Merge pull request #292 from erikdarlingdata/worktree-issue-287-qs-detection

Issue #287: Use database_query_store_options for QS detection

Author: erikdarlingdata

Lite/Services/RemoteCollectorService.QueryStore.cs

@@ -26,20 +26,69 @@ public partial class RemoteCollectorService
     /// </summary>
     private async Task<int> CollectQueryStoreAsync(ServerConnection server, CancellationToken cancellationToken)
     {
-        /* First, get databases with Query Store enabled */
+        /* First, get databases with Query Store actually enabled.
+           Uses sys.database_query_store_options.actual_state instead of
+           sys.databases.is_query_store_on, which can be out of sync on Azure SQL DB. */
         const string dbQuery = @"
+SET NOCOUNT ON;
 SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
 
-SELECT /* PerformanceMonitorLite */
-    d.name
-FROM sys.databases AS d
-WHERE d.is_query_store_on = 1
-AND   d.database_id > 4
-AND   d.database_id < 32761
-AND   d.state_desc = N'ONLINE'
-AND   d.name <> N'PerformanceMonitor'
-ORDER BY d.name
-OPTION(RECOMPILE);";
+DECLARE
+    @result TABLE (name sysname);
+
+DECLARE
+    @db sysname,
+    @sql NVARCHAR(500);
+
+DECLARE db_check CURSOR LOCAL FAST_FORWARD FOR
+    SELECT /* PerformanceMonitorLite */
+        d.name
+    FROM sys.databases AS d
+    WHERE d.database_id > 4
+    AND   d.database_id < 32761
+    AND   d.state_desc = N'ONLINE'
+    AND   d.name <> N'PerformanceMonitor'
+    OPTION(RECOMPILE);
+
+OPEN db_check;
+
+FETCH NEXT
+FROM db_check
+INTO @db;
+
+WHILE @@FETCH_STATUS = 0
+BEGIN
+    BEGIN TRY
+        SET @sql =
+            N'USE ' + QUOTENAME(@db) + N';
+            SELECT ' + QUOTENAME(@db, '''') + N'
+            WHERE EXISTS
+            (
+                SELECT
+                    1
+                FROM sys.database_query_store_options
+                WHERE actual_state > 0
+            );';
+
+        INSERT @result (name)
+        EXEC(@sql);
+    END TRY
+    BEGIN CATCH
+    END CATCH;
+
+    FETCH NEXT
+    FROM db_check
+    INTO @db;
+END;
+
+CLOSE db_check;
+DEALLOCATE db_check;
+
+SELECT
+    name
+FROM @result
+ORDER BY
+    name;";
 
         var serverId = GetServerId(server);
         var collectionTime = DateTime.UtcNow;

install/09_collect_query_store.sql

@@ -265,33 +265,88 @@ BEGIN
         );
 
         /*
-        Loop through databases where Query Store is enabled
+        Build list of databases where Query Store is actually enabled.
+        Uses sys.database_query_store_options.actual_state instead of
+        sys.databases.is_query_store_on, which can be out of sync on Azure SQL DB.
         */
         DECLARE
-            @database_name sysname;
-
-        DECLARE @database_cursor CURSOR 
-        
-            SET @database_cursor = 
-                CURSOR 
-                LOCAL 
-                FAST_FORWARD 
+            @database_name sysname,
+            @qs_check_sql NVARCHAR(500);
+
+        DECLARE
+            @qs_databases TABLE (name sysname);
+
+        DECLARE @db_check_cursor CURSOR
+
+            SET @db_check_cursor =
+                CURSOR
+                LOCAL
+                FAST_FORWARD
             FOR
             SELECT
                 d.name
             FROM sys.databases AS d
             WHERE d.state_desc = N'ONLINE'
             AND   d.database_id > 4
             AND   d.is_read_only = 0
-            AND   d.is_query_store_on = 1
             AND   d.name <> N'PerformanceMonitor'
             AND   d.database_id < 32761 /*exclude contained AG system databases*/
             OPTION(RECOMPILE);
 
+        OPEN @db_check_cursor;
+
+        FETCH NEXT
+        FROM @db_check_cursor
+        INTO @database_name;
+
+        WHILE @@FETCH_STATUS = 0
+        BEGIN
+            BEGIN TRY
+                SET @qs_check_sql =
+                    N'USE ' + QUOTENAME(@database_name) + N';
+                    SELECT ' + QUOTENAME(@database_name, '''') + N'
+                    WHERE EXISTS
+                    (
+                        SELECT
+                            1
+                        FROM sys.database_query_store_options
+                        WHERE actual_state > 0
+                    );';
+
+                INSERT @qs_databases (name)
+                EXEC(@qs_check_sql);
+            END TRY
+            BEGIN CATCH
+            END CATCH;
+
+            FETCH NEXT
+            FROM @db_check_cursor
+            INTO @database_name;
+        END;
+
+        CLOSE @db_check_cursor;
+        DEALLOCATE @db_check_cursor;
+
+        /*
+        Loop through databases where Query Store is enabled
+        */
+        DECLARE @database_cursor CURSOR
+
+            SET @database_cursor =
+                CURSOR
+                LOCAL
+                FAST_FORWARD
+            FOR
+            SELECT
+                q.name
+            FROM @qs_databases AS q
+            ORDER BY
+                q.name;
+
         OPEN @database_cursor;
 
-        FETCH NEXT 
-        FROM @database_cursor 
+        FETCH NEXT
+        FROM @database_cursor
         INTO @database_name;
 
         WHILE @@FETCH_STATUS = 0