MDEV-26440 Missing connection id value in I_S.thread_pool_queues

It turns out, Field::set_notnull is required for a nullable I_S field.
Rework thread_pool_info.test to test request queueing in threadpool.

mysql-test/main/thread_pool_info.opt

---thread-handling=pool-of-threads --loose-thread-pool-mode=generic --loose-thread-pool-groups=ON --loose-thread-pool-queues=ON --thread-pool-stats=ON --thread-pool-waits=ON
\ No newline at end of file
+--thread-handling=pool-of-threads --loose-thread-pool-mode=generic --loose-thread-pool-groups=ON --loose-thread-pool-queues=ON --thread-pool-stats=ON --thread-pool-waits=ON --thread-pool-size=1 --thread-pool-max-threads=2 --thread-pool-dedicated-listener

mysql-test/main/thread_pool_info.result

@@ -26,13 +26,6 @@ SUM(QUEUE_LENGTH)
 SELECT SUM(IS_STALLED) FROM INFORMATION_SCHEMA.THREAD_POOL_GROUPS;
 SUM(IS_STALLED)
 0
-DESC INFORMATION_SCHEMA.THREAD_POOL_QUEUES;
-Field	Type	Null	Key	Default	Extra
-GROUP_ID	int(6)	NO		0	
-POSITION	int(6)	NO		0	
-PRIORITY	int(1)	NO		0	
-CONNECTION_ID	bigint(19) unsigned	YES		NULL	
-QUEUEING_TIME_MICROSECONDS	bigint(19)	NO		0	
 DESC INFORMATION_SCHEMA.THREAD_POOL_STATS;
 Field	Type	Null	Key	Default	Extra
 GROUP_ID	int(6)	NO		0	
@@ -56,9 +49,12 @@ FLUSH THREAD_POOL_STATS;
 SELECT SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)  FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
 SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)
 1
-SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3 FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
-SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3
-1
+SELECT SUM(POLLS_BY_LISTENER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SUM(POLLS_BY_LISTENER)
+2
+SELECT SUM(POLLS_BY_WORKER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SUM(POLLS_BY_WORKER)
+0
 DESC INFORMATION_SCHEMA.THREAD_POOL_WAITS;
 Field	Type	Null	Key	Default	Extra
 REASON	varchar(16)	NO			
@@ -87,3 +83,29 @@ SELECT COUNT FROM INFORMATION_SCHEMA.THREAD_POOL_WAITS WHERE REASON='Sleep';
 COUNT
 1
 FLUSH THREAD_POOL_WAITS;
+DESC INFORMATION_SCHEMA.THREAD_POOL_QUEUES;
+Field	Type	Null	Key	Default	Extra
+GROUP_ID	int(6)	NO		0	
+POSITION	int(6)	NO		0	
+PRIORITY	int(1)	NO		0	
+CONNECTION_ID	bigint(19) unsigned	YES		NULL	
+QUEUEING_TIME_MICROSECONDS	bigint(19)	NO		0	
+# restart: with restart_parameters
+connect  con1, localhost, root,,test;
+connection con1;
+connect  con2, localhost, root,,test;
+connection con2;
+connect extra_con,127.0.0.1,root,,test,$extra_port,;
+connection con1;
+SELECT SLEEP(1000);
+connection extra_con;
+connection con2;
+DO 1;
+connection extra_con;
+KILL QUERY con1_id;
+disconnect extra_con;
+connection con1;
+disconnect con1;
+connection con2;
+disconnect con2;
+connection default;

mysql-test/main/thread_pool_info.test

@@ -15,9 +15,6 @@ SELECT SUM(ACTIVE_THREADS) > 0 FROM INFORMATION_SCHEMA.THREAD_POOL_GROUPS;
 SELECT SUM(QUEUE_LENGTH) FROM INFORMATION_SCHEMA.THREAD_POOL_GROUPS;
 SELECT SUM(IS_STALLED) FROM INFORMATION_SCHEMA.THREAD_POOL_GROUPS;
 
-# I_S.THREAD_POOL_QUEUES
-DESC INFORMATION_SCHEMA.THREAD_POOL_QUEUES;
-#Todo - figure out how to populate queue with debug test
 
 # I_S.THREAD_POOL_STATS
 DESC INFORMATION_SCHEMA.THREAD_POOL_STATS;
@@ -29,7 +26,8 @@ SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER) > 0 FROM INFORMATION_SCHEMA.THREAD
 --disable_ps_protocol
 FLUSH THREAD_POOL_STATS;
 SELECT SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)  FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
-SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3 FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SELECT SUM(POLLS_BY_LISTENER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SELECT SUM(POLLS_BY_WORKER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
 --enable_ps_protocol
 
 #I_S.THREAD_POOL_WAITS
@@ -39,3 +37,56 @@ SELECT COUNT FROM INFORMATION_SCHEMA.THREAD_POOL_WAITS WHERE REASON='Sleep';
 SELECT SLEEP(0.01);
 SELECT COUNT FROM INFORMATION_SCHEMA.THREAD_POOL_WAITS WHERE REASON='Sleep';
 FLUSH THREAD_POOL_WAITS;
+
+
+# I_S.THREAD_POOL_QUEUES
+DESC INFORMATION_SCHEMA.THREAD_POOL_QUEUES;
+let $extra_port=`select @@port+1`;
+
+let $restart_parameters=--extra-port=$extra_port;
+let $restart_noprint=1;
+source include/restart_mysqld.inc;
+
+connect (con1, localhost, root,,test);
+connection con1;
+let $con1_id=`SELECT CONNECTION_ID()`;
+
+connect (con2, localhost, root,,test);
+connection con2;
+let $con2_id=`SELECT CONNECTION_ID()`;
+
+connect(extra_con,127.0.0.1,root,,test,$extra_port,);
+
+connection con1;
+send SELECT SLEEP(1000);
+
+connection extra_con;
+let $wait_condition=
+  SELECT COUNT(*) > 0 FROM INFORMATION_SCHEMA.PROCESSLIST
+  WHERE STATE='User sleep' AND ID=$con1_id;
+--source include/wait_condition.inc
+
+connection con2;
+send DO 1;
+
+
+connection extra_con;
+let $wait_condition=
+  SELECT COUNT(*) > 0 FROM INFORMATION_SCHEMA.THREAD_POOL_QUEUES
+  WHERE CONNECTION_ID IS NOT NULL;
+--source include/wait_condition.inc
+
+--replace_result $con1_id con1_id
+eval KILL QUERY $con1_id;
+disconnect extra_con;
+
+connection con1;
+error 0,ER_QUERY_INTERRUPTED;
+reap;
+disconnect con1;
+
+connection con2;
+reap;
+disconnect con2;
+
+connection default;

sql/thread_pool_info.cc

@@ -131,7 +131,10 @@ static int queues_fill_table(THD* thd, TABLE_LIST* tables, COND*)
         table->field[2]->store(prio, true);
         /* CONNECTION_ID */
         if (c->thd)
+        {
+          table->field[3]->set_notnull();
           table->field[3]->store(c->thd->thread_id, true);
+        }
         /* QUEUEING_TIME */
         table->field[4]->store(now - c->enqueue_time, true);