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93c8252f02faa8ad8dc5f005e52f1990c29d4a0d
mariadb/sql/sql_alter.cc
Aleksey Midenkov 93c8252f02 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 through creating
a table with a temporary name and filling it with the data
(for CREATE OR REPLACE .. SELECT), then renaming the original table
to another temporary (backup) name and renaming the replacement table
to original table. The backup table is kept until the last chance of
failure and if that happens, the replacement table is thrown off and
backup recovered. 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 CREATE_TABLE_ACTION of TMP table (drops TMP table);
  2. Create new table as TMP;
  3. Do everything with TMP (like insert data);

  finalize_atomic_replace():
  4. Link chains: (D) is executed only if (C) is closed;
  5. (D) Log DROP_ACTION of BACKUP;
  6. (C) Log RENAME_TABLE_ACTION from ORIG to BACKUP (replays BACKUP -> ORIG);
  7. Rename ORIG to BACKUP;
  8. (C) Log CREATE_TABLE_ACTION of ORIG (drops ORIG);
  9. Rename TMP to ORIG;

  finalize_ddl() in case of success:
  10. Close (C);
  11. Replay (D): BACKUP is dropped.

  finalize_ddl() in case of error:
  10. Close (D);
  11. Replay (C):
    1) ORIG is dropped (only after finalize_atomic_replace());
    2) BACKUP renamed to ORIG (only after finalize_atomic_replace());
    3) drop TMP.

  If crash happens (C) or (D) is replayed in reverse order. (C) is
  replayed if crash happens before it is closed, otherwise (D) is
  replayed.

Temporary table for CREATE OR REPLACE

  Before dropping "old" table, CREATE OR REPLACE creates "tmp" table.
  ddl_log_state_create holds the drop of the "tmp" table.  When
  everything is OK (data is inserted, "tmp" is ready) ddl_log_state_rm
  is written to replace "old" with "tmp". Until ddl_log_state_create
  is closed ddl_log_state_rm is not executed.

  After the binlogging is done ddl_log_state_create is closed. At that
  point ddl_log_state_rm is executed and "tmp" is replaced with
  "old". That is: final rename is done by the DDL log.

  With that important role of DDL log for CREATE OR REPLACE operation
  replay of ddl_log_state_rm must fail at the first hit error and
  print the error message if possible. F.ex. foreign key error is
  discovered at this phase: InnoDB rejects to drop the "old" table and
  returns corresponding foreign key error code.

Additional notes

  - CREATE TABLE without REPLACE is not affected by this commit.

  - Engines having HTON_EXPENSIVE_RENAME flag set are not affected by
    this commit.

  - 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 "rm"
    chain is replayed.

  - 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

Rename and drop via DDL log

  We replay ddl_log_state_rm to drop the old table and rename the
  temporary table. In that case we must throw the correct error
  message if ddl_log_revert() fails (f.ex. on FK error).

  If table is deleted earlier and not via DDL log and the crash
  happened, the create chain is not closed. Linked drop chain is not
  executed and the new table is not installed. But the old table is
  already deleted.

ddl_log.cc changes

  Now we can place action before DDL_LOG_DROP_INIT_ACTION and it will
  be replayed after DDL_LOG_DROP_TABLE_ACTION.

  report_error parameter for ddl_log_revert() allows to fail at first
  error and print the error message if possible.
  ddl_log_execute_action() now can print error message.

  Since we now can handle errors from ddl_log_execute_action() (in
  case of non-recovery execution) unconditional setting "error= TRUE"
  is wrong (it was wrong anyway because it was overwritten at the end
  of the function).

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 done in "MDEV-22166
  ddl_log_write_execute_entry() extension".

More on CREATE OR REPLACE .. SELECT

  We use create_and_open_tmp_table() like in ALTER TABLE to create
  temporary TABLE object (tmp_table is (NON_)TRANSACTIONAL_TMP_TABLE).

  After we created such TABLE object we use create_info->tmp_table()
  instead of table->s->tmp_table when we need to check for
  parser-requested tmp-table.

