MDEV-34915 Sort output of session track system variable in mysqltest

Updated the output format too.

Before:

-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
-- autocommit
-- ON
-- time_zone
-- SYSTEM
-- character_set_client
-- latin1
-- character_set_connection
-- latin1
-- redirect_url
--

After:

-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
-- autocommit: ON
-- character_set_client: latin1
-- character_set_connection: latin1
-- redirect_url:
-- time_zone: SYSTEM

client/mysqltest.cc

@@ -7898,6 +7898,20 @@ static const char *trking_info_desc[SESSION_TRACK_END + 1]=
 /**
   @brief Append state change information (received through Ok packet) to the output.
 
+  @details The appended string is lines prefixed with "-- ". Only
+  tracking types with info sent from the server are displayed. For
+  each tracking type, the first line is the type name e.g.
+  "-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES".
+
+  The subsequent lines are the actual tracking info. When type is
+  SESSION_TRACK_SYSTEM_VARIABLES, the actual tracking info is a list
+  of name-value pairs of lines, sorted by name, e.g. if the info
+  received from the server is "autocommit=ON;time_zone=SYSTEM", the
+  corresponding string is
+
+  -- autocommit: ON
+  -- time_zone: SYSTEM
+
   @param [in,out] ds         Dynamic string to hold the content to be printed.
   @param [in] mysql          Connection handle.
 */
@@ -7905,11 +7919,16 @@ static const char *trking_info_desc[SESSION_TRACK_END + 1]=
 static void append_session_track_info(DYNAMIC_STRING *ds, MYSQL *mysql)
 {
 #ifndef EMBEDDED_LIBRARY
+  DYNAMIC_STRING ds_sort, *ds_type= NULL;
   for (unsigned int type= SESSION_TRACK_BEGIN; type <= SESSION_TRACK_END; type++)
   {
     const char *data;
     size_t data_length;
 
+    /*
+      Append the tracking type line, if any corresponding tracking
+      info is received.
+    */
     if (!mysql_session_track_get_first(mysql,
                                        (enum_session_state_type) type,
                                        &data, &data_length))
@@ -7925,26 +7944,56 @@ static void append_session_track_info(DYNAMIC_STRING *ds, MYSQL *mysql)
         DBUG_ASSERT(0);
         dynstr_append_mem(ds, STRING_WITH_LEN("Tracker???\n"));
       }
-
-      dynstr_append_mem(ds, STRING_WITH_LEN("-- "));
-      dynstr_append_mem(ds, data, data_length);
     }
     else
       continue;
+
+    /*
+      The remaining of this function: format and append the actual
+      tracking info.
+    */
+    if (type == SESSION_TRACK_SYSTEM_VARIABLES)
+    {
+      /* Prepare a string to be sorted before being appended. */
+      if (init_dynamic_string(&ds_sort, "", 1024, 1024))
+        die("Out of memory");
+      ds_type= &ds_sort;
+    }
+    else
+      ds_type= ds;
+    /* Append the first piece of info */
+    dynstr_append_mem(ds_type, STRING_WITH_LEN("-- "));
+    dynstr_append_mem(ds_type, data, data_length);
+    /* Whether we are appending the value of a variable */
+    bool appending_value= type == SESSION_TRACK_SYSTEM_VARIABLES;
+    /* Append remaining pieces */
     while (!mysql_session_track_get_next(mysql,
                                         (enum_session_state_type) type,
                                         &data, &data_length))
     {
-      dynstr_append_mem(ds, STRING_WITH_LEN("\n-- "));
+      if (appending_value)
+        dynstr_append_mem(ds_type, STRING_WITH_LEN(": "));
+      else
+        dynstr_append_mem(ds_type, STRING_WITH_LEN("\n-- "));
+      appending_value= !appending_value && type == SESSION_TRACK_SYSTEM_VARIABLES;
       if (data == NULL)
       {
         DBUG_ASSERT(data_length == 0);
-        dynstr_append_mem(ds, STRING_WITH_LEN("<NULL>"));
+        dynstr_append_mem(ds_type, STRING_WITH_LEN("<NULL>"));
       }
       else
-        dynstr_append_mem(ds, data, data_length);
+        dynstr_append_mem(ds_type, data, data_length);
+    }
+    DBUG_ASSERT(!appending_value);
+    if (type == SESSION_TRACK_SYSTEM_VARIABLES)
+    {
+      dynstr_append_mem(ds_type, STRING_WITH_LEN("\n"));
+      dynstr_append_sorted(ds, ds_type, false);
+      dynstr_append_mem(ds, STRING_WITH_LEN("\n"));
+      dynstr_free(&ds_sort);
     }
-    dynstr_append_mem(ds, STRING_WITH_LEN("\n\n"));
+    else
+      dynstr_append_mem(ds, STRING_WITH_LEN("\n\n"));
   }
 #endif /* EMBEDDED_LIBRARY */
 }
@@ -12018,7 +12067,8 @@ void replace_dynstr_append_uint(DYNAMIC_STRING *ds, uint val)
 /*
   Build a list of pointer to each line in ds_input, sort
   the list and use the sorted list to append the strings
-  sorted to the output ds
+  sorted to the output ds. The string ds_input needs to
+  end with a newline.
 
