Version

Argent Advanced Technology 3.1A-1407-A and later

Date

Tuesday, 2 Sep 2014

Summary

When running Windows Performance Rule in dynamic pool, the Rule can fail with PDH error 0x102 and no data is collected

The issue happens intermittently

It is directly related to how busy the system is

A typical error logged in trace log is shown as following:

This Microsoft bug has been circumvented in Argent AT 3.1A-1407-T3

Technical Background

Microsoft reveals the internals of PDH to be as following:

Basically PDH uses internal mutex to synchronize access

PDH is a top level wrapper around RegQueryValueEx(HKEY_PERFORMANCE_DATA, …)

Even though the application can create a query and add/monitor counters from multiple threads, we internally have a timeout to break the call

If PDH gets more than a single request (any PDH call) per process at a time, PDH implementation will block the second call until the first one completes

It is up to the application to recover from this error code when PDH is used from multiple threads

In other words, PDH is single threaded but is not documented as such

Argent AT 3.1A-1407-T3 has implemented the retry mechanism to recover from the Microsoft error

Resolution

Upgrade to Argent Advanced Technology 3.1A-1407-T3 or later

For customer who experiences such an issue and cannot upgrade immediately, he may use the Relator option ‘Spawn New Monitoring Engine Process‘ to avoid the issue

But as nothing in life is free, this can add additional load to the operating system