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mariadb/sql/sql_table.h
Monty c4cad8d50c MDEV-33449 improving repair of tables 
This task is to ensure we have a clear definition and rules of how to
repair or optimize a table.

The rules are:

- REPAIR should be used with tables that are crashed and are
  unreadable (hardware issues with not readable blocks, blocks with
  'unexpected data' etc)
- OPTIMIZE table should be used to optimize the storage layout for the
  table (recover space for delete rows and optimize the index
  structure.
- ALTER TABLE table_name FORCE should be used to rebuild the .frm file
  (the table definition) and the table (with the original table row
  format). If the table is from and older MariaDB/MySQL release with a
  different storage format, it will convert the data to the new
  format. ALTER TABLE ... FORCE is used as part of mariadb-upgrade

Here follows some more background:

The 3 ways to repair a table are:
1) ALTER TABLE table_name FORCE" (not other options).
   As an alias we allow: "ALTER TABLE table_name ENGINE=original_engine"
2) "REPAIR TABLE" (without FORCE)
3) "OPTIMIZE TABLE"

All of the above commands will optimize row space usage (which means that
space will be needed to hold a temporary copy of the table) and
re-generate all indexes. They will also try to replicate the original
table definition as exact as possible.

For ALTER TABLE and "REPAIR TABLE without FORCE", the following will hold:
If the table is from an older MariaDB version and data conversion is
needed (for example for old type HASH columns, MySQL JSON type or new
TIMESTAMP format) "ALTER TABLE table_name FORCE, algorithm=COPY" will be
used.

The differences between the algorithms are
1) Will use the fastest algorithm the engine supports to do a full repair
   of the table (except if data conversions are is needed).
2) Will use the storage engine internal REPAIR facility (MyISAM, Aria).
   If the engine does not support REPAIR then
   "ALTER TABLE FORCE, ALGORITHM=COPY" will be used.
   If there was data incompatibilities (which means that FORCE was used)
   then there will be a warning after REPAIR that ALTER TABLE FORCE is
   still needed.
   The reason for this is that REPAIR may be able to go around data
   errors (wrong incompatible data, crashed or unreadable sectors) that
   ALTER TABLE cannot do.
3) Will use the storage engine internal OPTIMIZE. If engine does not
   support optimize, then "ALTER TABLE FORCE" is used.

The above will ensure that ALTER TABLE FORCE is able to
correct almost any errors in the row or index data.  In case of
corrupted blocks then REPAIR possible followed by ALTER TABLE is needed.
This is important as mariadb-upgrade executes ALTER TABLE table_name
FORCE for any table that must be re-created.

Bugs fixed with InnoDB tables when using ALTER TABLE FORCE:
- No error for INNODB_DEFAULT_ROW_FORMAT=COMPACT even if row length
  would be too wide. (Independent of innodb_strict_mode).
- Tables using symlinks will be symlinked after any of the above commands
  (Independent of the setting of --symbolic-links)

If one specifies an algorithm together with ALTER TABLE FORCE, things
will work as before (except if data conversion is required as then
the COPY algorithm is enforced).

ALTER TABLE .. OPTIMIZE ALL PARTITIONS will work as before.

Other things:
- FORCE argument added to REPAIR to allow one to first run internal
  repair to fix damaged blocks and then follow it with ALTER TABLE.
- REPAIR will not update frm_version if ha_check_for_upgrade() finds
  that table is still incompatible with current version. In this case the
  REPAIR will end with an error.
- REPAIR for storage engines that does not have native repair, like InnoDB,
  is now using ALTER TABLE FORCE.
- REPAIR csv-table USE_FRM now works.
  - It did not work before as CSV tables had extension list in wrong
    order.
- Default error messages length for %M increased from 128 to 256 to not
  cut information from REPAIR.
- Documented HA_ADMIN_XX variables related to repair.
- Added HA_ADMIN_NEEDS_DATA_CONVERSION to signal that we have to
  do data conversions when converting the table (and thus ALTER TABLE
  copy algorithm is needed).
- Fixed typo in error message (caused test changes).
2024-05-27 12:39:03 +02:00

