There was a question in this forum about Extended Event module_end duration unit, which I answered. Details here.

Is it always in microseconds for all events?

2 Answers 2


It is a mix of Millisecond, Microsecond and some are unknown. Easiest way to find I used below tsql code to determine which is what.

SELECT p.name package_name,
       o.name event_name,
       c.name event_field,
       DurationUnit= CASE
                         WHEN c.description LIKE '%milli%' 
                         THEN SUBSTRING(c.description, CHARINDEX('milli', c.description),12)
                         WHEN c.description LIKE '%micro%' 
                         THEN SUBSTRING(c.description, CHARINDEX('micro', c.description),12)
                         ELSE NULL
       c.type_name field_type,
       c.column_type column_type
FROM sys.dm_xe_objects o
JOIN sys.dm_xe_packages p ON o.package_guid = p.guid
JOIN sys.dm_xe_object_columns c ON o.name = c.object_name
WHERE o.object_type = 'event'
AND c.name ='duration'

Here is the result set from a SQL 2016 SP1 server. I only posting part of it. Look at the DurationUnit column and you can see 3 different values.

enter image description here

For NULL ones I find the best option is to run (if possible with start and end time) and find what the unit is.

I ran the same query against vnext SQL Server and confirmed we will carry the same confusion to the future.


You can also 'crack open' the XE Session in SSMS and check out the details in the 'configure' part of the Events tab - as the description for duration fields typically provides the unit of time being used.

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