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mariadb/sql/sql_sequence.cc
Monty 171c909f3c MDEV-25292 Atomic CREATE OR REPLACE TABLE 
Atomic CREATE OR REPLACE allows to keep an old table intact if the
command fails or during the crash. That is done by renaming the
original table to temporary name, as a backup and restoring it if the
CREATE fails. When the command is complete and logged the backup
table is deleted.

Atomic replace algorithm

  Two DDL chains are used for CREATE OR REPLACE:
  ddl_log_state_create (C) and ddl_log_state_rm (D).

  1. (C) Log rename of ORIG to TMP table (Rename TMP to original).
  2. Rename orignal to TMP.
  3. (C) Log CREATE_TABLE_ACTION of ORIG (drops ORIG);
  4. Do everything with ORIG (like insert data)
  5. (D) Log drop of TMP
  6. Write query to binlog (this marks (C) to be closed in
     case of failure)
  7. Execute drop of TMP through (D)
  8. Close (C) and (D)

  If there is a failure before 6) we revert the changes in (C)
  Chain (D) is only executed if 6) succeded (C is closed on
  crash recovery).

Foreign key errors will be found at the 1) stage.

Additional notes

  - CREATE TABLE without REPLACE and temporary tables is not affected
    by this commit.
    set @@drop_before_create_or_replace=1 can be used to
    get old behaviour where existing tables are dropped
    in CREATE OR REPLACE.

  - CREATE TABLE is reverted if binlogging the query fails.

  - Engines having HTON_EXPENSIVE_RENAME flag set are not affected by
    this commit. Conflicting tables marked with this flag will be
    deleted with CREATE OR REPLACE.

  - Replication execution is not affected by this commit.
    - Replication will first drop the conflicting table and then
      creating the new one.

  - CREATE TABLE .. SELECT XID usage is fixed and now there is no need
    to log DROP TABLE via DDL_CREATE_TABLE_PHASE_LOG (see comments in
    do_postlock()). XID is now correctly updated so it disables
    DDL_LOG_DROP_TABLE_ACTION. Note that binary log is flushed at the
    final stage when the table is ready. So if we have XID in the
    binary log we don't need to drop the table.

  - Three variations of CREATE OR REPLACE handled:

    1. CREATE OR REPLACE TABLE t1 (..);
    2. CREATE OR REPLACE TABLE t1 LIKE t2;
    3. CREATE OR REPLACE TABLE t1 SELECT ..;

  - Test case uses 6 combinations for engines (aria, aria_notrans,
    myisam, ib, lock_tables, expensive_rename) and 2 combinations for
    binlog types (row, stmt). Combinations help to check differences
    between the results. Error failures are tested for the above three
    variations.

  - expensive_rename tests CREATE OR REPLACE without atomic
    replace. The effect should be the same as with the old behaviour
    before this commit.

  - Triggers mechanism is unaffected by this change. This is tested in
    create_replace.test.

  - LOCK TABLES is affected. Lock restoration must be done after new
    table is created or TMP is renamed back to ORIG

  - Moved ddl_log_complete() from send_eof() to finalize_ddl(). This
    checkpoint was not executed before for normal CREATE TABLE but is
    executed now.

  - CREATE TABLE will now rollback also if writing to the binary
    logging failed. See rpl_gtid_strict.test

backup ddl log changes

- In case of a successfull CREATE OR REPLACE we only log
  the CREATE event, not the DROP TABLE event of the old table.

ddl_log.cc changes

  ddl_log_execute_action() now properly return error conditions.
  ddl_log_disable_entry() added to allow one to disable one entry.
  The entry on disk is still reserved until ddl_log_complete() is
  executed.

On XID usage

  Like with all other atomic DDL operations XID is used to avoid
  inconsistency between master and slave in the case of a crash after
  binary log is written and before ddl_log_state_create is closed. On
  recovery XIDs are taken from binary log and corresponding DDL log
  events get disabled.  That is done by
  ddl_log_close_binlogged_events().

On linking two chains together

  Chains are executed in the ascending order of entry_pos of execute
  entries. But entry_pos assignment order is undefined: it may assign
  bigger number for the first chain and then smaller number for the
  second chain. So the execution order in that case will be reverse:
  second chain will be executed first.

  To avoid that we link one chain to another. While the base chain
  (ddl_log_state_create) is active the secondary chain
  (ddl_log_state_rm) is not executed. That is: only one chain can be
  executed in two linked chains.

  The interface ddl_log_link_chains() was defined in "MDEV-22166
  ddl_log_write_execute_entry() extension".

Atomic info parameters in HA_CREATE_INFO

  Many functions in CREATE TABLE pass the same parameters. These
  parameters are part of table creation info and should be in
  HA_CREATE_INFO (or whatever). Passing parameters via single
  structure is much easier for adding new data and
  refactoring.

InnoDB changes
  Added ha_innobase::can_be_renamed_to_backup() to check if
  a table with foreign keys can be renamed.

Aria changes:
- Fixed issue in Aria engine with CREATE + locked tables
  that data was not properly commited in some cases in
  case of crashes.

Known issues:
- InnoDB tables with foreign key definitions are not fully supported
  with atomic create and replace:
  - ha_innobase::can_be_renamed_to_backup() can detect some cases
    where InnoDB does not support renaming table with foreign key
    constraints.  In this case MariaDB will drop the old table before
    creating the new one.
    The detected cases are:
    - The new and old table is using the same foreign key constraint
      name.
    - The old table has self referencing constraints.
  - If the old and new table uses the same name for a constraint the
    create of the new table will fail. The orignal table will be
    restored in this case.
  - The above issues will be fixed in a future commit.
- CREATE OR REPLACE TEMPORARY table is not full atomic. Any conflicting
  table will always be dropped before creating a new one. (Old behaviour).

