[GetCatalogExtendedContentData] procedure killing server

I'm not sure if this is useful. But the SSRS ReportServer DB has two tables in it worth looking at

NOTE MS deliberately don't provide much (if any) documentation on this stuff as they may change the schema/behaviour entirely in any given SSRS release.

dbo.Catalog which holds the information about the reports. If the thing is an old fashioned SSRS report or a KPI etc the actual definition (the content of the RDL file) is held in the Content column

The Type column in this has previously been documented as (I can't remember wher I got this list)

1 = Folder
2 = Report
3 = Resources
4 = Linked Report
5 = Data Source
6 = Report Model
7 = Report Part (SQL 2008 R2, unverified)
8 = Shared Dataset (SQL 2008 R2)

we do seem to have a new type value of 13 which is a PBIX report

When the report is a PBIX report then you will see that the content column of dbo.Catalog is NULL

At this point you can take a look in dbo.CatalogItemExtendedContent table and you will see multiple rows for the PBIX each with a different ContentType

CatalogItem
DataModel
PowerBIReportDefinition

So when you save a report onto the PBI-SSRSS Server you get the actual PBIX file (PowerBIReportDefinition) it also gets split into its visualisation (CatalogItem) and the compressed data blob (DataModel) this is so that scheduled refresh of the data can push data into just the data blob.

When you view a report the datablob gets spun up in a cpative SSAS instance and the visualisation bit gets sent to be rendered on the client, the two are hooked togetehr with some services so as the usre clicks aorund new queries get generated and sent to the data model and returned to the client to be re-rendered.

So I suspect you've got somehting funny going on with the fetch of the content blobs.

You can take a look at the sizes of these using a query like this

SELECT	c.Path,
		c.Name
	   ,cic.ContentType
	   ,CAST(LEN(cic.Content) AS MONEY) / CAST(1024 * 1024 AS MONEY) AS ContentMb
	   ,cic.ModifiedDate
FROM	dbo.CatalogItemExtendedContent cic
			LEFT OUTER JOIN dbo.Catalog c
				ON c.ItemID = cic.ItemId
ORDER BY c.Path, c.Name, c.ItemID

I do find that once the data blob gets beyond a certain size the server does feel unresponsive at certain points.

Quite how all this is handled when the data blob is being refreshed I'm not entirely sure. DOes a read get blocked while a refresh happens?

I would speculate that the data blob for the example you are looking at is pretty sizeable and that may be part of your problem.

While this isn't an answer, I hope it will point you at some things to look at or investigate that might help.

regards

Steve