Merge magare.gmz:/home/kgeorge/mysql/work/B29325-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/work/B29325-5.1-opt

include/my_base.h

@@ -299,6 +299,7 @@ enum ha_base_keytype {
 #define HA_PACK_RECORD		2	/* Request packed record format */
 #define HA_CREATE_TMP_TABLE	4
 #define HA_CREATE_CHECKSUM	8
+#define HA_CREATE_KEEP_FILES	16      /* don't overwrite .MYD and MYI */
 #define HA_CREATE_DELAY_KEY_WRITE 64
 #define HA_CREATE_RELIES_ON_SQL_LAYER 128
 

mysql-test/r/create.result

@@ -1516,6 +1516,23 @@ t1	CREATE TABLE `t1` (
   `c17` int(11) DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
+CREATE DATABASE db1;
+CREATE DATABASE db2;
+USE db2;
+INSERT INTO db2.t1 VALUES (1);
+SELECT * FROM db2.t1;
+b
+1
+RESET QUERY CACHE;
+USE db1;
+SET SESSION keep_files_on_create = TRUE;
+CREATE TABLE t1 (a INT) ENGINE MYISAM;
+ERROR HY000: Can't create/write to file './db1/t1.MYD' (Errcode: 17)
+SET SESSION keep_files_on_create = DEFAULT;
+DROP TABLE db2.t1;
+DROP DATABASE db1;
+DROP DATABASE db2;
+USE test;
 End of 5.0 tests
 CREATE TABLE t1 (a int, b int);
 insert into t1 values (1,1),(1,2);

mysql-test/t/create.test

@@ -1122,6 +1122,37 @@ show create table t1;
 
 drop table t1;
 
+#
+# Bug #29325: create table overwrites .MYD file of other table (datadir)
+#
+
+CREATE DATABASE db1; 
+CREATE DATABASE db2;
+
+USE db2;
+--disable_query_log
+eval CREATE TABLE t1 (b INT) ENGINE MYISAM
+DATA DIRECTORY = '$MYSQLTEST_VARDIR/master-data/db1/';
+--enable_query_log
+
+INSERT INTO db2.t1 VALUES (1);
+SELECT * FROM db2.t1;
+RESET QUERY CACHE;
+
+USE db1;
+
+#no warning from create table
+SET SESSION keep_files_on_create = TRUE;
+--disable_abort_on_error
+CREATE TABLE t1 (a INT) ENGINE MYISAM;
+--enable_abort_on_error
+SET SESSION keep_files_on_create = DEFAULT;
+
+DROP TABLE db2.t1;
+DROP DATABASE db1;
+DROP DATABASE db2;
+USE test;
+
 
 --echo End of 5.0 tests
 

sql/set_var.cc

@@ -616,6 +616,8 @@ sys_var_thd_time_zone            sys_time_zone(&vars, "time_zone");
 /* Global read-only variable containing hostname */
 static sys_var_const_str        sys_hostname(&vars, "hostname", glob_hostname);
 
+sys_var_thd_bool  sys_keep_files_on_create(&vars, "keep_files_on_create", 
+                                           &SV::keep_files_on_create);
 /* Read only variables */
 
 static sys_var_have_variable sys_have_compress(&vars, "have_compress", &have_compress);

sql/sql_class.h

@@ -305,6 +305,7 @@ struct system_variables
   my_bool old_mode;
   my_bool query_cache_wlock_invalidate;
   my_bool engine_condition_pushdown;
+  my_bool keep_files_on_create;
   my_bool ndb_force_send;
   my_bool ndb_use_copying_alter_table;
   my_bool ndb_use_exact_count;

sql/sql_table.cc

@@ -4697,8 +4697,11 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table, TABLE_LIST* src_table,
   DBUG_EXECUTE_IF("sleep_create_like_before_ha_create", my_sleep(6000000););
 
   dst_path[dst_path_length - reg_ext_length]= '\0';  // Remove .frm
+  if (thd->variables.keep_files_on_create)
+    create_info->options|= HA_CREATE_KEEP_FILES;
   err= ha_create_table(thd, dst_path, db, table_name, create_info, 1);
   VOID(pthread_mutex_unlock(&LOCK_open));
+
   if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
   {
     if (err || !open_temporary_table(thd, dst_path, db, table_name, 1))

sql/unireg.cc

@@ -355,6 +355,8 @@ int rea_create_table(THD *thd, const char *path,
 
   // Make sure mysql_create_frm din't remove extension
   DBUG_ASSERT(*fn_rext(frm_name));
+  if (thd->variables.keep_files_on_create)
+    create_info->options|= HA_CREATE_KEEP_FILES;
   if (file->create_handler_files(path, NULL, CHF_CREATE_FLAG, create_info))
     goto err_handler;
   if (!create_info->frm_only && ha_create_table(thd, path, db, table_name,

storage/myisam/ha_myisam.cc

@@ -1889,6 +1889,8 @@ int ha_myisam::create(const char *name, register TABLE *table_arg,
 
   if (ha_create_info->options & HA_LEX_CREATE_TMP_TABLE)
     create_flags|= HA_CREATE_TMP_TABLE;
+  if (ha_create_info->options & HA_CREATE_KEEP_FILES)
+    create_flags|= HA_CREATE_KEEP_FILES;
   if (options & HA_OPTION_PACK_RECORD)
     create_flags|= HA_PACK_RECORD;
   if (options & HA_OPTION_CHECKSUM)

storage/myisam/mi_create.c

@@ -615,6 +615,7 @@ int mi_create(const char *name,uint keys,MI_KEYDEF *keydefs,
               (have_iext ? MY_REPLACE_EXT : MY_APPEND_EXT));
     linkname_ptr=0;
     /* Replace the current file */
+    if (!(flags & HA_CREATE_KEEP_FILES))
       create_flag=MY_DELETE_OLD;
   }
 
@@ -689,6 +690,7 @@ int mi_create(const char *name,uint keys,MI_KEYDEF *keydefs,
 	fn_format(filename,name,"", MI_NAME_DEXT,
 	          MY_UNPACK_FILENAME | MY_APPEND_EXT);
 	linkname_ptr=0;
+        if (!(flags & HA_CREATE_KEEP_FILES))
           create_flag=MY_DELETE_OLD;
       }
       if ((dfile=