Merge patch for bug #15195 from 5.0 -> 5.0-release (for 5.0.24)

mysql-test/r/warnings.result

@@ -173,6 +173,13 @@ alter table t1 engine=isam;
 Warnings:
 Warning	1266	Using storage engine MyISAM for table 't1'
 drop table t1;
+create table t1 (id int) engine=merge;
+Warnings:
+Warning	1266	Using storage engine MyISAM for table 't1'
+alter table t1 engine=merge;
+Warnings:
+Warning	1266	Using storage engine MyISAM for table 't1'
+drop table t1;
 create table t1 (id int) type=heap;
 Warnings:
 Warning	1287	'TYPE=storage_engine' is deprecated; use 'ENGINE=storage_engine' instead

mysql-test/t/warnings-master.opt

---skip-isam
+--skip-isam --skip-merge

mysql-test/t/warnings.test

@@ -117,6 +117,10 @@ create table t1 (id int) engine=isam;
 alter table t1 engine=isam;
 drop table t1;
 
+create table t1 (id int) engine=merge;
+alter table t1 engine=merge;
+drop table t1;
+
 #
 # Test for deprecated TYPE= syntax
 #

sql/handler.cc

@@ -302,7 +302,9 @@ handler *get_new_handler(TABLE *table, MEM_ROOT *alloc, enum db_type db_type)
 #endif
   case DB_TYPE_MRG_MYISAM:
   case DB_TYPE_MRG_ISAM:
-    return new (alloc) ha_myisammrg(table);
+    if (have_merge_db == SHOW_OPTION_YES)
+      return new (alloc) ha_myisammrg(table);
+    return NULL;
 #ifdef HAVE_BERKELEY_DB
   case DB_TYPE_BERKELEY_DB:
     if (have_berkeley_db == SHOW_OPTION_YES)

sql/mysql_priv.h

@@ -1304,6 +1304,10 @@ extern handlerton ndbcluster_hton;
 extern SHOW_COMP_OPTION have_ndbcluster;
 #endif
 
+/* MRG_MYISAM handler is always built, but may be skipped */
+extern handlerton myisammrg_hton;
+#define have_merge_db myisammrg_hton.state
+
 extern SHOW_COMP_OPTION have_isam;
 extern SHOW_COMP_OPTION have_raid, have_openssl, have_symlink, have_dlopen;
 extern SHOW_COMP_OPTION have_query_cache;

sql/mysqld.cc

@@ -300,7 +300,7 @@ static bool lower_case_table_names_used= 0;
 static bool volatile select_thread_in_use, signal_thread_in_use;
 static bool volatile ready_to_exit;
 static my_bool opt_debugging= 0, opt_external_locking= 0, opt_console= 0;
-static my_bool opt_bdb, opt_isam, opt_ndbcluster;
+static my_bool opt_bdb, opt_isam, opt_ndbcluster, opt_merge;
 static my_bool opt_short_log_format= 0;
 static uint kill_cached_threads, wake_thread;
 static ulong killed_threads, thread_created;
@@ -4648,7 +4648,8 @@ enum options_mysqld
   OPT_OLD_STYLE_USER_LIMITS,
   OPT_LOG_SLOW_ADMIN_STATEMENTS,
   OPT_TABLE_LOCK_WAIT_TIMEOUT,
-  OPT_PORT_OPEN_TIMEOUT
+  OPT_PORT_OPEN_TIMEOUT,
+  OPT_MERGE
 };
 
 
@@ -5101,6 +5102,9 @@ master-ssl",
 #endif /* HAVE_REPLICATION */
   {"memlock", OPT_MEMLOCK, "Lock mysqld in memory.", (gptr*) &locked_in_memory,
    (gptr*) &locked_in_memory, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
+  {"merge", OPT_MERGE, "Enable Merge storage engine. Disable with \
+--skip-merge.",
+   (gptr*) &opt_merge, (gptr*) &opt_merge, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0},
   {"myisam-recover", OPT_MYISAM_RECOVER,
    "Syntax: myisam-recover[=option[,option...]], where option can be DEFAULT, BACKUP, FORCE or QUICK.",
    (gptr*) &myisam_recover_options_str, (gptr*) &myisam_recover_options_str, 0,
@@ -6883,6 +6887,11 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
     global_system_variables.tx_isolation= (type-1);
     break;
   }
+  case OPT_MERGE:
+    if (opt_merge)
+      have_merge_db= SHOW_OPTION_YES;
+    else
+      have_merge_db= SHOW_OPTION_DISABLED;
 #ifdef HAVE_BERKELEY_DB
   case OPT_BDB_NOSYNC:
     /* Deprecated option */

sql/set_var.cc

@@ -865,6 +865,7 @@ struct show_var_st init_vars[]= {
   {"have_innodb",	      (char*) &have_innodb,		    SHOW_HAVE},
   {"have_isam",		      (char*) &have_isam,		    SHOW_HAVE},
   {"have_ndbcluster",         (char*) &have_ndbcluster,             SHOW_HAVE},
+  {"have_merge_engine",       (char*) &have_merge_db,               SHOW_HAVE},
   {"have_openssl",	      (char*) &have_openssl,		    SHOW_HAVE},
   {"have_query_cache",        (char*) &have_query_cache,            SHOW_HAVE},
   {"have_raid",		      (char*) &have_raid,		    SHOW_HAVE},