MDEV-27025 insert-intention lock conflicts with waiting ORDINARY lock

The code was backported from 10.6 bd03c0e commit. See that commit message for details. Apart from the above commit trx_lock_t::wait_trx was also backported from MDEV-24738. trx_lock_t::wait_trx is protected with lock_sys.wait_mutex in 10.6, but that mutex was implemented only in MDEV-24789. As there is no need to backport MDEV-24789 for MDEV-27025, trx_lock_t::wait_trx is protected with the same mutexes as trx_lock_t::wait_lock. This fix should not break innodb-lock-schedule-algorithm=VATS. This algorithm uses an Eldest-Transaction-First (ETF) heuristic, which prefers older transactions over new ones. In this fix we just insert granted lock just before the last granted lock of the same transaction, what does not change transactions execution order. The changes in lock_rec_create_low() should not break Galera Cluster, there is a big "if" branch for WSREP. This branch is necessary to provide the correct transactions execution order, and should not be changed for the current bug fix.
MariaDB · Jan 18, 2022 · be81138 · be81138
1 parent e44439a
commit be81138
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diff --git a/mysql-test/suite/innodb/r/lock_wait_conflict.result b/mysql-test/suite/innodb/r/lock_wait_conflict.result
@@ -0,0 +1,27 @@
+#
+# MDEV-27025 insert-intention lock conflicts with waiting ORDINARY lock
+#
+CREATE TABLE t (a INT PRIMARY KEY, b INT NOT NULL UNIQUE) ENGINE=InnoDB;
+connect prevent_purge,localhost,root,,;
+start transaction with consistent snapshot;
+connection default;
+INSERT INTO t VALUES (20,20);
+DELETE FROM t WHERE b = 20;
+connect con_ins,localhost,root,,;
+SET DEBUG_SYNC = 'row_ins_sec_index_entry_dup_locks_created SIGNAL ins_set_locks WAIT_FOR ins_cont';
+INSERT INTO t VALUES(10, 20);
+connect con_del,localhost,root,,;
+SET DEBUG_SYNC = 'now WAIT_FOR ins_set_locks';
+SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL del_locked';
+DELETE FROM t WHERE b = 20;
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR del_locked';
+SET DEBUG_SYNC = 'now SIGNAL ins_cont';
+connection con_ins;
+disconnect con_ins;
+connection con_del;
+disconnect con_del;
+disconnect prevent_purge;
+connection default;
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t;
diff --git a/mysql-test/suite/innodb/t/lock_wait_conflict.test b/mysql-test/suite/innodb/t/lock_wait_conflict.test
@@ -0,0 +1,60 @@
+--source include/have_innodb.inc
+--source include/count_sessions.inc
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+
+--echo #
+--echo # MDEV-27025 insert-intention lock conflicts with waiting ORDINARY lock
+--echo #
+
+# The test checks the ability to acquire exclusive record lock if the acquiring
+# transaction already holds a shared lock on the record and another transaction
+# is waiting for a lock.
+
+CREATE TABLE t (a INT PRIMARY KEY, b INT NOT NULL UNIQUE) ENGINE=InnoDB;
+
+--connect(prevent_purge,localhost,root,,)
+start transaction with consistent snapshot;
+
+--connection default
+INSERT INTO t VALUES (20,20);
+DELETE FROM t WHERE b = 20;
+
+--connect(con_ins,localhost,root,,)
+SET DEBUG_SYNC = 'row_ins_sec_index_entry_dup_locks_created SIGNAL ins_set_locks WAIT_FOR ins_cont';
+send
+INSERT INTO t VALUES(10, 20);
+
+--connect(con_del,localhost,root,,)
+SET DEBUG_SYNC = 'now WAIT_FOR ins_set_locks';
+SET DEBUG_SYNC = 'lock_wait_suspend_thread_enter SIGNAL del_locked';
+###############################################################################
+# This DELETE creates waiting ORDINARY X-lock for heap_no 2 as the record is
+# delete-marked, this lock conflicts with ORDINARY S-lock set by the the last
+# INSERT. After the last INSERT creates insert-intention lock on
+# heap_no 2, this lock will conflict with waiting ORDINARY X-lock of this
+# DELETE, what causes DEADLOCK error for this DELETE.
+###############################################################################
+send
+DELETE FROM t WHERE b = 20;
+
+--connection default
+SET DEBUG_SYNC = 'now WAIT_FOR del_locked';
+SET DEBUG_SYNC = 'now SIGNAL ins_cont';
+
+--connection con_ins
+--reap
+--disconnect con_ins
+
+--connection con_del
+# Without the fix, ER_LOCK_DEADLOCK would be reported here.
+--reap
+--disconnect con_del
+
+--disconnect prevent_purge
+
+--connection default
+
+SET DEBUG_SYNC = 'RESET';
+DROP TABLE t;
+--source include/wait_until_count_sessions.inc
diff --git a/mysql-test/suite/versioning/r/update.result b/mysql-test/suite/versioning/r/update.result
@@ -283,7 +283,6 @@ connection default;
 update t1 set b = 'foo';
 connection con1;
 update t1 set a = 'bar';
-ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
 disconnect con1;
 connection default;
 drop table t1;