Bug fixes related to this MDEV:

MDEV-36435 Assertion failure in finalize_locked_tables()
MDEV-36439 Assertion `thd_arg->lex->sql_command != SQLCOM_CREATE_SEQUENCE...
2025-04-09 12:39:42 +03:00

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/*
Copyright (c) 2017, MariaDB Corporation, Alibaba Corporation
Copyright (c) 2020, 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 02110-1301 USA
*/
#include "mariadb.h"
#include "sql_class.h"
#include "sql_list.h"
#include "sql_sequence.h"
#include "ha_sequence.h"
#include "sql_base.h"
#include "sql_table.h" // write_bin_log
#include "transaction.h"
#include "lock.h"
#include "sql_acl.h"
#ifdef WITH_WSREP
#include "wsrep_mysqld.h"
bool wsrep_check_sequence(THD* thd,
const sequence_definition *seq,
const bool used_engine);
#endif
#define MAX_AUTO_INCREMENT_VALUE 65535
/**
Structure for SEQUENCE tables of a certain value type
@param in handler The handler of a sequence value type
@return The sequence table structure given the value type
*/
Sequence_row_definition sequence_structure(const Type_handler* handler)
{
/*
We don't really care about src because it is unused in
max_display_length_for_field().
*/
const Conv_source src(handler, 0, system_charset_info);
const uint32 len= handler->max_display_length_for_field(src) + 1;
const LEX_CSTRING empty= {STRING_WITH_LEN("")};
const uint flag_unsigned= handler->is_unsigned() ? UNSIGNED_FLAG : 0;
#define FNND (NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG)
#define FNNDFU (NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG | flag_unsigned)
return {{{"next_not_cached_value", len, handler, empty, FNNDFU},
{"minimum_value", len, handler, empty, FNNDFU},
{"maximum_value", len, handler, empty, FNNDFU},
{"start_value", len, handler,
{STRING_WITH_LEN("start value when sequences is created or value "
"if RESTART is used")}, FNNDFU},
{"increment", 21, &type_handler_slonglong,
{STRING_WITH_LEN("increment value")}, FNND},
{"cache_size", 21, &type_handler_ulonglong, empty,
FNND | UNSIGNED_FLAG},
{"cycle_option", 1, &type_handler_utiny,
{STRING_WITH_LEN("0 if no cycles are allowed, 1 if the sequence "
"should begin a new cycle when maximum_value is "
"passed")}, FNND | UNSIGNED_FLAG},
{"cycle_count", 21, &type_handler_slonglong,
{STRING_WITH_LEN("How many cycles have been done")}, FNND},
{NULL, 0, &type_handler_slonglong, {STRING_WITH_LEN("")}, 0}}};
#undef FNNDFU
#undef FNND
}
/**
Whether a type is allowed as a sequence value type.
@param in type The type to check
@retval true allowed
false not allowed
*/
bool sequence_definition::is_allowed_value_type(enum_field_types type)
{
switch (type)
{
case MYSQL_TYPE_TINY:
case MYSQL_TYPE_SHORT:
case MYSQL_TYPE_LONG:
case MYSQL_TYPE_INT24:
case MYSQL_TYPE_LONGLONG:
return true;
default:
return false;
}
}
/*
Get the type handler for the value type of a sequence.
*/
Type_handler const *sequence_definition::value_type_handler()
{
const Type_handler *handler=
Type_handler::get_handler_by_field_type(value_type);
return is_unsigned ? handler->type_handler_unsigned() : handler;
}
/*
Get the upper bound for a sequence value type.
*/
longlong sequence_definition::value_type_max()
{
/*
Use value_type != MYSQL_TYPE_LONGLONG to avoid undefined behaviour
https://stackoverflow.com/questions/9429156/by-left-shifting-can-a-number-be-set-to-zero
*/
return is_unsigned && value_type != MYSQL_TYPE_LONGLONG ?
~(~0ULL << 8 * value_type_handler()->calc_pack_length(0)) :
~value_type_min();
}
/*
Get the lower bound for a sequence value type.
*/
longlong sequence_definition::value_type_min() {
return is_unsigned ? 0 :
~0ULL << (8 * value_type_handler()->calc_pack_length(0) - 1);
}
/**
Truncate a Longlong_hybrid.
If `original` is greater than value_type_max(), truncate down to
value_type_max()
If `original` is less than value_type_min(), truncate up to
value_type_min()
Whenever a truncation happens, the resulting value is just out of
bounds for sequence values because value_type_max() is the maximum
possible sequence value + 1, and the same applies to
value_type_min().
@param in original The value to truncate
@return The truncated value
*/
longlong sequence_definition::truncate_value(const Longlong_hybrid& original)
{
if (is_unsigned)
return original.to_ulonglong(value_type_max());
if (original.is_unsigned_outside_of_signed_range())
return value_type_max();
const longlong value= original.value();
return (value > value_type_max() ? value_type_max() :
value < value_type_min() ? value_type_min() : value);
}
/**
Check whether sequence values are valid.
Sets default values for fields that are not used, according to Oracle spec.
@param in thd The connection
@param in set_reserved_until Whether to set reserved_until to start
@retval false valid
true invalid
*/
bool sequence_definition::check_and_adjust(THD *thd, bool set_reserved_until)
{
DBUG_ENTER("sequence_definition::check_and_adjust");
/* Easy error to detect. */
if (!is_allowed_value_type(value_type) || cache < 0)
DBUG_RETURN(TRUE);
if (!(real_increment= increment))
real_increment= global_system_variables.auto_increment_increment;
/*
If min_value is not set, in case of signed sequence, set it to
