diff --git a/mysql-test/r/lock_wait_timeout_fractional.result b/mysql-test/r/lock_wait_timeout_fractional.result
new file mode 100644
index 00000000..bd81f307
--- /dev/null
+++ b/mysql-test/r/lock_wait_timeout_fractional.result
@@ -0,0 +1,26 @@
+SET @start_global  = @@global.lock_wait_timeout;
+SET @start_session = @@session.lock_wait_timeout;
+# sub-second timeout fires on MDL contention.
+CREATE TABLE t1 (a INT) ENGINE=InnoDB;
+# Connection con1
+LOCK TABLES t1 WRITE;
+# Connection default
+SET @@session.lock_wait_timeout = 0.2;
+SET @t0 = NOW(6);
+ALTER TABLE t1 ADD COLUMN b INT;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+SELECT TIMESTAMPDIFF(MICROSECOND, @t0, NOW(6)) < 500000 AS sub_second_wait;
+sub_second_wait
+1
+SET @t0 = NOW(6);
+LOCK TABLES t1 WRITE;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+SELECT TIMESTAMPDIFF(MICROSECOND, @t0, NOW(6)) < 500000 AS sub_second_wait;
+sub_second_wait
+1
+# Connection con1
+UNLOCK TABLES;
+# Connection default
+DROP TABLE t1;
+SET @@global.lock_wait_timeout  = @start_global;
+SET @@session.lock_wait_timeout = @start_session;
diff --git a/mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result b/mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result
index 7d41318b..4859a719 100644
--- a/mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result
+++ b/mysql-test/suite/sys_vars/r/lock_wait_timeout_basic.result
@@ -11,12 +11,12 @@ SET @@global.lock_wait_timeout = 100;
 SET @@global.lock_wait_timeout = DEFAULT;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@session.lock_wait_timeout = 200;
 SET @@session.lock_wait_timeout = DEFAULT;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-31536000
+31536000.000000
 '#--------------------FN_DYNVARS_002_02-------------------------#'
 SET @@global.lock_wait_timeout = @start_global_value;
 SELECT @@global.lock_wait_timeout = 31536000;
@@ -27,158 +27,168 @@ SELECT @@session.lock_wait_timeout = 31536000;
 @@session.lock_wait_timeout = 31536000
 1
 '#--------------------FN_DYNVARS_002_03-------------------------#'
+SET @@global.lock_wait_timeout = 0;
+SELECT @@global.lock_wait_timeout;
+@@global.lock_wait_timeout
+0.000000
 SET @@global.lock_wait_timeout = 1;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-1
+1.000000
 SET @@global.lock_wait_timeout = 60020;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-60020
+60020.000000
 SET @@global.lock_wait_timeout = 65535;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-65535
+65535.000000
 SET @@global.lock_wait_timeout = 31536000;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
+SET @@global.lock_wait_timeout = 0.5;
+SELECT @@global.lock_wait_timeout;
+@@global.lock_wait_timeout
+0.500000
+SET @@global.lock_wait_timeout = 0.001;
+SELECT @@global.lock_wait_timeout;
+@@global.lock_wait_timeout
+0.001000
+SET @@global.lock_wait_timeout = 65532.01;
+SELECT @@global.lock_wait_timeout;
+@@global.lock_wait_timeout
+65532.010000
 '#--------------------FN_DYNVARS_002_04-------------------------#'
+SET @@session.lock_wait_timeout = 0;
+SELECT @@session.lock_wait_timeout;
+@@session.lock_wait_timeout
+0.000000
 SET @@session.lock_wait_timeout = 1;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+1.000000
 SET @@session.lock_wait_timeout = 50050;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-50050
+50050.000000
 SET @@session.lock_wait_timeout = 65535;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-65535
+65535.000000
 SET @@session.lock_wait_timeout = 31536000;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-31536000
+31536000.000000
+SET @@session.lock_wait_timeout = 0.2;
+SELECT @@session.lock_wait_timeout;
+@@session.lock_wait_timeout
+0.200000
+SET @@session.lock_wait_timeout = 1.25;
+SELECT @@session.lock_wait_timeout;
+@@session.lock_wait_timeout
+1.250000
+SET @@session.lock_wait_timeout = 65532.01;
+SELECT @@session.lock_wait_timeout;
+@@session.lock_wait_timeout
+65532.010000
 '#------------------FN_DYNVARS_002_05-----------------------#'
-SET @@global.lock_wait_timeout = 0;
-Warnings:
-Warning	1292	Truncated incorrect lock_wait_timeout value: '0'
-SELECT @@global.lock_wait_timeout;
-@@global.lock_wait_timeout
-1
 SET @@global.lock_wait_timeout = -1024;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '-1024'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-1
+0.000000
 SET @@global.lock_wait_timeout = 31536001;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '31536001'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = 3153600112;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '3153600112'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
-SET @@global.lock_wait_timeout = 65532.01;
-ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
-SELECT @@global.lock_wait_timeout;
-@@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = ON;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = OFF;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = test;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = " ";
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@global.lock_wait_timeout = ' ';
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
-SET @@session.lock_wait_timeout = 0;
-Warnings:
-Warning	1292	Truncated incorrect lock_wait_timeout value: '0'
-SELECT @@session.lock_wait_timeout;
-@@session.lock_wait_timeout
-1
+31536000.000000
 SET @@session.lock_wait_timeout = -2;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '-2'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+0.000000
