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MDEV-33449 improving repair of tables

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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).
This commit is contained in:
Monty
2024-01-29 11:52:44 +02:00
committed by Sergei Golubchik
parent 2464ee758a
commit c4cad8d50c
41 changed files with 410 additions and 193 deletions
Download Patch File Download Diff File Expand all files Collapse all files

109
sql/sql_admin.cc
View File

@@ -48,9 +48,11 @@ const LEX_CSTRING msg_optimize= { STRING_WITH_LEN("optimize") };
/* Prepare, run and cleanup for mysql_recreate_table() */
static bool admin_recreate_table(THD *thd, TABLE_LIST *table_list,
Recreate_info *recreate_info)
Recreate_info *recreate_info,
bool table_copy)
{
bool result_code;
TABLE_LIST *save_next_global;
DBUG_ENTER("admin_recreate_table");
trans_rollback_stmt(thd);
@@ -68,8 +70,13 @@ static bool admin_recreate_table(THD *thd, TABLE_LIST *table_list,
DEBUG_SYNC(thd, "ha_admin_try_alter");
tmp_disable_binlog(thd); // binlogging is done by caller if wanted
/* Ignore if there is more than one table in the list */
save_next_global= table_list->next_global;
table_list->next_global= 0;
result_code= (thd->open_temporary_tables(table_list) ||
mysql_recreate_table(thd, table_list, recreate_info, false));
mysql_recreate_table(thd, table_list, recreate_info,
table_copy));
table_list->next_global= save_next_global;
reenable_binlog(thd);
/*
mysql_recreate_table() can push OK or ERROR.
@@ -286,6 +293,11 @@ static int prepare_for_repair(THD *thd, TABLE_LIST *table_list,
goto end;
}
}
/*
We have now fixed the table. However the frm file is still of old format.
We cannot update the frm_file to FRM_VER_TRUE_VARCHAR as the new format
are not compatible with the data.
*/
end:
thd->locked_tables_list.unlink_all_closed_tables(thd, NULL, 0);
@@ -532,7 +544,7 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
const LEX_CSTRING *operator_name,
thr_lock_type lock_type,
bool org_open_for_modify,
bool repair_table_use_frm,
bool no_errors_from_open,
uint extra_open_options,
int (*prepare_func)(THD *, TABLE_LIST *,
HA_CHECK_OPT *),
@@ -597,7 +609,8 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
uchar tabledef_version_buff[MY_UUID_SIZE];
const char *db= table->db.str;
bool fatal_error=0;
bool open_error= 0;
bool open_error= 0, recreate_used= 0;
bool require_data_conversion= 0, require_alter_table= 0;
bool collect_eis= FALSE;
bool open_for_modify= org_open_for_modify;
Recreate_info recreate_info;
@@ -635,7 +648,7 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
while (1)
{
open_error= open_only_one_table(thd, table,
repair_table_use_frm,
no_errors_from_open,
(view_operator_func != NULL));
thd->open_options&= ~extra_open_options;
@@ -859,28 +872,37 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
/* purecov: end */
}
if (operator_func == &handler::ha_repair &&
!(check_opt->sql_flags & TT_USEFRM))
if (operator_func == &handler::ha_repair)
{
handler *file= table->table->file;
int check_for_upgrade= file->ha_check_for_upgrade(check_opt);
require_data_conversion=
check_for_upgrade == HA_ADMIN_NEEDS_DATA_CONVERSION;
require_alter_table= check_for_upgrade == HA_ADMIN_NEEDS_ALTER;
if (check_for_upgrade == HA_ADMIN_NEEDS_ALTER)
if (!(check_opt->sql_flags & (TT_USEFRM | TT_FORCE)))
{
/* We use extra_open_options to be able to open crashed tables */
thd->open_options|= extra_open_options;
result_code= admin_recreate_table(thd, table, &recreate_info) ?
HA_ADMIN_FAILED : HA_ADMIN_OK;
thd->open_options&= ~extra_open_options;
goto send_result;
}
if (check_for_upgrade)
{
/* If repair is not implemented for the engine, run ALTER TABLE */
need_repair_or_alter= 1;
if (require_data_conversion || require_alter_table)
{
/* We use extra_open_options to be able to open crashed tables */
thd->open_options|= extra_open_options;
result_code= (admin_recreate_table(thd, table, &recreate_info, 1) ?
