Adding high_priority syntax in DDL commands

Summary:
This diff introduces `HIGH_PRIORITY` syntax in some DDL commands and optimize
command. The purpose is the same as the system variable `high_priority_ddl`
which is described in D4784076.

The list of commands that support `HIGH_PRIORITY` syntax is:
- create/drop/alter/truncate table
- create/drop index
- create/drop trigger
- optimize table

With this diff, there are two ways of issuing high priority DDLs:
  e.g. `CREATE HIGH_PRIORITY INDEX ...`

Recap of the high_priority ddl feature:

- Only the shared locks (read/write) will be affected, which are DML queries
  such as select, insert, update, etc. Any lock higher than upgradable MDL
  (i.e. from conflicting DDL) will not be affected.
- When killing the blocking connections, their transactions will automatically
  be rolled back. This is the same behavior as `kill processlist_id` command.
- The DDL will kill blocking connections at the end of the timeout instead of
  instantly. Admin can control the waiting period by setting the session
  lock_wait_timeout before issuing the DDL.

Reviewed By: abhinav04sharma

Differential Revision: D5635549

fbshipit-source-id: e51ed02

mysql-test/include/ddl_high_priority.inc

@@ -0,0 +1,174 @@
+###############################################################################
+# Common test file for high priority DDL
+###############################################################################
+
+
+create user test_user1@localhost;
+grant all on test to test_user1@localhost;
+create user test_user2@localhost;
+grant all on test to test_user2@localhost;
+
+# Default values
+--let $con_block = con1
+--let $con_kill = default
+--let $should_kill = 1
+--let $recreate_table = 1
+--let $throw_error = 1
+
+##
+## killing conflicting shared locks by alter table
+##
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = alter table t1 modify i bigint;
+--let $high_priority_cmd = alter high_priority table t1 modify i bigint;
+
+--source include/ddl_high_priority_module.inc
+
+##
+## killing conflicting shared lock in a transaction
+## transaction will rollback
+##
+
+--let $blocking_sql = begin; insert into t1 values (4); select i from t1;
+--let $cmd = alter table t1 rename t1_new;
+--let $high_priority_cmd = alter high_priority table t1 rename t1_new;
+
+--source include/ddl_high_priority_module.inc
+
+select * from t1_new;
+drop table t1_new;
+
+##
+## simulate conflicting DDL which will not be killed
+##
+
+# Simulate conflicting DDL
+# This will hold MDL_SHARED_NO_READ_WRITE, which may be upgraded to exclusive
+# locks to run DDLs like ALTER TABLE
+# the upgradable/exclusive lock should not be killed
+
+--let $should_kill = 0
+
+--let $blocking_sql = lock tables t1 write;
+--let $cmd = drop table t1;
+--let $high_priority_cmd = drop high_priority table t1;
+
+--source include/ddl_high_priority_module.inc
+
+# restore $should_kill
+--let $should_kill = 1
+
+##
+## killing conflicting transaction by drop table DDL
+##
+
+--let $blocking_sql = lock tables t1 read; begin; insert into t1 values (4);
+--let $cmd = drop table t1;
+--let $high_priority_cmd = drop high_priority table t1;
+
+--source include/ddl_high_priority_module.inc
+
+##
+## no effect for regular users
+##
+
+connect (con2,localhost,test_user2,,test,,);
+# $con_kill is regular user
+--let $con_kill = con2
+--let $should_kill = 0
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = alter table t1 modify i bigint;
+--let $high_priority_cmd = alter high_priority table t1 modify i bigint;
+
+--source include/ddl_high_priority_module.inc
+
+disconnect con2;
+
+# restore $con_kill
+--let $con_kill = default
+# restore $should_kill
+--let $should_kill = 1
+
+##
+## create/drop index
+##
+
+# create index
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = create index idx1 on t1 (i);
+--let $high_priority_cmd = create high_priority index idx1 on t1 (i);
+
+--source include/ddl_high_priority_module.inc
+
+# drop index (use the previously created table)
+--let $recreate_table = 0
+
+--let $cmd = drop index idx1 on t1;
+--let $high_priority_cmd = drop high_priority index idx1 on t1;
+
+--source include/ddl_high_priority_module.inc
+
+# restore $recreate_table
+--let $recreate_table = 1
+
+##
+## high_priority truncate table
+##
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = truncate t1;
+--let $high_priority_cmd = truncate high_priority t1;
+
+--source include/ddl_high_priority_module.inc
+
+##
+## high_priority create/drop trigger
+##
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = create trigger ins_sum before insert on t1 for each row set @sum = @sum + new.i;
+--let $high_priority_cmd = create high_priority trigger ins_sum before insert on t1 for each row set @sum = @sum + new.i;
+
+--source include/ddl_high_priority_module.inc
+
+# drop trigger (use the previously created table)
+--let $recreate_table = 0
+
+--let $cmd = drop trigger ins_sum;
+--let $high_priority_cmd = drop high_priority trigger ins_sum;
+
+--source include/ddl_high_priority_module.inc
+
+# restore $recreate_table
+--let $recreate_table = 1
+
+##
+## high_priority optimize table
+##
+## "optimize table" doesn't throw errors. It catches all errors, and
+## returns a result set in a table
+##
+
+--let $throw_error = 0
+
+--let $blocking_sql = lock tables t1 read;
+--let $cmd = optimize table t1;
+--let $high_priority_cmd = optimize high_priority table t1;
+
+--source include/ddl_high_priority_module.inc
+
+# restore throw_error
+--let $throw_error = 1
+
+##
+## clean up
+##
+
+drop user test_user1@localhost;
+drop user test_user2@localhost;
+--disable_warnings
+drop table if exists t1;
+--enable_warnings

