MDEV-33145 Add FLUSH GLOBAL STATUS

- FLUSH GLOBAL STATUS now resets most global_status_vars.
  At this stage, this is mainly to be used for testing.
- FLUSH SESSION STATUS added as an alias for FLUSH STATUS.
- FLUSH STATUS does not require any privilege (before required RELOAD).
- FLUSH GLOBAL STATUS requires RELOAD privilege.
- All global status reset moved to FLUSH GLOBAL STATUS.
- Replication semisync status variables are now reset by
  FLUSH GLOBAL STATUS.
- In test cases, the only changes are:
  - Replace FLUSH STATUS with FLUSH GLOBAL STATUS
  - Replace FLUSH STATUS with FLUSH STATUS; FLUSH GLOBAL STATUS.
    This was only done in a few tests where the test was using SHOW STATUS
    for both local and global variables.
- Uptime_since_flush_status is now always provided, independent if
  ENABLED_PROFILING is enabled when compiling MariaDB.
- @@global.Uptime_since_flush_status is reset on FLUSH GLOBAL STATUS
  and @@session.Uptime_since_flush_status is reset on FLUSH SESSION STATUS.
- When connected, @@session.Uptime_since_flush_status is set to 0.

mysql-test/main/query_cache.test

@@ -24,7 +24,7 @@ SET LOCAL query_cache_type= ON;
 flush query cache; # This crashed in some versions
 flush query cache; # This crashed in some versions
 reset query cache;
-flush status;
+flush global status;
 --disable_warnings
 drop table if exists t1,t2,t3,t4,t11,t21,t1_1,t1_2,t9,t9_1,t9_2;
 drop database if exists mysqltest;
@@ -465,7 +465,7 @@ drop table t1;
 #
 flush query cache;
 reset query cache;
-flush status;
+flush global status;
 set GLOBAL query_cache_size=1048576;
 
 create table t1 (a int not null);
@@ -732,7 +732,7 @@ set GLOBAL query_cache_size=1355776;
 #
 # Query with warning prohibited to query cache (BUG#9414)
 #
-flush status;
+flush global status;
 CREATE TABLE t1 (
   `date` datetime NOT NULL default '0000-00-00 00:00:00',
   KEY `date` (`date`)
@@ -754,7 +754,7 @@ drop table t1;
 create table t1 (a int);
 insert into t1 values (1);
 reset query cache;
-flush status;
+flush global status;
 select * from (select * from t1) a;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
@@ -777,7 +777,7 @@ drop table t1;
 # BUG#14652: Queries with leading '(' characters.
 #
 create table t1 (a int);
-flush status;
+flush global status;
 (select a from t1) union (select a from t1);
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
@@ -845,7 +845,7 @@ delimiter ;//
 #
 flush query cache;
 reset query cache;
-flush status;
+flush global status;
 delimiter //;
 create table t1 (s1 int)//
 create procedure f1 () begin
@@ -880,7 +880,7 @@ call f1();
 select sql_cache * from t1;
 flush query cache;
 reset query cache;
-flush status;
+flush global status;
 select sql_cache * from t1;
 select sql_cache * from t1 where s1=1;
 call f1();
@@ -926,7 +926,7 @@ SET GLOBAL query_cache_size=0;
 # Bug #20045: Server crash on INSERT ... SELECT ... FROM non-mergeable view
 #
 set global query_cache_size=1024*1024;
-flush status;
+flush global status;
 create table t1 (a int);
 insert into t1 (a) values (1), (2), (3);
 select * from t1;
@@ -1282,7 +1282,7 @@ set local query_cache_type=on;
 #
 # Bug#33756 - query cache with concurrent_insert=0 appears broken
 #
-FLUSH STATUS;
+FLUSH GLOBAL STATUS;
 SET GLOBAL query_cache_size=10*1024*1024;
 SET @save_concurrent_insert= @@concurrent_insert;
 SET GLOBAL concurrent_insert= 0;
@@ -1306,7 +1306,7 @@ SET GLOBAL query_cache_size= default;
 DROP TABLE IF EXISTS t1;
 --enable_warnings
 
-FLUSH STATUS;
+FLUSH GLOBAL STATUS;
 SET GLOBAL query_cache_size=1048576;
 CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (1),(2),(3),(4),(5);
@@ -1645,7 +1645,7 @@ set GLOBAL query_cache_size=1355776;
 FLUSH USER_STATISTICS;
 FLUSH CLIENT_STATISTICS;
 reset query cache;
-flush status;
+flush global status;
 
 create table t1 (a int);
 insert into t1 values (1);
@@ -1666,7 +1666,7 @@ show status like "Qcache_hits";
 drop table t1;
 FLUSH USER_STATISTICS;
 FLUSH CLIENT_STATISTICS;
-flush status;
+flush global status;
 
 create table t1 (a int);
 select * from t1;
@@ -1685,7 +1685,7 @@ show status like "Qcache_hits";
 
 FLUSH USER_STATISTICS;
 FLUSH CLIENT_STATISTICS;
-flush status;
+flush global status;
 
 create procedure p1()
   select * from t1;
@@ -1705,7 +1705,7 @@ show status like "Qcache_hits";
 
 FLUSH USER_STATISTICS;
 FLUSH CLIENT_STATISTICS;
-flush status;
+flush global status;
 
 SET GLOBAL query_cache_size= 0;
 call p1;
@@ -1761,7 +1761,7 @@ SET GLOBAL query_cache_size= @qc;
 --echo #
 CREATE DATABASE `foo.bar`;
 use `foo.bar`;
-flush status;
+flush global status;
 CREATE TABLE moocow (a int);
 INSERT INTO moocow VALUES (1), (2), (3);
 SHOW STATUS LIKE 'Qcache_inserts';
@@ -1779,7 +1779,7 @@ drop database `foo.bar`;
 --echo # MDEV-10766 Queries which start with WITH clause do not get
 --echo # inserted into query cache
 --echo #
-flush status;
+flush global status;
 show status like "Qcache_inserts";
 create table t1 (i int);
 with cte as (select * from t1) select * from cte;
@@ -1859,7 +1859,7 @@ SET GLOBAL query_cache_size= @qc;
 --echo #
 create table t1 (a text);
 insert into t1 values ('{"a":"foo"}');
-flush status;
+flush global status;
 SHOW STATUS LIKE 'Qcache_inserts';
 select * from t1, json_table(t1.a, '$' columns (f varchar(20) path '$.a')) as jt;
 SHOW STATUS LIKE 'Qcache_inserts';
@@ -1889,7 +1889,7 @@ set query_cache_type= 1;
 create table t1 (a int);
 insert into t1 values (1000);
 
-flush status;
+flush global status;
 --let $v1 = `select hex(random_bytes(a)) from t1`
 select * from information_schema.global_status where variable_name in ('Qcache_inserts','Qcache_hits') order by variable_name;