BUG#30435 loading large LOAD DATA INFILE breaks slave with

          read_buffer_size set on master
BUG#33413 show binlog events fails if binlog has event size of close
          to max_allowed_packet


The size of Append_block replication event was determined solely by
read_buffer_size whereas the rest of replication code deals with
max_allowed_packet.
When the former parameter was set to larger than the latter there were
two artifacts: the master could not read events from binlog;
show master events did not show.

Fixed with 
- fragmenting the used io-cached buffer into pieces each size of less
  than max_allowed_packet (bug#30435)
- incrementing show-binlog-events handling thread's max_allowed_packet
  with the max estimated for the replication header size


include/my_sys.h:
  accessor-macros added in order not to mess with the io cache's implementation
  details in code that merely exploits the io-cache.
sql/sql_repl.cc:
  BUG#33413: incrementing thd->variables.max_allowed_packet with 
  the max estimation for the replication header size (from bug#19402);
  refactoring log_loaded_block() to fragment the io_cache buffer in case
   read_buffer_size > max_allowed_packet.
mysql-test/r/rpl_loaddata_map.result:
  New BitKeeper file ``mysql-test/r/rpl_loaddata_map.result''
mysql-test/t/rpl_loaddata_map-master.opt:
  specific options to trigger  BUG#30435,  BUG#33413 situations
mysql-test/t/rpl_loaddata_map-slave.opt:
  max_allowed_packet to be compatible with the master's version.
mysql-test/t/rpl_loaddata_map.test:
  regression tests for two bugs.

include/my_sys.h

@@ -530,6 +530,12 @@ typedef int (*qsort2_cmp)(const void *, const void *, const void *);
 #define my_b_tell(info) ((info)->pos_in_file + \
 			 (uint) (*(info)->current_pos - (info)->request_pos))
 
+#define my_b_get_buffer_start(info) (info)->request_pos 
+#define my_b_get_bytes_in_buffer(info) (char*) (info)->read_end -   \
+  (char*) my_b_get_buffer_start(info)
+#define my_b_get_pos_in_file(info) (info)->pos_in_file
+
+
 /* tell write offset in the SEQ_APPEND cache */
 my_off_t my_b_append_tell(IO_CACHE* info);
 my_off_t my_b_safe_tell(IO_CACHE* info); /* picks the correct tell() */

mysql-test/r/rpl_loaddata_map.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 table t2 (id int not null primary key auto_increment);
+show variables like 'max_allowed_packet' /* 8K */;
+Variable_name	Value
+max_allowed_packet	7168
+show variables like 'read_buffer_size'   /* 9K */;
+Variable_name	Value
+read_buffer_size	8228
+load data infile '/home/elkin/MySQL/TEAM/FIXES/5.0/bug33435-load_data_read_buffer_size/mysql-test/var/tmp/bug30435_5k.txt' into table t2;
+select count(*) from t2 /* 5 000 */;
+count(*)
+5000
+show binlog events in 'master-bin.000002' from 98;
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000002	98	Query	1	#	use `test`; create table t2 (id int not null primary key auto_increment)
+master-bin.000002	221	Begin_load_query	1	#	;file_id=1;block_len=7168
+master-bin.000002	7412	Append_block	1	#	;file_id=1;block_len=7168
+master-bin.000002	14603	Append_block	1	#	;file_id=1;block_len=2048
+master-bin.000002	16674	Append_block	1	#	;file_id=1;block_len=7168
+master-bin.000002	23865	Append_block	1	#	;file_id=1;block_len=341
+master-bin.000002	24229	Execute_load_query	1	#	use `test`; load data infile '/home/elkin/MySQL/TEAM/FIXES/5.0/bug33435-load_data_read_buffer_size/mysql-test/var/tmp/bug30435_5k.txt' into table t2 ;file_id=1
+select count(*) from t2 /* 5 000 */;
+count(*)
+5000
+drop table t1, t2;
+end of the tests