value_type_min()+1 or 1, depending on real_increment, and in case
of unsigned sequence, set it to value_type_min()+1
*/
if (!(used_fields & seq_field_specified_min_value))
min_value= real_increment < 0 || is_unsigned ? value_type_min()+1 : 1;
else
{
min_value= truncate_value(min_value_from_parser);
if ((is_unsigned &&
(ulonglong) min_value <= (ulonglong) value_type_min()) ||
(!is_unsigned && min_value <= value_type_min()))
{
push_warning_printf(
thd, Sql_condition::WARN_LEVEL_NOTE, ER_TRUNCATED_WRONG_VALUE,
ER_THD(thd, ER_TRUNCATED_WRONG_VALUE), "INTEGER", "MINVALUE");
min_value= value_type_min() + 1;
}
}
/*
If max_value is not set, in case of signed sequence set it to
value_type_max()-1 or -1, depending on real_increment, and in case
of unsigned sequence, set it to value_type_max()-1
*/
if (!(used_fields & seq_field_specified_max_value))
max_value= real_increment > 0 || is_unsigned ? value_type_max()-1 : -1;
else
{
max_value= truncate_value(max_value_from_parser);
if ((is_unsigned &&
(ulonglong) max_value >= (ulonglong) value_type_max()) ||
(!is_unsigned && max_value >= value_type_max()))
{
push_warning_printf(
thd, Sql_condition::WARN_LEVEL_NOTE, ER_TRUNCATED_WRONG_VALUE,
ER_THD(thd, ER_TRUNCATED_WRONG_VALUE), "INTEGER", "MAXVALUE");
max_value= value_type_max() - 1;
}
}
if (!(used_fields & seq_field_used_start))
{
/* Use min_value or max_value for start depending on real_increment */
start= real_increment < 0 ? max_value : min_value;
} else
/*
If the supplied start value is out of range for the value type,
instead of immediately reporting error, we truncate it to
value_type_min or value_type_max depending on which side it is
one. Whenever such truncation happens, the condition that
max_value >= start >= min_value will be violated, and the error
will be reported then.
*/
start= truncate_value(start_from_parser);
if (set_reserved_until)
reserved_until= start;
adjust_values(reserved_until);
/* To ensure that cache * real_increment will never overflow */
const longlong max_increment= (real_increment ?
llabs(real_increment) :
MAX_AUTO_INCREMENT_VALUE);
/*
To ensure that cache * real_increment will never overflow. See the
calculation of add_to below in SEQUENCE::next_value(). We need
this for unsigned too, because otherwise we will need to handle
add_to as an equivalent of Longlong_hybrid type in
SEQUENCE::increment_value().
*/
if (cache >= (LONGLONG_MAX - max_increment) / max_increment)
DBUG_RETURN(TRUE);
if (is_unsigned && (ulonglong) max_value >= (ulonglong) start &&
(ulonglong) max_value > (ulonglong) min_value &&
(ulonglong) start >= (ulonglong) min_value &&
((real_increment > 0 &&
(ulonglong) reserved_until >= (ulonglong) min_value) ||
(real_increment < 0 &&
(ulonglong) reserved_until <= (ulonglong) max_value)))
DBUG_RETURN(FALSE);
if (!is_unsigned && max_value >= start && max_value > min_value &&
start >= min_value &&
((real_increment > 0 && reserved_until >= min_value) ||
(real_increment < 0 && reserved_until <= max_value)))
DBUG_RETURN(FALSE);
DBUG_RETURN(TRUE); // Error
}
/*
Read sequence values from a table
*/
void sequence_definition::read_fields(TABLE *table)
{
MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, &table->read_set);
reserved_until= table->field[0]->val_int();
min_value= table->field[1]->val_int();
max_value= table->field[2]->val_int();
start= table->field[3]->val_int();
increment= table->field[4]->val_int();
cache= table->field[5]->val_int();
cycle= table->field[6]->val_int();
round= table->field[7]->val_int();
value_type= table->field[0]->type();
is_unsigned= table->field[0]->is_unsigned();
min_value_from_parser= Longlong_hybrid(min_value, is_unsigned);
max_value_from_parser= Longlong_hybrid(max_value, is_unsigned);
start_from_parser= Longlong_hybrid(start, is_unsigned);
dbug_tmp_restore_column_map(&table->read_set, old_map);
used_fields= ~(uint) 0;
print_dbug();
}
/*
Store sequence into a table row
*/
void sequence_definition::store_fields(TABLE *table)
{
MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, &table->write_set);
/* zero possible delete markers & null bits */
memcpy(table->record[0], table->s->default_values, table->s->null_bytes);
table->field[0]->store(reserved_until, is_unsigned);
table->field[1]->store(min_value, is_unsigned);
table->field[2]->store(max_value, is_unsigned);
table->field[3]->store(start, is_unsigned);
table->field[4]->store(increment, 0);
table->field[5]->store(cache, 0);
table->field[6]->store((longlong) cycle != 0, 0);
table->field[7]->store((longlong) round, 1);
dbug_tmp_restore_column_map(&table->write_set, old_map);
print_dbug();
}
/*
Check the sequence fields through seq_fields when creating a sequence.
RETURN VALUES
false Success
true Failure
*/
bool check_sequence_fields(LEX *lex, List<Create_field> *fields,
const LEX_CSTRING db, const LEX_CSTRING table_name)
{
Create_field *field;
List_iterator_fast<Create_field> it(*fields);
uint field_count;
uint field_no;
const char *reason;
Sequence_row_definition row_structure;
DBUG_ENTER("check_sequence_fields");
field_count= fields->elements;
if (!field_count)
{
reason= my_get_err_msg(ER_SEQUENCE_TABLE_HAS_WRONG_NUMBER_OF_COLUMNS);