HA_ADMIN_FAILED : HA_ADMIN_OK);
recreate_used= 1;
thd->open_options&= ~extra_open_options;
goto send_result;
}
if (check_for_upgrade ||
!(table->table->file->ha_table_flags() & HA_CAN_REPAIR))
{
/*
If data upgrade is needed or repair is not implemented for the
engine, run ALTER TABLE FORCE
*/
need_repair_or_alter= 1;
}
}
}
result_code= compl_result_code= HA_ADMIN_OK;
if (operator_func == &handler::ha_analyze)
@@ -949,7 +971,7 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
table->lock_type= TL_READ;
DBUG_ASSERT(view_operator_func == NULL);
open_error= open_only_one_table(thd, table,
repair_table_use_frm, FALSE);
no_errors_from_open, FALSE);
thd->open_options&= ~extra_open_options;
if (unlikely(!open_error))
@@ -1092,10 +1114,11 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
repair was not implemented and we need to upgrade the table
to a new version so we recreate the table with ALTER TABLE
*/
result_code= admin_recreate_table(thd, table, &recreate_info);
result_code= admin_recreate_table(thd, table, &recreate_info, 1);
recreate_used= 1;
}
send_result:
send_result:
lex->cleanup_after_one_table_open();
thd->clear_error(); // these errors shouldn't get client
@@ -1136,6 +1159,34 @@ send_result:
}
thd->get_stmt_da()->clear_warning_info(thd->query_id);
}
/*
Give a warning if REPAIR TABLE was used but table still needs an
ALTER TABLE. This can only happen for old type tables where REPAIR
was using FORCE to recover old data.
*/
if (operator_func == &handler::ha_repair && ! recreate_used &&
(require_data_conversion || require_alter_table))
{
char buf[MYSQL_ERRMSG_SIZE];
if (result_code == HA_ADMIN_OK)
{
protocol->prepare_for_resend();
protocol->store(&table_name, system_charset_info);
protocol->store(operator_name, system_charset_info);
protocol->store(STRING_WITH_LEN("note"), system_charset_info);
protocol->store(STRING_WITH_LEN("Table data recovered"),system_charset_info);
if (protocol->write())
goto err;
}
my_snprintf(buf, sizeof(buf),
ER_THD(thd, ER_TABLE_NEEDS_REBUILD),
table_name.str);
if (send_check_errmsg(thd, table, operator_name, buf) < 0)
goto err;
result_code= HA_ADMIN_FAILED;
}
protocol->prepare_for_resend();
protocol->store(&table_name, system_charset_info);
protocol->store(operator_name, system_charset_info);
@@ -1227,7 +1278,8 @@ send_result_message:
*save_next_global= table->next_global;
table->next_local= table->next_global= 0;
result_code= admin_recreate_table(thd, table, &recreate_info);
result_code= admin_recreate_table(thd, table, &recreate_info, 0);
recreate_used= 1;
trans_commit_stmt(thd);
trans_commit(thd);
close_thread_tables(thd);
@@ -1310,6 +1362,7 @@ send_result_message:
}
case HA_ADMIN_NEEDS_UPGRADE:
case HA_ADMIN_NEEDS_DATA_CONVERSION:
case HA_ADMIN_NEEDS_ALTER:
{
char buf[MYSQL_ERRMSG_SIZE];
@@ -1318,7 +1371,7 @@ send_result_message:
table->table->file->ha_table_flags() & HA_CAN_REPAIR ? "TABLE" : 0;
protocol->store(&error_clex_str, system_charset_info);
if (what_to_upgrade)
if (what_to_upgrade && result_code == HA_ADMIN_NEEDS_UPGRADE)
length= my_snprintf(buf, sizeof(buf),
ER_THD(thd, ER_TABLE_NEEDS_UPGRADE),
what_to_upgrade, table->table_name.str);
@@ -1611,7 +1664,8 @@ bool Sql_cmd_optimize_table::execute(THD *thd)
WSREP_TO_ISOLATION_BEGIN_WRTCHK(NULL, NULL, first_table);
res= (specialflag & SPECIAL_NO_NEW_FUNC) ?
mysql_recreate_table(thd, first_table, &recreate_info, true) :
mysql_recreate_table(thd, first_table, &recreate_info,
false) :
mysql_admin_table(thd, first_table, &m_lex->check_opt,
&msg_optimize, TL_WRITE, 1, 0, 0, 0,
&handler::ha_optimize, 0, true);
@@ -1639,7 +1693,8 @@ bool Sql_cmd_repair_table::execute(THD *thd)
WSREP_TO_ISOLATION_BEGIN_WRTCHK(NULL, NULL, first_table);
res= mysql_admin_table(thd, first_table, &m_lex->check_opt, &msg_repair,
TL_WRITE, 1,
MY_TEST(m_lex->check_opt.sql_flags & TT_USEFRM),
MY_TEST(m_lex->check_opt.sql_flags &
(TT_USEFRM | TT_FORCE)),
HA_OPEN_FOR_REPAIR, &prepare_for_repair,
&handler::ha_repair, &view_repair, true);