Hi, all

   Today,   we use optimize table in MariaDB 10.1.16.

    Table test01 have about 2 millions records. 

session 1:  optimize table test01;

session 2:  select count(*) from test01 ;

when session 1 run,   In processlist session 2 state:  Waiting FOR TABLE LEVEL LOCK

    we had set innodb_defragment=1 in my.cnf ,but run optimize table still have table lock？

reference link:　　https://mariadb.com/kb/en/mariadb/defragmenting-innodb-tablespaces/