MDEV-26: Global transaction ID.

Move combining slave and gtid binlog state into a separate function.

Make SHOW ALL SLAVES STATUS use the same function, so it shows the
same value used by slave connect.

Add a test case.

mysql-test/suite/rpl/r/rpl_gtid_startpos.result

@@ -149,5 +149,39 @@ a
 3
 4
 5
+*** Test modifying binlog on slave and the effect on GTID state. ***
+include/stop_slave.inc
+RESET MASTER;
+CHANGE MASTER TO master_gtid_pos='';
+RESET MASTER;
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (10);
+include/start_slave.inc
+SELECT * FROM t1;
+a
+10
+SELECT '1' AS Using_Gtid;
+Using_Gtid
+1
+SELECT '0-1-2' AS Gtid_Pos;
+Gtid_Pos
+0-1-2
+UPDATE t1 SET a=9 WHERE a=10;
+UPDATE t1 SET a=10 WHERE a=9;
+SELECT '0-2-4' AS Gtid_Pos;
+Gtid_Pos
+0-2-4
+include/stop_slave.inc
+CHANGE MASTER TO master_gtid_pos= '0-1-2';
+ERROR HY000: Requested MASTER_GTID_POS 0-1-2 conflicts with the binary log which contains a more recent GTID 0-2-4. To use the requested MASTER_GTID_POS, the old binlog must be removed with RESET MASTER to avoid out-of-order binlog
+RESET MASTER;
+SELECT '0-1-2' AS Gtid_Pos;
+Gtid_Pos
+0-1-2
+CHANGE MASTER TO master_gtid_pos= '0-1-2';
+include/start_slave.inc
+SELECT '0-1-2' AS Gtid_Pos;
+Gtid_Pos
+0-1-2
 DROP TABLE t1;
 include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_gtid_startpos.test

@@ -240,6 +240,46 @@ eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT;
 SELECT * FROM t1 ORDER BY a;
 
 
+--echo *** Test modifying binlog on slave and the effect on GTID state. ***
+
+--connection server_2
+--source include/stop_slave.inc
+RESET MASTER;
+CHANGE MASTER TO master_gtid_pos='';
+
+--connection server_1
+RESET MASTER;
+TRUNCATE TABLE t1;
+INSERT INTO t1 VALUES (10);   # Will be GTID 0-1-2
+--save_master_pos
+
+--connection server_2
+--source include/start_slave.inc
+--sync_with_master
+
+SELECT * FROM t1;
+--let $value= query_get_value(SHOW SLAVE STATUS, "Using_Gtid", 1)
+eval SELECT '$value' AS Using_Gtid;
+--let $value= query_get_value(SHOW ALL SLAVES STATUS, "Gtid_Pos", 1)
+eval SELECT '$value' AS Gtid_Pos;
+
+UPDATE t1 SET a=9 WHERE a=10;
+UPDATE t1 SET a=10 WHERE a=9;
+
+--let $value= query_get_value(SHOW ALL SLAVES STATUS, "Gtid_Pos", 1)
+eval SELECT '$value' AS Gtid_Pos;
+
+--source include/stop_slave.inc
+--error ER_MASTER_GTID_POS_CONFLICTS_WITH_BINLOG
+CHANGE MASTER TO master_gtid_pos= '0-1-2';
+RESET MASTER;
+--let $value= query_get_value(SHOW ALL SLAVES STATUS, "Gtid_Pos", 1)
+eval SELECT '$value' AS Gtid_Pos;
+CHANGE MASTER TO master_gtid_pos= '0-1-2';
+--source include/start_slave.inc
+--let $value= query_get_value(SHOW ALL SLAVES STATUS, "Gtid_Pos", 1)
+eval SELECT '$value' AS Gtid_Pos;
+
 # Clean up.
 --connection server_1
 DROP TABLE t1;

sql/slave.cc

@@ -1820,8 +1820,6 @@ after_set_capability:
     char str_buf[256];
     String connect_state(str_buf, sizeof(str_buf), system_charset_info);
     connect_state.length(0);
-    rpl_gtid *binlog_gtid_list= NULL;
-    uint32 num_binlog_gtids= 0;
 
