mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-16 03:52:35 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

MDEV-17595 - ALTER TABLE ADD FOREIGN KEY crash

Browse source 
ALTER TABLE ... ADD FOREIGN KEY may trigger assertion failure when
it has LOCK=EXCLUSIVE clause or concurrent FLUSH TABLES is being
executed.

In both cases being altered table is marked as flushed, which forces
subsequent attempt to open parent table to re-open. Which in turn is
not allowed while transaction is running.

Rather than opening parent table, just take appropriate MDL lock.

Also removed table_already_fk_prelocked() check: MDL itself has much
better methods to handle duplicate locks. E.g. the former won't acquire
MDL_SHARED_NO_WRITE if it already has MDL_SHARED_READ.
This commit is contained in:
Sergey Vojtovich 2019-03-07 13:43:53 +04:00
parent 0a0eed8016
commit 149b754768
3 changed files with 36 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
mysql-test/suite/innodb/r/foreign-keys.result
View file

@ -87,3 +87,16 @@ drop table t3;
drop table t2;
drop table t1;
set debug_sync='reset';
#
# MDEV-17595 - Server crashes in copy_data_between_tables or
# Assertion `thd->transaction.stmt.is_empty() ||
# (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)'
# fails in close_tables_for_reopen upon concurrent
# ALTER TABLE and FLUSH
#
CREATE TABLE t1 (a INT, KEY(a)) ENGINE=InnoDB;
INSERT INTO t1 VALUES(1),(2);
CREATE TABLE t2 (b INT, KEY(b)) ENGINE=InnoDB;
INSERT INTO t2 VALUES(2);
ALTER TABLE t2 ADD FOREIGN KEY(b) REFERENCES t1(a), LOCK=EXCLUSIVE;
DROP TABLE t2, t1;

15
mysql-test/suite/innodb/t/foreign-keys.test
View file

@ -111,3 +111,18 @@ drop table t3;
drop table t2;
drop table t1;
set debug_sync='reset';
--echo #
--echo # MDEV-17595 - Server crashes in copy_data_between_tables or
--echo # Assertion `thd->transaction.stmt.is_empty() ||
--echo # (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)'
--echo # fails in close_tables_for_reopen upon concurrent
--echo # ALTER TABLE and FLUSH
--echo #
CREATE TABLE t1 (a INT, KEY(a)) ENGINE=InnoDB;
INSERT INTO t1 VALUES(1),(2);
CREATE TABLE t2 (b INT, KEY(b)) ENGINE=InnoDB;
INSERT INTO t2 VALUES(2);
ALTER TABLE t2 ADD FOREIGN KEY(b) REFERENCES t1(a), LOCK=EXCLUSIVE;
DROP TABLE t2, t1;

20
sql/sql_table.cc
View file

@ -9074,6 +9074,8 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
new_table->file->get_foreign_key_list(thd, &fk_list);
while ((fk= fk_list_it++))
{
MDL_request mdl_request;
if (lower_case_table_names)
{
char buf[NAME_LEN];
@ -9085,20 +9087,14 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
len = my_casedn_str(files_charset_info, buf);
thd->make_lex_string(fk->referenced_table, buf, len);
}
if (table_already_fk_prelocked(table_list, fk->referenced_db,
fk->referenced_table, TL_READ_NO_INSERT))
continue;
TABLE_LIST *tl= (TABLE_LIST *) thd->alloc(sizeof(TABLE_LIST));
tl->init_one_table_for_prelocking(fk->referenced_db->str, fk->referenced_db->length,
fk->referenced_table->str, fk->referenced_table->length,
NULL, TL_READ_NO_INSERT, false, NULL, 0,
&thd->lex->query_tables_last);
mdl_request.init(MDL_key::TABLE,
fk->referenced_db->str, fk->referenced_table->str,
MDL_SHARED_NO_WRITE, MDL_TRANSACTION);
if (thd->mdl_context.acquire_lock(&mdl_request,
thd->variables.lock_wait_timeout))
goto err_new_table_cleanup;
}
if (open_tables(thd, &table_list->next_global, &tables_opened, 0,
&alter_prelocking_strategy))
goto err_new_table_cleanup;
}
}
/*