Logging Performance
A complete set of performance tests were run against each level noted above as relevant, and those results were captured in a separate document, called Qlik Sense Telemetry Logging Impacts – June 2018.doc.
A summary of those test results is shown here, for a test of 200 concurrent users hitting 8 apps simultaneously:
Having WARN level logging for the QIXPerformance_Engine log produced a small increase in response times (1.4%) over the OFF log level (no logging).
Having INFO level logging for the QIXPerformance_Engine log produced a larger increase in response times (7.0%) over the OFF log level (no logging).
Having WARN level logging for the QIXPerformance_Engine log produced a small decrease in % Processor Time (.92%) under the OFF log level (no logging).
Having INFO level logging for the QIXPerformance_Engine log produced a larger increase in % Processor time (4.1%) over the OFF log level (no logging).
Having WARN level logging for the QIXPerformance_Engine log produced a small decrease in Average IO Data Ops/Sec (.3%) under the OFF log level (no logging).
Having INFO level logging for the QIXPerformance_Engine log produced a very large increase in Average IO Data Ops/Sec (178.9%) over the OFF log level (no logging).
Having OFF level logging for the QIXPerformance_Engine log produced no records (0).
Having WARN level logging for the QIXPerformance_Engine log produced 784 records, with a total disk size (across segmented logs) of .4 mb.
Having INFO level logging for the QIXPerformance_Engine log produced 352,498 records, with a total disk size (across segmented logs) of 180 mb.
Note: these numbers will vary with actual usage, depending on the number of users, selections and objects in the apps.