 SET @@session.lock_wait_timeout = 3176990909;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '3176990909'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-31536000
+31536000.000000
 SET @@session.lock_wait_timeout = 31536001;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '31536001'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-31536000
+31536000.000000
 SET @@session.lock_wait_timeout = -1024;
 Warnings:
 Warning	1292	Truncated incorrect lock_wait_timeout value: '-1024'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
-SET @@session.lock_wait_timeout = 65532.01;
-ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
-SELECT @@session.lock_wait_timeout;
-@@session.lock_wait_timeout
-1
+0.000000
 SET @@session.lock_wait_timeout = ON;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+0.000000
 SET @@session.lock_wait_timeout = OFF;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+0.000000
 SET @@session.lock_wait_timeout = test;
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+0.000000
 SET @@session.lock_wait_timeout = ' ';
 ERROR 42000: Incorrect argument type to variable 'lock_wait_timeout'
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-1
+0.000000
 '#------------------FN_DYNVARS_002_06-----------------------#'
-SELECT @@global.lock_wait_timeout = VARIABLE_VALUE 
-FROM performance_schema.global_variables 
+SELECT @@global.lock_wait_timeout = VARIABLE_VALUE
+FROM performance_schema.global_variables
 WHERE VARIABLE_NAME='lock_wait_timeout';
 @@global.lock_wait_timeout = VARIABLE_VALUE
 1
 '#------------------FN_DYNVARS_002_07-----------------------#'
-SELECT @@session.lock_wait_timeout = VARIABLE_VALUE 
-FROM performance_schema.session_variables 
+SELECT @@session.lock_wait_timeout = VARIABLE_VALUE
+FROM performance_schema.session_variables
 WHERE VARIABLE_NAME='lock_wait_timeout';
 @@session.lock_wait_timeout = VARIABLE_VALUE
 1
@@ -186,13 +196,11 @@ WHERE VARIABLE_NAME='lock_wait_timeout';
 SET @@global.lock_wait_timeout = TRUE;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-1
+1.000000
 SET @@global.lock_wait_timeout = FALSE;
-Warnings:
-Warning	1292	Truncated incorrect lock_wait_timeout value: '0'
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-1
+0.000000
 '#---------------------FN_DYNVARS_001_09----------------------#'
 SET @@global.lock_wait_timeout = 10;
 SET @@session.lock_wait_timeout = 11;
@@ -211,7 +219,7 @@ SELECT @@local.lock_wait_timeout = @@session.lock_wait_timeout;
 SET lock_wait_timeout = 1;
 SELECT @@lock_wait_timeout;
 @@lock_wait_timeout
-1
+1.000000
 SELECT local.lock_wait_timeout;
 ERROR 42S02: Unknown table 'local' in field list
 SELECT session.lock_wait_timeout;
@@ -221,8 +229,8 @@ ERROR 42S22: Unknown column 'lock_wait_timeout' in 'field list'
 SET @@global.lock_wait_timeout = @start_global_value;
 SELECT @@global.lock_wait_timeout;
 @@global.lock_wait_timeout
-31536000
+31536000.000000
 SET @@session.lock_wait_timeout = @start_session_value;
 SELECT @@session.lock_wait_timeout;
 @@session.lock_wait_timeout
-31536000
+31536000.000000
diff --git a/mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test b/mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test
index d8fa3157..2054bdbb 100644
--- a/mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test
+++ b/mysql-test/suite/sys_vars/t/lock_wait_timeout_basic.test
@@ -3,11 +3,11 @@
 # Variable Name: lock_wait_timeout                                             #
 # Scope: GLOBAL & SESSION                                                      #
 # Access Type: Dynamic                                                         #
-# Data Type: Numeric                                                           #
-# Default Value: 1                                                             #
-# Range: 1 - 31536000                                                          #
-#                                                                              #
-#                                                                              #
+# Data Type: Numeric (fractional seconds)                                      #
+# Default Value: 31536000                                                      #
+# Range: 0 - 31536000                                                          #
+#
+#
 # Creation Date: 2010-02-08                                                    #
 # Author:  Jon Olav Hauglid                                                    #
 #                                                                              #
@@ -18,7 +18,7 @@
 #              * Scope & Access method                                         #
 #              * Data Integrity                                                #
 #                                                                              #
-# Reference: http://dev.mysql.com/doc/refman/5.5/en/                           #
+# Reference: http://dev.mysql.com/doc/refman/en/                               #
 #  server-system-variables.html#option_mysqld_lock-wait-timeout                #
 #                                                                              #
 ################################################################################
@@ -69,6 +69,8 @@ SELECT @@session.lock_wait_timeout = 31536000;
 # Change the value of lock_wait_timeout to a valid value for GLOBAL Scope     #
 ###############################################################################
 
