MDEV-27068 running mariadb-upgrade in parallel make it hangs forever

MDEV-27107 prevent two mariadb-upgrade running in parallel
MDEV-27279 mariadb_upgrade add --check-if-upgrade-is-needed /
           restrict tests to major version

Code is based of pull request from Daniel Black, but with a several
extensions.

- mysql_upgrade now locks the mysql_upgrade file with my_lock()
  (Advisory record locking). This ensures that two mysql_upgrades
   cannot be run in parallel.
- Added --check-if-upgrade-is-needed to mysql_upgrade. This will return
  0 if one has to run mysql_upgrade.

Other changes:
- mysql_upgrade will now immediately exit if the major version and minor
  version  (two first numbers in the version string) is same as last run.
  Before this change mysql_upgrade was run if the version string was different
  from last run.
- Better messages when there is no need to run mysql_upgrade.
- mysql_upgrade --verbose now prints out a lot more information about
  the version checking.
- mysql_upgrade --debug now uses default debug arguments if there is no
  option to --debug
- "MySQL" is renamed to MariaDB in the messages
- mysql_upgrade version increased to 2.0

Notes
Verifying "prevent two mariadb-upgrade running in parallel" was
done in a debugger as it would be a bit complex to do that in mtr.

Reviewer: Danial Black <daniel@mariadb.org>

client/client_priv.h

@@ -99,6 +99,7 @@ enum options_client
   OPT_SKIP_ANNOTATE_ROWS_EVENTS,
   OPT_SSL_CRL, OPT_SSL_CRLPATH,
   OPT_IGNORE_DATA,
+  OPT_CHECK_IF_UPGRADE_NEEDED,
   OPT_MAX_CLIENT_OPTION /* should be always the last */
 };
 

client/mysql_upgrade.c

@@ -22,7 +22,7 @@
 
 #include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
 
-#define VER "1.4"
+#define VER "2.0"
 
 #ifdef HAVE_SYS_WAIT_H
 #include <sys/wait.h>
@@ -37,13 +37,15 @@
 #endif
 
 static int phase = 0;
+static int info_file= -1;
 static const int phases_total = 7;
 static char mysql_path[FN_REFLEN];
 static char mysqlcheck_path[FN_REFLEN];
 
-static my_bool opt_force, opt_verbose, debug_info_flag, debug_check_flag,
+static my_bool debug_info_flag, debug_check_flag,
                opt_systables_only, opt_version_check;
-static my_bool opt_not_used, opt_silent;
+static my_bool opt_not_used, opt_silent, opt_check_upgrade;
+static uint opt_force, opt_verbose;
 static uint my_end_arg= 0;
 static char *opt_user= (char*)"root";
 
@@ -69,7 +71,7 @@ static char **defaults_argv;
 
 static my_bool not_used; /* Can't use GET_BOOL without a value pointer */
 
-char upgrade_from_version[sizeof("10.20.456-MariaDB")+1];
+char upgrade_from_version[sizeof("10.20.456-MariaDB")+30];
 
 static my_bool opt_write_binlog;
 
@@ -95,8 +97,8 @@ static struct my_option my_long_options[]=
   {"debug", '#', "This is a non-debug version. Catch this and exit.",
    0, 0, 0, GET_DISABLED, OPT_ARG, 0, 0, 0, 0, 0, 0},
 #else
-  {"debug", '#', "Output debug log.", &default_dbug_option,
+  {"debug", '#', "Output debug log.",
-   &default_dbug_option, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
+   0, 0, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
 #endif
   {"debug-check", OPT_DEBUG_CHECK, "Check memory and open file usage at exit.",
    &debug_check_flag, &debug_check_flag,
@@ -110,9 +112,13 @@ static struct my_option my_long_options[]=
    "Default authentication client-side plugin to use.",
    &opt_default_auth, &opt_default_auth, 0,
    GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+  {"check-if-upgrade-is-needed", OPT_CHECK_IF_UPGRADE_NEEDED,
+   "Exits with status 0 if an upgrades is required, 1 otherwise.",
+   &opt_check_upgrade, &opt_check_upgrade,
+   0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
   {"force", 'f', "Force execution of mysqlcheck even if mysql_upgrade "
-   "has already been executed for the current version of MySQL.",
+   "has already been executed for the current version of MariaDB.",
-   &opt_force, &opt_force, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
+   &opt_not_used, &opt_not_used, 0 , GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
   {"host", 'h', "Connect to host.", 0,
    0, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
 #define PASSWORD_OPT 12
@@ -193,6 +199,12 @@ static void free_used_memory(void)
   dynstr_free(&conn_args);
   if (cnf_file_path)
     my_delete(cnf_file_path, MYF(MY_WME));
+  if (info_file >= 0)
+  {
+    (void) my_lock(info_file, F_UNLCK, 0, 1, MYF(0));
+    my_close(info_file, MYF(MY_WME));
+    info_file= -1;
+  }
 }
 
