Isidor Zeuner wrote: > Dear MonetDB developers, Dear Isidor, MonetDB/SQL follows an optimistic concurrency control scheme. One of the properties of OCC is that it does not lock the database, except for validation of potential conflicts between the r/w sets. As such, it favors low update frequency.
There are no facilities to control, take control over this behavior. If you aim for a (extreme) high update rates you could consider a master/slave setup, where the master executes the update in serial way. In most cases this is more efficient as well. Alternatively, a middleware layer can perform a coarse grain locking scheme. regards, Martin > > on concurrently running writing transactions, I am getting a rather > narrowly descriptive error message: "!SQLException:sql.trans:COMMIT: > failed". > > My first attempts to deal with this issue suggest that it happens > exactly in those cases where the concurrent writes create some sort of > conflict. > > I am aware that MonetDB does not focus on concurrency, and of the > suggestion to serialize multiple writers. However, I'd like to > know what the current status of concurrency is. To what extent are SQL > primitives implemented which allow to let the server take care of > serializing writes, for example through explicit table locking or > transaction isolation? > > Best regards, > > Isidor Zeuner > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Monetdb-developers mailing list > Monetdb-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/monetdb-developers ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Monetdb-developers mailing list Monetdb-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-developers
