relay_log_space_limit

DBUG_ macro cleanup
buffer boundary cleanup
This changeset, although not fully tested, works for me better than 
anything I've had so far, including what is in the repository. I will 
push it unless something crashes while I am writing this :-)

mysql-test/r/rpl000014.result

@@ -7,22 +7,22 @@ show master status;
 File	Position	Binlog_do_db	Binlog_ignore_db
 master-bin.001	79		
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	1	master-bin.001	79	slave-relay-bin.002	120	master-bin.001	Yes	Yes			0		0	79
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	1	master-bin.001	79	slave-relay-bin.002	120	master-bin.001	Yes	Yes			0		0	79	124
 change master to master_log_pos=73;
 slave stop;
 change master to master_log_pos=73;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	1	master-bin.001	73	slave-relay-bin.001	4	master-bin.001	No	No			0		0	73
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	1	master-bin.001	73	slave-relay-bin.001	4	master-bin.001	No	No			0		0	73	4
 slave start;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	1	master-bin.001	73	slave-relay-bin.001	4	master-bin.001	Yes	Yes			0		0	73
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	1	master-bin.001	73	slave-relay-bin.001	4	master-bin.001	Yes	Yes			0		0	73	4
 change master to master_log_pos=173;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	1	master-bin.001	173	slave-relay-bin.001	4	master-bin.001	Yes	Yes			0		0	173
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	1	master-bin.001	173	slave-relay-bin.001	4	master-bin.001	Yes	Yes			0		0	173	4
 show master status;
 File	Position	Binlog_do_db	Binlog_ignore_db
 master-bin.001	79		

mysql-test/r/rpl000015.result

@@ -4,21 +4,21 @@ File	Position	Binlog_do_db	Binlog_ignore_db
 master-bin.001	79		
 reset slave;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-		0	0		0		0		No	No			0		0	0
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+		0	0		0		0		No	No			0		0	0	0
 change master to master_host='127.0.0.1';
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	test	MASTER_PORT	7		4	slave-relay-bin.001	4		No	No			0		0	0
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	test	MASTER_PORT	7		4	slave-relay-bin.001	4		No	No			0		0	0	4
 change master to master_host='127.0.0.1',master_user='root',
 master_password='',master_port=MASTER_PORT;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	7		4	slave-relay-bin.001	4		No	No			0		0	0
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	7		4	slave-relay-bin.001	4		No	No			0		0	0	4
 slave start;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	7	master-bin.001	79	slave-relay-bin.001	120	master-bin.001	Yes	Yes			0		0	79
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	7	master-bin.001	79	slave-relay-bin.001	120	master-bin.001	Yes	Yes			0		0	79	120
 drop table if exists t1;
 create table t1 (n int);
 insert into t1 values (10),(45),(90);

mysql-test/r/rpl000016.result

@@ -14,8 +14,8 @@ drop table if exists t1;
 create table t1 (s text);
 insert into t1 values('Could not break slave'),('Tried hard');
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	60	master-bin.001	234	slave-relay-bin.001	275	master-bin.001	Yes	Yes			0		0	234
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	60	master-bin.001	234	slave-relay-bin.001	275	master-bin.001	Yes	Yes			0		0	234	275
 select * from t1;
 s
 Could not break slave
@@ -41,8 +41,8 @@ Log_name
 master-bin.003
 insert into t2 values (65);
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	60	master-bin.003	155	slave-relay-bin.001	755	master-bin.003	Yes	Yes			0		0	155
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	60	master-bin.003	155	slave-relay-bin.001	755	master-bin.003	Yes	Yes			0		0	155	755
 select * from t2;
 m
 34
@@ -64,8 +64,8 @@ master-bin.006	445
 slave stop;
 slave start;
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	60	master-bin.006	445	slave-relay-bin.004	1229	master-bin.006	Yes	Yes			0		0	445
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	60	master-bin.006	445	slave-relay-bin.004	1229	master-bin.006	Yes	Yes			0		0	445	1229
 lock tables t3 read;
 select count(*) from t3 where n >= 4;
 count(*)

