MDEV-33169 Reset sequence used fields after check in alter sequence

The bitmap is temporarily flipped to ~0 for the sake of checking all
fields. It needs to be restored because it will be reused in second
and subsequent ps execution.

mysql-test/suite/sql_sequence/alter.result

@@ -252,3 +252,52 @@ SELECT NEXTVAL(s);
 NEXTVAL(s)
 1
 DROP SEQUENCE s;
+#
+# MDEV-33169 Alter sequence 2nd ps fails while alter sequence 2nd time (no ps) succeeds
+#
+create sequence s;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+alter sequence s maxvalue 123;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+alter sequence s maxvalue 123;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+drop sequence s;
+create sequence s;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+prepare stmt from 'alter sequence s maxvalue 123';
+execute stmt;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+execute stmt;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+deallocate prepare stmt;
+drop sequence s;
+create sequence s;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+create procedure p() alter sequence s maxvalue 123;
+call p;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+call p;
+show create sequence s;
+Table	Create Table
+s	CREATE SEQUENCE `s` start with 1 minvalue 1 maxvalue 123 increment by 1 cache 1000 nocycle ENGINE=MyISAM
+drop procedure p;
+drop sequence s;
+#
+# End of 10.4 tests
+#

mysql-test/suite/sql_sequence/alter.test

@@ -167,3 +167,38 @@ ALTER TABLE s ORDER BY cache_size;
 SELECT NEXTVAL(s);
 DROP SEQUENCE s;
 --enable_ps2_protocol
+
+--echo #
+--echo # MDEV-33169 Alter sequence 2nd ps fails while alter sequence 2nd time (no ps) succeeds
+--echo #
+create sequence s;
+show create sequence s;
+alter sequence s maxvalue 123;
+show create sequence s;
+alter sequence s maxvalue 123;
+show create sequence s;
+drop sequence s;
+
+create sequence s;
+show create sequence s;
+prepare stmt from 'alter sequence s maxvalue 123';
+execute stmt;
+show create sequence s;
+execute stmt;
+show create sequence s;
+deallocate prepare stmt;
+drop sequence s;
+
+create sequence s;
+show create sequence s;
+create procedure p() alter sequence s maxvalue 123;
+call p;
+show create sequence s;
+call p;
+show create sequence s;
+drop procedure p;
+drop sequence s;
+
+--echo #
+--echo # End of 10.4 tests
+--echo #

sql/sql_sequence.cc

@@ -924,6 +924,7 @@ bool Sql_cmd_alter_sequence::execute(THD *thd)
   TABLE_LIST *first_table= lex->query_tables;
   TABLE *table;
   sequence_definition *new_seq= lex->create_info.seq_create_info;
+  uint saved_used_fields= new_seq->used_fields;
   SEQUENCE *seq;
   No_such_table_error_handler no_such_table_handler;
   DBUG_ENTER("Sql_cmd_alter_sequence::execute");
@@ -1043,5 +1044,6 @@ bool Sql_cmd_alter_sequence::execute(THD *thd)
     my_ok(thd);
 
 end:
+  new_seq->used_fields= saved_used_fields;
   DBUG_RETURN(error);
 }