topic Re: how process instance know, the next step to execute in Alfresco Archive

how process instance know, the next step to execute

meenakshi — Fri, 01 May 2015 13:55:47 GMT

Hi,I would like to know how bpm files processed. When We Configure xml file like below then what happens . <bean id="processEngineConfiguration" class="org.activiti.spring.SpringProcessEngineConfiguration"> <property name="deploymentResources" > <list> <value>

Re: how process instance know, the next step to execute

balsarori — Sun, 03 May 2015 20:32:55 GMT

I would recommend that you read 6.3. Versioning of process definitions section of the user guide

http://activiti.org/userguide/index.html

ACT_RE_PROCDEF table contains the basic information of process definitions, the actual bpm file is stored in the ACT_GE_BYTEARRAY table. Process instances information are saved in ACT_HI_PROCINST table which contains a reference to the process definition (including the specific version) used.

Re: how process instance know, the next step to execute

meenakshi — Tue, 05 May 2015 00:12:29 GMT

Thanks for the answer!
So whenever server is restarted the bytecode taken from the database, parsed and loaded in to the memory?

Re: how process instance know, the next step to execute

balsarori — Tue, 05 May 2015 02:16:44 GMT

Only when needed. Whenever bytecode (xml of a process definition) is requested or needed it's fetched from the database, parsed and loaded into memory.

Re: how process instance know, the next step to execute

meenakshi — Tue, 05 May 2015 09:27:43 GMT

What does mean by whenever needed? Do you mean when taskService.complete() called that time also it happens? It takes the corresponding process, parse, load and then see which step to execute next?

Re: how process instance know, the next step to execute

balsarori — Tue, 05 May 2015 14:23:03 GMT

Means that not all process definitions are loaded to memory at once. Only when an operation that involves dealing with a process definition that isn't loaded it gets fetched from the database, parsed, and loaded to memory.

Re: how process instance know, the next step to execute

meenakshi — Tue, 05 May 2015 15:17:49 GMT

Operation means taskService.complete(taskId) or something else?

Re: how process instance know, the next step to execute

jbarrez — Thu, 07 May 2015 13:10:46 GMT

Any operation that need a process definition. Complete task is but one example

Re: how process instance know, the next step to execute

meenakshi — Fri, 08 May 2015 09:46:00 GMT

Thanks!
So whenever I invoke the sub workflow through callActivity , that time sub workflow will be parsed and loaded into the memory, Is this not the performance hit?
And in multi jvm environment, how it works , if one JVM is already loaded one bpm in memory and second time , if it goes to second JVM, then even if it is second time operation and not loaded in second jvm it will again parse and load in memory?

Re: how process instance know, the next step to execute

trademak — Wed, 13 May 2015 12:53:35 GMT

It's only happening on the first occurrence, and the parsing is quite fast.
In a multi JVM environment, all engines will have their own process definition cache, so yes, every engine loads the process definition.

Best regards,