diff --git a/mysql-test/suite/versioning/t/update.test b/mysql-test/suite/versioning/t/update.test
@@ -186,7 +186,9 @@ send update t1 set b = 'foo';
 connection con1;
 let $wait_condition= select count(*) from information_schema.innodb_lock_waits;
 source include/wait_condition.inc;
-error ER_LOCK_DEADLOCK;
+# There must no be DEADLOCK here as con1 transaction already holds locks, and
+# default's transaction lock is waiting, so the locks of the following "UPDATE"
+# must not conflict with waiting lock.
 update t1 set a = 'bar';
 disconnect con1;
 connection default;

diff --git a/storage/innobase/include/hash0hash.h b/storage/innobase/include/hash0hash.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2020, MariaDB Corporation.
+Copyright (c) 2018, 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
@@ -28,8 +28,29 @@ Created 5/20/1997 Heikki Tuuri
 #include "ut0rnd.h"
 
 struct hash_table_t;
-struct hash_cell_t{
-	void*	node;	/*!< hash chain node, NULL if none */
+struct hash_cell_t
+{
+  /** singly-linked, nullptr terminated list of hash buckets */
+  void *node;
+
+  /** Insert an element after another.
+  @tparam T  type of the element
+  @param after   the element after which to insert
+  @param insert  the being-inserted element
+  @param next    the next-element pointer in T */
+  template<typename T>
+  void insert_after(T &after, T &insert, T *T::*next)
+  {
+#ifdef UNIV_DEBUG
+    for (const T *c= static_cast<const T*>(node); c; c= c->*next)
+      if (c == &after)
+        goto found;
+    ut_error;
+  found:
+#endif
+    insert.*next= after.*next;
+    after.*next= &insert;
+  }
 };
 typedef void*	hash_node_t;
 

diff --git a/storage/innobase/include/lock0lock.h b/storage/innobase/include/lock0lock.h
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2021, MariaDB Corporation.
+Copyright (c) 2017, 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
@@ -832,26 +832,29 @@ class lock_sys_t
 /*********************************************************************//**
 Creates a new record lock and inserts it to the lock queue. Does NOT check
 for deadlocks or lock compatibility!
+@param[in] c_lock conflicting lock
+@param[in] thr thread owning trx
+@param[in] type_mode lock mode and wait flag, type is ignored and replaced by
+LOCK_REC
+@param[in] block buffer block containing the record
+@param[in] heap_no heap number of the record
+@param[in] index index of record
+@param[in,out] trx transaction
+@param[in] caller_owns_trx_mutex TRUE if caller owns trx mutex
+@param[in] insert_before_waiting if true, inserts new B-tree record lock
+just after the last non-waiting lock of the current transaction which is
+located before the first waiting for the current transaction lock, otherwise
+the lock is inserted at the end of the queue
 @return created lock */
 UNIV_INLINE
-lock_t*
-lock_rec_create(
-/*============*/
+lock_t *lock_rec_create(lock_t *c_lock,
 #ifdef WITH_WSREP
-	lock_t*			c_lock,	/*!< conflicting lock */
-	que_thr_t*		thr,	/*!< thread owning trx */
+                        que_thr_t *thr,
 #endif
-	unsigned		type_mode,/*!< in: lock mode and wait
-					flag, type is ignored and
-					replaced by LOCK_REC */
-	const buf_block_t*	block,	/*!< in: buffer block containing
-					the record */
-	ulint			heap_no,/*!< in: heap number of the record */
-	dict_index_t*		index,	/*!< in: index of record */
-	trx_t*			trx,	/*!< in,out: transaction */
-	bool			caller_owns_trx_mutex);
-					/*!< in: true if caller owns
-					trx mutex */
+                        unsigned type_mode, const buf_block_t *block,
+                        ulint heap_no, dict_index_t *index, trx_t *trx,
+                        bool caller_owns_trx_mutex,
+                        bool insert_before_waiting= false);
 
