Bug#27783 mysql_install_db should be able to install again, preserving existing files.

 - Allow mysql_install_db to be run a second time in the same
   datadir to create and fill any missing system tables


scripts/mysql_install_db.sh:
  Remove check that dissallowed running mysql_install_db a second time
  in same directory
scripts/mysql_system_tables.sql:
  Save information about if tables db and user already existed
scripts/mysql_system_tables_data.sql:
  Fill tables db and user with initial data if tables
  didn't already exist.

3 files changed, 20 insertions, 18 deletions

diff --git a/scripts/mysql_install_db.sh b/scripts/mysql_install_db.sh
index c1a27eb0bc8..63995eb1575 100644
--- a/scripts/mysql_install_db.sh
+++ b/scripts/mysql_install_db.sh
@@ -135,17 +135,6 @@ else
   fi
 fi
 
-# Check that no previous MySQL installation exist
-if test -f "$ldata/mysql/db.frm"
-then
-  echo "FATAL ERROR: Found already existing MySQL system tables"
-  echo "in $ldata."
-  echo "If you are upgrading from a previous MySQL version you"
-  echo "should run '$bindir/mysql_upgrade', "
-  echo "to upgrade all tables for this version of MySQL"
-  exit 1;
-fi
-
 # Find SQL scripts needed for bootstrap
 fill_help_tables="fill_help_tables.sql"
 create_system_tables="mysql_system_tables.sql"
diff --git a/scripts/mysql_system_tables.sql b/scripts/mysql_system_tables.sql
index 5f5aea20729..d9c870f1d73 100644
--- a/scripts/mysql_system_tables.sql
+++ b/scripts/mysql_system_tables.sql
@@ -6,12 +6,17 @@ set storage_engine=myisam;
 
 CREATE TABLE IF NOT EXISTS db (   Host char(60) binary DEFAULT '' NOT NULL, Db char(64) binary DEFAULT '' NOT NULL, User char(16) binary DEFAULT '' NOT NULL, Select_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Insert_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Update_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Delete_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Drop_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Grant_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, References_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Index_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_tmp_table_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Lock_tables_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Show_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Execute_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, PRIMARY KEY Host (Host,Db,User), KEY User (User) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Database privileges';
 
+-- Remember for later if db table already existed
+set @had_db_table= @@warning_count != 0;
 
 CREATE TABLE IF NOT EXISTS host (  Host char(60) binary DEFAULT '' NOT NULL, Db char(64) binary DEFAULT '' NOT NULL, Select_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Insert_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Update_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Delete_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Drop_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Grant_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, References_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Index_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_tmp_table_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Lock_tables_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Show_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Execute_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, PRIMARY KEY Host (Host,Db) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Host privileges;  Merged with database privileges';
 
 
 CREATE TABLE IF NOT EXISTS user (   Host char(60) binary DEFAULT '' NOT NULL, User char(16) binary DEFAULT '' NOT NULL, Password char(41) character set latin1 collate latin1_bin DEFAULT '' NOT NULL, Select_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Insert_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Update_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Delete_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Drop_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Reload_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Shutdown_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Process_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, File_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Grant_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, References_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Index_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Show_db_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Super_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_tmp_table_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Lock_tables_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Execute_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Repl_slave_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Repl_client_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Show_view_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Alter_routine_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, Create_user_priv enum('N','Y') COLLATE utf8_general_ci DEFAULT 'N' NOT NULL, ssl_type enum('','ANY','X509', 'SPECIFIED') COLLATE utf8_general_ci DEFAULT '' NOT NULL, ssl_cipher BLOB NOT NULL, x509_issuer BLOB NOT NULL, x509_subject BLOB NOT NULL, max_questions int(11) unsigned DEFAULT 0  NOT NULL, max_updates int(11) unsigned DEFAULT 0  NOT NULL, max_connections int(11) unsigned DEFAULT 0  NOT NULL, max_user_connections int(11) unsigned DEFAULT 0  NOT NULL, PRIMARY KEY Host (Host,User) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin comment='Users and global privileges';
 
+-- Remember for later if user table already existed
+set @had_user_table= @@warning_count != 0;
+
 
 CREATE TABLE IF NOT EXISTS func (  name char(64) binary DEFAULT '' NOT NULL, ret tinyint(1) DEFAULT '0' NOT NULL, dl char(128) DEFAULT '' NOT NULL, type enum ('function','aggregate') COLLATE utf8_general_ci NOT NULL, PRIMARY KEY (name) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin   comment='User defined functions';
 
diff --git a/scripts/mysql_system_tables_data.sql b/scripts/mysql_system_tables_data.sql
index a9c816f2896..5f0289ab197 100644
--- a/scripts/mysql_system_tables_data.sql
+++ b/scripts/mysql_system_tables_data.sql
@@ -2,12 +2,20 @@
 -- The inital data for system tables of MySQL Server
 --
 
--- default grants for anyone to access database 'test' and 'test_%'
-INSERT INTO db VALUES ('%','test','','Y','Y','Y','Y','Y','Y','N','Y','Y','Y','Y','Y','Y','Y','Y','N','N');
-INSERT INTO db VALUES ('%','test\_%','','Y','Y','Y','Y','Y','Y','N','Y','Y','Y','Y','Y','Y','Y','Y','N','N');
+-- Fill "db" table with default grants for anyone to
+-- access database 'test' and 'test_%' if "db" table didn't exist
+CREATE TEMPORARY TABLE tmp_db LIKE db;
+INSERT INTO tmp_db VALUES ('%','test','','Y','Y','Y','Y','Y','Y','N','Y','Y','Y','Y','Y','Y','Y','Y','N','N');
+INSERT INTO tmp_db VALUES ('%','test\_%','','Y','Y','Y','Y','Y','Y','N','Y','Y','Y','Y','Y','Y','Y','Y','N','N');
+INSERT INTO db SELECT * FROM tmp_db WHERE @had_db_table=0;
+DROP TABLE tmp_db;
 
--- default users allowing root access from local machine
-INSERT INTO user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
-REPLACE INTO user VALUES (@@hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
-REPLACE INTO user VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
 
+-- Fill "users" table with default users allowing root access
+-- from local machine if "users" table didn't exist before
+CREATE TEMPORARY TABLE tmp_user LIKE user;
+INSERT INTO tmp_user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
+REPLACE INTO tmp_user VALUES (@@hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
+REPLACE INTO tmp_user VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0);
+INSERT INTO user SELECT * FROM tmp_user WHERE @had_user_table=0;
+DROP TABLE tmp_user;