  External locking is required for temporary table created by
  create_and_open_tmp_table(). F.ex. that disables logging for Aria
  transactional tables and without that (when no mysql_lock_tables()
  is done) it cannot work correctly.

  For making external lock the patch requires Aria table to work in
  non-transactional mode. That is usually done by
  ha_enable_transaction(false). But we cannot disable transaction
  completely because: 1. binlog rollback removes pending row events
  (binlog_remove_pending_rows_event()). The row events are added
  during CREATE .. SELECT data insertion phase. 2. replication slave
  highly depends on transaction and cannot work without it.

  So we put temporary Aria table into non-transactional mode with
  "thd->transaction->on hack". See comment for on_save variable.

  Note that Aria table has internal_table mode. But we cannot use it
  because:

  if (!internal_table)
  {
    mysql_mutex_lock(&THR_LOCK_myisam);
    old_info= test_if_reopen(name_buff);
  }

  For internal_table test_if_reopen() is not called and we get a new
  MARIA_SHARE for each file handler. In that case duplicate errors are
  missed because insert and lookup in CREATE .. SELECT is done via two
  different handlers (see create_lookup_handler()).

  For temporary table before dropping TABLE_SHARE by
  drop_temporary_table() we must do ha_reset(). ha_reset() releases
  storage share. Without that the share is kept and the second CREATE
  OR REPLACE .. SELECT fails with:

    HA_ERR_TABLE_EXIST (156): MyISAM table '#sql-create-b5377-4-t2' is
    in use (most likely by a MERGE table). Try FLUSH TABLES.

    HA_EXTRA_PREPARE_FOR_DROP also removes MYISAM_SHARE, but that is
    not needed as ha_reset() does the job.

  ha_reset() is usually done by
  mark_tmp_table_as_free_for_reuse(). But we don't need that mechanism
  for our temporary table.

Atomic_info 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 (revised by Marko Mäkelä)

  row_rename_table_for_mysql(): Specify the treatment of FOREIGN KEY
  constraints in a 4-valued enum parameter. In cases where FOREIGN KEY
  constraints cannot exist (partitioned tables, or internal tables of
  FULLTEXT INDEX), we can use the mode RENAME_IGNORE_FK.
  The mod RENAME_REBUILD is for any DDL operation that rebuilds the
  table inside InnoDB, such as TRUNCATE and native ALTER TABLE
  (or OPTIMIZE TABLE). The mode RENAME_ALTER_COPY is used solely
  during non-native ALTER TABLE in ha_innobase::rename_table().
  Normal ha_innobase::rename_table() will use the mode RENAME_FK.

  CREATE OR REPLACE will rename the old table (if one exists) along
  with its FOREIGN KEY constraints into a temporary name. The replacement
  table will be initially created with another temporary name.
  Unlike in ALTER TABLE, all FOREIGN KEY constraints must be renamed
  and not inherited as part of these operations, using the mode RENAME_FK.

  dict_get_referenced_table(): Let the callers convert names when needed.

  create_table_info_t::create_foreign_keys(): CREATE OR REPLACE creates
  the replacement table with a temporary name table, so for
  self-references foreign->referenced_table will be a table with
  temporary name and charset conversion must be skipped for it.

Reviewed by:

