mariadb/sql/sql_partition_admin.h
Davi Arnaut 5f911fa874 Bug#49938: Failing assertion: inode or deadlock in fsp/fsp0fsp.c
Bug#54678: InnoDB, TRUNCATE, ALTER, I_S SELECT, crash or deadlock

- Incompatible change: truncate no longer resorts to a row by
row delete if the storage engine does not support the truncate
method. Consequently, the count of affected rows does not, in
any case, reflect the actual number of rows.

- Incompatible change: it is no longer possible to truncate a
table that participates as a parent in a foreign key constraint,
unless it is a self-referencing constraint (both parent and child
are in the same table). To work around this incompatible change
and still be able to truncate such tables, disable foreign checks
with SET foreign_key_checks=0 before truncate. Alternatively, if
foreign key checks are necessary, please use a DELETE statement
without a WHERE condition.

Problem description:

The problem was that for storage engines that do not support
truncate table via a external drop and recreate, such as InnoDB
which implements truncate via a internal drop and recreate, the
delete_all_rows method could be invoked with a shared metadata
lock, causing problems if the engine needed exclusive access
to some internal metadata. This problem originated with the
fact that there is no truncate specific handler method, which
ended up leading to a abuse of the delete_all_rows method that
is primarily used for delete operations without a condition.

Solution:

The solution is to introduce a truncate handler method that is
invoked when the engine does not support truncation via a table
drop and recreate. This method is invoked under a exclusive
metadata lock, so that there is only a single instance of the
table when the method is invoked.

Also, the method is not invoked and a error is thrown if
the table is a parent in a non-self-referencing foreign key
relationship. This was necessary to avoid inconsistency as
some integrity checks are bypassed. This is inline with the
fact that truncate is primarily a DDL operation that was
designed to quickly remove all data from a table.
2010-10-06 11:34:28 -03:00

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/* Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifndef SQL_PARTITION_ADMIN_H
#define SQL_PARTITION_ADMIN_H
#ifndef WITH_PARTITION_STORAGE_ENGINE
/**
Stub class that returns a error if the partition storage engine is
not supported.
*/
class Partition_statement_unsupported : public Sql_statement
{
public:
Partition_statement_unsupported(LEX *lex)
: Sql_statement(lex)
{}
~Partition_statement_unsupported()
{}
bool execute(THD *thd);
};
class Alter_table_analyze_partition_statement :
public Partition_statement_unsupported
{
public:
Alter_table_analyze_partition_statement(LEX *lex)
: Partition_statement_unsupported(lex)
{}
~Alter_table_analyze_partition_statement()
{}
};
class Alter_table_check_partition_statement :
public Partition_statement_unsupported
{
public:
Alter_table_check_partition_statement(LEX *lex)
: Partition_statement_unsupported(lex)
{}
~Alter_table_check_partition_statement()
{}
};
class Alter_table_optimize_partition_statement :
public Partition_statement_unsupported
{
public:
Alter_table_optimize_partition_statement(LEX *lex)
: Partition_statement_unsupported(lex)
{}
~Alter_table_optimize_partition_statement()
{}
};
class Alter_table_repair_partition_statement :
public Partition_statement_unsupported
{
public:
Alter_table_repair_partition_statement(LEX *lex)
: Partition_statement_unsupported(lex)
{}
~Alter_table_repair_partition_statement()
{}
};
class Alter_table_truncate_partition_statement :
public Partition_statement_unsupported
{
public:
Alter_table_truncate_partition_statement(LEX *lex)
: Partition_statement_unsupported(lex)
{}
~Alter_table_truncate_partition_statement()
{}
};
#else
/**
Class that represents the ALTER TABLE t1 ANALYZE PARTITION p statement.
*/
class Alter_table_analyze_partition_statement : public Analyze_table_statement
{
public:
/**
Constructor, used to represent a ALTER TABLE ANALYZE PARTITION statement.
@param lex the LEX structure for this statement.
*/
Alter_table_analyze_partition_statement(LEX *lex)
: Analyze_table_statement(lex)
{}
~Alter_table_analyze_partition_statement()
{}
/**
Execute a ALTER TABLE ANALYZE PARTITION statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
};
/**
Class that represents the ALTER TABLE t1 CHECK PARTITION p statement.
*/
class Alter_table_check_partition_statement : public Check_table_statement
{
public:
/**
Constructor, used to represent a ALTER TABLE CHECK PARTITION statement.
@param lex the LEX structure for this statement.
*/
Alter_table_check_partition_statement(LEX *lex)
: Check_table_statement(lex)
{}
~Alter_table_check_partition_statement()
{}
/**
Execute a ALTER TABLE CHECK PARTITION statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
};
/**
Class that represents the ALTER TABLE t1 OPTIMIZE PARTITION p statement.
*/
class Alter_table_optimize_partition_statement : public Optimize_table_statement
{
public:
/**
Constructor, used to represent a ALTER TABLE OPTIMIZE PARTITION statement.
@param lex the LEX structure for this statement.
*/
Alter_table_optimize_partition_statement(LEX *lex)
: Optimize_table_statement(lex)
{}
~Alter_table_optimize_partition_statement()
{}
/**
Execute a ALTER TABLE OPTIMIZE PARTITION statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
};
/**
Class that represents the ALTER TABLE t1 REPAIR PARTITION p statement.
*/
class Alter_table_repair_partition_statement : public Repair_table_statement
{
public:
/**
Constructor, used to represent a ALTER TABLE REPAIR PARTITION statement.
@param lex the LEX structure for this statement.
*/
Alter_table_repair_partition_statement(LEX *lex)
: Repair_table_statement(lex)
{}
~Alter_table_repair_partition_statement()
{}
/**
Execute a ALTER TABLE REPAIR PARTITION statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
};
/**
Class that represents the ALTER TABLE t1 TRUNCATE PARTITION p statement.
*/
class Alter_table_truncate_partition_statement : public Sql_statement
{
public:
/**
Constructor, used to represent a ALTER TABLE TRUNCATE PARTITION statement.
@param lex the LEX structure for this statement.
*/
Alter_table_truncate_partition_statement(LEX *lex)
: Sql_statement(lex)
{}
virtual ~Alter_table_truncate_partition_statement()
{}
/**
Execute a ALTER TABLE TRUNCATE PARTITION statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
};
#endif /* WITH_PARTITION_STORAGE_ENGINE */
#endif /* SQL_PARTITION_ADMIN_H */