mysql-test/t/rpl_loaddata_map-master.opt

+--read_buffer_size=9K --max_allowed_packet=8K

mysql-test/t/rpl_loaddata_map-slave.opt

+--max_allowed_packet=8K

mysql-test/t/rpl_loaddata_map.test

+#
+#  check replication of load data with the server parameters subjected to
+#  read_buffer_size > max_allowed_packet
+#
+#  BUG#30435 loading large LOAD DATA INFILE breaks slave with 
+#            read_buffer_size set on master
+#  BUG#33413 show binlog events fails if binlog has event size of close
+#            to max_allowed_packet
+
+source include/master-slave.inc;
+source include/have_innodb.inc;
+
+--disable_query_log
+let $rows= 5000;
+create table t1 (id int not null primary key auto_increment);
+
+while($rows)
+{
+  eval insert into t1 values (null);
+  dec $rows;
+}
+eval select * into outfile '$MYSQLTEST_VARDIR/tmp/bug30435_5k.txt' from t1;
+flush logs;
+--enable_query_log
+
+connection master;
+create table t2 (id int not null primary key auto_increment);
+
+show variables like 'max_allowed_packet' /* 8K */;
+show variables like 'read_buffer_size'   /* 9K */;
+
+eval load data infile '$MYSQLTEST_VARDIR/tmp/bug30435_5k.txt' into table t2;
+select count(*) from t2 /* 5 000 */;
+
+# the binglog will show fragmented Append_block events
+--let $binlog_start=98
+--replace_column 5 #
+--replace_regex /\/\* xid=.* \*\//\/* XID *\//
+--eval show binlog events in 'master-bin.000002' from $binlog_start
+
+
+sync_slave_with_master;
+#connection slave;
+select count(*) from t2 /* 5 000 */;
+
+connection master;
+drop table t1, t2;
+sync_slave_with_master;
+remove_file $MYSQLTEST_VARDIR/tmp/bug30435_5k.txt;
+
+--echo end of the tests

sql/sql_repl.cc

@@ -1355,6 +1355,11 @@ bool mysql_show_binlog_events(THD* thd)
     if ((file=open_binlog(&log, linfo.log_file_name, &errmsg)) < 0)
       goto err;
 
+    /*
+      to account binlog event header size
+    */
+    thd->variables.max_allowed_packet += MAX_LOG_EVENT_HEADER;
+
     pthread_mutex_lock(log_lock);
 
     /*
@@ -1365,7 +1370,6 @@ bool mysql_show_binlog_events(THD* thd)
        This code will fail on a mixed relay log (one which has Format_desc then
        Rotate then Format_desc).
     */
-
     ev = Log_event::read_log_event(&log,(pthread_mutex_t*)0,description_event);
     if (ev)
     {
@@ -1556,37 +1560,52 @@ bool show_binlogs(THD* thd)
   DBUG_RETURN(TRUE);
 }
 
-
+/**
+   Load data's io cache specific hook to be executed
+   before a chunk of data is being read into the cache's buffer
+   The fuction instantianates and writes into the binlog
+   replication events along LOAD DATA processing.
+   
+   @param file  pointer to io-cache
+   @return 0
+*/
 int log_loaded_block(IO_CACHE* file)
 {
+  DBUG_ENTER("log_loaded_block");
   LOAD_FILE_INFO *lf_info;
-  uint block_len ;
-
-  /* file->request_pos contains position where we started last read */
-  char* buffer = (char*) file->request_pos;
-  if (!(block_len = (char*) file->read_end - (char*) buffer))
-    return 0;
-  lf_info = (LOAD_FILE_INFO*) file->arg;
+  uint block_len;
+  /* buffer contains position where we started last read */
+  char* buffer= my_b_get_buffer_start(file);
+  uint max_event_size= current_thd->variables.max_allowed_packet;
+  lf_info= (LOAD_FILE_INFO*) file->arg;
   if (lf_info->last_pos_in_file != HA_POS_ERROR &&
-      lf_info->last_pos_in_file >= file->pos_in_file)
+      lf_info->last_pos_in_file >= my_b_get_pos_in_file(file))
     return 0;
-  lf_info->last_pos_in_file = file->pos_in_file;
-  if (lf_info->wrote_create_file)
-  {
-    Append_block_log_event a(lf_info->thd, lf_info->thd->db, buffer,
-                             block_len, lf_info->log_delayed);
-    mysql_bin_log.write(&a);
-  }
-  else
+  
+  for (block_len= my_b_get_bytes_in_buffer(file); block_len > 0;
+       buffer += min(block_len, max_event_size),
+       block_len -= min(block_len, max_event_size))
   {
-    Begin_load_query_log_event b(lf_info->thd, lf_info->thd->db,
-                                 buffer, block_len,
-                                 lf_info->log_delayed);
-    mysql_bin_log.write(&b);
-    lf_info->wrote_create_file = 1;
-    DBUG_SYNC_POINT("debug_lock.created_file_event",10);
+    lf_info->last_pos_in_file= my_b_get_pos_in_file(file);
+    if (lf_info->wrote_create_file)
+    {
+      Append_block_log_event a(lf_info->thd, lf_info->thd->db, buffer,
+                               min(block_len, max_event_size),
+                               lf_info->log_delayed);
+      mysql_bin_log.write(&a);
+    }
+    else
+    {
+      Begin_load_query_log_event b(lf_info->thd, lf_info->thd->db,
+                                   buffer,
+                                   min(block_len, max_event_size),
+                                   lf_info->log_delayed);
+      mysql_bin_log.write(&b);
+      lf_info->wrote_create_file= 1;
+      DBUG_SYNC_POINT("debug_lock.created_file_event",10);
+    }
   }
-  return 0;
+  DBUG_RETURN(0);
 }
 
 #endif /* HAVE_REPLICATION */