Ulm http://www.inworks.de > > _______________________________________________ > sapdb.general mailing list > [EMAIL PROTECTED] > http://listserv.sap.com/mailman/listinfo/sapdb.general > _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
