MDEV-24395 Atomic DROP TRIGGER

The purpose of this task is to ensure that DROP TRIGGER is atomic.

Description of how atomic drop trigger works:

Logging of DROP TRIGGER
    Log the following information:
    db
    table name
    trigger name
    xid /* Used to check if query was already logged to binary log */
    initial length of the .TRG file
    query if there is space for it, if not log a zero length query.

Recovery operations:
- Delete if exists 'database/trigger_name.TRN~'
  - If this file existed, it means that we crashed before the trigger
    was deleted and there is nothing else to do.
- Get length of .TRG file
  - If file length is unchanged, trigger was not dropped. Nothing else to
    do.
- Log original query to binary, if it was stored in the ddl log. If it was
  not stored (long query string), log the following query to binary log:
  use `database` ; DROP TRIGGER IF EXISTS `trigger_name`
  /* generated by ddl log */;

Other things:
- Added trigger name and DDL_LOG_STATE to drop_trigger()
  Trigger name was added to make the interface more consistent and
  more general.

2 files changed, 172 insertions, 0 deletions

diff --git a/mysql-test/suite/atomic/drop_trigger.result b/mysql-test/suite/atomic/drop_trigger.result
new file mode 100644
index 00000000000..265f06f31ed
--- /dev/null
+++ b/mysql-test/suite/atomic/drop_trigger.result
@@ -0,0 +1,49 @@
+"engine: aria  crash point: ddl_log_drop_before_drop_trigger  position: 1"
+t1.TRG
+t1_trg.TRN
+t2_trg.TRN
+"engine: aria  crash point: ddl_log_drop_before_drop_trigger  position: 2"
+t1.TRG
+t2_trg.TRN
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+"engine: aria  crash point: ddl_log_drop_before_drop_trn  position: 1"
+t1.TRG
+t2_trg.TRN
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+"engine: aria  crash point: ddl_log_drop_before_drop_trn  position: 2"
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t2_trg /* some comment */
+"engine: aria  crash point: ddl_log_drop_after_drop_trigger  position: 1"
+t1.TRG
+t2_trg.TRN
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+"engine: aria  crash point: ddl_log_drop_after_drop_trigger  position: 2"
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t2_trg /* some comment */
+"engine: aria  crash point: definition_file_after_create  position: 1"
+t1.TRG
+t1_trg.TRN
+t2_trg.TRN
+"engine: aria  crash point: definition_file_after_create  position: 2"
+"No crash!"
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t2_trg /* some comment */
+"engine: aria  crash point: ddl_log_drop_before_binlog  position: 1"
+t1.TRG
+t2_trg.TRN
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+"engine: aria  crash point: ddl_log_drop_before_binlog  position: 2"
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+master-bin.000002	#	Query	#	#	use `test`; DROP TRIGGER t2_trg /* some comment */
+"engine: aria  crash point: ddl_log_drop_after_binlog  position: 1"
+t1.TRG
+t2_trg.TRN
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+"engine: aria  crash point: ddl_log_drop_after_binlog  position: 2"
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t1_trg
+master-bin.000001	#	Query	#	#	use `test`; DROP TRIGGER t2_trg /* some comment */
+
+# Test deleting not existing trigger
+#
+Warnings:
+Note	1360	Trigger does not exist
diff --git a/mysql-test/suite/atomic/drop_trigger.test b/mysql-test/suite/atomic/drop_trigger.test
new file mode 100644
index 00000000000..24c44cd2f2a
--- /dev/null
+++ b/mysql-test/suite/atomic/drop_trigger.test
@@ -0,0 +1,123 @@
+--source include/have_debug.inc
+--source include/have_log_bin.inc
+--source include/not_valgrind.inc
+
+#
+# Testing of atomic drop with crashes in a lot of different places
+#
+
+let $MYSQLD_DATADIR= `SELECT @@datadir`;
+
+let long_comment=`select repeat('a',16384)`;
+let $engine_count=1;
+let $engines='aria';
+
+let $crash_count=6;
+let $crash_points='ddl_log_drop_before_drop_trigger', 'ddl_log_drop_before_drop_trn','ddl_log_drop_after_drop_trigger', 'definition_file_after_create', 'ddl_log_drop_before_binlog', 'ddl_log_drop_after_binlog';
+
+# Number of drops in the tested statement
+let $drops=2;
+
+let $old_debug=`select @@debug_dbug`;
+
+let $e=0;
+let $keep_include_silent=1;
+let $grep_script=DROP TRIGGER;
+--disable_query_log
+
+while ($e < $engine_count)
+{
+  inc $e;
+  let $engine=`select ELT($e, $engines)`;
+  let $default_engine=$engine;
+  let $extra_option=;
+
+  if ($engine == "aria")
+  {
+    let $extra_option=transactional=1;
+  }
+  if ($engine == "aria_notrans")
+  {
+    let $default_engine="aria";
+    let $extra_option=transactional=0;
+  }
+  let $c=0;
+  while ($c < $crash_count)
+  {
+    inc $c;
+    let $crash=`select ELT($c, $crash_points)`;
+    let $r=0;
+    while ($r < $drops)
+    {
+      inc $r;
+
+      --eval set @@default_storage_engine=$default_engine
+      --eval create table t1 (a int not null, b int not null) $extra_option;
+      insert into t1 values(1,1);
+      flush tables;
+      delimiter |;
+      create trigger t1_trg before insert on t1 for each row
+      begin
+        if isnull(new.a) then
+          set new.a:= 1000;
+        end if;
+      end|
+      create trigger t2_trg before insert on t1 for each row
+      begin
+        if isnull(new.b) then
+          set new.b:= 2000;
+        end if;
+      end|
+      delimiter ;|
+
+      RESET MASTER;
+
+      echo "engine: $engine  crash point: $crash  position: $r";
+      --exec echo "restart" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+      --disable_reconnect
+      --eval set @@debug_dbug="+d,$crash",@debug_crash_counter=$r
+      let $errno=0;
+      let $crashed=1;
+      --error 0,2013
+      DROP TRIGGER t1_trg;
+      let $error=$errno;
+      if ($error == 0)
+      {
+        --error 0,2013
+        --eval DROP TRIGGER t2_trg /* $long_comment */;
+        let $error=$errno;
+      }
+      --enable_reconnect
+      --source include/wait_until_connected_again.inc
+      --disable_query_log
+      --eval set @@debug_dbug="$old_debug"
+
+      if ($error == 0)
+      {
+        echo "No crash!";
+      }
+      # Check which tables still exists
+      --list_files $MYSQLD_DATADIR/test *TR*
+
+      --let $binlog_file=master-bin.000001
+      --source include/show_binlog_events.inc
+      if ($error)
+      {
+        --let $binlog_file=master-bin.000002
+        --source include/show_binlog_events.inc
+      }
+      --disable_warnings
+      drop table if exists t1;
+      --enable_warnings
+    }
+    let long_comment=some comment;
+  }
+}
+
+--echo
+--echo # Test deleting not existing trigger
+--echo #
+
+drop trigger if exists `t1_trg`;
+
+--enable_query_log