Out of nowhere we started seeing this error and it seems to occur fairly frequently when making calls to the database or any other database in our Elastic Pool. The DTUs aren't being maxed out and the resource dmvs don't seem bad.
Failed to enter Common Language Runtime (CLR) with HRESULT
0x80131022. This may be due to low resource conditions. (db)
Here's what I got from the system resource governor pool
Resource Pool Name cache_memory (MB) used_memory (MB)
internal 104.773437 1577.125000
default 37.609375 38.796875
SloSecSharedPool 2.914062 8.156250
InMemBackupRestorePool 26.210937 101.437500
InMemDmvCollectorPool 186.195312 203.406250
InMemMetricsDownloaderPool 2.234375 2.250000
InMemDTAPool 0.000000 0.000000
SloHkPool 0.000000 0.031250
InMemQueryStorePool 22.453125 35.304687
InMemWIAutoTuningPool 3.312500 4.062500
InMemXdbLoginPool 3.976562 6.250000
PVSCleanerPool 0.000000 0.000000
InMemTdeScanPool 0.000000 0.000000
SloSharedPool1 1108.890625 1234.312500
From the sys.dm_os_performance_counters this is what it looks like for the past 3 hours.
cpu% data_io% log_write% memory_usage% max_worker% sessions%
22.37 73.51 16.54 41.56 5.50 0.43
This doesn't seem like a common error for SQL Azure as I cannot find anything that pertains to this happening past SQL Server 2008. Any help would be appreciated.
Update:
We got a response from the Microsoft support rep and it looks like our memory usage was completely capped out.
After moving the elastic pool up a tier the error has gone away. We have ~56GB of memory instead of the ~28GB we had previously and the error ceased. This would have probably also moved us to a different server on Azure which may have fixed the problem for now. The site has been running at around 78% on memory usage with the buffer cache hit ratio @ 8588 and PLE of 87332. Now it's operating at usage under 2% across the board for CPU, Workers, DataIO, etc. during normal load which seems like a huge waste.
We could not definitively identify what was causing the errors but we assume it was the complete memory usage as the site is running fine for now…
Best Answer
While Azure SQL Database (not the new Managed Instance) does not support custom SQLCLR Assemblies (i.e. the "CLR enabled" server-level configuration option), CLR is still used internally for the following features:
FORMAT
PARSE
TRY_PARSE
AT TIME ZONE
COMPRESS
DECOMPRESS
sys.time_zone_info
sp_FuzzyLookupTableMaintenanceInvoke
, etc)Of course, this does not point to what would be hogging memory. But it should help identify the affected area(s).