 
@@ -238,6 +250,13 @@ static void verbose(const char *fmt, ...)
 }
 
 
+static void print_error(const char *error_msg, DYNAMIC_STRING *output)
+{
+  fprintf(stderr, "%s\n", error_msg);
+  fprintf(stderr, "%s", output->str);
+}
+
+
 /*
   Add one option - passed to mysql_upgrade on command line
   or by defaults file(my.cnf) - to a dynamic string, in
@@ -271,6 +290,7 @@ static void add_one_option_cnf_file(DYNAMIC_STRING *ds,
   dynstr_append(ds, "\n");
 }
 
+
 static my_bool
 get_one_option(int optid, const struct my_option *opt,
                char *argument)
@@ -339,11 +359,17 @@ get_one_option(int optid, const struct my_option *opt,
            my_progname, VER, MYSQL_SERVER_VERSION, SYSTEM_TYPE, MACHINE_TYPE);
     die(0);
     break;
+  case 'f': /* --force     */
+    opt_force++;
+    if (argument == disabled_my_option)
+      opt_force= 0;
+    add_option= 0;
+    break;
   case OPT_SILENT:
     opt_verbose= 0;
     add_option= 0;
     break;
-  case 'f': /* --force     */
+  case OPT_CHECK_IF_UPGRADE_NEEDED: /* --check-if-upgrade-needed */
   case 's':                                     /* --upgrade-system-tables */
   case OPT_WRITE_BINLOG:                        /* --write-binlog */
     add_option= FALSE;
@@ -374,6 +400,18 @@ get_one_option(int optid, const struct my_option *opt,
 }
 
 
+/* Convert the specified version string into the numeric format. */
+
+static ulong STDCALL calc_server_version(char *some_version)
+{
+  uint major, minor, version;
+  char *point= some_version, *end_point;
+  major=   (uint) strtoul(point, &end_point, 10);   point=end_point+1;
+  minor=   (uint) strtoul(point, &end_point, 10);   point=end_point+1;
+  version= (uint) strtoul(point, &end_point, 10);
+  return (ulong) major * 10000L + (ulong)(minor * 100 + version);
+}
+
 /**
   Run a command using the shell, storing its output in the supplied dynamic
   string.
@@ -572,7 +610,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
     if (my_write(fd, sql_log_bin, sizeof(sql_log_bin)-1,
                  MYF(MY_FNABP | MY_WME)))
     {
-      my_close(fd, MYF(0));
+      my_close(fd, MYF(MY_WME));
       my_delete(query_file_path, MYF(0));
       die("Failed to write to '%s'", query_file_path);
     }
@@ -581,7 +619,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
   if (my_write(fd, (uchar*) query, strlen(query),
                MYF(MY_FNABP | MY_WME)))
   {
-    my_close(fd, MYF(0));
+    my_close(fd, MYF(MY_WME));
     my_delete(query_file_path, MYF(0));
     die("Failed to write to '%s'", query_file_path);
   }
@@ -598,7 +636,7 @@ static int run_query(const char *query, DYNAMIC_STRING *ds_res,
                 "2>&1",
                 NULL);
 
-  my_close(fd, MYF(0));
+  my_close(fd, MYF(MY_WME));
   my_delete(query_file_path, MYF(0));
 
   DBUG_RETURN(ret);
@@ -645,6 +683,9 @@ static int get_upgrade_info_file_name(char* name)
                 &ds_datadir, FALSE) ||
       extract_variable_from_show(&ds_datadir, name))
   {
+    print_error("Reading datadir from the MariaDB server failed. Got the "
+                "following error when executing the 'mysql' command line client",
+                &ds_datadir);
     dynstr_free(&ds_datadir);
     DBUG_RETURN(1); /* Query failed */
   }
@@ -656,6 +697,83 @@ static int get_upgrade_info_file_name(char* name)
   DBUG_RETURN(0);
 }
 
