How Is Data Files(s) Used (MB) calculated?

question
1

As per the screenshot below, does anybody know how the Data Files(s) Used (MB) figure is calculated?

Capture
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I thought it might be the amount of data stored in each of the Hangfire tables, so I ran

EXEC sp_spaceused 'tablename'

for each of the tables prefixed with Hangfire, i.e.:

EXEC sp_spaceused 'Hangfire.AggregatedCounter'
EXEC sp_spaceused 'Hangfire.Counter'
EXEC sp_spaceused 'Hangfire.Hash'
EXEC sp_spaceused 'Hangfire.Job'
EXEC sp_spaceused 'Hangfire.JobParameter'
EXEC sp_spaceused 'Hangfire.JobQueue'
EXEC sp_spaceused 'Hangfire.List'
EXEC sp_spaceused 'Hangfire.Schema'
EXEC sp_spaceused 'Hangfire.Server'
EXEC sp_spaceused 'Hangfire.Set'
EXEC sp_spaceused 'Hangfire.State'

Summing up the ‘data’ column returned for each of the stored procs run gave me 565120 KB (565.12 MB) so not even close to the 273157.63 MB figure displayed.

It doesn’t correlate with the size of my entire database either (which I got by running EXEC sp_helpdb) and which returns 425789.44 MB for the ‘db_size’ column, so far greater than the dashboard figure shown.

2

I checked the source code of Hangfire available in github. The logic how the metrics values are calculated is implemented in this file: https://github.com/HangfireIO/Hangfire/blob/main/src/Hangfire.SqlServer/SqlServerStorage.cs

The data files size is calculated using this sql query:

select SUM(CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0) as RowsSizeMB from sys.database_files where type = 0;