mysql-test/r/rpl_log.result

@@ -74,8 +74,8 @@ slave-bin.002	57	Query	1	4	use test; create table t1 (n int)
 slave-bin.002	115	Query	1	62	use test; insert into t1 values (1)
 slave-bin.002	175	Query	1	122	use test; drop table t1
 show slave status;
-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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos
-127.0.0.1	root	MASTER_PORT	1	master-bin.002	170	slave-relay-bin.002	916	master-bin.002	Yes	Yes			0		0	170
+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	Last_errno	Last_error	Skip_counter	Exec_master_log_pos	Relay_log_space
+127.0.0.1	root	MASTER_PORT	1	master-bin.002	170	slave-relay-bin.002	916	master-bin.002	Yes	Yes			0		0	170	920
 show new master for slave with master_log_file='master-bin.001' and
 master_log_pos=4 and  master_server_id=1;
 Log_name	Log_pos

mysys/mf_iocache.c

@@ -906,7 +906,7 @@ int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
   uint length;
   my_bool append_cache;
   my_off_t pos_in_file;
-  DBUG_ENTER("flush_io_cache");
+  DBUG_ENTER("_flush_io_cache");
 
   if (!(append_cache = (info->type == SEQ_READ_APPEND)))
     need_append_buffer_lock=0;

mysys/mf_iocache2.c

@@ -117,6 +117,7 @@ void my_b_seek(IO_CACHE *info,my_off_t pos)
   }
   info->pos_in_file=pos;
   info->seek_not_done=1;
+  DBUG_VOID_RETURN;
 }
 
 

sql/log.cc

@@ -83,7 +83,7 @@ static int find_uniq_filename(char *name)
 MYSQL_LOG::MYSQL_LOG(): last_time(0), query_start(0),index_file(-1),
 			name(0), log_type(LOG_CLOSED),write_error(0),
 			inited(0), file_id(1),no_rotate(0),
-			need_start_event(1)
+			need_start_event(1),bytes_written(0)
 {
   /*
     We don't want to intialize LOCK_Log here as the thread system may
@@ -99,6 +99,7 @@ MYSQL_LOG::~MYSQL_LOG()
   {
     (void) pthread_mutex_destroy(&LOCK_log);
     (void) pthread_mutex_destroy(&LOCK_index);
+    (void) pthread_cond_destroy(&update_cond);
   }
 }
 
@@ -233,18 +234,14 @@ void MYSQL_LOG::open(const char *log_name, enum_log_type log_type_arg,
   }
   else if (log_type == LOG_BIN)
   {
-      bool error;
-    /*
-      Explanation of the boolean black magic:
-      if we are supposed to write magic number try write
-      clean 
-up if failed
-      then if index_file has not been previously opened, try to open it
-      clean up if failed
-    */
-    if ((do_magic && my_b_write(&log_file, (byte*) BINLOG_MAGIC, 4)) ||
+    bool error;
+    if (do_magic)
+    {
+      if (my_b_write(&log_file, (byte*) BINLOG_MAGIC, 4) ||
 	open_index(O_APPEND | O_RDWR | O_CREAT))
-      goto err;
+        goto err;
+      bytes_written += 4;
+    }
 