+SET @@global.lock_wait_timeout = 0;
+SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = 1;
 SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = 60020;
@@ -77,12 +79,21 @@ SET @@global.lock_wait_timeout = 65535;
 SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = 31536000;
 SELECT @@global.lock_wait_timeout;
+# Fractional values are valid.
+SET @@global.lock_wait_timeout = 0.5;
+SELECT @@global.lock_wait_timeout;
+SET @@global.lock_wait_timeout = 0.001;
+SELECT @@global.lock_wait_timeout;
+SET @@global.lock_wait_timeout = 65532.01;
+SELECT @@global.lock_wait_timeout;
 
 --echo '#--------------------FN_DYNVARS_002_04-------------------------#'
 ###############################################################################
 # Change the value of lock_wait_timeout to a valid value for SESSION Scope    #
 ###############################################################################
 
+SET @@session.lock_wait_timeout = 0;
+SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = 1;
 SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = 50050;
@@ -91,6 +102,13 @@ SET @@session.lock_wait_timeout = 65535;
 SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = 31536000;
 SELECT @@session.lock_wait_timeout;
+# Fractional values are valid.
+SET @@session.lock_wait_timeout = 0.2;
+SELECT @@session.lock_wait_timeout;
+SET @@session.lock_wait_timeout = 1.25;
+SELECT @@session.lock_wait_timeout;
+SET @@session.lock_wait_timeout = 65532.01;
+SELECT @@session.lock_wait_timeout;
 
 
 --echo '#------------------FN_DYNVARS_002_05-----------------------#'
@@ -98,8 +116,6 @@ SELECT @@session.lock_wait_timeout;
 # Change the value of lock_wait_timeout to an invalid value     #
 #################################################################
 # for global scope
-SET @@global.lock_wait_timeout = 0;
-SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = -1024;
 SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = 31536001;
@@ -107,9 +123,6 @@ SELECT @@global.lock_wait_timeout;
 SET @@global.lock_wait_timeout = 3153600112;
 SELECT @@global.lock_wait_timeout;
 
---Error ER_WRONG_TYPE_FOR_VAR
-SET @@global.lock_wait_timeout = 65532.01;
-SELECT @@global.lock_wait_timeout;
 --Error ER_WRONG_TYPE_FOR_VAR
 SET @@global.lock_wait_timeout = ON;
 SELECT @@global.lock_wait_timeout;
@@ -127,8 +140,6 @@ SET @@global.lock_wait_timeout = ' ';
 SELECT @@global.lock_wait_timeout;
 
 # for session scope
-SET @@session.lock_wait_timeout = 0;
-SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = -2;
 SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = 3176990909;
@@ -138,9 +149,6 @@ SELECT @@session.lock_wait_timeout;
 SET @@session.lock_wait_timeout = -1024;
 SELECT @@session.lock_wait_timeout;
 
---Error ER_WRONG_TYPE_FOR_VAR
-SET @@session.lock_wait_timeout = 65532.01;
-SELECT @@session.lock_wait_timeout;
 --Error ER_WRONG_TYPE_FOR_VAR
 SET @@session.lock_wait_timeout = ON;
 SELECT @@session.lock_wait_timeout;
@@ -162,8 +170,8 @@ SELECT @@session.lock_wait_timeout;
 ####################################################################
 
 --disable_warnings
-SELECT @@global.lock_wait_timeout = VARIABLE_VALUE 
-FROM performance_schema.global_variables 
+SELECT @@global.lock_wait_timeout = VARIABLE_VALUE
+FROM performance_schema.global_variables
 WHERE VARIABLE_NAME='lock_wait_timeout';
 --enable_warnings
 
@@ -174,8 +182,8 @@ WHERE VARIABLE_NAME='lock_wait_timeout';
 ####################################################################
 
 --disable_warnings
-SELECT @@session.lock_wait_timeout = VARIABLE_VALUE 
-FROM performance_schema.session_variables 
+SELECT @@session.lock_wait_timeout = VARIABLE_VALUE
+FROM performance_schema.session_variables
 WHERE VARIABLE_NAME='lock_wait_timeout';
 --enable_warnings
 
diff --git a/mysql-test/t/lock_wait_timeout_fractional.test b/mysql-test/t/lock_wait_timeout_fractional.test
new file mode 100644
index 00000000..9880659d
--- /dev/null
+++ b/mysql-test/t/lock_wait_timeout_fractional.test
@@ -0,0 +1,45 @@
+################################################################################
+# t/lock_wait_timeout_fractional.test
+#
+# Bug#114949 (lock_wait_timeout high resolution)
+# Verify that the session/global system variable @@lock_wait_timeout accepts
+# fractional (sub-second) values, and that an MDL wait actually fires with
+# sub-second precision when contention exists.
+################################################################################
+
+SET @start_global  = @@global.lock_wait_timeout;
+SET @start_session = @@session.lock_wait_timeout;
+
+--echo # sub-second timeout fires on MDL contention.
+CREATE TABLE t1 (a INT) ENGINE=InnoDB;
+
+--echo # Connection con1
+connect (con1, localhost, root,,);
+LOCK TABLES t1 WRITE;
+
+--echo # Connection default
+connection default;
+SET @@session.lock_wait_timeout = 0.2;
+
+SET @t0 = NOW(6);
+--error ER_LOCK_WAIT_TIMEOUT
+ALTER TABLE t1 ADD COLUMN b INT;
+SELECT TIMESTAMPDIFF(MICROSECOND, @t0, NOW(6)) < 500000 AS sub_second_wait;
+
+SET @t0 = NOW(6);
+--error ER_LOCK_WAIT_TIMEOUT
+LOCK TABLES t1 WRITE;
+SELECT TIMESTAMPDIFF(MICROSECOND, @t0, NOW(6)) < 500000 AS sub_second_wait;
+
+--echo # Connection con1
+connection con1;
+UNLOCK TABLES;
+disconnect con1;
+
+--echo # Connection default
+connection default;
+DROP TABLE t1;
+
+# Restore initial values.
+SET @@global.lock_wait_timeout  = @start_global;
+SET @@session.lock_wait_timeout = @start_session;
diff --git a/sql/dd/dictionary.h b/sql/dd/dictionary.h
index 9c5c373a..30c4a254 100644
--- a/sql/dd/dictionary.h
+++ b/sql/dd/dictionary.h
@@ -326,7 +326,7 @@ bool has_exclusive_tablespace_mdl(THD *thd, const char *tablespace_name);
 
 [[nodiscard]] bool acquire_exclusive_table_mdl(
     THD *thd, const char *schema_name, const char *table_name,
-    unsigned long int lock_wait_timeout, MDL_ticket **out_mdl_ticket);
+    ulonglong lock_wait_timeout, MDL_ticket **out_mdl_ticket);
 