+static char upgrade_info_file[FN_REFLEN]= {0};
+
+
+/*
+  Open or create mysql_upgrade_info file in servers data dir.
+
+  Take a lock to ensure there cannot be any other mysql_upgrades
+  runninc concurrently
+*/
+
+const char *create_error_message=
+  "%sCould not open or create the upgrade info file '%s' in "
+  "the MariaDB Servers data directory, errno: %d (%s)\n";
+
+
+
+static void open_mysql_upgrade_file()
+{
+  char errbuff[80];
+  if (get_upgrade_info_file_name(upgrade_info_file))
+  {
+    die("Upgrade failed");
+  }
+  if ((info_file= my_create(upgrade_info_file, 0,
+                            O_RDWR | O_NOFOLLOW,
+                            MYF(0))) < 0)
+  {
+    if (opt_force >= 2)
+    {
+      fprintf(stdout, create_error_message,
+              "", upgrade_info_file, errno,
+              my_strerror(errbuff, sizeof(errbuff)-1, errno));
+      fprintf(stdout,
+              "--force --force used, continuing without using the %s file.\n"
+              "Note that this means that there is no protection against "
+              "concurrent mysql_upgrade executions and next mysql_upgrade run "
+              "will do a full upgrade again!\n",
+              upgrade_info_file);
+      return;
+    }
+    fprintf(stdout, create_error_message,
+            "FATAL ERROR: ",
+            upgrade_info_file, errno,
+            my_strerror(errbuff, sizeof(errbuff)-1, errno));
+    if (errno == EACCES)
+    {
+      fprintf(stderr,
+              "Note that mysql_upgrade should be run as the same user as the "
+              "MariaDB server binary, normally 'mysql' or 'root'.\n"
+              "Alternatively you can use mysql_upgrade --force --force. "
+              "Please check the documentation if you decide to use the force "
+              "option!\n");
+    }
+    fflush(stderr);
+    die(0);
+  }
+  if (my_lock(info_file, F_WRLCK, 0, 1, MYF(0)))
+  {
+    die("Could not exclusively lock on file '%s'. Error %d: %s\n",
+        upgrade_info_file, my_errno,
+        my_strerror(errbuff, sizeof(errbuff)-1, my_errno));
+  }
+}
+
+
+/**
+  Place holder for versions that require a major upgrade
+
+  @return 0  upgrade has alredy been run on this version
+  @return 1  upgrade has to be run
+
+*/
+
+static int faulty_server_versions(const char *version)
+{
+  return 0;
+}
 
 /*
   Read the content of mysql_upgrade_info file and
@@ -665,79 +783,111 @@ static int get_upgrade_info_file_name(char* name)
   NOTE
   This is an optimization to avoid running mysql_upgrade
   when it's already been performed for the particular
-  version of MySQL.
+  version of MariaDB.
 
-  In case the MySQL server can't return the upgrade info
+  In case the MariaDBL server can't return the upgrade info
   file it's always better to report that the upgrade hasn't
   been performed.
 
+  @return 0   Upgrade has alredy been run on this version
+  @return > 0 Upgrade has to be run
 */
 
-static int upgrade_already_done(void)
+static int upgrade_already_done(int silent)
 {
-  FILE *in;
+  const char *version = MYSQL_SERVER_VERSION;
-  char upgrade_info_file[FN_REFLEN]= {0};
+  const char *s;
+  char *pos;
+  my_off_t length;
 
-  if (get_upgrade_info_file_name(upgrade_info_file))
+  if (info_file < 0)
-    return 0; /* Could not get filename => not sure */
+  {
-
+    DBUG_ASSERT(opt_force > 1);
-  if (!(in= my_fopen(upgrade_info_file, O_RDONLY, MYF(0))))
+    return 1;                                   /* No info file and --force */
-    return 0; /* Could not open file => not sure */
+  }
 
   bzero(upgrade_from_version, sizeof(upgrade_from_version));
-  if (!fgets(upgrade_from_version, sizeof(upgrade_from_version), in))
+
+  (void) my_seek(info_file, 0, SEEK_SET, MYF(0));
+  /* We have -3 here to make calc_server_version() safe */
+  length= my_read(info_file, (uchar*) upgrade_from_version,
+                  sizeof(upgrade_from_version)-3,
+                  MYF(MY_WME));
+
+  if (!length)
   {
-    /* Ignore, will be detected by strncmp() below */
+    if (opt_verbose)
+      verbose("Empty or non existent %s. Assuming mysql_upgrade has to be run!",
+              upgrade_info_file);
+    return 1;
   }
 