     if (need_start_event && !no_auto_events)
     {
@@ -462,12 +459,30 @@ err:
     my_delete(fname, MYF(0)); // do not report error if the file is not there
   else
   {
+    MY_STAT s;
     my_close(index_file, MYF(MY_WME));
+    if (!my_stat(rli->relay_log_name,&s,MYF(0)))
+    {
+      sql_print_error("The first log %s failed to stat during purge",
+		      rli->relay_log_name);
+      error=1;
+      goto err;
+    }
     if (my_rename(fname,index_file_name,MYF(MY_WME)) ||
 	(index_file=my_open(index_file_name,O_BINARY|O_RDWR|O_APPEND,
 			    MYF(MY_WME)))<0 ||
 	my_delete(rli->relay_log_name, MYF(MY_WME)))
       error=1;
+    
+    pthread_mutex_lock(&rli->log_space_lock);
+    rli->log_space_total -= s.st_size;
+    fprintf(stderr,"purge_first_log: %ld\n", rli->log_space_total);
+    pthread_mutex_unlock(&rli->log_space_lock);
+    // ok to broadcast after the critical region as there is no risk of
+    // the mutex being destroyed by this thread later - this helps save
+    // context switches
+    pthread_cond_broadcast(&rli->log_space_cond);
+    
     if ((error=find_first_log(&rli->linfo,"",0/*no mutex*/)))
     {
       char buff[22];
@@ -695,6 +710,7 @@ void MYSQL_LOG::new_file(bool inside_mutex)
 	  if (thd && thd->slave_thread)
 	    r.flags |= LOG_EVENT_FORCED_ROTATE_F;
 	  r.write(&log_file);
+	  bytes_written += r.get_event_len();
 	}
 	// update needs to be signaled even if there is no rotate event
 	// log rotation should give the waiting thread a signal to
@@ -728,6 +744,7 @@ bool MYSQL_LOG::append(Log_event* ev)
     error=1;
     goto err;
   }
+  bytes_written += ev->get_event_len();
   if ((uint)my_b_append_tell(&log_file) > max_binlog_size)
   {
     new_file(1);
@@ -754,6 +771,7 @@ bool MYSQL_LOG::appendv(const char* buf, uint len,...)
       error = 1;
       break;
     }
+    bytes_written += len;
   } while ((buf=va_arg(args,const char*)) && (len=va_arg(args,uint)));
   
   if ((uint) my_b_append_tell(&log_file) > max_binlog_size)

sql/mysqld.cc

@@ -3042,6 +3042,8 @@ CHANGEABLE_VAR changeable_vars[] = {
       128*1024L, IO_SIZE*2+MALLOC_OVERHEAD, ~0L, MALLOC_OVERHEAD, IO_SIZE },
   { "record_rnd_buffer",           (long*) &record_rnd_cache_size,
       0, IO_SIZE*2+MALLOC_OVERHEAD, ~0L, MALLOC_OVERHEAD, IO_SIZE },
+  { "relay_log_space_limit",  (long*) &relay_log_space_limit, 0L, 0L,ULONG_MAX,
+    0, 1},
   { "slave_net_timeout",        (long*) &slave_net_timeout, 
       SLAVE_NET_TIMEOUT, 1, LONG_TIMEOUT, 0, 1 },
   { "slow_launch_time",        (long*) &slow_launch_time, 

sql/slave.cc

@@ -42,6 +42,8 @@ bool do_table_inited = 0, ignore_table_inited = 0;
 bool wild_do_table_inited = 0, wild_ignore_table_inited = 0;
 bool table_rules_on = 0;
 static TABLE* save_temporary_tables = 0;
+ulong relay_log_space_limit = 0; /* TODO: fix variables to access ulonglong
+				    values and make it ulonglong */
 // when slave thread exits, we need to remember the temporary tables so we
 // can re-use them on slave start
 
@@ -60,8 +62,10 @@ static int process_io_rotate(MASTER_INFO* mi, Rotate_log_event* rev);
 static int process_io_create_file(MASTER_INFO* mi, Create_file_log_event* cev);
 static int queue_old_event(MASTER_INFO* mi, const char* buf,
 			   uint event_len);
+static bool wait_for_relay_log_space(RELAY_LOG_INFO* rli);
 static inline bool io_slave_killed(THD* thd,MASTER_INFO* mi);
 static inline bool sql_slave_killed(THD* thd,RELAY_LOG_INFO* rli);
+static int count_relay_log_space(RELAY_LOG_INFO* rli);
 static int init_slave_thread(THD* thd, SLAVE_THD_TYPE thd_type);
 static int safe_connect(THD* thd, MYSQL* mysql, MASTER_INFO* mi);
 static int safe_reconnect(THD* thd, MYSQL* mysql, MASTER_INFO* mi);
@@ -264,8 +268,9 @@ void init_slave_skip_errors(char* arg)
 // are not running
 int purge_relay_logs(RELAY_LOG_INFO* rli, bool just_reset, const char** errmsg)
 {
+  DBUG_ENTER("purge_relay_logs");
   if (!rli->inited)
-    return 0; /* successfully do nothing */
+    DBUG_RETURN(0); /* successfully do nothing */
   DBUG_ASSERT(rli->slave_running == 0);
   DBUG_ASSERT(rli->mi->slave_running == 0);
   int error=0;
@@ -282,14 +287,20 @@ int purge_relay_logs(RELAY_LOG_INFO* rli, bool just_reset, const char** errmsg)
     goto err;
   }
   strnmov(rli->relay_log_name,rli->linfo.log_file_name,
-	  sizeof(rli->relay_log_name));
+	  sizeof(rli->relay_log_name)-1);
+  rli->log_space_total=4; //just first log with magic number and nothing else
   rli->relay_log_pos=4;
+  rli->relay_log.reset_bytes_written();
   rli->log_pos_current=0;
   if (!just_reset)
     error =  init_relay_log_pos(rli,0,0,0/*do not need data lock*/,errmsg);
-err:  
+err:
+#ifndef DBUG_OFF
+  char buf[22];
+#endif  
+  DBUG_PRINT("info",("log_space_total=%s",llstr(rli->log_space_total,buf)));
   pthread_mutex_unlock(&rli->data_lock);
-  return error;
+  DBUG_RETURN(error);
 }
 