  Michael Widenius <monty@mariadb.org>
2022-08-31 11:55:04 +03:00

588 lines
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/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2016, 2022, 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 */
#include "mariadb.h"
#include "sql_parse.h" // check_access
#include "sql_table.h" // mysql_alter_table,
// mysql_exchange_partition
#include "sql_alter.h"
#include "rpl_mi.h"
#include "slave.h"
#include "debug_sync.h"
#include "wsrep_mysqld.h"
Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
:drop_list(rhs.drop_list, mem_root),
alter_list(rhs.alter_list, mem_root),
key_list(rhs.key_list, mem_root),
alter_rename_key_list(rhs.alter_rename_key_list, mem_root),
create_list(rhs.create_list, mem_root),
select_field_count(rhs.select_field_count),
alter_index_ignorability_list(rhs.alter_index_ignorability_list, mem_root),
check_constraint_list(rhs.check_constraint_list, mem_root),
flags(rhs.flags), partition_flags(rhs.partition_flags),
keys_onoff(rhs.keys_onoff),
partition_names(rhs.partition_names, mem_root),
num_parts(rhs.num_parts),
requested_algorithm(rhs.requested_algorithm),
requested_lock(rhs.requested_lock)
{
/*
Make deep copies of used objects.
This is not a fully deep copy - clone() implementations
of Alter_drop, Alter_column, Key, foreign_key, Key_part_spec
do not copy string constants. At the same length the only
reason we make a copy currently is that ALTER/CREATE TABLE
code changes input Alter_info definitions, but string
constants never change.
*/
list_copy_and_replace_each_value(drop_list, mem_root);
list_copy_and_replace_each_value(alter_list, mem_root);
list_copy_and_replace_each_value(key_list, mem_root);
list_copy_and_replace_each_value(alter_rename_key_list, mem_root);
list_copy_and_replace_each_value(create_list, mem_root);
/* partition_names are not deeply copied currently */
}
bool Alter_info::set_requested_algorithm(const LEX_CSTRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (lex_string_eq(str, STRING_WITH_LEN("INPLACE")))
requested_algorithm= ALTER_TABLE_ALGORITHM_INPLACE;
else if (lex_string_eq(str, STRING_WITH_LEN("COPY")))
requested_algorithm= ALTER_TABLE_ALGORITHM_COPY;
else if (lex_string_eq(str, STRING_WITH_LEN("DEFAULT")))
requested_algorithm= ALTER_TABLE_ALGORITHM_DEFAULT;
else if (lex_string_eq(str, STRING_WITH_LEN("NOCOPY")))
requested_algorithm= ALTER_TABLE_ALGORITHM_NOCOPY;
else if (lex_string_eq(str, STRING_WITH_LEN("INSTANT")))
requested_algorithm= ALTER_TABLE_ALGORITHM_INSTANT;
else
return true;
return false;
}
void Alter_info::set_requested_algorithm(enum_alter_table_algorithm algo_val)
{
requested_algorithm= algo_val;
}
bool Alter_info::set_requested_lock(const LEX_CSTRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (lex_string_eq(str, STRING_WITH_LEN("NONE")))
requested_lock= ALTER_TABLE_LOCK_NONE;
else if (lex_string_eq(str, STRING_WITH_LEN("SHARED")))
requested_lock= ALTER_TABLE_LOCK_SHARED;
else if (lex_string_eq(str, STRING_WITH_LEN("EXCLUSIVE")))
requested_lock= ALTER_TABLE_LOCK_EXCLUSIVE;
else if (lex_string_eq(str, STRING_WITH_LEN("DEFAULT")))
requested_lock= ALTER_TABLE_LOCK_DEFAULT;
else
return true;
return false;
}
const char* Alter_info::algorithm_clause(THD *thd) const
{
switch (algorithm(thd)) {
case ALTER_TABLE_ALGORITHM_INPLACE:
return "ALGORITHM=INPLACE";
case ALTER_TABLE_ALGORITHM_COPY:
return "ALGORITHM=COPY";
case ALTER_TABLE_ALGORITHM_NONE:
DBUG_ASSERT(0);
/* Fall through */
