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MDEV-5616 - Deadlock between CREATE/DROP FUNCTION and SELECT from view

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Deadlock happened due to mixed lock order.
CREATE/DROP function: wrlock(THR_LOCK_udf) -> lock(LOCK_open)
SELECT from view: lock(LOCK_open) -> rdlock(THR_LOCK_udf)

Fixed CREATE/DROP function so that LOCK_open does not intersect with
wrlock(THR_LOCK_udf).

10.0 is not affected: it doesn't hold LOCK_open while opening view.
This commit is contained in:
Sergey Vojtovich
2014-02-13 16:41:08 +04:00
parent 528df1df45
commit e2a99f1863
3 changed files with 73 additions and 5 deletions
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20
mysql-test/r/udf_debug_sync.result Normal file
View File

@ -0,0 +1,20 @@
CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME "UDF_EXAMPLE_LIB";
CREATE VIEW v1 AS SELECT myfunc_int(1);
SET debug_sync='mysql_create_function_after_lock SIGNAL locked WAIT_FOR go';
CREATE FUNCTION myfunc_double RETURNS REAL SONAME "UDF_EXAMPLE_LIB";
SET debug_sync='now WAIT_FOR locked';
SET debug_sync='find_udf_before_lock SIGNAL go';
SELECT * FROM v1;
myfunc_int(1)
1
FLUSH TABLES;
SET debug_sync='mysql_drop_function_after_lock SIGNAL locked WAIT_FOR go';
DROP FUNCTION myfunc_double;
SET debug_sync='now WAIT_FOR locked';
SET debug_sync='find_udf_before_lock SIGNAL go';
SELECT * FROM v1;
myfunc_int(1)
1
SET debug_sync='RESET';
DROP VIEW v1;
DROP FUNCTION myfunc_int;