goto err;
}
if (!sequence_definition::is_allowed_value_type(
fields->head()->type_handler()->field_type()))
{
reason= fields->head()->field_name.str;
goto err;
}
row_structure= sequence_structure(fields->head()->type_handler());
if (field_count != array_elements(row_structure.fields)-1)
{
reason= my_get_err_msg(ER_SEQUENCE_TABLE_HAS_WRONG_NUMBER_OF_COLUMNS);
goto err;
}
if (lex->alter_info.key_list.elements > 0)
{
reason= my_get_err_msg(ER_SEQUENCE_TABLE_CANNOT_HAVE_ANY_KEYS);
goto err;
}
if (lex->alter_info.check_constraint_list.elements > 0)
{
reason= my_get_err_msg(ER_SEQUENCE_TABLE_CANNOT_HAVE_ANY_CONSTRAINTS);
goto err;
}
if (lex->alter_info.flags & ALTER_ORDER)
{
reason= my_get_err_msg(ER_SEQUENCE_TABLE_ORDER_BY);
goto err;
}
for (field_no= 0; (field= it++); field_no++)
{
const Sequence_field_definition *field_def= &row_structure.fields[field_no];
if (!field->field_name.streq(Lex_cstring_strlen(field_def->field_name)) ||
field->flags != field_def->flags ||
field->type_handler() != field_def->type_handler ||
field->check_constraint || field->vcol_info)
{
reason= field->field_name.str;
goto err;
}
}
DBUG_RETURN(FALSE);
err:
my_error(ER_SEQUENCE_INVALID_TABLE_STRUCTURE, MYF(0),
db.str, table_name.str, reason);
DBUG_RETURN(TRUE);
}
/*
Create the fields for a SEQUENCE TABLE
RETURN VALUES
false Success
true Failure (out of memory)
*/
bool sequence_definition::prepare_sequence_fields(List<Create_field> *fields,
bool alter)
{
DBUG_ENTER("prepare_sequence_fields");
const Sequence_row_definition row_def=
sequence_structure(value_type_handler());
for (const Sequence_field_definition *field_info= row_def.fields;
field_info->field_name; field_info++)
{
Create_field *new_field;
const Lex_ident_column field_name= Lex_cstring_strlen(field_info->
field_name);
if (unlikely(!(new_field= new Create_field())))
DBUG_RETURN(TRUE); /* purify inspected */
new_field->field_name= field_name;
new_field->set_handler(field_info->type_handler);
new_field->length= field_info->length;
new_field->char_length= field_info->length;
new_field->comment= field_info->comment;
new_field->flags= field_info->flags;
if (alter)
new_field->change = field_name;
if (unlikely(fields->push_back(new_field)))
DBUG_RETURN(TRUE); /* purify inspected */
}
DBUG_RETURN(FALSE);
}
/*
Initialize the sequence table record as part of CREATE SEQUENCE
Store one row with sequence information.
RETURN VALUES
false Success
true Failure. Error reported.
NOTES
This function is called as part of CREATE SEQUENCE. When called
there are now active transactions and no open tables.
There is also a MDL lock on the table.
*/
bool sequence_insert(THD *thd, LEX *lex, TABLE_LIST *org_table_list)
{
int error;
TABLE *table;
Reprepare_observer *save_reprepare_observer;
sequence_definition *seq= lex->create_info.seq_create_info;
bool temporary_table= org_table_list->table != 0;
/*
seq is 0 if sequence was created with CREATE TABLE instead of
CREATE SEQUENCE
*/
bool create_new= !seq;
Open_tables_backup open_tables_backup;
Query_tables_list query_tables_list_backup;
TABLE_LIST table_list; // For sequence table
DBUG_ENTER("sequence_insert");
DBUG_EXECUTE_IF("kill_query_on_sequence_insert",
thd->set_killed(KILL_QUERY););
if (create_new && !(seq= new (thd->mem_root) sequence_definition))
DBUG_RETURN(TRUE);
/* If not temporary table */
if (!temporary_table)
{
/*
The following code works like open_system_tables_for_read()
The idea is:
- Copy the table_list object for the sequence that was created
- Backup the current state of open tables and create a new
environment for open tables without any tables opened
- open the newly sequence table for write
This is safe as the sequence table has a mdl lock thanks to the
create sequence statement that is calling this function
*/
table_list.init_one_table(&org_table_list->db,
&org_table_list->table_name,
NULL, TL_WRITE_DEFAULT);
table_list.updating= 1;
table_list.open_strategy= TABLE_LIST::OPEN_IF_EXISTS;
table_list.open_type= OT_BASE_ONLY;
DBUG_ASSERT(!thd->locked_tables_mode ||
(thd->variables.option_bits & OPTION_TABLE_LOCK));
lex->reset_n_backup_query_tables_list(&query_tables_list_backup);
thd->reset_n_backup_open_tables_state(&open_tables_backup);
/*
The FOR CREATE flag is needed to ensure that ha_open() doesn't try to
read the not yet existing row in the sequence table
*/
thd->open_options|= HA_OPEN_FOR_CREATE;
/*
We have to reset the reprepare observer to be able to open the
table under prepared statements.
*/
save_reprepare_observer= thd->m_reprepare_observer;
thd->m_reprepare_observer= 0;
lex->sql_command= SQLCOM_CREATE_SEQUENCE;
error= open_and_lock_tables(thd, &table_list, FALSE,
MYSQL_LOCK_IGNORE_TIMEOUT |
MYSQL_OPEN_HAS_MDL_LOCK);
thd->open_options&= ~HA_OPEN_FOR_CREATE;
thd->m_reprepare_observer= save_reprepare_observer;
if (unlikely(error))
{
lex->restore_backup_query_tables_list(&query_tables_list_backup);
thd->restore_backup_open_tables_state(&open_tables_backup);
DBUG_RETURN(error);
}
table= table_list.table;
}
else
table= org_table_list->table;
if (create_new)
{
seq->value_type= (*table->s->field)->type();
seq->is_unsigned= (*table->s->field)->is_unsigned();
