Adding Database IO Tempdb per Azure DB collection, Fixing PerfmonV2 collection for on-prem

[denzilribeiro]

Required for all PRs:

• [X ] Signed CLA.
• Associated README.md updated.
• [] Has appropriate unit tests.

Datababase IO changes
Today on Azure SQL DB there was a bug where left outer join from virtual file stats and database_files was only on file_id. Tempdb was exposed on virtual file stats, but not in Database files. On Azure SQL DB have to use tempdb.sys.database_files. In addition each Azure SQL DB has its own tempdb so needed to add Database_id/File ID to be able to distinguish so that reporting can be done by Logical Server + Azure DB + database_id. If you just looked at tempdb for a logical server would get multiple tempdb's belonging to different Azure SQL DB's as the logical server construct is just that a placeholder logical server not actual physical server.
Also corrected bug introduced earlier

PerfmonV2 Fix for #7164

[denzilribeiro]

@Trovalo overlapped with your PR #7161 just submitted as I was in process of submitting didn't realize - can you take a look at this one and see if addresses issues as I also added additional logic to pull tempdb IO for Azure SQL so is a bit more than the bug fix

[Trovalo]

I will have a look at it in a few minutes.

But I found a bigger problem while testing the whole plugin on multiple versions earlier.
While testing on SQL 2012. SQL 2019 and Azure SQL DB, I get an error

I! Invalid column name 'physical_database_name'.
E! [inputs.sqlserver] Error in plugin: mssql: Invalid column name 'physical_database_name'.

It is caused by the latest changes (January) made to the query and not yet published (in fact those are not in telegraf 1.13.4).
The field [physical_database_name] exists only in azure SQL DB and SQL Server 2019. Any other version will fail to gather the metrics due to a validation error.

I'm opening an issue now, the best solution probably is to add dynamic SQL, so it is not validated by SQL Server until it has to execute it

[denzilribeiro]

I will add the dynamic SQL and resubmit shortly

[denzilribeiro]

@Trovalo - actually go ahead and open an issue for that as is in a different part not IO :) misunderstood

[Trovalo]

I did it few minutes ago
#7164

[Trovalo]

I've cloned and tested this on SQL 2012, SQL 2019 and Azure SQL DB (even if the issue was only on the last one).
It works perfectly.

[denzilribeiro]

@Trovalo - one last validation - pushed commit for the Perfmon counters too

[Trovalo]

I will run the tests tomorrow morning and let you know

[Trovalo]

I've tested the latest changes and everything works fine from SQL 2012 to SQL 2019 (On-Prem) and also on Azure SQL DB.

You still get an error in the 'Scheduler' query which is not compatible before SQL 2016 but there is already an issue and related PR for that. (see #7144)