 /*************************************************************//**
 Removes a record lock request, waiting or granted, from the queue. */
@@ -864,6 +867,7 @@ lock_rec_discard(
 
 /** Create a new record lock and inserts it to the lock queue,
 without checking for deadlocks or conflicts.
+@param[in]	c_lock		conflicting lock
 @param[in]	type_mode	lock mode and wait flag; type will be replaced
 				with LOCK_REC
 @param[in]	page_id		index page number
@@ -872,11 +876,15 @@ without checking for deadlocks or conflicts.
 @param[in]	index		the index tree
 @param[in,out]	trx		transaction
 @param[in]	holds_trx_mutex	whether the caller holds trx->mutex
+@param[in]	insert_before_waiting if true, inserts new B-tree record lock
+just after the last non-waiting lock of the current transaction which is
+located before the first waiting for the current transaction lock, otherwise
+the lock is inserted at the end of the queue
 @return created lock */
 lock_t*
 lock_rec_create_low(
+	lock_t*		c_lock,
 #ifdef WITH_WSREP
-	lock_t*		c_lock,	/*!< conflicting lock */
 	que_thr_t*	thr,	/*!< thread owning trx */
 #endif
 	unsigned	type_mode,
@@ -885,7 +893,9 @@ lock_rec_create_low(
 	ulint		heap_no,
 	dict_index_t*	index,
 	trx_t*		trx,
-	bool		holds_trx_mutex);
+	bool		holds_trx_mutex,
+	bool		insert_before_waiting = false);
+
 /** Enqueue a waiting request for a lock which cannot be granted immediately.
 Check for deadlocks.
 @param[in]	type_mode	the requested lock mode (LOCK_S or LOCK_X)
@@ -906,9 +916,7 @@ Check for deadlocks.
 				(or it happened to commit) */
 dberr_t
 lock_rec_enqueue_waiting(
-#ifdef WITH_WSREP
 	lock_t*			c_lock,	/*!< conflicting lock */
-#endif
 	unsigned		type_mode,
 	const buf_block_t*	block,
 	ulint			heap_no,

diff --git a/storage/innobase/include/lock0lock.ic b/storage/innobase/include/lock0lock.ic
@@ -72,32 +72,35 @@ lock_hash_get(
 /*********************************************************************//**
 Creates a new record lock and inserts it to the lock queue. Does NOT check
 for deadlocks or lock compatibility!
+@param[in] c_lock conflicting lock
+@param[in] thr thread owning trx
+@param[in] type_mode lock mode and wait flag, type is ignored and replaced by
+LOCK_REC
+@param[in] block buffer block containing the record
+@param[in] heap_no heap number of the record
+@param[in] index index of record
+@param[in,out] trx transaction
+@param[in] caller_owns_trx_mutex TRUE if caller owns trx mutex
+@param[in] insert_before_waiting if true, inserts new B-tree record lock
+just after the last non-waiting lock of the current transaction which is
+located before the first waiting for the current transaction lock, otherwise
+the lock is inserted at the end of the queue
 @return created lock */
 UNIV_INLINE
-lock_t*
-lock_rec_create(
-/*============*/
+lock_t *lock_rec_create(lock_t *c_lock,
 #ifdef WITH_WSREP
-	lock_t*			c_lock,	/*!< conflicting lock */
-	que_thr_t*		thr,	/*!< thread owning trx */
+                        que_thr_t *thr,
 #endif
-	unsigned		type_mode,/*!< in: lock mode and wait
-					flag, type is ignored and
-					replaced by LOCK_REC */
-	const buf_block_t*	block,	/*!< in: buffer block containing
-					the record */
-	ulint			heap_no,/*!< in: heap number of the record */
-	dict_index_t*		index,	/*!< in: index of record */
-	trx_t*			trx,	/*!< in,out: transaction */
-	bool			caller_owns_trx_mutex)
-					/*!< in: TRUE if caller owns
-					trx mutex */
+                        unsigned type_mode, const buf_block_t *block,
+                        ulint heap_no, dict_index_t *index, trx_t *trx,
+                        bool caller_owns_trx_mutex,
+                        bool insert_before_waiting)
 {
 	btr_assert_not_corrupted(block, index);
-	return lock_rec_create_low(
+	return lock_rec_create_low(c_lock,
 #ifdef WITH_WSREP
-		c_lock, thr,
+		thr,
 #endif
 		type_mode, block->page.id(), block->frame, heap_no,
-		index, trx, caller_owns_trx_mutex);
+		index, trx, caller_owns_trx_mutex, insert_before_waiting);
 }
diff --git a/storage/innobase/include/lock0priv.h b/storage/innobase/include/lock0priv.h
@@ -562,14 +562,13 @@ lock_rec_get_next_const(
 
