Making DROP TABLE IF EXISTS, DROP DATABASE IF EXISTS, DELETE FROM, UPDATE be logged to

binlog even if they changed nothing, and a test for this.
This is useful when users use these commands to clean up their master and slave by issuing
one command on master (assume master and slave have slightly different data for some
reason and you want to clean up both).
Note that I have not changed multi-table DELETE and multi-table UPDATE because their
error-reporting mechanism is more complicated.

mysql-test/r/mysqlbinlog.result

-drop table if exists t1,t2;
 set timestamp=1000000000;
+drop table if exists t1,t2;
 create table t1 (word varchar(20));
 create table t2 (id int auto_increment not null primary key);
 insert into t1 values ("abirvalg");
@@ -17,6 +17,8 @@ flush logs;
 /*!40019 SET @@session.max_insert_delayed_threads=0*/;
 use test;
 SET TIMESTAMP=1000000000;
+drop table if exists t1,t2;
+SET TIMESTAMP=1000000000;
 create table t1 (word varchar(20));
 SET TIMESTAMP=1000000000;
 create table t2 (id int auto_increment not null primary key);
@@ -51,6 +53,8 @@ insert into t1 values ("Alas");
 /*!40019 SET @@session.max_insert_delayed_threads=0*/;
 use test;
 SET TIMESTAMP=1000000000;
+drop table if exists t1,t2;
+SET TIMESTAMP=1000000000;
 create table t1 (word varchar(20));
 SET TIMESTAMP=1000000000;
 create table t2 (id int auto_increment not null primary key);

mysql-test/r/rpl_delete_all.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+create database test1;
+drop database if exists test1;
+Warnings:
+Note	1008	Can't drop database 'test1'; database doesn't exist
+show tables from test1;
+ERROR HY000: Can't read dir of './test1/' (Errcode: 2)
+create table t1 (a int);
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+select * from t1;
+ERROR 42S02: Table 'test.t1' doesn't exist
+create table t1 (a int);
+insert into t1 values(1);
+delete from t1;
+select * from t1;
+a
+insert into t1 values(1);
+insert into t1 values(2);
+update t1 set a=2;
+select * from t1;
+a
+2
+2
+drop table t1;

mysql-test/r/rpl_flush_log_loop.result

@@ -14,4 +14,4 @@ start slave;
 flush logs;
 show slave status;
 Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
-#	127.0.0.1	root	SLAVE_PORT	60	slave-bin.000001	79	relay-log.000002	4	slave-bin.000001	Yes	Yes							0		0	79	4	None		0	No						#
+#	127.0.0.1	root	SLAVE_PORT	60	slave-bin.000001	161	relay-log.000002	4	slave-bin.000001	Yes	Yes							0		0	161	4	None		0	No						#

mysql-test/r/rpl_replicate_do.result

@@ -28,4 +28,4 @@ ERROR 42S02: Table 'test.t11' doesn't exist
 drop table if exists t1,t2,t11;
 show slave status;
 Slave_IO_State	Master_Host	Master_User	Master_Port	Connect_Retry	Master_Log_File	Read_Master_Log_Pos	Relay_Log_File	Relay_Log_Pos	Relay_Master_Log_File	Slave_IO_Running	Slave_SQL_Running	Replicate_Do_DB	Replicate_Ignore_DB	Replicate_Do_Table	Replicate_Ignore_Table	Replicate_Wild_Do_Table	Replicate_Wild_Ignore_Table	Last_Errno	Last_Error	Skip_Counter	Exec_Master_Log_Pos	Relay_Log_Space	Until_Condition	Until_Log_File	Until_Log_Pos	Master_SSL_Allowed	Master_SSL_CA_File	Master_SSL_CA_Path	Master_SSL_Cert	Master_SSL_Cipher	Master_SSL_Key	Seconds_Behind_Master
-#	127.0.0.1	root	MASTER_PORT	1	master-bin.000001	1281	slave-relay-bin.000002	1325	master-bin.000001	Yes	Yes			test.t1				0		0	1281	1325	None		0	No						#
+#	127.0.0.1	root	MASTER_PORT	1	master-bin.000001	1340	slave-relay-bin.000002	1384	master-bin.000001	Yes	Yes			test.t1				0		0	1340	1384	None		0	No						#