 /**
   Acquire exclusive metadata lock on the given schema name with
diff --git a/sql/dd/impl/dictionary_impl.cc b/sql/dd/impl/dictionary_impl.cc
index 9c878869..1367f6e0 100644
--- a/sql/dd/impl/dictionary_impl.cc
+++ b/sql/dd/impl/dictionary_impl.cc
@@ -414,7 +414,7 @@ bool Dictionary_impl::is_system_view_name(const char *schema_name,
 static bool acquire_shared_mdl(THD *thd,
                                MDL_key::enum_mdl_namespace lock_namespace,
                                const char *schema_name, const char *table_name,
-                               bool no_wait, ulong lock_wait_timeout,
+                               bool no_wait, ulonglong lock_wait_timeout,
                                enum_mdl_duration lock_duration,
                                MDL_ticket **out_mdl_ticket) {
   DBUG_TRACE;
@@ -439,7 +439,7 @@ static bool acquire_exclusive_mdl(THD *thd,
                                   MDL_key::enum_mdl_namespace lock_namespace,
                                   const char *schema_name,
                                   const char *table_name, bool no_wait,
-                                  ulong lock_wait_timeout,
+                                  ulonglong lock_wait_timeout,
                                   enum_mdl_duration lock_duration,
                                   MDL_ticket **out_mdl_ticket) {
   DBUG_TRACE;
@@ -557,7 +557,7 @@ bool acquire_exclusive_table_mdl(THD *thd, const char *schema_name,
 
 bool acquire_exclusive_table_mdl(THD *thd, const char *schema_name,
                                  const char *table_name,
-                                 unsigned long int lock_wait_timeout,
+                                 ulonglong lock_wait_timeout,
                                  MDL_ticket **out_mdl_ticket) {
   return acquire_exclusive_mdl(thd, MDL_key::TABLE, schema_name, table_name,
                                false, lock_wait_timeout, MDL_TRANSACTION,
diff --git a/sql/lock.cc b/sql/lock.cc
index 7cd62133..a3081566 100644
--- a/sql/lock.cc
+++ b/sql/lock.cc
@@ -794,7 +794,7 @@ bool lock_schema_name(THD *thd, const char *db) {
   @return false - On Success.
 */
 bool lock_tablespace_names(THD *thd, Tablespace_hash_set *tablespace_set,
-                           ulong lock_wait_timeout, MEM_ROOT *mem_root) {
+                           ulonglong lock_wait_timeout, MEM_ROOT *mem_root) {
   // Stop if we have nothing to lock
   if (tablespace_set->empty()) return false;
 
@@ -1013,7 +1013,7 @@ static void print_lock_error(int error, const char *table) {
 */
 
 bool acquire_shared_global_read_lock(THD *thd,
-                                     unsigned long lock_wait_timeout) {
+                                     ulonglong lock_wait_timeout) {
   // If we cannot acquire protection against GRL, err out.
   if (thd->global_read_lock.can_acquire_protection()) return true;
 
diff --git a/sql/lock.h b/sql/lock.h
index 433dae89..547cf4eb 100644
--- a/sql/lock.h
+++ b/sql/lock.h
@@ -58,13 +58,13 @@ typedef malloc_unordered_set<std::string> Tablespace_hash_set;
 
 // Lock tablespace names.
 bool lock_tablespace_names(THD *thd, Tablespace_hash_set *tablespace_set,
-                           ulong lock_wait_timeout, MEM_ROOT *mem_root);
+                           ulonglong lock_wait_timeout, MEM_ROOT *mem_root);
 
 /* Lock based on stored routine name */
 bool lock_object_name(THD *thd, MDL_key::enum_mdl_namespace mdl_type,
                       const char *db, const char *name);
 
 /* Acquire protection against the global read lock. */
-bool acquire_shared_global_read_lock(THD *thd, unsigned long lock_wait_timeout);
+bool acquire_shared_global_read_lock(THD *thd, ulonglong lock_wait_timeout);
 
 #endif /* LOCK_INCLUDED */
diff --git a/sql/mdl.cc b/sql/mdl.cc
index 846b4fd6..d7d364d7 100644
--- a/sql/mdl.cc
+++ b/sql/mdl.cc
@@ -3354,7 +3354,7 @@ void MDL_lock::object_lock_notify_conflicting_locks(MDL_context *ctx,
 
   @param [in,out] mdl_request Lock request object for lock to be acquired
 
-  @param lock_wait_timeout Seconds to wait before timeout.
+  @param lock_wait_timeout Nanoseconds to wait before timeout.
 
   @retval  false   Success. MDL_request::ticket points to the ticket
                    for the lock.
@@ -3399,7 +3399,7 @@ bool MDL_context::acquire_lock(MDL_request *mdl_request,
   struct timespec abs_timeout;
   MDL_wait::enum_wait_status wait_status;
   /* Do some work outside the critical section. */
-  set_timespec(&abs_timeout, lock_wait_timeout);
+  set_timespec_nsec(&abs_timeout, lock_wait_timeout);
 
   if (try_acquire_lock_impl(mdl_request, &ticket)) return true;
 
@@ -3623,7 +3623,7 @@ class MDL_request_cmp {
 
   @param  mdl_requests  List of requests for locks to be acquired.
 
-  @param lock_wait_timeout  Seconds to wait before timeout.
+  @param lock_wait_timeout  Nanoseconds to wait before timeout.
 
