Initial updates in a ViewApp with more than 50,000 I/O may take several minutes


In a ViewApp with an overview graphic that has more than 50,000 I/O, initial updates can take up to several minutes for engines that are providing data in excess of the initial 50,000 I/O.

Application Version:

  • Wonderware System Platform 2017



When you start up the ViewApp and open a window with an overview graphic having more than 50,000 I/O, you will see the following info message in the SMC logger.

PreboundReference cache limit read from registry is XXXX entries.

You might also see this message:

Prebound Reference cache contains xxxxx entries, removing yyyy least recently used entries


The default LMX Prebound Reference cache limit is 50,000.




You can configure the cache limit in the registry. The physical registry entry does not exist, but by adding the entry, you can override the default.

Complete the following steps to modify the cache limit.

  1. Open Registry (Run regedit)
  2. Locate the following registry key:On 32 bit machines:


    On 64 bit machines:


  3. Create a DWORD value and name it PreboundReferenceCacheLimit.
  4. Set the value for this new DWORD entry to > 50,000 (for example, 200,000).
  5. Close the registry.
  6. Start the ViewApp and check for the following info message in the SMC logger:PreboundReference cache limit read from registry is xxxxxx entries (xxxxxx should match the DWORD value the registry)


  • You can add the registry key at any time. The new limit value takes effect the next time you start a ViewApp on that machine.
  • You can apply this workaround to any platform running a ViewApp with a total number of item references greater than 50,000 if enough memory is available and faster performance is needed.


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