mysql-test/r/rpl_temporary.result

@@ -39,17 +39,18 @@ f
 show binlog events;
 Log_name	Pos	Event_type	Server_id	Orig_log_pos	Info
 master-bin.000001	4	Start	1	4	Server ver: VERSION, Binlog ver: 3
-master-bin.000001	79	Query	1	79	use `test`; create table t1(f int)
-master-bin.000001	136	Query	1	136	use `test`; create table t2(f int)
-master-bin.000001	193	Query	1	193	use `test`; insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10)
-master-bin.000001	290	Query	1	290	use `test`; create temporary table t3(f int)
-master-bin.000001	357	Query	1	357	use `test`; insert into t3 select * from t1 where f<6
-master-bin.000001	433	Query	1	433	use `test`; create temporary table t3(f int)
-master-bin.000001	500	Query	1	500	use `test`; insert into t2 select count(*) from t3
-master-bin.000001	573	Query	1	573	use `test`; insert into t3 select * from t1 where f>=4
-master-bin.000001	650	Query	1	650	use `test`; drop temporary table t3
-master-bin.000001	708	Query	1	708	use `test`; insert into t2 select count(*) from t3
-master-bin.000001	781	Query	1	781	use `test`; drop temporary table t3
+master-bin.000001	79	Query	1	79	use `test`; drop table if exists t1,t2
+master-bin.000001	140	Query	1	140	use `test`; create table t1(f int)
+master-bin.000001	197	Query	1	197	use `test`; create table t2(f int)
+master-bin.000001	254	Query	1	254	use `test`; insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10)
+master-bin.000001	351	Query	1	351	use `test`; create temporary table t3(f int)
+master-bin.000001	418	Query	1	418	use `test`; insert into t3 select * from t1 where f<6
+master-bin.000001	494	Query	1	494	use `test`; create temporary table t3(f int)
+master-bin.000001	561	Query	1	561	use `test`; insert into t2 select count(*) from t3
+master-bin.000001	634	Query	1	634	use `test`; insert into t3 select * from t1 where f>=4
+master-bin.000001	711	Query	1	711	use `test`; drop temporary table t3
+master-bin.000001	769	Query	1	769	use `test`; insert into t2 select count(*) from t3
+master-bin.000001	842	Query	1	842	use `test`; drop temporary table t3
 drop table t1, t2;
 use test;
 SET TIMESTAMP=1040323920;

mysql-test/t/mysqlbinlog.test

 # We are using .opt file since we need small binlog size
---disable_warnings
-drop table if exists t1,t2;
---enable_warnings
 
 # we need this for getting fixed timestamps inside of this test
 set timestamp=1000000000;
 
+--disable_warnings
+drop table if exists t1,t2;
+--enable_warnings
+
 create table t1 (word varchar(20));
 create table t2 (id int auto_increment not null primary key);
 

mysql-test/t/rpl_delete_all.test

+source include/master-slave.inc;
+
+connection slave;
+create database test1;
+connection master;
+drop database if exists test1;
+sync_slave_with_master;
+# can't read dir
+error 12;
+show tables from test1;
+
+connection slave;
+create table t1 (a int);
+connection master;
+drop table if exists t1;
+sync_slave_with_master;
+# table does not exist
+error 1146;
+select * from t1;
+
+connection master;
+create table t1 (a int);
+sync_slave_with_master;
+insert into t1 values(1);
+connection master;
+delete from t1;
+sync_slave_with_master;
+select * from t1;
+
+insert into t1 values(1);
+connection master;
+insert into t1 values(2);
+update t1 set a=2;
+sync_slave_with_master;
+select * from t1;
+
+# cleanup
+connection master;
+drop table t1;
+sync_slave_with_master;

sql/sql_db.cc

@@ -358,34 +358,34 @@ int mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
     {
       error= -1;
       my_error(ER_DB_DROP_EXISTS,MYF(0),db);
+      goto exit;
     }
     else
-    {
       push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
 			  ER_DB_DROP_EXISTS, ER(ER_DB_DROP_EXISTS), db);
-      if (!silent)
-        send_ok(thd,0);
-    }
-    goto exit;
   }
-  if (lower_case_table_names)
+  else
   {
-    /* Convert database to lower case */
-    strmov(tmp_db, db);
-    my_casedn_str(files_charset_info, tmp_db);
-    db= tmp_db;
-  }
-
     pthread_mutex_lock(&LOCK_open);
     remove_db_from_cache(db);
     pthread_mutex_unlock(&LOCK_open);
     