   @note The list of requests should not contain non-exclusive lock requests.
         There should not be any acquired locks in the context.
@@ -3729,7 +3729,7 @@ bool MDL_context::clone_tickets(const MDL_context *ticket_owner,
 
   @param mdl_ticket         Lock to upgrade.
   @param new_type           Lock type to upgrade to.
-  @param lock_wait_timeout  Seconds to wait before timeout.
+  @param lock_wait_timeout  Nanoseconds to wait before timeout.
 
   @note In case of failure to upgrade lock (e.g. because upgrader
         was killed) leaves lock in its original state (locked in
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 7b5e75b4..123e92a9 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -13418,6 +13418,9 @@ static int get_options(int *argc_ptr, char ***argv_ptr) {
   global_system_variables.long_query_time =
       (ulonglong)(global_system_variables.long_query_time_double * 1e6);
 
+  global_system_variables.lock_wait_timeout =
+      (ulonglong)(global_system_variables.lock_wait_timeout_double * 1e9);
+
   if (opt_short_log_format) opt_specialflag |= SPECIAL_SHORT_LOG_FORMAT;
 
   if (Connection_handler_manager::init()) {
diff --git a/sql/sql_backup_lock.cc b/sql/sql_backup_lock.cc
index f9ad7dbc..a00283db 100644
--- a/sql/sql_backup_lock.cc
+++ b/sql/sql_backup_lock.cc
@@ -125,7 +125,7 @@ Shared_backup_lock_guard::try_acquire_shared_backup_lock(THD *thd,
   @param[in] thd                    Current thread context
   @param[in] mdl_type               Type of metadata lock to acquire for backup
   @param[in] mdl_duration           Duration of metadata lock
-  @param[in] lock_wait_timeout      How many seconds to wait before timeout.
+  @param[in] lock_wait_timeout      How many nanoseconds to wait before timeout.
 
   @return Operation status.
     @retval false Success
@@ -134,7 +134,7 @@ Shared_backup_lock_guard::try_acquire_shared_backup_lock(THD *thd,
 
 static bool acquire_mdl_for_backup(THD *thd, enum_mdl_type mdl_type,
                                    enum_mdl_duration mdl_duration,
-                                   ulong lock_wait_timeout) {
+                                   ulonglong lock_wait_timeout) {
   MDL_request mdl_request;
 
   assert(mdl_type == MDL_SHARED || mdl_type == MDL_INTENTION_EXCLUSIVE);
@@ -174,13 +174,13 @@ void release_backup_lock(THD *thd) {
   Backup Lock and IX lock should be considered as Shared Backup Lock.
 */
 
-bool acquire_exclusive_backup_lock(THD *thd, ulong lock_wait_timeout,
+bool acquire_exclusive_backup_lock(THD *thd, ulonglong lock_wait_timeout,
                                    bool for_trx) {
   const enum_mdl_duration duration = (for_trx ? MDL_TRANSACTION : MDL_EXPLICIT);
   return acquire_mdl_for_backup(thd, MDL_SHARED, duration, lock_wait_timeout);
 }
 
-bool acquire_shared_backup_lock(THD *thd, ulong lock_wait_timeout,
+bool acquire_shared_backup_lock(THD *thd, ulonglong lock_wait_timeout,
                                 bool for_trx) {
   const enum_mdl_duration duration = (for_trx ? MDL_TRANSACTION : MDL_EXPLICIT);
   return acquire_mdl_for_backup(thd, MDL_INTENTION_EXCLUSIVE, duration,
diff --git a/sql/sql_backup_lock.h b/sql/sql_backup_lock.h
index f303fac3..ba609b1c 100644
--- a/sql/sql_backup_lock.h
+++ b/sql/sql_backup_lock.h
@@ -26,6 +26,7 @@
 
 #include <sys/types.h>
 
+#include "my_inttypes.h"    // ulonglong
 #include "my_sqlcommand.h"  // SQLCOM_LOCK_INSTANCE, SQLCOM_UNLOCK_INSTANCE
 #include "sql/sql_cmd.h"    // Sql_cmd
 
@@ -121,7 +122,7 @@ class Shared_backup_lock_guard {
   Acquire exclusive Backup Lock.
 
   @param[in] thd                Current thread context
-  @param[in] lock_wait_timeout  How many seconds to wait before timeout.
+  @param[in] lock_wait_timeout  How many nanoseconds to wait before timeout.
   @param[in] for_trx            true if MDL duration is MDL_TRANSACTION
                                 false if MDL duration is MDL_EXPLICIT
 
@@ -130,14 +131,14 @@ class Shared_backup_lock_guard {
     @retval true  Failure
 */
 
-bool acquire_exclusive_backup_lock(THD *thd, unsigned long lock_wait_timeout,
+bool acquire_exclusive_backup_lock(THD *thd, ulonglong lock_wait_timeout,
                                    bool for_trx);
 
 /**
   Acquire shared Backup Lock.
 