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/* Copyright (c) 2006, 2014, Oracle and/or its affiliates.
Copyright (c) 2011, 2017, MariaDB Corporation.
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 02110-1335 USA */
#ifndef SQL_TABLE_INCLUDED
#define SQL_TABLE_INCLUDED
#include <my_sys.h> // pthread_mutex_t
#include "m_string.h" // LEX_CUSTRING
#include "lex_charset.h"
#include "lex_ident.h"
#define ERROR_INJECT(code) \
((DBUG_IF("crash_" code) && (DBUG_SUICIDE(), 0)) || \
(DBUG_IF("fail_" code) && (my_error(ER_UNKNOWN_ERROR, MYF(0)), 1)))
class Alter_info;
class Alter_table_ctx;
class Column_definition;
class Create_field;
struct TABLE_LIST;
class THD;
struct TABLE;
struct handlerton;
class handler;
class String;
typedef struct st_ha_check_opt HA_CHECK_OPT;
struct HA_CREATE_INFO;
struct Table_specification_st;
typedef struct st_key KEY;
typedef struct st_key_cache KEY_CACHE;
typedef struct st_lock_param_type ALTER_PARTITION_PARAM_TYPE;
typedef struct st_order ORDER;
typedef struct st_ddl_log_state DDL_LOG_STATE;
enum enum_explain_filename_mode
{
EXPLAIN_ALL_VERBOSE= 0,
EXPLAIN_PARTITIONS_VERBOSE,
EXPLAIN_PARTITIONS_AS_COMMENT
};
/* depends on errmsg.txt Database `db`, Table `t` ... */
#define EXPLAIN_FILENAME_MAX_EXTRA_LENGTH 63
#define WFRM_WRITE_SHADOW 1
#define WFRM_INSTALL_SHADOW 2
#define WFRM_KEEP_SHARE 4
#define WFRM_WRITE_CONVERTED_TO 8
#define WFRM_BACKUP_ORIGINAL 16
/* Flags for conversion functions. */
static const uint FN_FROM_IS_TMP= 1 << 0;
static const uint FN_TO_IS_TMP= 1 << 1;
static const uint FN_IS_TMP= FN_FROM_IS_TMP | FN_TO_IS_TMP;
static const uint NO_FRM_RENAME= 1 << 2;
static const uint FRM_ONLY= 1 << 3;
/** Don't remove table in engine. Remove only .FRM and maybe .PAR files. */
static const uint NO_HA_TABLE= 1 << 4;
/** Don't resolve MySQL's fake "foo.sym" symbolic directory names. */
static const uint SKIP_SYMDIR_ACCESS= 1 << 5;
/** Don't check foreign key constraints while renaming table */
static const uint NO_FK_CHECKS= 1 << 6;
/* Don't delete .par table in quick_rm_table() */
static const uint NO_PAR_TABLE= 1 << 7;
uint filename_to_tablename(const char *from, char *to, size_t to_length,
bool stay_quiet = false);
uint tablename_to_filename(const char *from, char *to, size_t to_length);
uint check_n_cut_mysql50_prefix(const char *from, char *to, size_t to_length);
bool check_mysql50_prefix(const char *name);
uint build_table_filename(char *buff, size_t bufflen, const char *db,
const char *table, const char *ext, uint flags);
uint build_table_shadow_filename(char *buff, size_t bufflen,
ALTER_PARTITION_PARAM_TYPE *lpt,
bool backup= false);
void build_lower_case_table_filename(char *buff, size_t bufflen,
const LEX_CSTRING *db,
const LEX_CSTRING *table,
uint flags);
uint build_tmptable_filename(THD* thd, char *buff, size_t bufflen);
bool add_keyword_to_query(THD *thd, String *result, const LEX_CSTRING *keyword,
const LEX_CSTRING *add);
/*
mysql_create_table_no_lock can be called in one of the following
mutually exclusive situations:
- Just a normal ordinary CREATE TABLE statement that explicitly
defines the table structure.
- CREATE TABLE ... SELECT. It is special, because only in this case,
the list of fields is allowed to have duplicates, as long as one of the
duplicates comes from the select list, and the other doesn't. For
example in
CREATE TABLE t1 (a int(5) NOT NUL) SELECT b+10 as a FROM t2;
the list in alter_info->create_list will have two fields `a`.
- ALTER TABLE, that creates a temporary table #sql-xxx, which will be later
renamed to replace the original table.
- ALTER TABLE as above, but which only modifies the frm file, it only
creates an frm file for the #sql-xxx, the table in the engine is not
created.
- Assisted discovery, CREATE TABLE statement without the table structure.
