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extend prelocking to FK-accessed tables

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Backport of f1362910980
This commit is contained in:
Sergei Golubchik 2018-07-17 16:56:40 +02:00
parent 3b365fa829
commit 64a23c1c8a
6 changed files with 157 additions and 4 deletions
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37
mysql-test/suite/innodb/r/foreign-keys.result
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@ -14,3 +14,40 @@ ALTER TABLE `title` ADD FOREIGN KEY (`title_manager_fk`) REFERENCES `people`
ALTER TABLE `title` ADD FOREIGN KEY (`title_reporter_fk`) REFERENCES `people`
(`people_id`);
drop table title, department, people;
create table t1 (a int primary key, b int) engine=innodb;
create table t2 (c int primary key, d int,
foreign key (d) references t1 (a) on update cascade) engine=innodb;
insert t1 values (1,1),(2,2),(3,3);
insert t2 values (4,1),(5,2),(6,3);
flush table t2 with read lock;
connect con1,localhost,root;
delete from t1 where a=2;
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`d`) REFERENCES `t1` (`a`) ON UPDATE CASCADE)
update t1 set a=10 where a=1;
connection default;
unlock tables;
connection con1;
connection default;
lock table t2 write;
connection con1;
delete from t1 where a=2;
connection default;
unlock tables;
connection con1;
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`d`) REFERENCES `t1` (`a`) ON UPDATE CASCADE)
connection default;
unlock tables;
disconnect con1;
create user foo;
grant select,update on test.t1 to foo;
connect foo,localhost,foo;
update t1 set a=30 where a=3;
disconnect foo;
connection default;
select * from t2;
c d
5 2
4 10
6 30
drop table t2, t1;
drop user foo;

48
mysql-test/suite/innodb/t/foreign-keys.test
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@ -1,6 +1,8 @@
--source include/have_innodb.inc
--source include/have_debug.inc
--enable_connect_log
--echo #
--echo # Bug #19471516 SERVER CRASHES WHEN EXECUTING ALTER TABLE
--echo # ADD FOREIGN KEY
@ -24,3 +26,49 @@ ALTER TABLE `title` ADD FOREIGN KEY (`title_reporter_fk`) REFERENCES `people`
(`people_id`);
drop table title, department, people;
#
# FK and prelocking:
# child table accesses (reads and writes) wait for locks.
#
create table t1 (a int primary key, b int) engine=innodb;
create table t2 (c int primary key, d int,
foreign key (d) references t1 (a) on update cascade) engine=innodb;
insert t1 values (1,1),(2,2),(3,3);
insert t2 values (4,1),(5,2),(6,3);
flush table t2 with read lock; # this takes MDL_SHARED_NO_WRITE
connect (con1,localhost,root);
--error ER_ROW_IS_REFERENCED_2
delete from t1 where a=2;
send update t1 set a=10 where a=1;
connection default;
let $wait_condition= select 1 from information_schema.processlist where state='Waiting for table metadata lock';
source include/wait_condition.inc;
unlock tables;
connection con1;
reap;
connection default;
lock table t2 write; # this takes MDL_SHARED_NO_READ_WRITE
connection con1;
send delete from t1 where a=2;
connection default;
let $wait_condition= select 1 from information_schema.processlist where state='Waiting for table metadata lock';
source include/wait_condition.inc;
unlock tables;
connection con1;
--error ER_ROW_IS_REFERENCED_2
reap;
connection default;
unlock tables;
disconnect con1;
# but privileges should not be checked
create user foo;
grant select,update on test.t1 to foo;
connect(foo,localhost,foo);
update t1 set a=30 where a=3;
disconnect foo;
connection default;
select * from t2;
drop table t2, t1;
drop user foo;

2
sql/sp_head.cc
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@ -4231,7 +4231,7 @@ sp_head::add_used_tables_to_table_list(THD *thd,
table->init_one_table_for_prelocking(key_buff, stab->db_length,
key_buff + stab->db_length + 1, stab->table_name_length,
key_buff + stab->db_length + stab->table_name_length + 2,
stab->lock_type, belong_to_view, stab->trg_event_map,
stab->lock_type, true, belong_to_view, stab->trg_event_map,
query_tables_last_ptr);
tab_buff+= ALIGN_SIZE(sizeof(TABLE_LIST));