   @param[in] thd                Current thread context
-  @param[in] lock_wait_timeout  How many seconds to wait before timeout.
+  @param[in] lock_wait_timeout  How many nanoseconds to wait before timeout.
   @param[in] for_trx            true if MDL duration is MDL_TRANSACTION
                                 false if MDL duration is MDL_EXPLICIT
 
@@ -146,7 +147,7 @@ bool acquire_exclusive_backup_lock(THD *thd, unsigned long lock_wait_timeout,
     @retval true  Failure
 */
 
-bool acquire_shared_backup_lock(THD *thd, unsigned long lock_wait_timeout,
+bool acquire_shared_backup_lock(THD *thd, ulonglong lock_wait_timeout,
                                 bool for_trx = true);
 
 /**
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 93aba7cd..06359216 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -5523,7 +5523,7 @@ static inline bool is_temporary_table_being_opened(const Table_ref *table) {
   @param tables_start      Start of list of tables on which locks
                            should be acquired.
   @param tables_end        End of list of tables.
-  @param lock_wait_timeout Seconds to wait before timeout.
+  @param lock_wait_timeout Nanoseconds to wait before timeout.
   @param flags             Bitmap of flags to modify how the
                            tables will be open, see open_table()
                            description for details.
@@ -5533,7 +5533,7 @@ static inline bool is_temporary_table_being_opened(const Table_ref *table) {
 */
 bool get_and_lock_tablespace_names(THD *thd, Table_ref *tables_start,
                                    Table_ref *tables_end,
-                                   ulong lock_wait_timeout, uint flags) {
+                                   ulonglong lock_wait_timeout, uint flags) {
   // If this is a DISCARD or IMPORT TABLESPACE command (indicated by
   // the THD:: tablespace_op flag), we skip this phase, because these
   // commands are only used for file-per-table tablespaces, which we
@@ -5648,7 +5648,7 @@ bool get_and_lock_tablespace_names(THD *thd, Table_ref *tables_start,
   @param tables_start      Start of list of tables on which locks
                            should be acquired.
   @param tables_end        End of list of tables.
-  @param lock_wait_timeout Seconds to wait before timeout.
+  @param lock_wait_timeout Nanoseconds to wait before timeout.
   @param flags             Bitmap of flags to modify how the tables will be
                            open, see open_table() description for details.
   @param schema_reqs       When non-nullptr, pointer to array in which
@@ -5661,7 +5661,7 @@ bool get_and_lock_tablespace_names(THD *thd, Table_ref *tables_start,
   @retval true   Failure (e.g. connection was killed)
 */
 bool lock_table_names(THD *thd, Table_ref *tables_start, Table_ref *tables_end,
-                      ulong lock_wait_timeout, uint flags,
+                      ulonglong lock_wait_timeout, uint flags,
                       Prealloced_array<MDL_request *, 1> *schema_reqs) {
   MDL_request_list mdl_requests;
   Table_ref *table;
diff --git a/sql/sql_base.h b/sql/sql_base.h
index 820dbe88..b1e047f9 100644
--- a/sql/sql_base.h
+++ b/sql/sql_base.h
@@ -278,10 +278,10 @@ bool init_ftfuncs(THD *thd, Query_block *select);
 int run_before_dml_hook(THD *thd);
 bool get_and_lock_tablespace_names(THD *thd, Table_ref *tables_start,
                                    Table_ref *tables_end,
-                                   ulong lock_wait_timeout, uint flags);
+                                   ulonglong lock_wait_timeout, uint flags);
 bool lock_table_names(
     THD *thd, Table_ref *table_list, Table_ref *table_list_end,
-    ulong lock_wait_timeout, uint flags,
+    ulonglong lock_wait_timeout, uint flags,
     Prealloced_array<MDL_request *, 1> *schema_reqs = nullptr);
 bool open_tables(THD *thd, Table_ref **tables, uint *counter, uint flags,
                  Prelocking_strategy *prelocking_strategy);
diff --git a/sql/sql_partition_admin.cc b/sql/sql_partition_admin.cc
index 70232b90..0265107d 100644
--- a/sql/sql_partition_admin.cc
+++ b/sql/sql_partition_admin.cc
@@ -585,7 +585,7 @@ bool Sql_cmd_alter_table_repair_partition::execute(THD *thd) {
 
 bool Sql_cmd_alter_table_truncate_partition::execute(THD *thd) {
   int error;
-  ulong timeout = thd->variables.lock_wait_timeout;
+  ulonglong timeout = thd->variables.lock_wait_timeout;
   Table_ref *first_table = thd->lex->query_block->get_table_list();
   uint table_counter;
   Partition_handler *part_handler = nullptr;
diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc
index 8ef0199c..649342ee 100644
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@@ -2375,11 +2375,26 @@ static Sys_var_bool Sys_local_infile("local_infile",
                                      GLOBAL_VAR(opt_local_infile),
                                      CMD_LINE(OPT_ARG), DEFAULT(false));
 
-static Sys_var_ulong Sys_lock_wait_timeout(
+static bool update_cached_lock_wait_timeout(sys_var *, THD *thd,
+                                            enum_var_type type) {
+  if (type == OPT_SESSION)
+    thd->variables.lock_wait_timeout = static_cast<ulonglong>(
+        thd->variables.lock_wait_timeout_double * 1e9);
+  else
+    global_system_variables.lock_wait_timeout = static_cast<ulonglong>(
+        global_system_variables.lock_wait_timeout_double * 1e9);
+  return false;
+}
+
+static Sys_var_double Sys_lock_wait_timeout(
     "lock_wait_timeout",
-    "Timeout in seconds to wait for a lock before returning an error.",
-    HINT_UPDATEABLE SESSION_VAR(lock_wait_timeout), CMD_LINE(REQUIRED_ARG),
-    VALID_RANGE(1, LONG_TIMEOUT), DEFAULT(LONG_TIMEOUT), BLOCK_SIZE(1));
+    "Timeout in seconds to wait for a lock before returning an error. "
+    "The argument will be treated as a decimal value with nanosecond "
+    "precision.",
+    HINT_UPDATEABLE SESSION_VAR(lock_wait_timeout_double),
+    CMD_LINE(REQUIRED_ARG), VALID_RANGE(0, LONG_TIMEOUT),
+    DEFAULT(LONG_TIMEOUT), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(nullptr),
+    ON_UPDATE(update_cached_lock_wait_timeout));
 