 /*********************************************************************//**
 Gets the first explicit lock request on a record.
+@param[in] hash hash chain the lock on
+@param[in] page_id page id
+@param[in] heap_no heap number of the record
 @return first lock, NULL if none exists */
 UNIV_INLINE
-lock_t*
-lock_rec_get_first(
-/*===============*/
-	hash_table_t*		hash,	/*!< in: hash chain the lock on */
-	const buf_block_t*	block,	/*!< in: block containing the record */
-	ulint			heap_no);/*!< in: heap number of the record */
+lock_t *lock_rec_get_first(hash_table_t *hash, page_id_t page_id,
+                           ulint heap_no);
 
 /*********************************************************************//**
 Gets the mode of a lock.
@@ -623,15 +622,26 @@ lock_table_has(
 
 /** Set the wait status of a lock.
 @param[in,out]	lock	lock that will be waited for
-@param[in,out]	trx	transaction that will wait for the lock */
-inline void lock_set_lock_and_trx_wait(lock_t* lock, trx_t* trx)
+@param[in,out]	trx	transaction that will wait for the lock
+@param[in]      c_lock   conflicting lock */
+inline void lock_set_lock_and_trx_wait(lock_t* lock, trx_t* trx,
+	const lock_t *c_lock)
 {
 	ut_ad(lock);
 	ut_ad(lock->trx == trx);
-	ut_ad(trx->lock.wait_lock == NULL);
 	ut_ad(lock_mutex_own());
 	ut_ad(trx_mutex_own(trx));
 
+	if (trx->lock.wait_trx) {
+		ut_ad(!c_lock || trx->lock.wait_trx == c_lock->trx);
+		ut_ad(trx->lock.wait_lock);
+		ut_ad((*trx->lock.wait_lock).trx == trx);
+	} else {
+		ut_ad(c_lock);
+		trx->lock.wait_trx = c_lock->trx;
+		ut_ad(!trx->lock.wait_lock);
+	}
+
 	trx->lock.wait_lock = lock;
 	lock->type_mode |= LOCK_WAIT;
 }
@@ -644,6 +654,7 @@ inline void lock_reset_lock_and_trx_wait(lock_t* lock)
 	ut_ad(lock_mutex_own());
 	ut_ad(lock->trx->lock.wait_lock == NULL
 	      || lock->trx->lock.wait_lock == lock);
+	lock->trx->lock.wait_trx= nullptr;
 	lock->trx->lock.wait_lock = NULL;
 	lock->type_mode &= ~LOCK_WAIT;
 }

diff --git a/storage/innobase/include/lock0priv.ic b/storage/innobase/include/lock0priv.ic
@@ -156,16 +156,15 @@ lock_rec_get_next_const(
 
 /*********************************************************************//**
 Gets the first explicit lock request on a record.
-@return	first lock, NULL if none exists */
+@param[in] hash hash chain the lock on
+@param[in] page_id page id
+@param[in] heap_no heap number of the record
+@return first lock, NULL if none exists */
 UNIV_INLINE
-lock_t*
-lock_rec_get_first(
-/*===============*/
-	hash_table_t*		hash,	/*!< in: hash chain the lock on */
-	const buf_block_t*	block,	/*!< in: block containing the record */
-	ulint			heap_no)/*!< in: heap number of the record */
+lock_t *lock_rec_get_first(hash_table_t *hash, page_id_t page_id,
+                           ulint heap_no)
 {
-  for (lock_t *lock= lock_sys.get_first(*hash, block->page.id());
+  for (lock_t *lock= lock_sys.get_first(*hash, page_id);
        lock; lock= lock_rec_get_next_on_page(lock))
     if (lock_rec_get_nth_bit(lock, heap_no))
       return lock;

diff --git a/storage/innobase/include/trx0trx.h b/storage/innobase/include/trx0trx.h
@@ -426,7 +426,9 @@ struct trx_lock_t {
 	trx_que_t	que_state;	/*!< valid when trx->state
 					== TRX_STATE_ACTIVE: TRX_QUE_RUNNING,
 					TRX_QUE_LOCK_WAIT, ... */
-
+	/** Transaction being waited for; protected by the same mutexes as
+	wait_lock */
+	trx_t*		wait_trx;
 	lock_t*		wait_lock;	/*!< if trx execution state is
 					TRX_QUE_LOCK_WAIT, this points to
 					the lock request, otherwise this is