This document explains how caching works in Vizit and outlines the configurations that can be made to ensure optimal performance. It also addresses a few areas where additional troubleshooting may be required. Vizit Essential and Vizit Pro use two different caching techniques due to their intended use cases and both of these caches are described below.
Documents viewed in Vizit Essential are stored in SharePoint's content database. More specifically, they are stored as Files in an Document LIbrary in the root web of the Site Collection that the original file resides. This location is not configurable, but it is cleaned continuously by timer job which removes documents that have not been viewed in a 36 hour window.
Documents are identified in the cache by their URL, last modified date, and version of Vizit. If a document that had been cached is modified, there will be no item in the cache that matches. Because of this, a new cached copy will be created the next time that the document is opened in Vizit Essential. The previously cached file will be cleaned up 36 hours after it was last viewed. This technique is employed so that users will not be interrupted if they are viewing documents that are modified or deleted during their session.
Vizit Essential's cache folder is locked down to the SharePoint SystemAccount. Only this user can read or modify files in this directory.
Documents viewed or modified in Vizit Pro are stored in a Temp directory on the Web Front End that is being accessed by the end user. One of Vizit Pro's intended use cases is to modify documents (Rotate Pages, Rearrange, Split, Merge, etc). Because of this, a working file is created when a document is opened.
Local Caching is used in Vizit Pro to cache files locally on the Web Front End that is serving out files to the end user. In the Local Path field on the Configure Caches page in Central Administration, Environment variables can be used, such as %SystemRoot% to make setting that path easier for scenarios where there are multiple Web Front Ends.
As an example, %SystemDrive%\Temp would resolve to C:\Temp. You must enter a path that exists on all Web Front Ends. This must not be a UNC path. If this field is left blank, it defaults to the running IIS Application Pool identity's TEMP directory.
Vizit requires Session Affinity for Vizit Pro cache.
Vizit Pro's cache is locked down to the IIS Application Pool user. Only this user has access to read or modify files in that directory. Because of this, if the IIS Application Pool account is changed, you will experience Unauthorized Access exceptions when using Vizit Pro. To remedy this issue, you must navigate to the Vizit Pro's cache folder, take ownership of it, and delete it.