-  my_fclose(in, MYF(0));
+  /* Remove possible \ŋ that may end in output */
+  if ((pos= strchr(upgrade_from_version, '\n')))
+    *pos= 0;
 
-  return (strncmp(upgrade_from_version, MYSQL_SERVER_VERSION,
+  if (faulty_server_versions(upgrade_from_version))
-                  sizeof(MYSQL_SERVER_VERSION)-1)==0);
+  {
+    if (opt_verbose)
+      verbose("Upgrading from version %s requires mysql_upgrade to be run!",
+              upgrade_from_version);
+    return 2;
+  }
+
+  s= strchr(version, '.');
+  s= strchr(s + 1, '.');
+
+  if (strncmp(upgrade_from_version, version,
+              (size_t)(s - version + 1)))
+  {
+    if (calc_server_version(upgrade_from_version) <= MYSQL_VERSION_ID)
+    {
+      verbose("Major version upgrade detected from %s to %s. Check required!",
+              upgrade_from_version, version);
+      return 3;
+    }
+    die("Version mismatch (%s -> %s): Trying to downgrade from a higher to "
+        "lower version is not supported!",
+        upgrade_from_version, version);
+  }
+  if (!silent)
+  {
+    verbose("This installation of MariaDB is already upgraded to %s.\n"
+            "There is no need to run mysql_upgrade again for %s.",
+            upgrade_from_version, version);
+    if (!opt_check_upgrade)
+      verbose("You can use --force if you still want to run mysql_upgrade",
+              upgrade_from_version, version);
+  }
+  return 0;
 }
 
-
+static void finish_mysql_upgrade_info_file(void)
-/*
-  Write mysql_upgrade_info file in servers data dir indicating that
-  upgrade has been done for this version
-
-  NOTE
-  This might very well fail but since it's just an optimization
-  to run mysql_upgrade only when necessary the error can be
-  ignored.
-
-*/
-
-static void create_mysql_upgrade_info_file(void)
 {
-  FILE *out;
+  if (info_file < 0)
-  char upgrade_info_file[FN_REFLEN]= {0};
-
-  if (get_upgrade_info_file_name(upgrade_info_file))
-    return; /* Could not get filename => skip */
-
-  if (!(out= my_fopen(upgrade_info_file, O_TRUNC | O_WRONLY, MYF(0))))
-  {
-    fprintf(stderr,
-            "Could not create the upgrade info file '%s' in "
-            "the MySQL Servers datadir, errno: %d\n",
-            upgrade_info_file, errno);
     return;
-  }
 
   /* Write new version to file */
-  fputs(MYSQL_SERVER_VERSION, out);
+  (void) my_seek(info_file, 0, SEEK_CUR, MYF(0));
-  my_fclose(out, MYF(0));
+  (void) my_chsize(info_file, 0, 0, MYF(0));
+  (void) my_seek(info_file, 0, 0, MYF(0));
+  (void) my_write(info_file, (uchar*) MYSQL_SERVER_VERSION,
+                  sizeof(MYSQL_SERVER_VERSION)-1, MYF(MY_WME));
+  (void) my_write(info_file, (uchar*) "\n", 1, MYF(MY_WME));
+  (void) my_lock(info_file, F_UNLCK, 0, 1, MYF(0));
 
   /*
-    Check if the upgrad_info_file was properly created/updated
+    Check if the upgrade_info_file was properly created/updated
     It's not a fatal error -> just print a message if it fails
   */
-  if (!upgrade_already_done())
+  if (upgrade_already_done(1))
     fprintf(stderr,
             "Could not write to the upgrade info file '%s' in "
-            "the MySQL Servers datadir, errno: %d\n",
+            "the MariaDB Servers datadir, errno: %d\n",
             upgrade_info_file, errno);
+
+  my_close(info_file, MYF(MY_WME));
+  info_file= -1;
   return;
 }
 
