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Bug #47863 binlog_format should be writable only at transaction boundaries
 When @@session.binlog_format is modified inside a transaction, it can cause slave to go out of sync. To fix the problem, make the session variable 'binlog_format' read-only inside a transaction.
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‎mysql-test/suite/binlog/r/binlog_format_switch_inside_trans.result

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set @save_binlog_format= @@global.binlog_format;
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create table t1 (a int) engine= myisam;
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create table t2 (a int) engine= innodb;
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SELECT @@session.binlog_format;
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@@session.binlog_format
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ROW
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SET AUTOCOMMIT=1;
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# Test that the session variable 'binlog_format'
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# is writable outside a transaction.
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set @@session.binlog_format= statement;
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SELECT @@session.binlog_format;
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@@session.binlog_format
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STATEMENT
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begin;
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# Test that the session variable 'binlog_format' is read-only
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# inside a transaction with no preceding updates.
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set @@session.binlog_format= mixed;
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ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
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insert into t2 values (1);
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# Test that the session variable 'binlog_format' is read-only
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# inside a transaction with preceding transactional updates.
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set @@session.binlog_format= row;
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ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
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commit;
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begin;
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insert into t1 values (2);
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# Test that the session variable 'binlog_format' is read-only
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# inside a transaction with preceding non-transactional updates.
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set @@session.binlog_format= statement;
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ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
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commit;
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# Test that the session variable 'binlog_format' is writable
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# when AUTOCOMMIT=0, before a transaction has started.
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set AUTOCOMMIT=0;
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set @@session.binlog_format= row;
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SELECT @@session.binlog_format;
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@@session.binlog_format
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ROW
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insert into t1 values (4);
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# Test that the session variable 'binlog_format' is read-only inside an
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# AUTOCOMMIT=0 transaction with preceding non-transactional updates.
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set @@session.binlog_format= statement;
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ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
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SELECT @@session.binlog_format;
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@@session.binlog_format
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ROW
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commit;
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insert into t2 values (5);
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# Test that the session variable 'binlog_format' is read-only inside an
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# AUTOCOMMIT=0 transaction with preceding transactional updates.
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set @@session.binlog_format= row;
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ERROR HY000: Cannot modify @@session.binlog_format inside a transaction
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SELECT @@session.binlog_format;
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@@session.binlog_format
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ROW
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commit;
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begin;
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insert into t2 values (6);
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# Test that the global variable 'binlog_format' is writable
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# inside a transaction.
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SELECT @@global.binlog_format;
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@@global.binlog_format
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ROW
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set @@global.binlog_format= statement;
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SELECT @@global.binlog_format;
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@@global.binlog_format
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STATEMENT
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commit;
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set @@global.binlog_format= @save_binlog_format;
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create table t3(a int, b int) engine= innodb;
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create table t4(a int) engine= innodb;
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create table t5(a int) engine= innodb;
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create trigger tr2 after insert on t3 for each row begin
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insert into t4(a) values(1);
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set @@session.binlog_format= statement;
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insert into t4(a) values(2);
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insert into t5(a) values(3);
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end |
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# Test that the session variable 'binlog_format' is read-only
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# in sub-statements.
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insert into t3(a,b) values(1,1);
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ERROR HY000: Cannot change the binary logging format inside a stored function or trigger
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SELECT @@session.binlog_format;
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@@session.binlog_format
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ROW
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drop table t1;
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drop table t2;
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drop table t3;
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drop table t4;
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drop table t5;

‎mysql-test/suite/binlog/t/binlog_format_switch_inside_trans.test

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#
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# BUG#47863
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# This test verifies if the session variable 'binlog_format'
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# is read-only inside a transaction and in sub-statements.
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#
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source include/have_innodb.inc;
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source include/have_binlog_format_row.inc;
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set @save_binlog_format= @@global.binlog_format;
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create table t1 (a int) engine= myisam;
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create table t2 (a int) engine= innodb;
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SELECT @@session.binlog_format;
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SET AUTOCOMMIT=1;
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--echo # Test that the session variable 'binlog_format'
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--echo # is writable outside a transaction.
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set @@session.binlog_format= statement;
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SELECT @@session.binlog_format;
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begin;
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--echo # Test that the session variable 'binlog_format' is read-only
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--echo # inside a transaction with no preceding updates.
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--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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set @@session.binlog_format= mixed;
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insert into t2 values (1);
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--echo # Test that the session variable 'binlog_format' is read-only
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--echo # inside a transaction with preceding transactional updates.
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--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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set @@session.binlog_format= row;
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commit;
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begin;
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insert into t1 values (2);
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--echo # Test that the session variable 'binlog_format' is read-only
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--echo # inside a transaction with preceding non-transactional updates.
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--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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set @@session.binlog_format= statement;
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commit;
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--echo # Test that the session variable 'binlog_format' is writable
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--echo # when AUTOCOMMIT=0, before a transaction has started.
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set AUTOCOMMIT=0;
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set @@session.binlog_format= row;
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SELECT @@session.binlog_format;
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insert into t1 values (4);
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--echo # Test that the session variable 'binlog_format' is read-only inside an
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--echo # AUTOCOMMIT=0 transaction with preceding non-transactional updates.
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--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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set @@session.binlog_format= statement;
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SELECT @@session.binlog_format;
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commit;
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insert into t2 values (5);
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--echo # Test that the session variable 'binlog_format' is read-only inside an
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--echo # AUTOCOMMIT=0 transaction with preceding transactional updates.
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--error ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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set @@session.binlog_format= row;
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SELECT @@session.binlog_format;
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commit;
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begin;
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insert into t2 values (6);
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--echo # Test that the global variable 'binlog_format' is writable
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--echo # inside a transaction.
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SELECT @@global.binlog_format;
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set @@global.binlog_format= statement;
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SELECT @@global.binlog_format;
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commit;
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set @@global.binlog_format= @save_binlog_format;
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create table t3(a int, b int) engine= innodb;
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create table t4(a int) engine= innodb;
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create table t5(a int) engine= innodb;
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delimiter |;
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eval create trigger tr2 after insert on t3 for each row begin
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insert into t4(a) values(1);
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set @@session.binlog_format= statement;
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insert into t4(a) values(2);
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insert into t5(a) values(3);
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end |
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delimiter ;|
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--echo # Test that the session variable 'binlog_format' is read-only
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--echo # in sub-statements.
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--error ER_STORED_FUNCTION_PREVENTS_SWITCH_BINLOG_FORMAT
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insert into t3(a,b) values(1,1);
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SELECT @@session.binlog_format;
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drop table t1;
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drop table t2;
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drop table t3;
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drop table t4;
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drop table t5;
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‎sql/set_var.cc

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bool sys_var_thd_binlog_format::check(THD *thd, set_var *var) {
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/*
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Make the session variable 'binlog_format' read-only inside a transaction.
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*/
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if (thd->active_transaction() && (var->type == OPT_SESSION))
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{
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my_error(ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT, MYF(0));
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return 1;
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}
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/*
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All variables that affect writing to binary log (either format or
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turning logging on and off) use the same checking. We call the

‎sql/share/errmsg.txt

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ER_DEBUG_SYNC_HIT_LIMIT
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eng "debug sync point hit limit reached"
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ger "Debug Sync Point Hit Limit erreicht"
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ER_INSIDE_TRANSACTION_PREVENTS_SWITCH_BINLOG_FORMAT
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eng "Cannot modify @@session.binlog_format inside a transaction"

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