/* We set reserved_until when creating a new sequence. */
if (seq->check_and_adjust(thd, true))
DBUG_RETURN(TRUE);
}
error= seq->write_initial_sequence(table);
{
uint save_unsafe_rollback_flags=
thd->transaction->stmt.m_unsafe_rollback_flags;
if (trans_commit_stmt(thd))
error= 1;
thd->transaction->stmt.m_unsafe_rollback_flags=
save_unsafe_rollback_flags;
}
if (trans_commit_implicit(thd))
error= 1;
if (!temporary_table)
{
close_thread_tables(thd);
lex->restore_backup_query_tables_list(&query_tables_list_backup);
thd->restore_backup_open_tables_state(&open_tables_backup);
/* OPTION_TABLE_LOCK was reset in trans_commit_implicit */
if (thd->locked_tables_mode)
thd->variables.option_bits|= OPTION_TABLE_LOCK;
}
DBUG_RETURN(error);
}
/* Create a SEQUENCE object */
SEQUENCE::SEQUENCE() :all_values_used(0), initialized(SEQ_UNINTIALIZED)
{
mysql_rwlock_init(key_LOCK_SEQUENCE, &mutex);
}
SEQUENCE::~SEQUENCE()
{
mysql_rwlock_destroy(&mutex);
}
/*
The following functions is to ensure that we when reserve new values
trough sequence object sequence we have only one writer at at time.
A sequence table can have many readers (trough normal SELECT's).
We mark that we have a write lock in the table object so that
ha_sequence::write_row() can check if we have a lock. If already locked, then
ha_write() knows that we are running a sequence operation. If not, then
ha_write() knows that it's an INSERT statement.
*/
void SEQUENCE::write_lock(TABLE *table)
{
DBUG_ASSERT(((ha_sequence*) table->file)->is_locked() == 0);
mysql_rwlock_wrlock(&mutex);
((ha_sequence*) table->file)->write_lock();
}
void SEQUENCE::write_unlock(TABLE *table)
{
((ha_sequence*) table->file)->unlock();
mysql_rwlock_unlock(&mutex);
}
void SEQUENCE::read_lock(TABLE *table)
{
if (!((ha_sequence*) table->file)->is_locked())
mysql_rwlock_rdlock(&mutex);
}
void SEQUENCE::read_unlock(TABLE *table)
{
if (!((ha_sequence*) table->file)->is_locked())
mysql_rwlock_unlock(&mutex);
}
/**
Read values from the sequence tables to table_share->sequence.
This is called from ha_open() when the table is not yet locked
*/
int SEQUENCE::read_initial_values(TABLE *table)
{
int error= 0;
enum thr_lock_type save_lock_type;
MDL_request mdl_request; // Empty constructor!
DBUG_ENTER("SEQUENCE::read_initial_values");
if (likely(initialized != SEQ_UNINTIALIZED))
DBUG_RETURN(0);
write_lock(table);
if (likely(initialized == SEQ_UNINTIALIZED))
{
MYSQL_LOCK *lock;
bool mdl_lock_used= 0;
THD *thd= table->in_use;
bool has_active_transaction= !thd->transaction->stmt.is_empty();
/*
There is already a mdl_ticket for this table. However, for list_fields
the MDL lock is of type MDL_SHARED_HIGH_PRIO which is not usable
for doing a table lock. Get a proper read lock to solve this.
*/
if (table->mdl_ticket == 0)
{
MDL_request_list mdl_requests;
mdl_lock_used= 1;
/*
This happens if first request is SHOW CREATE TABLE or LIST FIELDS
where we don't have a mdl lock on the table
*/
MDL_REQUEST_INIT(&mdl_request, MDL_key::TABLE, table->s->db.str,
table->s->table_name.str, MDL_SHARED_READ,
MDL_EXPLICIT);
mdl_requests.push_front(&mdl_request);
if (thd->mdl_context.acquire_locks(&mdl_requests,
thd->variables.lock_wait_timeout))
{
write_unlock(table);
DBUG_RETURN(HA_ERR_LOCK_WAIT_TIMEOUT);
}
}
save_lock_type= table->reginfo.lock_type;
table->reginfo.lock_type= TL_READ;
if (!(lock= mysql_lock_tables(thd, &table, 1,
MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY)))
{
if (mdl_lock_used)
thd->mdl_context.release_lock(mdl_request.ticket);
write_unlock(table);
if (!has_active_transaction && !thd->transaction->stmt.is_empty() &&
!thd->in_sub_stmt)
trans_commit_stmt(thd);
DBUG_RETURN(HA_ERR_LOCK_WAIT_TIMEOUT);
}
DBUG_ASSERT(table->reginfo.lock_type == TL_READ);
if (likely(!(error= read_stored_values(table))))
initialized= SEQ_READY_TO_USE;
mysql_unlock_tables(thd, lock);
if (mdl_lock_used)
thd->mdl_context.release_lock(mdl_request.ticket);
/* Reset value to default */
table->reginfo.lock_type= save_lock_type;
/*
Doing mysql_lock_tables() may have started a read only transaction.
If that happend, it's better that we commit it now, as a lot of
code assumes that there is no active stmt transaction directly after
open_tables().
But we also don't want to commit the stmt transaction while in a
substatement, see MDEV-15977.
*/
if (!has_active_transaction && !thd->transaction->stmt.is_empty() &&
!thd->in_sub_stmt)
{
/*
We have to preserve the rollback flag marking this statement as
a DDL because Gtid_log_event::Gtid_log_event may be called later
as part of CREATE OR REPLACE and it needs to know if the statement
was a DDL.
*/
uint save_unsafe_rollback_flags=
thd->transaction->stmt.m_unsafe_rollback_flags;
if (trans_commit_stmt(thd))
error= HA_ERR_COMMIT_ERROR;
thd->transaction->stmt.m_unsafe_rollback_flags=
save_unsafe_rollback_flags;
}
}
write_unlock(table);
DBUG_RETURN(error);
}
/*
This class is here to allow one to use import table space on sequences
*/
class Silence_table_space_errors : public Internal_error_handler
{
public:
Silence_table_space_errors() {}
~Silence_table_space_errors() override = default;
bool handle_condition(THD *thd,
uint sql_errno,
const char* sql_state,