case ALTER_TABLE_ALGORITHM_DEFAULT:
return "ALGORITHM=DEFAULT";
case ALTER_TABLE_ALGORITHM_NOCOPY:
return "ALGORITHM=NOCOPY";
case ALTER_TABLE_ALGORITHM_INSTANT:
return "ALGORITHM=INSTANT";
}
return NULL; /* purecov: begin deadcode */
}
const char* Alter_info::lock() const
{
switch (requested_lock) {
case ALTER_TABLE_LOCK_SHARED:
return "LOCK=SHARED";
case ALTER_TABLE_LOCK_NONE:
return "LOCK=NONE";
case ALTER_TABLE_LOCK_DEFAULT:
return "LOCK=DEFAULT";
case ALTER_TABLE_LOCK_EXCLUSIVE:
return "LOCK=EXCLUSIVE";
}
return NULL; /* purecov: begin deadcode */
}
bool Alter_info::supports_algorithm(THD *thd,
const Alter_inplace_info *ha_alter_info)
{
switch (ha_alter_info->inplace_supported) {
case HA_ALTER_INPLACE_EXCLUSIVE_LOCK:
case HA_ALTER_INPLACE_SHARED_LOCK:
case HA_ALTER_INPLACE_NO_LOCK:
case HA_ALTER_INPLACE_INSTANT:
return false;
case HA_ALTER_INPLACE_COPY_NO_LOCK:
case HA_ALTER_INPLACE_COPY_LOCK:
if (algorithm(thd) >= Alter_info::ALTER_TABLE_ALGORITHM_NOCOPY)
{
ha_alter_info->report_unsupported_error(algorithm_clause(thd),
"ALGORITHM=INPLACE");
return true;
}
return false;
case HA_ALTER_INPLACE_NOCOPY_NO_LOCK:
case HA_ALTER_INPLACE_NOCOPY_LOCK:
if (algorithm(thd) == Alter_info::ALTER_TABLE_ALGORITHM_INSTANT)
{
ha_alter_info->report_unsupported_error("ALGORITHM=INSTANT",
"ALGORITHM=NOCOPY");
return true;
}
return false;
case HA_ALTER_INPLACE_NOT_SUPPORTED:
if (algorithm(thd) >= Alter_info::ALTER_TABLE_ALGORITHM_INPLACE)
{
ha_alter_info->report_unsupported_error(algorithm_clause(thd),
"ALGORITHM=COPY");
return true;
}
return false;
case HA_ALTER_ERROR:
return true;
}
/* purecov: begin deadcode */
DBUG_ASSERT(0);
return false;
}
bool Alter_info::supports_lock(THD *thd,
const Alter_inplace_info *ha_alter_info)
{
switch (ha_alter_info->inplace_supported) {
case HA_ALTER_INPLACE_EXCLUSIVE_LOCK:
// If SHARED lock and no particular algorithm was requested, use COPY.
if (requested_lock == Alter_info::ALTER_TABLE_LOCK_SHARED &&
algorithm(thd) == Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT &&
thd->variables.alter_algorithm ==
Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT)
return false;
if (requested_lock == Alter_info::ALTER_TABLE_LOCK_SHARED ||
requested_lock == Alter_info::ALTER_TABLE_LOCK_NONE)
{
ha_alter_info->report_unsupported_error(lock(), "LOCK=EXCLUSIVE");
return true;
}
return false;
case HA_ALTER_INPLACE_NO_LOCK:
case HA_ALTER_INPLACE_INSTANT:
case HA_ALTER_INPLACE_COPY_NO_LOCK:
case HA_ALTER_INPLACE_NOCOPY_NO_LOCK:
return false;
case HA_ALTER_INPLACE_COPY_LOCK:
case HA_ALTER_INPLACE_NOCOPY_LOCK:
case HA_ALTER_INPLACE_NOT_SUPPORTED:
case HA_ALTER_INPLACE_SHARED_LOCK:
if (requested_lock == Alter_info::ALTER_TABLE_LOCK_NONE)
{
ha_alter_info->report_unsupported_error("LOCK=NONE", "LOCK=SHARED");
return true;
}
return false;
case HA_ALTER_ERROR:
return true;
}
/* purecov: begin deadcode */
DBUG_ASSERT(0);
return false;
}
bool Alter_info::vers_prohibited(THD *thd) const
{
if (thd->slave_thread ||
thd->variables.vers_alter_history != VERS_ALTER_HISTORY_ERROR)
{
return false;
}
if (flags & (
ALTER_PARSER_ADD_COLUMN |
ALTER_PARSER_DROP_COLUMN |
ALTER_CHANGE_COLUMN |
ALTER_COLUMN_ORDER))
{
return true;
}
if (flags & ALTER_ADD_INDEX)
{
List_iterator_fast<Key> key_it(const_cast<List<Key> &>(key_list));
Key *key;
while ((key= key_it++))
{
if (key->type == Key::PRIMARY || key->type == Key::UNIQUE)
return true;
}
}
return false;
}
Alter_info::enum_alter_table_algorithm
