Fix query_stats collector causing SQL dumps on passive mirrors (#632)

Removed CROSS APPLY sys.dm_exec_plan_attributes and the direct
sys.databases join. Both dm_exec_plan_attributes and dm_exec_sql_text
can trigger severity 22 engine crashes when plan handles reference
RESTORING databases on passive mirror servers.

Now pre-builds a temp table of ONLINE, accessible database IDs
(filtered by state = 0 + HAS_DBACCESS) before the main query runs.
The staging INSERT joins to this temp table instead of sys.databases,
preventing any DMV from being evaluated against RESTORING databases.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: erikdarlingdata

install/08_collect_query_stats.sql

@@ -222,6 +222,38 @@ BEGIN
             row_hash binary(32) NULL
         );
 
+        /*
+        Pre-build list of ONLINE, accessible database IDs.
+        This prevents any downstream DMV calls (dm_exec_sql_text,
+        dm_exec_plan_attributes) from touching RESTORING databases
+        on passive mirror servers — which triggers severity 22 dumps.
+        */
+        CREATE TABLE 
+            #online_databases
+        (
+            database_id integer NOT NULL PRIMARY KEY,
+            database_name sysname NOT NULL
+        );
+
+        INSERT INTO 
+            #online_databases
+        (
+            database_id,
+            database_name
+        )
+        SELECT
+            d.database_id,
+            d.name
+        FROM sys.databases AS d
+        WHERE d.state = 0
+        AND   HAS_DBACCESS(d.name) = 1
+        AND   d.database_id NOT IN
+        (
+            1, 2, 3, 4, 32761, 32767,
+            DB_ID(N'PerformanceMonitor')
+        )
+        AND   d.database_id < 32761;
+
         INSERT INTO
             #query_stats_staging
         (
@@ -274,7 +306,7 @@ BEGIN
         )
         SELECT
             server_start_time = @server_start_time,
-            database_name = d.name,
+            database_name = od.database_name,
             sql_handle = qs.sql_handle,
             statement_start_offset = qs.statement_start_offset,
             statement_end_offset = qs.statement_end_offset,
@@ -353,23 +385,9 @@ BEGIN
                 qs.statement_start_offset,
                 qs.statement_end_offset
             ) AS tqp
-        CROSS APPLY
-        (
-            SELECT
-                dbid = CONVERT(integer, pa.value)
-            FROM sys.dm_exec_plan_attributes(qs.plan_handle) AS pa
-            WHERE pa.attribute = N'dbid'
-        ) AS pa
-        INNER JOIN sys.databases AS d
-          ON pa.dbid = d.database_id
+        INNER JOIN #online_databases AS od
+          ON st.dbid = od.database_id
         WHERE qs.last_execution_time >= @cutoff_time
-        AND   d.state = 0 /*ONLINE only — skip RESTORING databases (mirroring/AG secondary)*/
-        AND   pa.dbid NOT IN
-        (
-            1, 2, 3, 4, 32761, 32767,
-            DB_ID(N'PerformanceMonitor')
-        )
-        AND   pa.dbid < 32761 /*exclude contained AG system databases*/
         OPTION(RECOMPILE);
 
         /*