Sql_condition::enum_warning_level *level,
const char* msg,
Sql_condition ** cond_hdl) override
{
if (sql_errno == ER_TABLESPACE_DISCARDED || HA_ERR_TABLESPACE_MISSING)
return true; // Silence it
return false;
}
};
/*
Do the actual reading of data from sequence table and
update values in the sequence object.
Called once from when table is opened
*/
int SEQUENCE::read_stored_values(TABLE *table)
{
int error;
Silence_table_space_errors error_handler;
THD *thd= table->in_use;
DBUG_ENTER("SEQUENCE::read_stored_values");
thd->push_internal_handler(&error_handler);
MY_BITMAP *save_read_set= tmp_use_all_columns(table, &table->read_set);
error= table->file->ha_read_first_row(table->record[0], MAX_KEY);
tmp_restore_column_map(&table->read_set, save_read_set);
if (unlikely(error))
{
thd->pop_internal_handler();
if (error == HA_ERR_TABLESPACE_MISSING && thd->tablespace_op)
DBUG_RETURN(0); // Ignore error for ALTER TABLESPACE
table->file->print_error(error, MYF(0));
DBUG_RETURN(error);
}
read_fields(table);
adjust_values(reserved_until);
all_values_used= 0;
thd->pop_internal_handler();
DBUG_RETURN(0);
}
/*
Adjust values after reading a the stored state
*/
void sequence_definition::adjust_values(longlong next_value)
{
next_free_value= next_value;
if (!(real_increment= increment))
{
longlong offset= 0;
longlong off, to_add;
/* Use auto_increment_increment and auto_increment_offset */
if ((real_increment= global_system_variables.auto_increment_increment)
!= 1)
offset= (global_system_variables.auto_increment_offset %
global_system_variables.auto_increment_increment);
/*
Ensure that next_free_value has the right offset, so that we can
generate a serie by just adding real_increment. The goal is to
adjust next_free_value upwards such that
next_free_value % real_increment == offset
*/
if (is_unsigned)
off= (ulonglong) next_free_value % real_increment;
else
off= next_free_value % real_increment;
if (off < 0)
off+= real_increment;
to_add= (real_increment + offset - off) % real_increment;
/*
Check if add will make next_free_value bigger than max_value,
taken into account that next_free_value or max_value addition
may overflow.
0 <= to_add <= auto_increment_increment <= 65535 so we do not
need to cast to_add.
*/
if ((is_unsigned &&
((ulonglong) next_free_value > (ulonglong) max_value - to_add ||
(ulonglong) next_free_value + to_add > (ulonglong) max_value ||
(ulonglong) next_free_value > (ulonglong) max_value)) ||
(!is_unsigned &&
(next_free_value > (longlong) ((ulonglong) max_value - to_add) ||
(longlong) ((ulonglong) next_free_value + to_add) > max_value ||
next_free_value > max_value)))
next_free_value= max_value+1;
else
{
next_free_value=
(longlong) ((ulonglong) next_free_value + (ulonglong) to_add);
if (is_unsigned)
DBUG_ASSERT((ulonglong) next_free_value % real_increment ==
(ulonglong) offset);
else
DBUG_ASSERT(llabs(next_free_value % real_increment) == offset);
}
}
}
/**
Write initial sequence information for CREATE and ALTER to sequence table
*/
int sequence_definition::write_initial_sequence(TABLE *table)
{
int error;
MY_BITMAP *save_write_set;
store_fields(table);
/* Store the sequence values in table share */
table->s->sequence->copy(this);
/*
Sequence values will be replicated as a statement
like 'create sequence'. So disable row logging for this table & statement
*/
table->file->row_logging= table->file->row_logging_init= 0;
save_write_set= table->write_set;
table->write_set= &table->s->all_set;
table->s->sequence->initialized= SEQUENCE::SEQ_IN_PREPARE;
error= table->file->ha_write_row(table->record[0]);
table->s->sequence->initialized= SEQUENCE::SEQ_UNINTIALIZED;
table->write_set= save_write_set;
if (unlikely(error))
table->file->print_error(error, MYF(0));
else
{
/*
Sequence structure is up to date and table has one row,
sequence is now usable
*/
table->s->sequence->initialized= SEQUENCE::SEQ_READY_TO_USE;
}
return error;
}
/**
Store current sequence values into the sequence table
*/
int sequence_definition::write(TABLE *table, bool all_fields)
{
int error;
MY_BITMAP *save_rpl_write_set, *save_write_set, *save_read_set;
DBUG_ASSERT(((ha_sequence*) table->file)->is_locked());
save_rpl_write_set= table->rpl_write_set;
if (likely(!all_fields))
{
/* Only write next_value and round to binary log */
table->rpl_write_set= &table->def_rpl_write_set;
bitmap_clear_all(table->rpl_write_set);
bitmap_set_bit(table->rpl_write_set, NEXT_FIELD_NO);
bitmap_set_bit(table->rpl_write_set, ROUND_FIELD_NO);
}
else
table->rpl_write_set= &table->s->all_set;
/* Update table */
save_write_set= table->write_set;
save_read_set= table->read_set;
table->read_set= table->write_set= &table->s->all_set;
table->file->column_bitmaps_signal();
store_fields(table);
if (unlikely((error= table->file->ha_write_row(table->record[0]))))
table->file->print_error(error, MYF(0));
table->rpl_write_set= save_rpl_write_set;
table->read_set= save_read_set;
table->write_set= save_write_set;
table->file->column_bitmaps_signal();
return error;
}
/**
Get next value for sequence
@param in table Sequence table
@param in second_round
1 if recursive call (out of values once)
@param out error Set this to <> 0 in case of error
