- Fix for BUG#1858 "SQL-Thread stops working when using optimize table":

we change THD::system_thread from a 'bool' to a bitmap to be able to
distinguish between delayed-insert threads and slave threads.
- Fix for BUG#1701 "Update from multiple tables" (one line in sql_parse.cc,
plus a new test rpl_multi_update.test). That's just adding an initialization.


sql/repl_failsafe.cc:
  comment to warn about this unused code
sql/slave.cc:
  Now thd->system_thread is a bitmap, not a bool.
sql/sql_class.h:
  'bool' for THD::system_thread is not accurate enough; sometimes we need
  to distinguish between delayed-insert threads and slave threads;
  so changing THD::system_thread to a bitmap (uint).
sql/sql_insert.cc:
  thd.system_thread is now a bitmap
sql/sql_parse.cc:
  We need to initialize thd->lex.select_lex.options in mysql_init_query();
  it's already initialized in dispatch_command() but replication calls
  mysql_parse() directly, thus bypassing dispatch_command().
  Not initing it here leads to a query influencing the next query,
  in the slave SQL thread.
  The initialization in dispatch_command() must be kept as this
  command uses the variable in tests, even when the command was not a
  query (i.e. when mysql_init_query() was not called).

mysql-test/r/rpl_multi_update.result

+slave stop;
+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;
+slave start;
+drop table if exists t1,t2;
+CREATE TABLE t1 (
+a int unsigned not null auto_increment primary key,
+b int unsigned,
+) TYPE=MyISAM;
+CREATE TABLE t2 (
+a int unsigned not null auto_increment primary key,
+b int unsigned
+) TYPE=MyISAM;
+INSERT INTO t1 VALUES (NULL, 0);
+INSERT INTO t1 SELECT NULL, 0 FROM t1;
+INSERT INTO t2 VALUES (NULL, 0), (NULL,1);
+SELECT * FROM t1 ORDER BY a;
+a	b
+1	0
+2	0
+SELECT * FROM t2 ORDER BY a;
+a	b
+1	0
+2	1
+UPDATE t1, t2 SET t1.b = t2.b WHERE t1.a = t2.a;

mysql-test/t/rpl_multi_update.test

+source include/master-slave.inc;
+drop table if exists t1,t2;
+
+CREATE TABLE t1 (
+ a int unsigned not null auto_increment primary key,
+ b int unsigned,
+) TYPE=MyISAM;
+
+CREATE TABLE t2 (
+ a int unsigned not null auto_increment primary key,
+ b int unsigned
+) TYPE=MyISAM;
+
+INSERT INTO t1 VALUES (NULL, 0);
+INSERT INTO t1 SELECT NULL, 0 FROM t1;
+
+INSERT INTO t2 VALUES (NULL, 0), (NULL,1);
+
+SELECT * FROM t1 ORDER BY a;
+SELECT * FROM t2 ORDER BY a;
+
+UPDATE t1, t2 SET t1.b = t2.b WHERE t1.a = t2.a;
+save_master_pos;
+connection slave;
+sync_with_master;

sql/repl_failsafe.cc

@@ -52,6 +52,13 @@ static Slave_log_event* find_slave_event(IO_CACHE* log,
 					 const char* log_file_name,
 					 char* errmsg);
 
+/*
+  All of the functions defined in this file which are not used (the ones to
+  handle failsafe) are not used; their code has not been updated for more than
+  one year now so should be considered as BADLY BROKEN. Do not enable it.
+  The used functions (to handle LOAD DATA FROM MASTER, plus some small
+  functions like register_slave()) are working.
+*/
 
 static int init_failsafe_rpl_thread(THD* thd)
 {

sql/slave.cc

@@ -2021,7 +2021,9 @@ improper_arguments: %d  timed_out: %d",
 static int init_slave_thread(THD* thd, SLAVE_THD_TYPE thd_type)
 {
   DBUG_ENTER("init_slave_thread");
-  thd->system_thread = thd->bootstrap = 1;
+  thd->system_thread = (thd_type == SLAVE_THD_SQL) ?
+    SYSTEM_THREAD_SLAVE_SQL : SYSTEM_THREAD_SLAVE_IO; 
+  thd->bootstrap= 1;
   thd->host_or_ip= "";
   thd->client_capabilities = 0;
   my_net_init(&thd->net, 0);

sql/sql_class.h

@@ -460,7 +460,7 @@ public:
   long	     dbug_thread_id;
   pthread_t  real_id;
   uint	     current_tablenr,tmp_table,cond_count;
-  uint	     server_status,open_options;
+  uint	     server_status,open_options,system_thread;
   uint32     query_length;
   uint32     db_length;
   /* variables.transaction_isolation is reset to this after each commit */
@@ -470,7 +470,7 @@ public:
   bool	     set_query_id,locked,count_cuted_fields,some_tables_deleted;
   bool	     no_errors, allow_sum_func, password, fatal_error;
   bool	     query_start_used,last_insert_id_used,insert_id_used,rand_used;
-  bool	     system_thread,in_lock_tables,global_read_lock;
+  bool	     in_lock_tables,global_read_lock;
   bool       query_error, bootstrap, cleanup_done;
   bool	     safe_to_cache_query;
   bool	     volatile killed;
@@ -592,6 +592,11 @@ public:
   CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
 };
 
+/* Flags for the THD::system_thread (bitmap) variable */
+#define SYSTEM_THREAD_DELAYED_INSERT 1
+#define SYSTEM_THREAD_SLAVE_IO 2
+#define SYSTEM_THREAD_SLAVE_SQL 4
+
 /*
   Used to hold information about file and file structure in exchainge 
   via non-DB file (...INTO OUTFILE..., ...LOAD DATA...)

sql/sql_insert.cc

@@ -550,7 +550,7 @@ public:
     thd.command=COM_DELAYED_INSERT;
 
     bzero((char*) &thd.net,sizeof(thd.net));	// Safety
-    thd.system_thread=1;
+    thd.system_thread= SYSTEM_THREAD_DELAYED_INSERT;
     thd.host_or_ip= "";
     bzero((char*) &info,sizeof(info));
     pthread_mutex_init(&mutex,MY_MUTEX_INIT_FAST);

sql/sql_parse.cc

@@ -2902,6 +2902,12 @@ mysql_init_query(THD *thd)
   thd->lex.select_lex.table_list.first=0;
   thd->lex.select_lex.table_list.next= (byte**) &thd->lex.select_lex.table_list.first;
   thd->lex.select_lex.next=0;
+  /*
+    select_lex.options is also inited in dispatch_command(), but for
+    replication (which bypasses dispatch_command() and calls mysql_parse()
+    directly) we must do it here.
+  */
+  thd->lex.select_lex.options=0;
   thd->lex.olap=0;
   thd->lex.select->olap= UNSPECIFIED_OLAP_TYPE;
   thd->fatal_error=0;				// Safety