These situations are distinguished by the following "create table mode"
values, where a CREATE ... SELECT is denoted by any non-negative number
(which should be the number of fields in the SELECT ... part), and other
cases use constants as defined below.
*/
#define C_CREATE_SELECT(X) ((X) > 0 ? (X) : 0)
#define C_ORDINARY_CREATE 0
#define C_ALTER_TABLE -1
#define C_ALTER_TABLE_FRM_ONLY -2
#define C_ASSISTED_DISCOVERY -3
int mysql_create_table_no_lock(THD *thd,
DDL_LOG_STATE *ddl_log_state,
DDL_LOG_STATE *ddl_log_state_rm,
Table_specification_st *create_info,
Alter_info *alter_info, bool *is_trans,
int create_table_mode, TABLE_LIST *table);
handler *mysql_create_frm_image(THD *thd, HA_CREATE_INFO *create_info,
Alter_info *alter_info, int create_table_mode,
KEY **key_info, uint *key_count,
LEX_CUSTRING *frm);
int mysql_discard_or_import_tablespace(THD *thd, TABLE_LIST *table_list,
bool discard);
bool mysql_prepare_alter_table(THD *thd, TABLE *table,
Table_specification_st *create_info,
Alter_info *alter_info,
Alter_table_ctx *alter_ctx);
bool mysql_trans_prepare_alter_copy_data(THD *thd);
bool mysql_trans_commit_alter_copy_data(THD *thd);
bool mysql_alter_table(THD *thd, const LEX_CSTRING *new_db,
const LEX_CSTRING *new_name,
Table_specification_st *create_info,
TABLE_LIST *table_list,
class Recreate_info *recreate_info,
Alter_info *alter_info,
uint order_num, ORDER *order, bool ignore,
bool if_exists);
bool mysql_compare_tables(TABLE *table,
Alter_info *alter_info,
HA_CREATE_INFO *create_info,
bool *metadata_equal);
bool mysql_recreate_table(THD *thd, TABLE_LIST *table_list,
class Recreate_info *recreate_info,
bool table_copy);
bool mysql_rename_table(handlerton *base, const LEX_CSTRING *old_db,
const LEX_CSTRING *old_name, const LEX_CSTRING *new_db,
const LEX_CSTRING *new_name, const LEX_CUSTRING *id,
uint flags);
bool mysql_backup_table(THD* thd, TABLE_LIST* table_list);
bool mysql_restore_table(THD* thd, TABLE_LIST* table_list);
template<typename T> class List;
void fill_checksum_table_metadata_fields(THD *thd, List<Item> *fields);
bool mysql_checksum_table(THD* thd, TABLE_LIST* table_list,
HA_CHECK_OPT* check_opt);
bool mysql_rm_table(THD *thd,TABLE_LIST *tables, bool if_exists,
bool drop_temporary, bool drop_sequence,
bool dont_log_query);
int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables,
const LEX_CSTRING *db,
DDL_LOG_STATE *ddl_log_state,
bool if_exists,
bool drop_temporary, bool drop_view,
bool drop_sequence,
bool dont_log_query, bool dont_free_locks);
bool log_drop_table(THD *thd, const LEX_CSTRING *db_name,
const LEX_CSTRING *table_name, const LEX_CSTRING *handler,
bool partitioned, const LEX_CUSTRING *id,
bool temporary_table);
bool quick_rm_table(THD *thd, handlerton *base, const LEX_CSTRING *db,
const LEX_CSTRING *table_name, uint flags,
const char *table_path=0);
void close_cached_table(THD *thd, TABLE *table);
void sp_prepare_create_field(THD *thd, Column_definition *sql_field);
bool mysql_write_frm(ALTER_PARTITION_PARAM_TYPE *lpt, uint flags);
int write_bin_log(THD *thd, bool clear_error,
char const *query, ulong query_length,
bool is_trans= FALSE);
int write_bin_log_with_if_exists(THD *thd, bool clear_error,
bool is_trans, bool add_if_exists,
bool commit_alter= false);
void promote_first_timestamp_column(List<Create_field> *column_definitions);
/*
These prototypes where under INNODB_COMPATIBILITY_HOOKS.
*/
uint explain_filename(THD* thd, const char *from, char *to, uint to_length,
enum_explain_filename_mode explain_mode);
extern MYSQL_PLUGIN_IMPORT const Lex_ident_column primary_key_name;
bool check_engine(THD *, const char *, const char *, HA_CREATE_INFO *);
#endif /* SQL_TABLE_INCLUDED */
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