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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.
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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 out of in the total number of XPDLs.
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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 unsed 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.
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