 int terminate_slave_threads(MASTER_INFO* mi,int thread_mask,bool skip_lock)
@@ -953,8 +964,9 @@ void end_master_info(MASTER_INFO* mi)
 
 int init_relay_log_info(RELAY_LOG_INFO* rli, const char* info_fname)
 {
+  DBUG_ENTER("init_relay_log_info");
   if (rli->inited)
-    return 0;
+    DBUG_RETURN(0);
   MY_STAT stat_area;
   char fname[FN_REFLEN+128];
   int info_fd;
@@ -970,6 +982,8 @@ int init_relay_log_info(RELAY_LOG_INFO* rli, const char* info_fname)
   rli->log_pos_current=0;
   rli->abort_pos_wait=0;
   rli->skip_log_purge=0;
+  rli->log_space_limit = relay_log_space_limit;
+  rli->log_space_total = 0;
   // TODO: make this work with multi-master
   if (!opt_relay_logname)
   {
@@ -1001,7 +1015,7 @@ int init_relay_log_info(RELAY_LOG_INFO* rli, const char* info_fname)
 	my_close(info_fd, MYF(0));
       rli->info_fd=-1;
       pthread_mutex_unlock(&rli->data_lock);
-      return 1;
+      DBUG_RETURN(1);
     }
     if (init_relay_log_pos(rli,"",4,0/*no data mutex*/,&msg))
       goto err;
@@ -1021,7 +1035,7 @@ int init_relay_log_info(RELAY_LOG_INFO* rli, const char* info_fname)
 	my_close(info_fd, MYF(0));
       rli->info_fd=-1;
       pthread_mutex_unlock(&rli->data_lock);
-      return 1;
+      DBUG_RETURN(1);
     }
       
     rli->info_fd = info_fd;
@@ -1052,8 +1066,13 @@ int init_relay_log_info(RELAY_LOG_INFO* rli, const char* info_fname)
   // before flush_relay_log_info
   reinit_io_cache(&rli->info_file, WRITE_CACHE,0L,0,1);
   error=test(flush_relay_log_info(rli));
+  if (count_relay_log_space(rli))
+  {
+    msg="Error counting relay log space";
+    goto err;
+  }
   pthread_mutex_unlock(&rli->data_lock);
-  return error;
+  DBUG_RETURN(error);
 
 err:
   sql_print_error(msg);
@@ -1061,9 +1080,66 @@ err:
   my_close(info_fd, MYF(0));
   rli->info_fd=-1;
   pthread_mutex_unlock(&rli->data_lock);
-  return 1;
+  DBUG_RETURN(1);
 }
 
