#3690 sp_Blitz memory pressure

Add warning about low memory recently. Closes #3690.

Author: BrentOzar

Documentation/sp_Blitz_Checks_by_Priority.md

@@ -6,8 +6,8 @@ Before adding a new check, make sure to add a Github issue for it first, and hav
 
 If you want to change anything about a check - the priority, finding, URL, or ID - open a Github issue first. The relevant scripts have to be updated too.
 
-CURRENT HIGH CHECKID: 269.
-If you want to add a new one, start at 270.
+CURRENT HIGH CHECKID: 270.
+If you want to add a new one, start at 271.
 
 | Priority | FindingsGroup | Finding | URL | CheckID |
 |----------|-----------------------------|---------------------------------------------------------|------------------------------------------------------------------------|----------|
@@ -26,6 +26,7 @@ If you want to add a new one, start at 270.
 | 1 | Corruption | Database Corruption Detected | https://www.BrentOzar.com/go/repair | 90 |
 | 1 | Performance | Memory Dangerously Low | https://www.BrentOzar.com/go/max | 51 |
 | 1 | Performance | Memory Dangerously Low in NUMA Nodes | https://www.BrentOzar.com/go/max | 159 |
+| 1 | Performance | Memory Dangerously Low Recently | https://www.BrentOzar.com/go/memhistory | 270 |
 | 1 | Reliability | Evaluation Edition | https://www.BrentOzar.com/go/workgroup | 229 |
 | 1 | Reliability | Last good DBCC CHECKDB over 2 weeks old | https://www.BrentOzar.com/go/checkdb | 68 |
 | 1 | Security | Dangerous Service Account | https://vladdba.com/SQLServerSvcAccount | 258 |

sp_Blitz.sql

@@ -3936,6 +3936,38 @@ AS
 									AND SUM([wait_time_ms]) > 60000;
 						END;
 
+					IF NOT EXISTS ( SELECT 1
+										 FROM   #SkipChecks
+										 WHERE  DatabaseName IS NULL AND CheckID = 270 )
+						AND EXISTS (SELECT * FROM sys.all_objects WHERE name = 'dm_os_memory_health_history')
+						BEGIN
+
+							IF @Debug IN (1, 2) RAISERROR('Running CheckId [%d].', 0, 1, 270) WITH NOWAIT;
+
+							INSERT  INTO #BlitzResults
+									( CheckID ,
+									  Priority ,
+									  FindingsGroup ,
+									  Finding ,
+									  URL ,
+									  Details
+									)
+									SELECT  270 AS CheckID ,
+											1 AS Priority ,
+											'Performance' AS FindingGroup ,
+											'Memory Dangerous Low Recently'  AS Finding ,
+											'https://www.brentozar.com/go/memhist' AS URL ,
+											CAST(SUM(1) AS NVARCHAR(10)) + N' instances of ' + CAST(severity_level_desc AS NVARCHAR(100))
+											+ N' severity level memory issues reported in the last 4 hours in sys.dm_os_memory_health_history.'
+									FROM sys.dm_os_memory_health_history
+									WHERE severity_level > 1
+									GROUP BY severity_level, severity_level_desc;
+						END;
+
+
+
+
+
 					IF NOT EXISTS ( SELECT 1
 										 FROM   #SkipChecks
 										 WHERE  DatabaseName IS NULL AND CheckID = 121 )