@@ -808,7 +958,7 @@ static my_bool is_mysql()
       strstr(ds_events_struct.str, "IGNORE_BAD_TABLE_OPTIONS") != NULL)
     ret= FALSE;
   else
-    verbose("MySQL upgrade detected");
+    verbose("MariaDB upgrade detected");
 
   dynstr_free(&ds_events_struct);
   return(ret);
@@ -1059,7 +1209,7 @@ static int check_slave_repositories(void)
 }
 
 /*
-  Update all system tables in MySQL Server to current
+  Update all system tables in MariaDB Server to current
   version using "mysql" to execute all the SQL commands
   compiled into the mysql_fix_privilege_tables array
 */
@@ -1128,24 +1278,6 @@ static int run_sql_fix_privilege_tables(void)
 }
 
 
-static void print_error(const char *error_msg, DYNAMIC_STRING *output)
-{
-  fprintf(stderr, "%s\n", error_msg);
-  fprintf(stderr, "%s", output->str);
-}
-
-
-/* Convert the specified version string into the numeric format. */
-static ulong STDCALL calc_server_version(char *some_version)
-{
-  uint major, minor, version;
-  char *point= some_version, *end_point;
-  major=   (uint) strtoul(point, &end_point, 10);   point=end_point+1;
-  minor=   (uint) strtoul(point, &end_point, 10);   point=end_point+1;
-  version= (uint) strtoul(point, &end_point, 10);
-  return (ulong) major * 10000L + (ulong)(minor * 100 + version);
-}
-
 /**
   Check if the server version matches with the server version mysql_upgrade
   was compiled with.
@@ -1181,7 +1313,6 @@ static int check_version_match(void)
             "check.\n", version_str, MYSQL_SERVER_VERSION);
     return 1;
   }
-  else
   return 0;
 }
 
@@ -1191,6 +1322,8 @@ int main(int argc, char **argv)
   char self_name[FN_REFLEN + 1];
 
   MY_INIT(argv[0]);
+  DBUG_PROCESS(argv[0]);
+
   load_defaults_or_exit("my", load_default_groups, &argc, &argv);
   defaults_argv= argv; /* Must be freed by 'free_defaults' */
 
@@ -1231,12 +1364,17 @@ int main(int argc, char **argv)
       die(NULL);
     my_write(fd, USTRING_WITH_LEN( "[client]\n"), MYF(MY_FAE));
     my_write(fd, (uchar*)ds_args.str, ds_args.length, MYF(MY_FAE));
-    my_close(fd, MYF(0));
+    my_close(fd, MYF(MY_WME));
   }
 
   /* Find mysql */
   find_tool(mysql_path, IF_WIN("mysql.exe", "mysql"), self_name);
 
+  open_mysql_upgrade_file();
+
+  if (opt_check_upgrade)
+    exit(upgrade_already_done(0) == 0);
+
   /* Find mysqlcheck */
   find_tool(mysqlcheck_path, IF_WIN("mysqlcheck.exe", "mysqlcheck"), self_name);
 
@@ -1245,15 +1383,10 @@ int main(int argc, char **argv)
 
   /*
     Read the mysql_upgrade_info file to check if mysql_upgrade
-    already has been run for this installation of MySQL
+    already has been run for this installation of MariaDB
   */
-  if (!opt_force && upgrade_already_done())
+  if (!opt_force && !upgrade_already_done(0))
-  {
+    goto end;                                   /* Upgrade already done */
-    printf("This installation of MySQL is already upgraded to %s, "
-           "use --force if you still need to run mysql_upgrade\n",
-           MYSQL_SERVER_VERSION);
-    goto end;
-  }
 
   if (opt_version_check && check_version_match())
     die("Upgrade failed");
@@ -1278,8 +1411,8 @@ int main(int argc, char **argv)
 
   verbose("OK");
 
-  /* Create a file indicating upgrade has been performed */
+  /* Finish writing indicating upgrade has been performed */
-  create_mysql_upgrade_info_file();
+  finish_mysql_upgrade_info_file();
 
