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BUG#12400221 - 60926: BINARY LOG EVENTS LARGER THAN MAX_ALLOWED_PACKET

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Problem
========
            
SQL statements close to the size of max_allowed_packet produce binary
log events larger than max_allowed_packet.
              
The reason why this failure is occuring is because the event length is
more than the total size of the max_allowed_packet + max_event_header
length. Now since the event length exceeds this size master Dump
thread is unable to send the packet on to the slave.
                      
That can happen e.g with row-based replication in Update_rows event.
            
Fix
====
          
The problem was fixed by increasing the max_allowed_packet for the
slave's threads (IO/SQL) by increasing it to 1GB.
This is done using the new server option included which is used to
regulate the max_allowed_packet of the slave thread (IO/SQL).
This causes the large packets to be received by the slave and apply
it successfully.

sql/log_event.h:
  Added the new option in the log_event.h file.
sql/mysqld.cc:
  Added a new option to the server.
sql/slave.cc:
  Increasing the session max_allowed_packet to a large value ,
  i.e. not taking global(max_allowed) into consideration, for the slave's threads.
This commit is contained in:
Manish Kumar
2012-05-21 12:57:39 +05:30
parent 781137c0dd
commit 1605b7f68f
17 changed files with 252 additions and 36 deletions
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2
sql/sql_repl.cc
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@ -469,7 +469,7 @@ impossible position";
this larger than the corresponding packet (query) sent
from client to master.
*/
thd->variables.max_allowed_packet+= MAX_LOG_EVENT_HEADER;
thd->variables.max_allowed_packet= ULONG_MAX;
/*
We can set log_lock now, it does not move (it's a member of