In development server, due to the fact that process design will always get updated and developed, there will be more and more XPDLs cached in the memory. In the long run, this may cause "java.lang.OutOfMemoryError" exception during runtime or server startup. To solve this issue, we will need to clean up the unused XPDLs with following steps. The following example queries are written in MySQL and MSSQL syntax.
1. Please shutdown your application server.
2. Please do a full database backup before proceeding to the following steps.
1. Check existing count of XPDLs
On a common production server, normally there are only few app versions and each version only tied to 1 process version. This is because we won't do any development in production server, so the process version is only increased during the app imported. But in the development server, it will be a different case. The process version will be going up to few hundred process version which also means there are few hundred of XPDL data are cached in memory. To check how many XPDLs are cached, please run the following query in your database server.
2. Check the count of unused XPDLs
In all the cached process version XPDLs, there is a case that some process version is not used by any process instances. These unused XPDLs can be safely deleted. The check the number of unused XPDLs, we can use the following query. Then, we can know how many are unused in the total number of XPDLs.
If you would like to list the process versions, you can use the following query.
3. Delete completed process instances data to clean up more XPDLs from cache
If the process instances data are not important to you or you have your process instance data captured a copy by the Process Data Collector plugin, you can delete your process instances data to increase the number of unused XPDLs. In this case, only the process version for running process instances and the latest process version for each app version will be kept.
If you would like to clean the all the process instances data including the running process instances, you can use the following query.
4. Delete the unused XDPLs
Now, you can delete the unused XPDLs and it will be free from your memory cache when next server startup.