   DBUG_ASSERT(phase == phases_total);
 

man/mysql_upgrade.1

@@ -239,6 +239,21 @@ Old option accepted for backward compatibility but ignored\&.
 .sp -1
 .IP \(bu 2.3
 .\}
+.\" mysql_upgrade: check-if-upgrade-is-needed option
+.\" check-if-upgrade-is-needed option: mysql_upgrade
+\fB\-\-check\-if\-upgrade\-is\-needed\fR
+.sp
+Exit with a status code indicating if an upgrade is needed\&. Returns 0 if upgrade needed or current version couldn't be determined, 1 when no action required\&.
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
 .\" mysql_upgrade: datadir option
 .\" datadir option: mysql_upgrade
 \fB\-\-datadir=\fR\fB\fIpath\fR\fR

mysql-test/r/mysql_upgrade.result

@@ -46,7 +46,9 @@ test
 Phase 7/7: Running 'FLUSH PRIVILEGES'
 OK
 Run it again - should say already completed
-This installation of MySQL is already upgraded to VERSION, use --force if you still need to run mysql_upgrade
+This installation of MariaDB is already upgraded to VERSION.
+There is no need to run mysql_upgrade again for VERSION.
+You can use --force if you still want to run mysql_upgrade
 Force should run it regardless of whether it has been run before
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
@@ -142,11 +144,12 @@ test
 Phase 7/7: Running 'FLUSH PRIVILEGES'
 OK
 DROP USER mysqltest1@'%';
-Version check failed. Got the following error when calling the 'mysql' command line client
+Reading datadir from the MariaDB server failed. Got the following error when executing the 'mysql' command line client
 ERROR 1045 (28000): Access denied for user 'mysqltest1'@'localhost' (using password: YES)
 FATAL ERROR: Upgrade failed
 Run mysql_upgrade with a non existing server socket
-mysqlcheck: Got error: 2005: Unknown MySQL server host 'not_existing_host' (errno) when trying to connect
+Reading datadir from the MariaDB server failed. Got the following error when executing the 'mysql' command line client
+ERROR 2005 (HY000): Unknown MySQL server host 'not_existing_host' (errno)
 FATAL ERROR: Upgrade failed
 set GLOBAL sql_mode='STRICT_ALL_TABLES,ANSI_QUOTES,NO_ZERO_DATE';
 Phase 1/7: Checking and upgrading mysql database
@@ -405,9 +408,12 @@ OK
 # Bug #21489398: MYSQL_UPGRADE: FATAL ERROR: UPGRADE FAILED - IMPROVE ERROR
 #
 Run mysql_upgrade with unauthorized access
-Version check failed. Got the following error when calling the 'mysql' command line client
+Reading datadir from the MariaDB server failed. Got the following error when executing the 'mysql' command line client
 ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
 FATAL ERROR: Upgrade failed
+Reading datadir from the MariaDB server failed. Got the following error when executing the 'mysql' command line client
+ERROR 1045 (errno): Access denied for user 'root'@'localhost' (using password: YES)
+FATAL ERROR: Upgrade failed
 #
 # MDEV-4332 Increase username length from 16 characters
 # MDEV-6068, MDEV-6178 mysql_upgrade breaks databases with long user names
@@ -854,4 +860,32 @@ GRANT PROXY ON ''@'%' TO 'root'@'localhost' WITH GRANT OPTION
 GRANT USAGE ON *.* TO 'aRole'
 DROP ROLE `aRole`;
 FLUSH PRIVILEGES;
+#
+# MDEV-27279: mariadb_upgrade add --check-if-upgrade-is-needed
+#
+This installation of MariaDB is already upgraded to MariaDB .
+There is no need to run mysql_upgrade again for MariaDB .
+Looking for 'mysql' as: mysql
+This installation of MariaDB is already upgraded to MariaDB .
+There is no need to run mysql_upgrade again for MariaDB .
+#
+# MDEV-27279: mariadb_upgrade check-if-upgrade absence is do it
+#
+Looking for 'mysql' as: mysql
+Empty or non existent ...mysql_upgrade_info. Assuming mysql_upgrade has to be run!
+#
+# MDEV-27279: mariadb_upgrade check-if-upgrade with minor version change
+#
+Looking for 'mysql' as: mysql
+This installation of MariaDB is already upgraded to MariaDB .
+There is no need to run mysql_upgrade again for MariaDB .
+This installation of MariaDB is already upgraded to MariaDB .
+There is no need to run mysql_upgrade again for MariaDB .
+You can use --force if you still want to run mysql_upgrade
+#
+# MDEV-27279: mariadb_upgrade check-if-upgrade with major version change
+#
+Major version upgrade detected from MariaDB  to MariaDB . Check required!
+Looking for 'mysql' as: mysql
+Major version upgrade detected from MariaDB  to MariaDB . Check required!
 End of 10.2 tests