+static inline int add_relay_log(RELAY_LOG_INFO* rli,LOG_INFO* linfo)
+{
+  MY_STAT s;
+  DBUG_ENTER("add_relay_log");
+  if (!my_stat(linfo->log_file_name,&s,MYF(0)))
+  {
+    sql_print_error("log %s listed in the index, but failed to stat",
+		    linfo->log_file_name);
+    DBUG_RETURN(1);
+  }
+  rli->log_space_total += s.st_size;
+#ifndef DBUG_OFF
+  char buf[22];
+#endif  
+  DBUG_PRINT("info",("log_space_total: %s", llstr(rli->log_space_total,buf)));
+  DBUG_RETURN(0);
+}
+
+static bool wait_for_relay_log_space(RELAY_LOG_INFO* rli)
+{
+  bool slave_killed;
+  MASTER_INFO* mi = rli->mi;
+  const char* save_proc_info;
+  THD* thd = mi->io_thd;
+  DBUG_ENTER("wait_for_relay_log_space");
+  pthread_mutex_lock(&rli->log_space_lock);
+  save_proc_info = thd->proc_info;
+  thd->proc_info = "Waiting for relay log space to free";
+  while (rli->log_space_limit < rli->log_space_total &&
+	 !(slave_killed=io_slave_killed(thd,mi)))
+  {
+    pthread_cond_wait(&rli->log_space_cond, &rli->log_space_lock);
+  }
+  thd->proc_info = save_proc_info;
+  pthread_mutex_unlock(&rli->log_space_lock);
+  DBUG_RETURN(slave_killed);
+}
+
+static int count_relay_log_space(RELAY_LOG_INFO* rli)
+{
+  LOG_INFO linfo;
+  DBUG_ENTER("count_relay_log_space");
+  rli->log_space_total = 0;
+  if (rli->relay_log.find_first_log(&linfo,""))
+  {
+    sql_print_error("Could not find first log while counting relay log space");
+    DBUG_RETURN(1);
+  }
+  if (add_relay_log(rli,&linfo))
+    DBUG_RETURN(1);
+  while (!rli->relay_log.find_next_log(&linfo))
+  {
+    if (add_relay_log(rli,&linfo))
+      DBUG_RETURN(1);
+  }
+  DBUG_RETURN(0);
+}
 
 int init_master_info(MASTER_INFO* mi, const char* master_info_fname,
 		     const char* slave_info_fname)
@@ -1242,6 +1318,7 @@ int show_master_info(THD* thd, MASTER_INFO* mi)
   field_list.push_back(new Item_empty_string("Last_error", 20));
   field_list.push_back(new Item_empty_string("Skip_counter", 12));
   field_list.push_back(new Item_empty_string("Exec_master_log_pos", 12));
+  field_list.push_back(new Item_empty_string("Relay_log_space", 12));
   if(send_fields(thd, field_list, 1))
     DBUG_RETURN(-1);
 
@@ -1268,6 +1345,7 @@ int show_master_info(THD* thd, MASTER_INFO* mi)
   net_store_data(packet, mi->rli.last_slave_error);
   net_store_data(packet, mi->rli.slave_skip_counter);
   net_store_data(packet, (longlong) mi->rli.master_log_pos);
+  net_store_data(packet, (longlong) mi->rli.log_space_total);
   pthread_mutex_unlock(&mi->rli.data_lock);
   pthread_mutex_unlock(&mi->data_lock);
   
@@ -1783,6 +1861,14 @@ from master");
 	goto err;
       }
       flush_master_info(mi);
+      if (mi->rli.log_space_limit && mi->rli.log_space_limit <
+	  mi->rli.log_space_total)
+	if (wait_for_relay_log_space(&mi->rli))
+	{
+	  sql_print_error("Slave I/O thread aborted while waiting for relay \
+log space");
+	  goto err;
+	}
       // TODO: check debugging abort code
 #ifndef DBUG_OFF
       if (abort_slave_event_count && !--events_till_abort)
@@ -1986,7 +2072,7 @@ static int process_io_create_file(MASTER_INFO* mi, Create_file_log_event* cev)
     goto err;
   }
 
-  /* this dummy block is so we could insantiate Append_block_log_event
+  /* this dummy block is so we could instantiate Append_block_log_event
      once and then modify it slightly instead of doing it multiple times
      in the loop
   */
@@ -2012,6 +2098,7 @@ static int process_io_create_file(MASTER_INFO* mi, Create_file_log_event* cev)
 relay log");
 	  goto err;
 	}
+	mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
 	break;
       }
       if (unlikely(cev_not_written))
@@ -2026,6 +2113,7 @@ relay log");
 	  goto err;
 	}
 	cev_not_written=0;
+	mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
       }
       else
       {
@@ -2038,6 +2126,7 @@ relay log");
 relay log");
 	  goto err;
 	}
+	mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total) ;
       }
     }
   }
@@ -2145,6 +2234,7 @@ static int queue_old_event(MASTER_INFO *mi, const char *buf,
       DBUG_ASSERT(!tmp_buf);
       return 1;
     }
+    mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
   }
   delete ev;
   if (likely(inc_pos))
@@ -2198,6 +2288,7 @@ int queue_event(MASTER_INFO* mi,const char* buf, ulong event_len)
   {
     if (likely(inc_pos))
       mi->master_log_pos += event_len;
+    mi->rli.relay_log.harvest_bytes_written(&mi->rli.log_space_total);
   }
   if (unlikely(processed_stop_event))
     mi->ignore_stop_event=1;

