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BUG#11758263 50440: MARK UNORDERED UPDATE WITH AUTOINC UNSAFE

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Problem: Statements that write to tables with auto_increment columns
         based on the selection from another table, may lead to master
         and slave going out of sync, as the order in which the rows
         are retrieved from the table may differ on master and slave.
            
Solution: We mark writing to a table with auto_increment table
          based on the rows selected from another table as unsafe. This
          will cause the execution of such statements to throw a warning
          and forces the statement to be logged in ROW if the logging
          format is mixed. 
            
Changes:
       1. All the statements that writes to a table with auto_increment 
          column(s) based on the rows fetched from another table, will now
          be unsafe.
       2. CREATE TABLE with SELECT will now be unsafe.
This commit is contained in:
Rohit Kalhans
2012-02-09 23:28:33 +05:30
parent 9153fddf58
commit 4f7e4c9d1b
28 changed files with 186 additions and 23 deletions
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49
sql/sql_base.cc
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@@ -214,7 +214,8 @@ static bool auto_repair_table(THD *thd, TABLE_LIST *table_list);
static void free_cache_entry(TABLE *entry);
static bool
has_write_table_with_auto_increment(TABLE_LIST *tables);
static bool
has_write_table_with_auto_increment_and_select(TABLE_LIST *tables);
uint cached_open_tables(void)
{
@@ -5683,6 +5684,17 @@ bool lock_tables(THD *thd, TABLE_LIST *tables, uint count,
/* We have to emulate LOCK TABLES if we are statement needs prelocking. */
if (thd->lex->requires_prelocking())
{
/*
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 (thd->variables.binlog_format != BINLOG_FORMAT_ROW && tables &&
has_write_table_with_auto_increment_and_select(tables))
thd->lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_WRITE_AUTOINC_SELECT);
/*
A query that modifies autoinc column in sub-statement can make the
master and slave inconsistent.
@@ -9080,6 +9092,41 @@ has_write_table_with_auto_increment(TABLE_LIST *tables)
return 0;
}
/*
checks if the tables 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);
}
/*
Open and lock system tables for read.