mysql-test/r/mysql_upgrade_noengine.result

@@ -50,6 +50,7 @@ Message	Unknown storage engine 'BLACKHOLE'
 Level	Warning
 Code	1286
 Message	Unknown storage engine 'ARCHIVE'
+# upgrade from 10.1 - engines aren't enabled
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
 mysql
@@ -136,6 +137,8 @@ Level	Warning
 Code	1286
 Message	Unknown storage engine 'ARCHIVE'
 alter table mysql.user drop column default_role, drop column max_statement_time;
+# still upgrade from 10.1
+Major version upgrade detected from MariaDB  to MariaDB . Check required!
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
 mysql
@@ -222,6 +225,7 @@ Level	Warning
 Code	1286
 Message	Unknown storage engine 'ARCHIVE'
 alter table mysql.user drop column default_role, drop column max_statement_time;
+# upgrade from 10.0 - engines are enabled
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
 mysql

mysql-test/r/mysql_upgrade_view.result

@@ -205,7 +205,7 @@ v3	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VI
 show create view v4;
 View	Create View	character_set_client	collation_connection
 v4	CREATE ALGORITHM=TEMPTABLE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v4` AS select `t1`.`a` AS `a` from `t1`	latin1	latin1_swedish_ci
-MySQL upgrade detected
+MariaDB upgrade detected
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
 mysql
@@ -324,7 +324,7 @@ drop view v1,v2,v3,v4;
 rename table mysql.event to mysql.ev_bk;
 flush tables;
 The --upgrade-system-tables option was used, user tables won't be touched.
-MySQL upgrade detected
+MariaDB upgrade detected
 Phase 1/7: Checking and upgrading mysql database
 Processing databases
 mysql

mysql-test/t/mysql_upgrade-6984.test

@@ -13,6 +13,7 @@
 
 update mysql.user set password=password("foo") where user='root';
 
+--replace_regex /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
 --exec $MYSQL_UPGRADE
 
 connect(con1,localhost,root,foo,,,);
@@ -21,3 +22,6 @@ update mysql.user set password='' where user='root';
 flush privileges;
 # Load event table
 set global event_scheduler=OFF;
+
+let MYSQLD_DATADIR= `select @@datadir`;
+--remove_file $MYSQLD_DATADIR/mysql_upgrade_info

mysql-test/t/mysql_upgrade.test

@@ -17,7 +17,7 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 file_exists $MYSQLD_DATADIR/mysql_upgrade_info;
 
 --echo Run it again - should say already completed
---replace_result $MYSQL_SERVER_VERSION VERSION
+--replace_regex /upgraded to [^\n]*/upgraded to VERSION./ /again for [^\n]*/again for VERSION./
 --exec $MYSQL_UPGRADE 2>&1
 
 # It should have created a file in the MySQL Servers datadir
@@ -126,7 +126,7 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 --remove_file $MYSQLD_DATADIR/mysql_upgrade_info
 
 --echo # Running mysql_upgrade with --skip-write-binlog..
---replace_result $MYSQLTEST_VARDIR var
+--replace_regex /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
 --exec $MYSQL_UPGRADE --skip-write-binlog
 
 # mysql_upgrade must have created mysql_upgrade_info file,
@@ -140,6 +140,9 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 --echo Run mysql_upgrade with unauthorized access
 --error 1
 --exec $MYSQL_UPGRADE --skip-verbose --user=root --password=wrong_password 2>&1
+--replace_regex /.*mysqlcheck.*: Got/mysqlcheck: Got/ /\([0-9|-]*\)/(errno)/
+--error 1
+--exec $MYSQL_UPGRADE --skip-verbose --skip-version-check --user=root --password=wrong_password 2>&1
 
 --echo #
 --echo # MDEV-4332 Increase username length from 16 characters
@@ -235,6 +238,7 @@ FLUSH TABLES mysql.user;
 FLUSH PRIVILEGES;
 SHOW CREATE TABLE mysql.user;
 
+--replace_result $MYSQLTEST_VARDIR var
 --exec $MYSQL_UPGRADE --force 2>&1
 SHOW CREATE TABLE mysql.user;
 