-  error = -1;
-  if ((deleted=mysql_rm_known_files(thd, dirp, db, path,0)) >= 0 && thd)
+    error= -1;
+    if ((deleted= mysql_rm_known_files(thd, dirp, db, path, 0)) >= 0)
     {
       ha_drop_database(path);
       query_cache_invalidate1(db);  
-    if (!silent)
+      error = 0;
+    }
+  }
+  if (lower_case_table_names)
+  {
+    /* Convert database to lower case */
+    strmov(tmp_db, db);
+    my_casedn_str(files_charset_info, tmp_db);
+    db= tmp_db;
+  }
+  if (!silent && deleted>=0 && thd)
   {
     const char *query;
     ulong query_length;
@@ -393,13 +393,13 @@ int mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
     {
       /* The client used the old obsolete mysql_drop_db() call */
       query= path;
-	query_length = (uint) (strxmov(path,"drop database `", db, "`",
-				       NullS)- path);
+      query_length= (uint) (strxmov(path, "drop database `", db, "`",
+                                     NullS) - path);
     }
     else
     {
-	query=thd->query;
-	query_length=thd->query_length;
+      query =thd->query;
+      query_length= thd->query_length;
     }
     mysql_update_log.write(thd, query, query_length);
     if (mysql_bin_log.is_open())
@@ -408,9 +408,7 @@ int mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent)
       thd->clear_error();
       mysql_bin_log.write(&qinfo);
     }
-      send_ok(thd,(ulong) deleted);
-    }
-    error = 0;
+    send_ok(thd, (ulong) deleted);
   }
 
 exit:

sql/sql_delete.cc

@@ -199,7 +199,15 @@ cleanup:
 
   transactional_table= table->file->has_transactions();
   log_delayed= (transactional_table || table->tmp_table);
-  if (deleted && (error <= 0 || !transactional_table))
+  /*
+    We write to the binary log even if we deleted no row, because maybe the
+    user is using this command to ensure that a table is clean on master *and
+    on slave*. Think of the case of a user having played separately with the
+    master's table and slave's table and wanting to take a fresh identical
+    start now.
+    error < 0 means "really no error". error <= 0 means "maybe some error".
+  */
+  if ((deleted || (error < 0)) && (error <= 0 || !transactional_table))
   {
     mysql_update_log.write(thd,thd->query, thd->query_length);
     if (mysql_bin_log.is_open())
@@ -544,6 +552,8 @@ bool multi_delete::send_eof()
     rows and we succeeded, or also in an error case when there
     was a non-transaction-safe table involved, since
     modifications in it cannot be rolled back.
+    Note that if we deleted nothing we don't write to the binlog (TODO:
+    fix this).
   */
   if (deleted && (error <= 0 || normal_tables))
   {

sql/sql_table.cc

@@ -254,7 +254,17 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     }
   }
   thd->tmp_table_used= tmp_table_deleted;
-  if (some_tables_deleted || tmp_table_deleted)
+  error= 0;
+  if (wrong_tables.length())
+  {
+    if (!foreign_key_error)
+      my_error(ER_BAD_TABLE_ERROR,MYF(0), wrong_tables.c_ptr());
+    else
+      my_error(ER_ROW_IS_REFERENCED, MYF(0));
+    error= 1;
+  }
+
+  if (some_tables_deleted || tmp_table_deleted || !error)
   {
     query_cache_invalidate3(thd, tables, 0);
     if (!dont_log_query)
@@ -262,6 +272,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
       mysql_update_log.write(thd, thd->query,thd->query_length);
       if (mysql_bin_log.is_open())
       {
+        if (!error)
           thd->clear_error();
 	Query_log_event qinfo(thd, thd->query, thd->query_length,
 			      tmp_table_deleted && !some_tables_deleted);
@@ -271,15 +282,6 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
   }
 
   unlock_table_names(thd, tables);
-  error= 0;
-  if (wrong_tables.length())
-  {
-    if (!foreign_key_error)
-      my_error(ER_BAD_TABLE_ERROR,MYF(0),wrong_tables.c_ptr());
-    else
-      my_error(ER_ROW_IS_REFERENCED,MYF(0));
-    error= 1;
-  }
   DBUG_RETURN(error);
 }
 

sql/sql_update.cc

@@ -331,7 +331,7 @@ int mysql_update(THD *thd,
 
   transactional_table= table->file->has_transactions();
   log_delayed= (transactional_table || table->tmp_table);
-  if (updated && (error <= 0 || !transactional_table))
+  if ((updated || (error < 0)) && (error <= 0 || !transactional_table))
   {
     mysql_update_log.write(thd,thd->query,thd->query_length);
     if (mysql_bin_log.is_open())
@@ -1092,7 +1092,9 @@ bool multi_update::send_eof()
   /*
     Write the SQL statement to the binlog if we updated
     rows and we succeeded or if we updated some non
-    transacational tables
+    transacational tables.
+    Note that if we updated nothing we don't write to the binlog (TODO:
+    fix this).
   */
 
   if (updated && (local_error <= 0 || !trans_safe))