mysql-test/include/ddl_high_priority_module.inc

@@ -0,0 +1,140 @@
+###############################################################################
+# This file plays as a function/module for ddl_high_priority test
+#
+# Usage: set the following variables before including
+#
+#       $use_sys_var: whether using sys_var or syntax to trigger high_priority
+#              value: 0/1
+#
+#         $con_block: a blocking connection
+#              value: con1/con2/default
+#
+#          $con_kill: a connection that will attempt to kill $con_blocking
+#              value: con1/con2/default
+#
+#               $cmd: a regular command to evaluate (to use with sys var)
+#              value: sql command
+#
+# $high_priority_cmd: a high_priority command to evaluate
+#              value: sql command
+#
+#       $should_kill: Expect the con_block to be killed or not
+#              value: 0/1
+#
+#    $recreate_table: Should recreate the test table or not
+#              value: 0/1
+#
+#       $throw_error: whether a command will throw lock_wait_timeout error.
+#                     Note, optimize table catches all errors.
+#              value: 0/1
+###############################################################################
+
+##
+## Print out the parameters of the test set
+## (useful for debugging)
+##
+--echo
+--echo ## Test parameters:
+--echo ## use_sys_var       = $use_sys_var
+--echo ## con_block         = $con_block
+--echo ## con_kill          = $con_kill
+--echo ## cmd               = $cmd
+--echo ## high_priority_cmd = $high_priority_cmd
+--echo ## should_kill       = $should_kill
+--echo ## recreate_table    = $recreate_table
+--echo ## throw_error       = $throw_error
+--echo
+
+
+##
+## Setup
+##
+
+connection default;
+
+# create con1
+connect (con1,localhost,test_user1,,test,,);
+
+if ($recreate_table) {
+  # create t1
+  --disable_warnings
+  drop table if exists t1;
+  --enable_warnings
+  create table t1 (i int);
+  show create table t1;
+  insert into t1 values (1), (2), (3);
+}
+
+##
+## Testing
+##
+
+--echo connection: $con_block
+--connection $con_block
+--eval $blocking_sql
+
+--echo connection: $con_kill
+--connection $con_kill
+set lock_wait_timeout = 0.02;
+
+describe t1;
+
+--echo connection: default (for show processlist)
+connection default;
+--echo # both $con_block and $con_kill exist
+--replace_column 1 <Id> 3 <Host> 5 <Command> 6 <Time> 7 <State> 8 <Info> 9 <RExam> 10 <RSent> 11 <TID>
+show processlist;
+
+--echo connection: $con_kill
+--connection $con_kill
+
+# command will fail without high_priority
+if ($throw_error) {
+  --error ER_LOCK_WAIT_TIMEOUT
+  --eval $cmd
+}
+
+if (!$throw_error) {
+  --eval $cmd
+}
+
+if ($use_sys_var) {
+  set high_priority_ddl = 1;
+  select @@high_priority_ddl;
+
+  # non-supported command will timeout
+  --error ER_LOCK_WAIT_TIMEOUT
+  lock tables t1 write;
+
+  if (!$should_kill) {
+    # regular user ddl will fail regardless of high_priority_ddl being on
+    --error ER_LOCK_WAIT_TIMEOUT
+    --eval $cmd
+  }
+
+  if ($should_kill) {
+    --eval $cmd
+  }
+
+  # reset high_priority_ddl
+  set high_priority_ddl = 0;
+}
+
+if (!$use_sys_var) {
+  if (!$should_kill) {
+    # regular user ddl will fail regardless of high_priority being on
+    --error ER_LOCK_WAIT_TIMEOUT
+    --eval $high_priority_cmd
+  }
+
+  if ($should_kill) {
+    --eval $high_priority_cmd
+  }
+}
+
+--echo connection: default (for show processlist)
+connection default;
+--replace_column 1 <Id> 3 <Host> 5 <Command> 6 <Time> 7 <State> 8 <Info> 9 <RExam> 10 <RSent> 11 <TID>
+show processlist;
+
+disconnect con1;

mysql-test/include/rpl_ddl_high_priority.inc

@@ -0,0 +1,71 @@
+###############################################################################
+# Test replication of the high_priority syntax
+###############################################################################
+
+
+--source include/master-slave.inc
+
+--let $rpl_connection_name= slave_block
+--let $rpl_server_number= 2
+--source include/rpl_connect.inc
+
+connection master;
+
+# create t1
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+create table t1 (i int);
+show create table t1;
+insert into t1 values (1), (2), (3);
+
+sync_slave_with_master;
+
+--echo connection slave
+connection slave;
+select * from t1;
+
+let $sql_thread=`select id from information_schema.processlist where state
+ like 'Slave has read all relay log; waiting for the slave I/O thread%'`;
+let $worker_thread=`select id from information_schema.processlist where state
+ like 'Waiting for%'`;
+
+--echo # set slave thread's lock_wait_timeout to a small value
+
+--replace_regex /session [0-9]*/session sql_thread/
+--eval set session $sql_thread lock_wait_timeout = 0.2
+
+--replace_regex /session [0-9]*/session sql_thread/
+--eval show session $sql_thread variables like 'lock_wait_timeout'
+
+--echo connection slave_block
+connection slave_block;
+
+# issue a bloking read from slave_block connection
+lock tables t1 read;
+
+--echo connection master;
+connection master;
+
+# issue a high_pri command from master
+create high_priority index idx1 on t1 (i);
+show create table t1;
+
+# sync
+sync_slave_with_master;
+
+--echo connection slave;
+connection slave;
+
+# the high_pri ddl replication should go through
+show create table t1;
+
+
+##
+## clean up
+##
+
+connection master;
+drop table t1;
+
+source include/rpl_end.inc;