push_warning_printf(WARN_LEVEL_WARN) has been called
@retval 0 Next number or error. Check error variable
# Next sequence number
NOTES:
Return next_free_value and increment next_free_value to next allowed
value or reserved_value if out of range
if next_free_value >= reserved_value reserve a new range by writing
a record to the sequence table.
The state of the variables:
next_free_value contains next value to use. It may be
bigger than max_value or less than min_value if end of sequence.
reserved_until contains the last value written to the file. All
values up to this one can be used.
If next_free_value >= reserved_until we have to reserve new
values from the sequence.
*/
longlong SEQUENCE::next_value(TABLE *table, bool second_round, int *error)
{
longlong res_value, org_reserved_until, add_to;
bool out_of_values;
THD *thd= table->in_use;
DBUG_ENTER("SEQUENCE::next_value");
DBUG_ASSERT(thd);
*error= 0;
if (!second_round)
write_lock(table);
res_value= next_free_value;
next_free_value= increment_value(next_free_value, real_increment);
if (within_bound(res_value, reserved_until, reserved_until,
real_increment > 0))
{
write_unlock(table);
DBUG_RETURN(res_value);
}
if (all_values_used)
goto err;
org_reserved_until= reserved_until;
/*
Out of cached values, reserve 'cache' new ones
The cache value is checked on insert so the following can't
overflow
*/
add_to= cache ? real_increment * cache : real_increment;
reserved_until= increment_value(reserved_until, add_to);
out_of_values= !within_bound(res_value, max_value + 1, min_value - 1,
add_to > 0);
if (out_of_values)
{
if (!cycle || second_round)
goto err;
round++;
reserved_until= real_increment >0 ? min_value : max_value;
adjust_values(reserved_until); // Fix next_free_value
/*
We have to do everything again to ensure that the given range was
not empty, which could happen if increment == 0
*/
DBUG_RETURN(next_value(table, 1, error));
}
if (unlikely((*error= write(table,
(thd->variables.binlog_row_image !=
BINLOG_ROW_IMAGE_MINIMAL)))))
{
reserved_until= org_reserved_until;
next_free_value= res_value;
}
write_unlock(table);
DBUG_RETURN(res_value);
err:
write_unlock(table);
my_error(ER_SEQUENCE_RUN_OUT, MYF(0), table->s->db.str,
table->s->table_name.str);
*error= ER_SEQUENCE_RUN_OUT;
all_values_used= 1;
DBUG_RETURN(0);
}
/*
The following functions is to detect if a table has been dropped
and re-created since last call to PREVIOUS VALUE.
This is needed as we don't delete dropped sequences from THD->sequence
for DROP TABLE.
*/
bool SEQUENCE_LAST_VALUE::check_version(TABLE *table)
{
DBUG_ASSERT(table->s->tabledef_version.length == MY_UUID_SIZE);
return memcmp(table->s->tabledef_version.str, table_version,
MY_UUID_SIZE) != 0;
}
void SEQUENCE_LAST_VALUE::set_version(TABLE *table)
{
memcpy(table_version, table->s->tabledef_version.str, MY_UUID_SIZE);
}
/**
Set the next value for sequence
@param in table Sequence table
@param in next_val Next free value
@param in next_round Round for 'next_value' (in case of cycles)
@param in is_used 1 if next_val is already used
@retval 0 ok, value adjusted
-1 value was less than current value
1 error when storing value
@comment
A new value is set only if "nextval,next_round" is less than
"next_free_value,round". This is needed as in replication
setvalue() calls may come out to the slave out-of-order.
Storing only the highest value ensures that sequence object will always
contain the highest used value when the slave is promoted to a master.
*/
int SEQUENCE::set_value(TABLE *table, longlong next_val, ulonglong next_round,
bool is_used)
{
int error= -1;
bool needs_to_be_stored= 0;
longlong org_reserved_until= reserved_until;
longlong org_next_free_value= next_free_value;
ulonglong org_round= round;
THD *thd= table->in_use;
DBUG_ENTER("SEQUENCE::set_value");
DBUG_ASSERT(thd);
write_lock(table);
if (is_used)
next_val= increment_value(next_val, real_increment);
if (round > next_round)
goto end; // error = -1
if (round == next_round)
{
if (within_bound(next_val, next_free_value, next_free_value,
real_increment > 0))
goto end; // error = -1
if (next_val == next_free_value)
{
error= 0;
goto end;
}
}
else if (cycle == 0)
{
// round < next_round && no cycles, which is impossible
my_error(ER_SEQUENCE_RUN_OUT, MYF(0), table->s->db.str,
table->s->table_name.str);
error= 1;
goto end;
}
else
needs_to_be_stored= 1;
round= next_round;
adjust_values(next_val);
if (within_bound(reserved_until, next_free_value, next_free_value,
real_increment > 0) ||
needs_to_be_stored)
{
reserved_until= next_free_value;
if (write(table,
thd->variables.binlog_row_image != BINLOG_ROW_IMAGE_MINIMAL))
{
reserved_until= org_reserved_until;
next_free_value= org_next_free_value;
round= org_round;
error= 1;
goto end;
}
}
error= 0;
end:
write_unlock(table);
DBUG_RETURN(error);
}
#if defined(HAVE_REPLICATION)
class wait_for_commit_raii
{
private:
THD *m_thd;
wait_for_commit *m_wfc;
public:
wait_for_commit_raii(THD* thd) :
m_thd(thd), m_wfc(thd->suspend_subsequent_commits())
{}
~wait_for_commit_raii() { m_thd->resume_subsequent_commits(m_wfc); }
};
#endif
bool Sql_cmd_alter_sequence::execute(THD *thd)
{
int error= 0;
int trapped_errors= 0;
