[Maria-discuss] Aria table with auto increment PK - no concurrent inserts?

Hello, Aria FAQ says: "Multiple concurrent inserters into the same table." However, if I create a table with autoincrement PK, ENGINE=Aria ROW_FORMAT=PAGE (tried also TRANSACTIONAL=1) then there is no concurrency - only 1 thread is working, others are stuck in "Waiting for table level lock". I couldn't find the exact description of Aria engine behaviour in docs/faq/discussions - is it the way it's supposed to be? Thank you!