Alter_info::algorithm(const THD *thd) const
{
if (requested_algorithm == ALTER_TABLE_ALGORITHM_NONE)
return (Alter_info::enum_alter_table_algorithm) thd->variables.alter_algorithm;
return requested_algorithm;
}
Alter_table_ctx::Alter_table_ctx()
: db(null_clex_str), table_name(null_clex_str), alias(null_clex_str),
new_db(null_clex_str), new_name(null_clex_str), new_alias(null_clex_str)
{
}
/*
TODO: new_name_arg changes if lower case table names.
Should be copied or converted before call
*/
Alter_table_ctx::Alter_table_ctx(THD *thd, TABLE_LIST *table_list,
uint tables_opened_arg,
const LEX_CSTRING *new_db_arg,
const LEX_CSTRING *new_name_arg)
: tables_opened(tables_opened_arg),
new_db(*new_db_arg), new_name(*new_name_arg)
{
/*
Assign members db, table_name, new_db and new_name
to simplify further comparisions: we want to see if it's a RENAME
later just by comparing the pointers, avoiding the need for strcmp.
*/
db= table_list->db;
table_name= table_list->table_name;
alias= (lower_case_table_names == 2) ? table_list->alias : table_name;
if (!new_db.str || !my_strcasecmp(table_alias_charset, new_db.str, db.str))
new_db= db;
if (new_name.str)
{
DBUG_PRINT("info", ("new_db.new_name: '%s'.'%s'", new_db.str, new_name.str));
if (lower_case_table_names == 1) // Convert new_name/new_alias to lower
{
new_name.length= my_casedn_str(files_charset_info, (char*) new_name.str);
new_alias= new_name;
}
else if (lower_case_table_names == 2) // Convert new_name to lower case
{
new_alias.str= new_alias_buff;
new_alias.length= new_name.length;
strmov(new_alias_buff, new_name.str);
new_name.length= my_casedn_str(files_charset_info, (char*) new_name.str);
}
else
new_alias= new_name; // LCTN=0 => case sensitive + case preserving
if (!is_database_changed() &&
!my_strcasecmp(table_alias_charset, new_name.str, table_name.str))
{
/*
Source and destination table names are equal:
make is_table_renamed() more efficient.
*/
new_alias= table_name;
new_name= table_name;
}
}
else
{
new_alias= alias;
new_name= table_name;
}
tmp_name.str= tmp_name_buff;
tmp_name.length= my_snprintf(tmp_name_buff, sizeof(tmp_name_buff),
"%s-alter-%lx-%llx",
tmp_file_prefix, current_pid, thd->thread_id);
/* Safety fix for InnoDB */
if (lower_case_table_names)
tmp_name.length= my_casedn_str(files_charset_info, tmp_name_buff);
if (table_list->table->s->tmp_table == NO_TMP_TABLE)
{
build_table_filename(path, sizeof(path) - 1, db.str, table_name.str, "", 0);
build_table_filename(new_path, sizeof(new_path) - 1, new_db.str, new_name.str, "", 0);
build_table_filename(new_filename, sizeof(new_filename) - 1,
new_db.str, new_name.str, reg_ext, 0);
build_table_filename(tmp_path, sizeof(tmp_path) - 1, new_db.str, tmp_name.str, "",
FN_IS_TMP);
}
else
{
/*
We are not filling path, new_path and new_filename members if
we are altering temporary table as these members are not used in
this case. This fact is enforced with assert.
*/
build_tmptable_filename(thd, tmp_path, sizeof(tmp_path));
tmp_table= true;
}
if ((id.length= table_list->table->s->tabledef_version.length))
memcpy(id_buff, table_list->table->s->tabledef_version.str, MY_UUID_SIZE);
id.str= id_buff;
storage_engine_partitioned= table_list->table->file->partition_engine();
storage_engine_name.str= storage_engine_buff;
storage_engine_name.length= ((strmake(storage_engine_buff,
table_list->table->file->
real_table_type(),
sizeof(storage_engine_buff)-1)) -
storage_engine_buff);
tmp_storage_engine_name.str= tmp_storage_engine_buff;