 #ifdef HAVE_MLOCKALL
 static Sys_var_bool Sys_locked_in_memory(
diff --git a/sql/system_variables.h b/sql/system_variables.h
index 2271656a..66d91c7c 100644
--- a/sql/system_variables.h
+++ b/sql/system_variables.h
@@ -240,7 +240,7 @@ struct System_variables {
   uint cte_max_recursion_depth;
   ulonglong histogram_generation_max_mem_size;
   ulong join_buff_size;
-  ulong lock_wait_timeout;
+  ulonglong lock_wait_timeout;
   ulong max_allowed_packet;
   ulong max_error_count;
   ulong max_length_for_sort_data;  ///< Unused.
@@ -345,6 +345,9 @@ struct System_variables {
 
   double long_query_time_double;
 
+  /* User-facing value of lock_wait_timeout (seconds, fractional). */
+  double lock_wait_timeout_double;
+
   bool pseudo_replica_mode;
 
   Gtid_specification gtid_next;
diff --git a/storage/innobase/dict/dict0dd.cc b/storage/innobase/dict/dict0dd.cc
index 55356dcc..4f07e45b 100644
--- a/storage/innobase/dict/dict0dd.cc
+++ b/storage/innobase/dict/dict0dd.cc
@@ -7033,7 +7033,7 @@ bool dd_tablespace_get_mdl(const char *space_name, MDL_ticket **mdl_ticket,
   bool trx_duration = foreground;
 
   /* Background thread should not block on MDL lock. */
-  ulong timeout = foreground ? thd->variables.lock_wait_timeout : 0;
+  ulonglong timeout = foreground ? thd->variables.lock_wait_timeout : 0;
   bool result = acquire_shared_backup_lock(thd, timeout, trx_duration);
 
   if (!result) {
diff --git a/storage/innobase/dict/dict0dict.cc b/storage/innobase/dict/dict0dict.cc
index 90a96222..a0fd5187 100644
--- a/storage/innobase/dict/dict0dict.cc
+++ b/storage/innobase/dict/dict0dict.cc
@@ -5857,14 +5857,15 @@ dberr_t dd_sdi_acquire_exclusive_mdl(THD *thd, space_id_t space_id,
 
   snprintf(tbl_buf, sizeof(tbl_buf), "SDI_" SPACE_ID_PF, space_id);
 
-  /* Submit a higher than default lock wait timeout, the timeout accepted by
-  dd::acquire_exclusive_table_mdl is in seconds. */
+  /* Submit a higher than default lock wait timeout. The timeout accepted by
+  dd::acquire_exclusive_table_mdl is in nanoseconds. */
   std::chrono::seconds lock_wait_timeout = thd_lock_wait_timeout(thd);
   if (lock_wait_timeout < std::chrono::hours(27)) {
     lock_wait_timeout += std::chrono::hours(27);
   }
   if (dd::acquire_exclusive_table_mdl(
-          thd, db_buf, tbl_buf, (unsigned long int)lock_wait_timeout.count(),
+          thd, db_buf, tbl_buf,
+          static_cast<ulonglong>(lock_wait_timeout.count()) * 1000000000ULL,
           sdi_mdl)) {
     /* MDL failure can happen with lower timeout
     values chosen by user */
diff --git a/storage/ndb/plugin/ha_ndbcluster_binlog.cc b/storage/ndb/plugin/ha_ndbcluster_binlog.cc
index 1dee6fe6..39297cc3 100644
--- a/storage/ndb/plugin/ha_ndbcluster_binlog.cc
+++ b/storage/ndb/plugin/ha_ndbcluster_binlog.cc
@@ -1758,7 +1758,7 @@ class Ndb_schema_event_handler {
 
   class Lock_wait_timeout_guard {
    public:
-    Lock_wait_timeout_guard(THD *thd, ulong lock_wait_timeout)
+    Lock_wait_timeout_guard(THD *thd, ulonglong lock_wait_timeout)
         : m_thd(thd),
           m_save_lock_wait_timeout(thd->variables.lock_wait_timeout) {
       m_thd->variables.lock_wait_timeout = lock_wait_timeout;
@@ -1770,7 +1770,7 @@ class Ndb_schema_event_handler {
 
    private:
     THD *const m_thd;
-    ulong m_save_lock_wait_timeout;
+    ulonglong m_save_lock_wait_timeout;
   };
 
   // Log error code and message returned from NDB
@@ -3774,8 +3774,11 @@ class Ndb_schema_event_handler {
       thd_ndb_options.set(Thd_ndb::IS_SCHEMA_DIST_PARTICIPANT);
 
       // Set the custom lock_wait_timeout for schema distribution
-      Lock_wait_timeout_guard lwt_guard(m_thd,
-                                        opt_ndb_schema_dist_lock_wait_timeout);
+      // (opt_ndb_schema_dist_lock_wait_timeout is in seconds, convert to ns).
+      Lock_wait_timeout_guard lwt_guard(
+          m_thd,
+          static_cast<ulonglong>(opt_ndb_schema_dist_lock_wait_timeout) *
+              1000000000ULL);
 
       Ndb_schema_op_result schema_op_result;
       switch (schema_type) {
@@ -3887,8 +3890,11 @@ class Ndb_schema_event_handler {
     thd_ndb_options.set(Thd_ndb::IS_SCHEMA_DIST_PARTICIPANT);
 