LEX *lex= thd->lex;
TABLE_LIST *first_table= lex->query_tables;
TABLE *table;
sequence_definition *new_seq= lex->create_info.seq_create_info;
uint saved_used_fields= new_seq->used_fields;
SEQUENCE *seq;
No_such_table_error_handler no_such_table_handler;
DBUG_ENTER("Sql_cmd_alter_sequence::execute");
#if defined(HAVE_REPLICATION)
/* No wakeup():s of subsequent commits is allowed in this function. */
wait_for_commit_raii suspend_wfc(thd);
#endif
if (check_access(thd, ALTER_ACL, first_table->db.str,
&first_table->grant.privilege,
&first_table->grant.m_internal,
0, 0))
DBUG_RETURN(TRUE); /* purecov: inspected */
if (check_grant(thd, ALTER_ACL, first_table, FALSE, 1, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
#ifdef WITH_WSREP
if (WSREP(thd) && wsrep_thd_is_local(thd))
{
const bool used_engine= lex->create_info.used_fields & HA_CREATE_USED_ENGINE;
if (wsrep_check_sequence(thd, new_seq, used_engine))
DBUG_RETURN(TRUE);
if (wsrep_to_isolation_begin(thd, first_table->db.str,
first_table->table_name.str,
first_table))
{
DBUG_RETURN(TRUE);
}
}
#endif /* WITH_WSREP */
if (new_seq->used_fields & seq_field_used_as)
{
/* This should have been prevented during parsing. */
DBUG_ASSERT(!(new_seq->used_fields - seq_field_used_as));
first_table->lock_type= TL_READ_NO_INSERT;
first_table->mdl_request.set_type(MDL_SHARED_NO_WRITE);
Alter_info alter_info;
alter_info.flags= ALTER_CHANGE_COLUMN;
if (new_seq->prepare_sequence_fields(&alter_info.create_list, true))
DBUG_RETURN(TRUE);
Table_specification_st create_info;
create_info.init();
create_info.alter_info= &alter_info;
if (if_exists())
thd->push_internal_handler(&no_such_table_handler);
Recreate_info recreate_info;
error= mysql_alter_table(thd, &null_clex_str, &null_clex_str,
&create_info, first_table, &recreate_info,
&alter_info, 0, (ORDER *) 0, 0, 0);
if (if_exists())
{
trapped_errors= no_such_table_handler.safely_trapped_errors();
thd->pop_internal_handler();
}
/* Do we need to store the sequence value in table share, like below? */
DBUG_RETURN(error);
}
if (if_exists())
thd->push_internal_handler(&no_such_table_handler);
error= open_and_lock_tables(thd, first_table, FALSE, 0);
if (if_exists())
{
trapped_errors= no_such_table_handler.safely_trapped_errors();
thd->pop_internal_handler();
}
if (unlikely(error))
{
if (trapped_errors)
{
StringBuffer<FN_REFLEN> tbl_name;
tbl_name.append(&first_table->db);
tbl_name.append('.');
tbl_name.append(&first_table->table_name);
push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
ER_UNKNOWN_SEQUENCES,
ER_THD(thd, ER_UNKNOWN_SEQUENCES),
tbl_name.c_ptr_safe());
my_ok(thd);
DBUG_RETURN(FALSE);
}
DBUG_RETURN(TRUE);
}
table= first_table->table;
seq= table->s->sequence;
seq->write_lock(table);
new_seq->reserved_until= seq->reserved_until;
/* Copy from old sequence those fields that the user didn't specified */
if (!(new_seq->used_fields & seq_field_used_increment))
new_seq->increment= seq->increment;
/*
We need to assign to foo_from_parser so that things get handled
properly in check_and_adjust() later
*/
if (!(new_seq->used_fields & seq_field_used_min_value))
new_seq->min_value_from_parser= Longlong_hybrid(seq->min_value, seq->is_unsigned);
if (!(new_seq->used_fields & seq_field_used_max_value))
new_seq->max_value_from_parser= Longlong_hybrid(seq->max_value, seq->is_unsigned);
if (!(new_seq->used_fields & seq_field_used_start))
new_seq->start_from_parser= Longlong_hybrid(seq->start, seq->is_unsigned);
if (!(new_seq->used_fields & seq_field_used_cache))
new_seq->cache= seq->cache;
if (!(new_seq->used_fields & seq_field_used_cycle))
new_seq->cycle= seq->cycle;
/* This should have been prevented during parsing. */
DBUG_ASSERT(!(new_seq->used_fields & seq_field_used_as));
new_seq->value_type= seq->value_type;
new_seq->is_unsigned= seq->is_unsigned;
/* If we should restart from a new value */
if (new_seq->used_fields & seq_field_used_restart)
{
if (!(new_seq->used_fields & seq_field_used_restart_value))
new_seq->restart_from_parser= new_seq->start_from_parser;
/*
Similar to start, we just need to truncate reserved_until and
the errors will be reported in check_and_adjust if truncation
happens on the wrong end.
*/
new_seq->reserved_until=
new_seq->truncate_value(new_seq->restart_from_parser);
}
/* Let check_and_adjust think all fields are used */
new_seq->used_fields= ~0;
if (new_seq->check_and_adjust(thd, 0))
{
my_error(ER_SEQUENCE_INVALID_DATA, MYF(0),
first_table->db.str,
first_table->table_name.str);
error= 1;
seq->write_unlock(table);
goto end;
}
if (likely(!(error= new_seq->write(table, 1))))
{
/* Store the sequence values in table share */
seq->copy(new_seq);
}
else
table->file->print_error(error, MYF(0));
seq->write_unlock(table);
if (trans_commit_stmt(thd))
error= 1;
if (trans_commit_implicit(thd))
error= 1;
DBUG_EXECUTE_IF("hold_worker_on_schedule",
{
/* delay binlogging of a parent trx in rpl_parallel_seq */
my_sleep(100000);
});
if (likely(!error))
error= write_bin_log(thd, 1, thd->query(), thd->query_length());
if (likely(!error))
my_ok(thd);
end:
new_seq->used_fields= saved_used_fields;
DBUG_RETURN(error);
}
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