sql/slave.h

@@ -31,6 +31,7 @@ extern char* slave_load_tmpdir;
 extern my_string master_info_file,relay_log_info_file;
 extern my_string opt_relay_logname, opt_relaylog_index_name;
 extern bool opt_skip_slave_start;
+extern ulong relay_log_space_limit;
 struct st_master_info;
 
 /*
@@ -153,6 +154,9 @@ typedef struct st_relay_log_info
   bool log_pos_current;
   bool abort_pos_wait;
   bool skip_log_purge;
+  ulonglong log_space_limit,log_space_total;
+  pthread_mutex_t log_space_lock;
+  pthread_cond_t log_space_cond;
   
   st_relay_log_info():info_fd(-1),cur_log_fd(-1),inited(0),
 		      cur_log_init_count(0),
@@ -163,17 +167,21 @@ typedef struct st_relay_log_info
       bzero(&info_file,sizeof(info_file));
       pthread_mutex_init(&run_lock, MY_MUTEX_INIT_FAST);
       pthread_mutex_init(&data_lock, MY_MUTEX_INIT_FAST);
+      pthread_mutex_init(&log_space_lock, MY_MUTEX_INIT_FAST);
       pthread_cond_init(&data_cond, NULL);
       pthread_cond_init(&start_cond, NULL);
       pthread_cond_init(&stop_cond, NULL);
+      pthread_cond_init(&log_space_cond, NULL);
     }
   ~st_relay_log_info()
     {
       pthread_mutex_destroy(&run_lock);
       pthread_mutex_destroy(&data_lock);
+      pthread_mutex_destroy(&log_space_lock);
       pthread_cond_destroy(&data_cond);
       pthread_cond_destroy(&start_cond);
       pthread_cond_destroy(&stop_cond);
+      pthread_cond_destroy(&log_space_cond);
     }
   inline void inc_pending(ulonglong val)
   {

sql/sql_class.h

@@ -78,12 +78,29 @@ class MYSQL_LOG {
   bool need_start_event;
   pthread_cond_t update_cond;
   bool no_auto_events; // for relay binlog
+  ulonglong bytes_written;
   friend class Log_event;
 
 public:
   MYSQL_LOG();
   ~MYSQL_LOG();
   pthread_mutex_t* get_log_lock() { return &LOCK_log; }
+  void reset_bytes_written()
+    {
+      bytes_written = 0;
+    }
+  void harvest_bytes_written(ulonglong* counter)
+    {
+#ifndef DBUG_OFF
+      char buf1[22],buf2[22];
+#endif	
+      DBUG_ENTER("harvest_bytes_written");
+      (*counter)+=bytes_written;
+      DBUG_PRINT("info",("counter=%s,bytes_written=%s", llstr(*counter,buf1),
+		  llstr(bytes_written,buf2)));
+      bytes_written=0;
+      DBUG_VOID_RETURN;
+    }
   IO_CACHE* get_log_file() { return &log_file; }
   void signal_update() { pthread_cond_broadcast(&update_cond);}
   void wait_for_update(THD* thd);

sql/sql_repl.cc

@@ -751,7 +751,7 @@ int change_master(THD* thd, MASTER_INFO* mi)
     need_relay_log_purge = 0;
     mi->rli.skip_log_purge=1;
     strnmov(mi->rli.relay_log_name,lex_mi->relay_log_name,
-	    sizeof(mi->rli.relay_log_name));
+	    sizeof(mi->rli.relay_log_name)-1);
   }
 
   if (lex_mi->relay_log_pos)