Version numbering and Caching.

PSVERSION table in peoplesoft stores an acronym for each object type e.g. RDM (Record Data Management), UPM(User Profile Management) etc. It is updated by the panel processor (component processor) and every time the peoplesoft component processor attempts to retrieve an object definition, it first checks the PSVERSION table which provides the most updated version of that specific object type. Whenever an object definition is changed, this table is updated i.e. if a record definition is updated through application designer, its version in PSRECDEFN is first updated and afterwards the application updates the PSVERSION table.

The application server compares the version number from the OBJTYPE.KEY file (e.g. RDM.KEY cache file) to that in the PSVERSION. If PSVERSION.VERSION is greater than that of IDX (the .KEY cache file) then it will retrieve object from database and OBJTYPE.DAT (e.g. RDM.DAT cache file) will be updated with the latest version of the object.

The PSxxxDEFN.VERSION must be less or equal to PSVERSION.VERSION for the corresponding object type name in order to application server's caching algorithm to work. To repair application server caching, we run VERSION AE program.

Generally, PSVERSION and PSLOCK, both the tables should have to be in sync, however the discrepancies are resolved by running the VERSION application engine from command line. It resets version number on all definition tables, PSVERSION and PSLOCK.

* Clear cache for two tier clients after running the VERSION app engine.

Application Server Caching - caching enables the application server to store object definitions locally on app server, thus eliminating unnecessary trips to database server. If caching were disabled, the system would need to retrieve definitions from database tables every time for each request which would add significant overhead to each transaction and adversely affect system response time.

Peoplesoft provides two types of app server caching -

1) Non-Shared Cache - enabled by default. In this mode, each server process maintains its own separate cache file.
2) Shared Cache - to enable this mode, set ServerCacheMode=1. In this configuration, system assumes that a pre-loaded cache exists. When application server is booted and it finds no cache, then it reverts to non-shared cache mode.


* The delivered application engine program- LOADCACHE preloads the cache. Before loading the shared cache, run SYSAUDIT report and make sure that it is clean otherwise cache loading may fail.