     /*
       Read the master @@GLOBAL.gtid_domain_id variable.
@@ -1844,27 +1842,18 @@ after_set_capability:
     mysql_free_result(master_res);
     master_res= NULL;
 
-    if (opt_bin_log)
-    {
-      int err= mysql_bin_log.get_most_recent_gtid_list(&binlog_gtid_list,
-                                                       &num_binlog_gtids);
-      if (err)
-      {
-        err_code= ER_OUTOFMEMORY;
-        errmsg= "The slave I/O thread stops because a fatal out-of-memory "
-          "error is encountered when it tries to compute @slave_connect_state.";
-        sprintf(err_buff, "%s Error: Out of memory", errmsg);
-        goto err;
-      }
-    }
-
     connect_state.append(STRING_WITH_LEN("SET @slave_connect_state='"),
                          system_charset_info);
-    rpl_global_gtid_slave_state.tostring(&connect_state, binlog_gtid_list,
+    if (rpl_append_gtid_state(&connect_state, true))
-                                         num_binlog_gtids);
+    {
-    if (binlog_gtid_list)
+      err_code= ER_OUTOFMEMORY;
-      my_free(binlog_gtid_list);
+      errmsg= "The slave I/O thread stops because a fatal out-of-memory "
+        "error is encountered when it tries to compute @slave_connect_state.";
+      sprintf(err_buff, "%s Error: Out of memory", errmsg);
+      goto err;
+    }
     connect_state.append(STRING_WITH_LEN("'"), system_charset_info);
+
     rc= mysql_real_query(mysql, connect_state.ptr(), connect_state.length());
     if (rc)
     {
@@ -2511,7 +2500,12 @@ bool show_all_master_info(THD* thd)
   DBUG_ENTER("show_master_info");
   mysql_mutex_assert_owner(&LOCK_active_mi);
 
-  rpl_global_gtid_slave_state.tostring(&gtid_pos, NULL, 0);
+  gtid_pos.length(0);
+  if (rpl_append_gtid_state(&gtid_pos, true))
+  {
+    my_error(ER_OUT_OF_RESOURCES, MYF(0));
+    DBUG_RETURN(TRUE);
+  }
 
   if (send_show_master_info_header(thd, 1, gtid_pos.length()))
     DBUG_RETURN(TRUE);

sql/sql_repl.cc

@@ -3360,4 +3360,30 @@ rpl_deinit_gtid_slave_state()
   rpl_global_gtid_slave_state.deinit();
 }
 
+
+/*
+  Format the current GTID state as a string, for use when connecting to a
+  master server with GTID, or for returning the value of @@global.gtid_state.
+
+  If the flag use_binlog is true, then the contents of the binary log (if
+  enabled) is merged into the current GTID state.
+*/
+int
+rpl_append_gtid_state(String *dest, bool use_binlog)
+{
+  int err;
+  rpl_gtid *gtid_list= NULL;
+  uint32 num_gtids= 0;
+
+  if (opt_bin_log &&
+      (err= mysql_bin_log.get_most_recent_gtid_list(&gtid_list, &num_gtids)))
+    return err;
+
+  rpl_global_gtid_slave_state.tostring(dest, gtid_list, num_gtids);
+  my_free(gtid_list);
+
+  return 0;
+}
+
+
 #endif /* HAVE_REPLICATION */

sql/sql_repl.h

@@ -69,6 +69,7 @@ extern PSI_mutex_key key_LOCK_slave_state, key_LOCK_binlog_state;
 void rpl_init_gtid_slave_state();
 void rpl_deinit_gtid_slave_state();
 int gtid_state_from_binlog_pos(const char *name, uint32 pos, String *out_str);
+int rpl_append_gtid_state(String *dest, bool use_binlog);
 
 #endif /* HAVE_REPLICATION */