Fix bug# 18274 InnoDB auto_increment field reset on OPTIMIZE TABLE

OPTIMIZE TABLE recreates the whole table. That is why the counter gets reset.
Making the next autoinc column persistent is a separate issue from resetting
the value after an OPTIMIZE TABLE. We already have a check for ALTER TABLE
and CREATE INDEX to preserve the value on table recreate. We should be able to
add an additional check for OPTIMIZE TABLE to preserve the next value.

rb://519 Approved by Jimmy Yang.

mysql-test/suite/innodb_plugin/r/innodb-autoinc-18274.result

+drop table if exists t1;
+SET @@SESSION.AUTO_INCREMENT_INCREMENT=1, @@SESSION.AUTO_INCREMENT_OFFSET=1;
+CREATE TABLE t1 (c1 INT PRIMARY KEY AUTO_INCREMENT) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (null);
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`c1`)
+) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1
+DELETE FROM t1;
+OPTIMIZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	optimize	note	Table does not support optimize, doing recreate + analyze instead
+test.t1	optimize	status	OK
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`c1`)
+) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1
+INSERT INTO t1 VALUES(null);
+SELECT * FROM t1;
+c1
+2
+DROP TABLE t1;

mysql-test/suite/innodb_plugin/t/innodb-autoinc-18274.test

+-- source include/have_innodb_plugin.inc
+# embedded server ignores 'delayed', so skip this
+-- source include/not_embedded.inc
+
+let $innodb_file_format_check_orig=`select @@innodb_file_format_check`;
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+#
+# Bug #18274	InnoDB auto_increment field reset on OPTIMIZE TABLE
+SET @@SESSION.AUTO_INCREMENT_INCREMENT=1, @@SESSION.AUTO_INCREMENT_OFFSET=1;
+CREATE TABLE t1 (c1 INT PRIMARY KEY AUTO_INCREMENT) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (null);
+SHOW CREATE TABLE t1;
+DELETE FROM t1;
+OPTIMIZE TABLE t1;
+SHOW CREATE TABLE t1;
+INSERT INTO t1 VALUES(null);
+SELECT * FROM t1;
+DROP TABLE t1;
+
+#
+# restore environment to the state it was before this test execution
+#
+
+-- disable_query_log
+eval set global innodb_file_format_check=$innodb_file_format_check_orig;

storage/innodb_plugin/handler/ha_innodb.cc

@@ -6808,23 +6808,25 @@ ha_innobase::create(
 	setup at this stage and so we use thd. */
 
 	/* We need to copy the AUTOINC value from the old table if
-	this is an ALTER TABLE or CREATE INDEX because CREATE INDEX
-	does a table copy too. */
+	this is an ALTER|OPTIMIZE TABLE or CREATE INDEX because CREATE INDEX
+	does a table copy too. If query was one of :
 
-	if (((create_info->used_fields & HA_CREATE_USED_AUTO)
-	    || thd_sql_command(thd) == SQLCOM_ALTER_TABLE
-	    || thd_sql_command(thd) == SQLCOM_CREATE_INDEX)
-	    && create_info->auto_increment_value > 0) {
-
-		/* Query was one of :
 		CREATE TABLE ...AUTO_INCREMENT = x; or
 		ALTER TABLE...AUTO_INCREMENT = x;   or
+		OPTIMIZE TABLE t; or
 		CREATE INDEX x on t(...);
+
 	Find out a table definition from the dictionary and get
 	the current value of the auto increment field. Set a new
 	value to the auto increment field if the value is greater
 	than the maximum value in the column. */
 
+	if (((create_info->used_fields & HA_CREATE_USED_AUTO)
+	    || thd_sql_command(thd) == SQLCOM_ALTER_TABLE
+	    || thd_sql_command(thd) == SQLCOM_OPTIMIZE
+	    || thd_sql_command(thd) == SQLCOM_CREATE_INDEX)
+	    && create_info->auto_increment_value > 0) {
+
 		auto_inc_value = create_info->auto_increment_value;
 
 		dict_table_autoinc_lock(innobase_table);