fixed drop/create database bug when holding global read lock

preserve originating server id in Intvar events to avoid inifinite loops

include/mysqld_error.h

@@ -208,4 +208,6 @@
 #define ER_LOCK_WAIT_TIMEOUT 1205
 #define ER_LOCK_TABLE_FULL 1206
 #define ER_READ_ONLY_TRANSACTION 1207
-#define ER_ERROR_MESSAGES 208
+#define ER_DROP_DB_WITH_READ_LOCK 1208
+#define ER_CREATE_DB_WITH_READ_LOCK 1209
+#define ER_ERROR_MESSAGES 210

mysql-test/r/drop.result

 n
 1
+Database
+foo
+mysql
+test
+Database
+mysql
+test

mysql-test/r/flush.result

 n
 3
 n
+23
+n
 345

mysql-test/t/drop.test

@@ -10,3 +10,16 @@ insert into t1 values(2);
 create table t1(n int);
 drop table t1;
 select * from t1;
+drop database if exists foo;
+flush tables with read lock;
+--error 1209
+create database foo;
+unlock tables;
+create database foo;
+show databases;
+flush tables with read lock;
+--error 1208
+drop database foo;
+unlock tables;
+drop database foo;
+show databases;

mysql-test/t/flush.test

@@ -33,6 +33,21 @@ unlock tables;
 connection con1;
 reap;
 
+#test if drop database will wait until we release the global read lock
+connection con1;
+drop database if exists foo;
+create database foo;
+create table foo.t1(n int);
+insert into foo.t1 values (23);
+flush tables with read lock;
+connection con2;
+send drop database foo;
+connection con1;
+select * from foo.t1;
+unlock tables;
+connection con2;
+reap;
+
 # test if dirty close releases global read lock
 connection con1;
 create table t1 (n int);

sql/log.cc

@@ -652,12 +652,16 @@ bool MYSQL_LOG::write(Query_log_event* event_info)
     if (thd->last_insert_id_used)
     {
       Intvar_log_event e((uchar)LAST_INSERT_ID_EVENT, thd->last_insert_id);
+      if(thd->server_id)
+	e.server_id = thd->server_id;
       if (e.write(file))
 	goto err;
     }
     if (thd->insert_id_used)
     {
       Intvar_log_event e((uchar)INSERT_ID_EVENT, thd->last_insert_id);
+      if(thd->server_id)
+	e.server_id = thd->server_id;
       if (e.write(file))
 	goto err;
     }

sql/share/czech/errmsg.txt

@@ -218,3 +218,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/danish/errmsg.txt

@@ -212,3 +212,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/dutch/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/english/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/estonian/errmsg.txt

@@ -213,3 +213,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/french/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/german/errmsg.txt

@@ -212,3 +212,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/greek/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/hungarian/errmsg.txt

@@ -211,3 +211,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/italian/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/japanese/errmsg.txt

@@ -211,3 +211,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/korean/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/norwegian-ny/errmsg.txt

@@ -211,3 +211,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/norwegian/errmsg.txt

@@ -211,3 +211,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/polish/errmsg.txt

@@ -213,3 +213,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/portuguese/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/romanian/errmsg.txt

@@ -213,3 +213,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/russian/errmsg.txt

@@ -212,3 +212,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/slovak/errmsg.txt

@@ -217,3 +217,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/spanish/errmsg.txt

@@ -210,3 +210,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/share/swedish/errmsg.txt

@@ -209,3 +209,5 @@
 "Lock wait timeout exceeded",
 "The total number of locks exceeds the lock table size",
 "Update locks cannot be acquired during a READ UNCOMMITTED transaction",
+"DROP DATABASE not allowed while thread is holding global read lock",
+"CREATE DATABASE not allowed while thread is holding global read lock",

sql/slave.cc

@@ -1367,7 +1367,7 @@ the slave thread with \"mysqladmin start-slave\". We stopped at log \
 	    {
 	      // show a little mercy, allow slave to read one more event
 	      // before cutting him off - otherwise he gets stuck
-	      // on Invar events, since they do not advance the offset
+	      // on Intvar events, since they do not advance the offset
 	      // immediately
 	      if (++stuck_count > 2)
 	        events_till_disconnect++;

sql/sql_db.cc

@@ -38,6 +38,32 @@ void mysql_create_db(THD *thd, char *db, uint create_options)
   DBUG_ENTER("mysql_create_db");
   
   VOID(pthread_mutex_lock(&LOCK_mysql_create_db));
+  VOID(pthread_mutex_lock(&LOCK_open));
+
+  // do not create database if another thread is holding read lock
+  if (global_read_lock)
+  {
+    if (thd->global_read_lock)
+    {
+      net_printf(&thd->net, ER_CREATE_DB_WITH_READ_LOCK);
+      VOID(pthread_mutex_unlock(&LOCK_open));
+      goto exit;
+    }
+    while (global_read_lock && ! thd->killed)
+    {
+      (void) pthread_cond_wait(&COND_refresh,&LOCK_open);
+    }
+    
+    if (thd->killed)
+    {
+      net_printf(&thd->net, ER_SERVER_SHUTDOWN);
+      VOID(pthread_mutex_unlock(&LOCK_open));
+      goto exit;
+    }
+
+  }
+  
+  VOID(pthread_mutex_unlock(&LOCK_open));
 
   /* Check directory */
   (void)sprintf(path,"%s/%s", mysql_data_home, db);
@@ -105,6 +131,26 @@ void mysql_rm_db(THD *thd,char *db,bool if_exists)
   VOID(pthread_mutex_lock(&LOCK_mysql_create_db));
   VOID(pthread_mutex_lock(&LOCK_open));
 
+  // do not drop database if another thread is holding read lock
+  if (global_read_lock)
+  {
+    if (thd->global_read_lock)
+    {
+      net_printf(&thd->net, ER_DROP_DB_WITH_READ_LOCK);
+      goto exit;
+    }
+    while (global_read_lock && ! thd->killed)
+    {
+      (void) pthread_cond_wait(&COND_refresh,&LOCK_open);
+    }
+
+    if (thd->killed)
+    {
+      net_printf(&thd->net, ER_SERVER_SHUTDOWN);
+      goto exit;
+    }
+  }
+
   (void) sprintf(path,"%s/%s",mysql_data_home,db);
   unpack_dirname(path,path);			// Convert if not unix
   /* See if the directory exists */