tmp_storage_engine_name.length= 0;
tmp_id.str= 0;
tmp_id.length= 0;
}
void Alter_table_ctx::report_implicit_default_value_error(THD *thd,
const TABLE_SHARE *s)
const
{
Create_field *error_field= implicit_default_value_error_field;
const Type_handler *h= error_field->type_handler();
thd->push_warning_truncated_value_for_field(Sql_condition::WARN_LEVEL_WARN,
h->name().ptr(),
h->default_value().ptr(),
s ? s->db.str : nullptr,
s ? s->table_name.str : nullptr,
error_field->field_name.str);
}
bool Sql_cmd_alter_table::execute(THD *thd)
{
LEX *lex= thd->lex;
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= lex->first_select_lex();
/* first table of first SELECT_LEX */
TABLE_LIST *first_table= (TABLE_LIST*) select_lex->table_list.first;
const bool used_engine= lex->create_info.used_fields & HA_CREATE_USED_ENGINE;
DBUG_ASSERT((m_storage_engine_name.str != NULL) == used_engine);
if (used_engine)
{
if (resolve_storage_engine_with_error(thd, &lex->create_info.db_type,
lex->create_info.tmp_table()))
return true; // Engine not found, substitution is not allowed
if (!lex->create_info.db_type) // Not found, but substitution is allowed
lex->create_info.used_fields&= ~HA_CREATE_USED_ENGINE;
}
/*
Code in mysql_alter_table() may modify its HA_CREATE_INFO argument,
so we have to use a copy of this structure to make execution
prepared statement- safe. A shallow copy is enough as no memory
referenced from this structure will be modified.
@todo move these into constructor...
*/
Table_specification_st create_info(lex->create_info);
Alter_info alter_info(lex->alter_info, thd->mem_root);
create_info.alter_info= &alter_info;
privilege_t priv(NO_ACL);
privilege_t priv_needed(ALTER_ACL);
bool result;
DBUG_ENTER("Sql_cmd_alter_table::execute");
if (unlikely(thd->is_fatal_error))
{
/* out of memory creating a copy of alter_info */
DBUG_RETURN(TRUE);
}
/*
We also require DROP priv for ALTER TABLE ... DROP PARTITION, as well
as for RENAME TO, as being done by SQLCOM_RENAME_TABLE
*/
if ((alter_info.partition_flags & ALTER_PARTITION_DROP) ||
(alter_info.partition_flags & ALTER_PARTITION_CONVERT_IN) ||
(alter_info.partition_flags & ALTER_PARTITION_CONVERT_OUT) ||
(alter_info.flags & ALTER_RENAME))
priv_needed|= DROP_ACL;
/* Must be set in the parser */
DBUG_ASSERT(select_lex->db.str);
DBUG_ASSERT(!(alter_info.partition_flags & ALTER_PARTITION_EXCHANGE));
DBUG_ASSERT(!(alter_info.partition_flags & ALTER_PARTITION_ADMIN));
if (check_access(thd, priv_needed, first_table->db.str,
&first_table->grant.privilege,
&first_table->grant.m_internal,
0, 0) ||
check_access(thd, INSERT_ACL | CREATE_ACL, select_lex->db.str,
&priv,
NULL, /* Don't use first_tab->grant with sel_lex->db */
0, 0))
DBUG_RETURN(TRUE); /* purecov: inspected */
/* If it is a merge table, check privileges for merge children. */
if (create_info.merge_list)
{
/*
The user must have (SELECT_ACL | UPDATE_ACL | DELETE_ACL) on the
underlying base tables, even if there are temporary tables with the same
names.
From user's point of view, it might look as if the user must have these
privileges on temporary tables to create a merge table over them. This is
one of two cases when a set of privileges is required for operations on
temporary tables (see also CREATE TABLE).
The reason for this behavior stems from the following facts:
- For merge tables, the underlying table privileges are checked only
at CREATE TABLE / ALTER TABLE time.
In other words, once a merge table is created, the privileges of
