[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [wsbpel-comment] Isolated scope semantics
Hello Artem, the semantics of isolated scopes w.r.t. concurrent access to variables follows the serializability semantics for concurrent transaction executions. However, the language in the WS-BPEL 2.0 standard, section 12.8.: "Suppose two concurrent isolated scopes, S1 and S2, access a common set of variables and partner links (external to them) for read or write operations. The semantics of isolated scopes ensure that the results would be no different if all conflicting activities (read/write and write/write activities) on all shared variables and partner links were conceptually reordered so that either all such activities within S1 are completed before any in S2 or vice versa. (...) The actual mechanisms used to ensure this are implementation dependent." leaves it to the implementation whether it completely serializes the execution of isolated scopes concurrently accessing variables or allows some degree of overlapping execution. Typically, overlapping execution of isolated scopes can be allowed up to the point of the first access to a concurrently accessed variable, without any limitation w.r.t. their contained control flow. This is different from the Interleaved Parallel Routing pattern where "no two activities from the set of activities subject to interleaved parallel routing may be executed at the same time". HTH Kind Regards DK Dieter König Mail: dieterkoenig@de.ibm.com IBM Deutschland Entwicklung GmbH Senior Technical Staff Member Tel (office): (+49) 7031-16-3426 Vorsitzender des Aufsichtsrats: Martin Jetter Architect, Business Process Fax (office): (+49) 7031-16-4890 Geschäftsführung: Herbert Kircher Choreographer Member, Technical Expert Council Tel (home office): (+49) 7032-201464 Sitz der Gesellschaft: Böblingen Schönaicher Strasse 220, 71032 Registergericht: Amtsgericht Böblingen, Germany Stuttgart, HRB 243294 From: "Artem Polyvyanyy" <artem.polyvyanyy@hpi.uni-potsdam.de> To: <wsbpel-comment@lists.oasis-open.org> Date: 10.12.2007 14:15 Subject: [wsbpel-comment] Isolated scope semantics Hello, I want to clarify the semantics of the Isolated Scope as defined in "Web Services Business Process Execution Language Version 2.0" specification. Let's define a use case as a process with two concurrent isolated scopes that work on a shared set of variables. What is the correct semantics of such process? a) 2 isolated scopes are seen as database serialization transactions. Once you enter each scope you work with the snapshot of variable values you observed. So commits in one scope will be not seen in the second scope; b) Within one (or) both scopes all the activities are done sequentially (no parallelism allowed); c) Not depending on which order you will execute activities from one (or both) scope(s) the end results on variables will be the same ??!! d) Another one. I ask because what I read and what I discuss with people varies. I am particularly interested in isolated scopes application for modeling interleaved parallel routing workflow pattern and it's relation to the fact that isolated scope might contain control flow. Best regards, Artem This publicly archived list offers a means to provide input to the OASIS Web Services Business Process Execution Language (WSBPEL) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: wsbpel-comment-subscribe@lists.oasis-open.org Unsubscribe: wsbpel-comment-unsubscribe@lists.oasis-open.org List help: wsbpel-comment-help@lists.oasis-open.org List archive: http://lists.oasis-open.org/archives/wsbpel-comment/ Feedback License: http://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: http://www.oasis-open.org/maillists/guidelines.php Committee: http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsbpel
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]