65
sql/sql_base.cc
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@ -4802,6 +4802,25 @@ handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
}
/*
@note this can be changed to use a hash, instead of scanning the linked
list, if the performance of this function will ever become an issue
*/
static bool table_already_fk_prelocked(TABLE_LIST *tl, LEX_STRING *db,
LEX_STRING *table, thr_lock_type lock_type)
{
for (; tl; tl= tl->next_global )
{
if (tl->lock_type >= lock_type &&
tl->prelocking_placeholder == TABLE_LIST::FK &&
strcmp(tl->db, db->str) == 0 &&
strcmp(tl->table_name, table->str) == 0)
return true;
}
return false;
}
/**
Defines how prelocking algorithm for DML statements should handle table list
elements:
@ -4841,6 +4860,52 @@ handle_table(THD *thd, Query_tables_list *prelocking_ctx,
add_tables_and_routines_for_triggers(thd, prelocking_ctx, table_list))
return TRUE;
}
if (table_list->table->file->referenced_by_foreign_key())
{
List <FOREIGN_KEY_INFO> fk_list;
List_iterator<FOREIGN_KEY_INFO> fk_list_it(fk_list);
FOREIGN_KEY_INFO *fk;
Query_arena *arena, backup;
arena= thd->activate_stmt_arena_if_needed(&backup);
table_list->table->file->get_parent_foreign_key_list(thd, &fk_list);
if (thd->is_error())
{
if (arena)
thd->restore_active_arena(arena, &backup);
return TRUE;
}
*need_prelocking= TRUE;
while ((fk= fk_list_it++))
{
// FK_OPTION_RESTRICT and FK_OPTION_NO_ACTION only need read access
static bool can_write[]= { true, false, true, true, false, true };
uint8 op= table_list->trg_event_map;
thr_lock_type lock_type;
if ((op & (1 << TRG_EVENT_DELETE) && can_write[fk->delete_method])
|| (op & (1 << TRG_EVENT_UPDATE) && can_write[fk->update_method]))
lock_type= TL_WRITE_ALLOW_WRITE;
else
lock_type= TL_READ;
if (table_already_fk_prelocked(table_list, fk->foreign_db,
fk->foreign_table, lock_type))
continue;
TABLE_LIST *tl= (TABLE_LIST *) thd->alloc(sizeof(TABLE_LIST));
tl->init_one_table_for_prelocking(fk->foreign_db->str, fk->foreign_db->length,
fk->foreign_table->str, fk->foreign_table->length,
NULL, lock_type, false, table_list->belong_to_view,
op, &prelocking_ctx->query_tables_last);
}
if (arena)
thd->restore_active_arena(arena, &backup);
}
}
return FALSE;

3
sql/sql_class.cc
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@ -5082,7 +5082,8 @@ has_write_table_with_auto_increment_and_select(TABLE_LIST *tables)
for(TABLE_LIST *table= tables; table; table= table->next_global)
{
if (!table->placeholder() &&
(table->lock_type <= TL_READ_NO_INSERT))
table->lock_type <= TL_READ_NO_INSERT &&
table->prelocking_placeholder != TABLE_LIST::FK)
{
has_select= true;
break;

6
sql/table.h
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@ -1713,6 +1713,7 @@ struct TABLE_LIST
size_t table_name_length_arg,
const char *alias_arg,
enum thr_lock_type lock_type_arg,
bool routine,
TABLE_LIST *belong_to_view_arg,
uint8 trg_event_map_arg,
TABLE_LIST ***last_ptr)
@ -1720,7 +1721,8 @@ struct TABLE_LIST
init_one_table(db_name_arg, db_length_arg, table_name_arg,
table_name_length_arg, alias_arg, lock_type_arg);
cacheable_table= 1;
prelocking_placeholder= 1;
prelocking_placeholder= routine ? ROUTINE : FK;
open_type= routine ? OT_TEMPORARY_OR_BASE : OT_BASE_ONLY;
belong_to_view= belong_to_view_arg;
trg_event_map= trg_event_map_arg;
@ -2004,7 +2006,7 @@ struct TABLE_LIST
This TABLE_LIST object is just placeholder for prelocking, it will be
used for implicit LOCK TABLES only and won't be used in real statement.
*/
bool prelocking_placeholder;
enum { USER, ROUTINE, FK } prelocking_placeholder;
/**
Indicates that if TABLE_LIST object corresponds to the table/view
which requires special handling.