the underlying tables can be revoked, but the user will still have
access to the merge table (provided that the user has privileges on
the merge table itself).
- Temporary tables shadow base tables.
I.e. there might be temporary and base tables with the same name, and
the temporary table takes the precedence in all operations.
- For temporary MERGE tables we do not track if their child tables are
base or temporary. As result we can't guarantee that privilege check
which was done in presence of temporary child will stay relevant
later as this temporary table might be removed.
If SELECT_ACL | UPDATE_ACL | DELETE_ACL privileges were not checked for
the underlying *base* tables, it would create a security breach as in
Bug#12771903.
*/
if (check_table_access(thd, SELECT_ACL | UPDATE_ACL | DELETE_ACL,
create_info.merge_list, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE);
}
if (check_grant(thd, priv_needed, first_table, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
#ifdef WITH_WSREP
if (WSREP(thd) &&
(!thd->is_current_stmt_binlog_format_row() ||
!thd->find_temporary_table(first_table)))
{
wsrep::key_array keys;
wsrep_append_fk_parent_table(thd, first_table, &keys);
WSREP_TO_ISOLATION_BEGIN_ALTER(lex->name.str ? select_lex->db.str
: first_table->db.str,
lex->name.str ? lex->name.str
: first_table->table_name.str,
first_table, &alter_info, &keys,
used_engine ? &create_info : nullptr)
{
WSREP_WARN("ALTER TABLE isolation failure");
DBUG_RETURN(TRUE);
}
thd->variables.auto_increment_offset = 1;
thd->variables.auto_increment_increment = 1;
}
#endif
if (lex->name.str && !test_all_bits(priv, INSERT_ACL | CREATE_ACL))
{
// Rename of table
TABLE_LIST tmp_table;
tmp_table.init_one_table(&select_lex->db, &lex->name, 0, TL_IGNORE);
tmp_table.grant.privilege= priv;
if (check_grant(thd, INSERT_ACL | CREATE_ACL, &tmp_table, FALSE,
UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
}
/* Don't yet allow changing of symlinks with ALTER TABLE */
if (create_info.data_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER_THD(thd, WARN_OPTION_IGNORED),
"DATA DIRECTORY");
if (create_info.index_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER_THD(thd, WARN_OPTION_IGNORED),
"INDEX DIRECTORY");
create_info.data_file_name= create_info.index_file_name= NULL;
#ifdef WITH_PARTITION_STORAGE_ENGINE
thd->work_part_info= 0;
#endif
result= mysql_alter_table(thd, &select_lex->db, &lex->name,
&create_info,
first_table,
&alter_info,
select_lex->order_list.elements,
select_lex->order_list.first,
lex->ignore, lex->if_exists());
DBUG_RETURN(result);
}
bool Sql_cmd_discard_import_tablespace::execute(THD *thd)
{
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= thd->lex->first_select_lex();
/* first table of first SELECT_LEX */
TABLE_LIST *table_list= (TABLE_LIST*) select_lex->table_list.first;
if (check_access(thd, ALTER_ACL, table_list->db.str,
&table_list->grant.privilege,
&table_list->grant.m_internal,
0, 0))
return true;
if (check_grant(thd, ALTER_ACL, table_list, false, UINT_MAX, false))
return true;
/*
Check if we attempt to alter mysql.slow_log or
mysql.general_log table and return an error if
it is the case.
TODO: this design is obsolete and will be removed.
*/
if (check_if_log_table(table_list, TRUE, "ALTER"))
return true;
return
mysql_discard_or_import_tablespace(thd, table_list,
m_tablespace_op == DISCARD_TABLESPACE);
}
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