@@ -279,6 +283,79 @@ SHOW GRANTS;
 DROP ROLE `aRole`;
 --exec $MYSQL mysql < $MYSQLTEST_VARDIR/tmp/user.sql
 FLUSH PRIVILEGES;
+
+--echo #
+--echo # MDEV-27279: mariadb_upgrade add --check-if-upgrade-is-needed
+--echo #
+
+--error 1
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --silent
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
+--error 1
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--error 1
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
+
+--echo #
+--echo # MDEV-27279: mariadb_upgrade check-if-upgrade absence is do it
+--echo #
+
+--remove_file $MYSQLD_DATADIR/mysql_upgrade_info
+--replace_regex /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
+
+--replace_regex /'mysql.* as:[^\n]*/'mysql' as: mysql/ /open .* Assuming/open XXX. Assuming/ /[^ ]*mysql_upgrade_info/...mysql_upgrade_info/
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
+
+--echo #
+--echo # MDEV-27279: mariadb_upgrade check-if-upgrade with minor version change
+--echo #
+
+# take 3rd number of version and change to 0
+
+let DATADIR= $MYSQLD_DATADIR;
+
+perl;
+  my $ver= $ENV{'MYSQL_SERVER_VERSION'} or die "MYSQL_SERVER_VERSION not set";
+  my $file= $ENV{'DATADIR'} or die "MYSQLD_DATADIR not set";
+  $ver =~ s/^(\d*)\.(\d*).(\d*)(.*)/$1.$2.0$4/;
+  open(FILE, ">$file/mysql_upgrade_info") or die "Failed to open $file";
+  print FILE "$ver\n";
+  close(FILE);
+EOF
+
+--error 1
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --silent
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--error 1
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
+--exec $MYSQL_UPGRADE
+--remove_file $MYSQLD_DATADIR/mysql_upgrade_info
+
+--echo #
+--echo # MDEV-27279: mariadb_upgrade check-if-upgrade with major version change
+--echo #
+
+# take 2rd number of version and change to 0
+
+let DATADIR= $MYSQLD_DATADIR;
+
+perl;
+  my $ver= $ENV{'MYSQL_SERVER_VERSION'} or die "MYSQL_SERVER_VERSION not set";
+  my $file= $ENV{'DATADIR'} or die "MYSQLD_DATADIR not set";
+  $ver =~ s/^(\d*)\.(\d*).(\d*)(.*)/$1.0.$3$4/;
+  open(FILE, ">$file/mysql_upgrade_info") or die "Failed to open $file";
+  print FILE "$ver\n";
+  close(FILE);
+EOF
+
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --silent
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB / /'mysql.* as:[^\n]*/'mysql' as: mysql/
+--exec $MYSQL_UPGRADE --check-if-upgrade-is-needed --verbose
 --remove_file $MYSQLD_DATADIR/mysql_upgrade_info
 
 --echo End of 10.2 tests

mysql-test/t/mysql_upgrade_noengine.test

@@ -26,7 +26,8 @@ uninstall plugin blackhole;
 uninstall plugin archive;
 select table_catalog, table_schema, table_name, table_type, engine, row_format, table_rows, data_length, table_comment from information_schema.tables where table_schema='test';
 
-# upgrade from 10.1 - engines aren't enabled
+--echo # upgrade from 10.1 - engines aren't enabled
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
 exec $MYSQL_UPGRADE 2>&1;
 select table_catalog, table_schema, table_name, table_type, engine, row_format, table_rows, data_length, table_comment from information_schema.tables where table_schema='test';
 
@@ -39,14 +40,16 @@ write_file $datadir/mysql_upgrade_info;
 10.1.10-MariaDB
 EOF
 
-# still upgrade from 10.1
+--echo # still upgrade from 10.1
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
 exec $MYSQL_UPGRADE 2>&1;
 select table_catalog, table_schema, table_name, table_type, engine, row_format, table_rows, data_length, table_comment from information_schema.tables where table_schema='test';
 
 alter table mysql.user drop column default_role, drop column max_statement_time;
 remove_file $datadir/mysql_upgrade_info;
 
-# upgrade from 10.0 - engines are enabled
+--echo # upgrade from 10.0 - engines are enabled
+--replace_regex /\d\d\.\d*\.\d*[^ .\n]*/MariaDB /
 exec $MYSQL_UPGRADE 2>&1;
 select table_catalog, table_schema, table_name, table_type, engine, row_format, table_rows, data_length, table_comment from information_schema.tables where table_schema='test';