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Bug#17327454:SEMI-SYNC REPLICATION MASTER CRASH WHEN SET

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RPL_SEMI_SYNC_MASTER_ENABLED OFF.

Problem:
=======
If master is waiting for a reply from slave, at this time
set global rpl_semi_sync_master_enabled=OFF, the master
server will crash.

Analysis:
========
When master is waiting for a reply from slave, at this time
if semi sync is switched off on master, during switch off if
active transactions are present the transactions will be
cleared and "active_tranxs_" variable will be set to NULL.

When the waiting master connection finds that semi sync is
switched of it tries to access "active_tranxs_" without
checking if the transaction list exists or not. Accessing
NULL transaction list causes the crash.

Fix:
===
A check has been added to see a valid list exists before
accessing the "active_tranxs_".
This commit is contained in:
Sujatha Sivakumar
2013-09-23 12:13:37 +05:30
parent d0941fbc4c
commit 5a5024a6bd
1 changed files with 2 additions and 1 deletions
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3
plugin/semisync/semisync_master.cc
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@ -752,7 +752,8 @@ int ReplSemiSyncMaster::commitTrx(const char* trx_wait_binlog_name,
At this point, the binlog file and position of this transaction
must have been removed from ActiveTranx.
*/
assert(!active_tranxs_->is_tranx_end_pos(trx_wait_binlog_name,
assert(!getMasterEnabled() ||
!active_tranxs_->is_tranx_end_pos(trx_wait_binlog_name,
trx_wait_binlog_pos));
/* Update the status counter. */