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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 retrived from the table may differ on master and slave.
      
      Solution: We mark writing to a table with auto_increment 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
2012-02-08 00:33:08 +05:30
parent c8d8a92300
commit 6df5a61d2e
27 changed files with 153 additions and 26 deletions
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41
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 +5684,11 @@ 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())
{
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 +9086,39 @@ 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.