   SYNOPSIS
   dynstr_append_sorted()

mysql-test/main/mysqltest_tracking_info.result

@@ -6,26 +6,22 @@ SET @@session.session_track_system_variables='character_set_connection';
 # tracking info on
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
+-- character_set_connection: utf8
 
 SET NAMES 'big5';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- big5
+-- character_set_connection: big5
 
 # tracking info on once
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
+-- character_set_connection: utf8
 
 SET NAMES 'big5';
 # tracking info on
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
+-- character_set_connection: utf8
 
 # tracking info off once
 SET NAMES 'big5';
@@ -37,8 +33,7 @@ set @save_optimizer_switch=@@optimizer_switch;
 SET @@session.session_track_system_variables='optimizer_switch';
 set optimizer_switch='index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- optimizer_switch
--- index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
+-- optimizer_switch: index_merge=off,index_merge_union=off,index_merge_sort_union=off,index_merge_intersection=off,index_merge_sort_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=on,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=on,mrr_cost_based=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=on,table_elimination=off,extended_keys=off,exists_to_in=off,orderby_uses_equalities=off,condition_pushdown_for_derived=off,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off
 
 Warnings:
 Warning	1681	'engine_condition_pushdown=on' is deprecated and will be removed in a future release
@@ -71,13 +66,11 @@ ERROR HY000: Unknown system variable 'a'
 connect  con,localhost,root,,test;
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
+-- character_set_connection: utf8
 
 SET NAMES 'big5';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- big5
+-- character_set_connection: big5
 
 select @@session_track_system_variables;
 @@session_track_system_variables

mysql-test/main/session_tracker_last_gtid.result

@@ -5,31 +5,26 @@ SET gtid_seq_no=1000;
 SET @@session.session_track_system_variables='last_gtid';
 create table t1 (a int) engine=innodb;
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- last_gtid
--- 0-1-1000
+-- last_gtid: 0-1-1000
 
 select @@last_gtid;
 @@last_gtid
 0-1-1000
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- last_gtid
--- 0-1-1000
+-- last_gtid: 0-1-1000
 
 insert into t1 values (1);
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- last_gtid
--- 0-1-1001
+-- last_gtid: 0-1-1001
 
 select @@last_gtid;
 @@last_gtid
 0-1-1001
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- last_gtid
--- 0-1-1001
+-- last_gtid: 0-1-1001
 
 drop table t1;
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- last_gtid
--- 0-1-1002
+-- last_gtid: 0-1-1002
 
 reset master;