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Bug#17047208 REPLICATION DIFFERENCE FOR MULTIPLE TRIGGERS

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Problem & Analysis: If DML invokes a trigger or a
    stored function that inserts into an AUTO_INCREMENT column,
    that DML has to be marked as 'unsafe' statement. If the
    tables are locked in the transaction prior to DML statement
    (using LOCK TABLES), then the same statement is not marked as
    'unsafe' statement. The logic of checking whether unsafeness
    is protected with if (!thd->locked_tables_mode). Hence if
    we lock the tables prior to DML statement, it is *not* entering
    into this if condition. Hence the statement is not marked
    as unsafe statement.

    Fix: Irrespective of locked_tables_mode value, the unsafeness
    check should be done. Now with this patch, the code is moved
    out to 'decide_logging_format()' function where all these checks
    are happening and also with out 'if(!thd->locked_tables_mode)'.
    Along with the specified test case in the bug scenario
    (BINLOG_STMT_UNSAFE_AUTOINC_COLUMNS), we also identified that
    other cases BINLOG_STMT_UNSAFE_AUTOINC_NOT_FIRST,
    BINLOG_STMT_UNSAFE_WRITE_AUTOINC_SELECT, BINLOG_STMT_UNSAFE_INSERT_TWO_KEYS
    are also protected with thd->locked_tables_mode which is not right. All
    of those checks also moved to 'decide_logging_format()' function.
This commit is contained in:
Venkatesh Duggirala
2015-11-19 13:59:27 +05:30
parent 63dc9c3f42
commit bb56c30ad7
5 changed files with 365 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files

131
sql/sql_class.cc
View File

@@ -4142,6 +4142,94 @@ void xid_cache_delete(XID_STATE *xid_state)
mysql_mutex_unlock(&LOCK_xid_cache);
}
/*
Tells if two (or more) tables have auto_increment columns and we want to
lock those tables with a write lock.
SYNOPSIS
has_two_write_locked_tables_with_auto_increment
tables Table list
NOTES:
Call this function only when you have established the list of all tables
which you'll want to update (including stored functions, triggers, views
inside your statement).
*/
static bool
has_write_table_with_auto_increment(TABLE_LIST *tables)
{
for (TABLE_LIST *table= tables; table; table= table->next_global)
{
/* we must do preliminary checks as table->table may be NULL */
if (!table->placeholder() &&
table->table->found_next_number_field &&
(table->lock_type >= TL_WRITE_ALLOW_WRITE))
return 1;
}
return 0;
}
/*
checks if we have select tables in the table list and write tables
with auto-increment column.
SYNOPSIS
has_two_write_locked_tables_with_auto_increment_and_select
tables Table list
RETURN VALUES
-true if the table list has atleast one table with auto-increment column
and atleast one table to select from.
-false otherwise
*/
static bool
has_write_table_with_auto_increment_and_select(TABLE_LIST *tables)
{
bool has_select= false;
bool has_auto_increment_tables = has_write_table_with_auto_increment(tables);
for(TABLE_LIST *table= tables; table; table= table->next_global)
{
if (!table->placeholder() &&
(table->lock_type <= TL_READ_NO_INSERT))
{
has_select= true;
break;
}
}
return(has_select && has_auto_increment_tables);
}
/*
Tells if there is a table whose auto_increment column is a part
of a compound primary key while is not the first column in
the table definition.
@param tables Table list
@return true if the table exists, fais if does not.
*/
static bool
has_write_table_auto_increment_not_first_in_pk(TABLE_LIST *tables)
{
for (TABLE_LIST *table= tables; table; table= table->next_global)
{
/* we must do preliminary checks as table->table may be NULL */
if (!table->placeholder() &&
table->table->found_next_number_field &&
(table->lock_type >= TL_WRITE_ALLOW_WRITE)
&& table->table->s->next_number_keypart != 0)
return 1;
}
return 0;
}
/**
Decide on logging format to use for the statement and issue errors
@@ -4305,6 +4393,31 @@ int THD::decide_logging_format(TABLE_LIST *tables)
}
#endif
if (variables.binlog_format != BINLOG_FORMAT_ROW && tables)
{
/*
DML statements that modify a table with an auto_increment column based on
rows selected from a table are unsafe as the order in which the rows are
fetched fron the select tables cannot be determined and may differ on
master and slave.
*/
if (has_write_table_with_auto_increment_and_select(tables))
lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_WRITE_AUTOINC_SELECT);
if (has_write_table_auto_increment_not_first_in_pk(tables))
lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_AUTOINC_NOT_FIRST);
/*
A query that modifies autoinc column in sub-statement can make the
master and slave inconsistent.
We can solve these problems in mixed mode by switching to binlogging
if at least one updated table is used by sub-statement
*/
if (lex->requires_prelocking() &&
has_write_table_with_auto_increment(lex->first_not_own_table()))
lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_AUTOINC_COLUMNS);
}
/*
Get the capabilities vector for all involved storage engines and
mask out the flags for the binary log.
@@ -4343,6 +4456,24 @@ int THD::decide_logging_format(TABLE_LIST *tables)
prev_write_table= table->table;
/*
INSERT...ON DUPLICATE KEY UPDATE on a table with more than one unique keys
can be unsafe. Check for it if the flag is already not marked for the
given statement.
*/
if (!lex->is_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_INSERT_TWO_KEYS) &&
lex->sql_command == SQLCOM_INSERT && lex->duplicates == DUP_UPDATE)
{
uint keys= table->table->s->keys, i= 0, unique_keys= 0;
for (KEY* keyinfo= table->table->s->key_info;
i < keys && unique_keys <= 1; i++, keyinfo++)
{
if (keyinfo->flags & HA_NOSAME)
unique_keys++;
}
if (unique_keys > 1 )
lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_INSERT_TWO_KEYS);
}
}
flags_access_some_set |= flags;