     // Set the custom lock_wait_timeout for schema distribution
-    Lock_wait_timeout_guard lwt_guard(m_thd,
-                                      opt_ndb_schema_dist_lock_wait_timeout);
+    // (opt_ndb_schema_dist_lock_wait_timeout is in seconds, convert to ns).
+    Lock_wait_timeout_guard lwt_guard(
+        m_thd,
+        static_cast<ulonglong>(opt_ndb_schema_dist_lock_wait_timeout) *
+            1000000000ULL);
 
     {
       const SCHEMA_OP_TYPE schema_type = (SCHEMA_OP_TYPE)schema->type;
diff --git a/storage/ndb/plugin/ndb_dd_client.cc b/storage/ndb/plugin/ndb_dd_client.cc
index fa64aca0..2a07fdd8 100644
--- a/storage/ndb/plugin/ndb_dd_client.cc
+++ b/storage/ndb/plugin/ndb_dd_client.cc
@@ -125,7 +125,7 @@ bool Ndb_dd_client::mdl_lock_table(const char *schema_name,
 
 bool Ndb_dd_client::mdl_lock_schema_exclusive(const char *schema_name,
                                               bool custom_lock_wait,
-                                              ulong lock_wait_timeout) {
+                                              ulonglong lock_wait_timeout) {
   MDL_request_list mdl_requests;
   MDL_request schema_request;
   MDL_request backup_lock_request;
@@ -181,7 +181,7 @@ bool Ndb_dd_client::mdl_lock_schema(const char *schema_name) {
 
 bool Ndb_dd_client::mdl_lock_logfile_group_exclusive(
     const char *logfile_group_name, bool custom_lock_wait,
-    ulong lock_wait_timeout) {
+    ulonglong lock_wait_timeout) {
   MDL_request_list mdl_requests;
   MDL_request logfile_group_request;
   MDL_request backup_lock_request;
@@ -241,7 +241,7 @@ bool Ndb_dd_client::mdl_lock_logfile_group(const char *logfile_group_name,
 
 bool Ndb_dd_client::mdl_lock_tablespace_exclusive(const char *tablespace_name,
                                                   bool custom_lock_wait,
-                                                  ulong lock_wait_timeout) {
+                                                  ulonglong lock_wait_timeout) {
   MDL_request_list mdl_requests;
   MDL_request tablespace_request;
   MDL_request backup_lock_request;
@@ -302,7 +302,7 @@ bool Ndb_dd_client::mdl_lock_tablespace(const char *tablespace_name,
 bool Ndb_dd_client::mdl_locks_acquire_exclusive(const char *schema_name,
                                                 const char *table_name,
                                                 bool custom_lock_wait,
-                                                ulong lock_wait_timeout) {
+                                                ulonglong lock_wait_timeout) {
   MDL_request_list mdl_requests;
   MDL_request schema_request;
   MDL_request mdl_request;
@@ -344,7 +344,7 @@ bool Ndb_dd_client::mdl_locks_acquire_exclusive(const char *schema_name,
 }
 
 bool Ndb_dd_client::mdl_locks_acquire(MDL_request_list mdl_requests,
-                                      ulong lock_wait_timeout) {
+                                      ulonglong lock_wait_timeout) {
   if (m_thd->mdl_context.acquire_locks(&mdl_requests, lock_wait_timeout)) {
     return false;
   }
diff --git a/storage/ndb/plugin/ndb_dd_client.h b/storage/ndb/plugin/ndb_dd_client.h
index 79a05cb6..9701f9b7 100644
--- a/storage/ndb/plugin/ndb_dd_client.h
+++ b/storage/ndb/plugin/ndb_dd_client.h
@@ -107,12 +107,12 @@ class Ndb_dd_client {
      @brief Acquire requested locks in list and register acquired lock tickets
 
      @param mdl_requests       List of MDL requests
-     @param lock_wait_timeout  Seconds to wait before timeout
+     @param lock_wait_timeout  Nanoseconds to wait before timeout
 
      @return true if acquired successfully, false if not
    */
   bool mdl_locks_acquire(MDL_request_list mdl_requests,
-                         ulong lock_wait_timeout);
+                         ulonglong lock_wait_timeout);
   /**
      @brief Release EXPLICIT locks held by the previous registered tickets
    */
@@ -144,7 +144,7 @@ class Ndb_dd_client {
   */
   bool mdl_lock_schema_exclusive(const char *schema_name,
                                  bool custom_lock_wait = false,
-                                 ulong lock_wait_timeout = 0);
+                                 ulonglong lock_wait_timeout = 0);
 
   /**
     @brief Acquire IX MDL on the table
@@ -170,7 +170,7 @@ class Ndb_dd_client {
   bool mdl_locks_acquire_exclusive(const char *schema_name,
                                    const char *table_name,
                                    bool custom_lock_wait = false,
-                                   ulong lock_wait_timeout = 0);
+                                   ulonglong lock_wait_timeout = 0);
 
   /**
     @brief Acquire IX or SR MDL on the Logfile Group
@@ -195,7 +195,7 @@ class Ndb_dd_client {
   */
   bool mdl_lock_logfile_group_exclusive(const char *logfile_group_name,
                                         bool custom_lock_wait = false,
-                                        ulong lock_wait_timeout = 0);
+                                        ulonglong lock_wait_timeout = 0);
 
   /**
     @brief Acquire IX or SR MDL on the tablespace
@@ -220,7 +220,7 @@ class Ndb_dd_client {
   */
   bool mdl_lock_tablespace_exclusive(const char *tablespace_name,
                                      bool custom_lock_wait = false,
-                                     ulong lock_wait_timeout = 0);
+                                     ulonglong lock_wait_timeout = 0);
 
   // Transaction handling functions
   void commit();