connect con1, localhost, root;
CREATE TABLE t(a INT PRIMARY KEY) ENGINE=InnoDB;
INSERT INTO t VALUES(1);
BEGIN;
INSERT INTO t VALUES(2);
DELETE FROM t WHERE a=2;
connection default;
# Normal MariaDB shutdown would roll back the above transaction.
# We want the transaction to remain open, so we will kill the server
# after ensuring that any non-transactional files are clean.
FLUSH TABLES;
# Ensure that the above incomplete transaction becomes durable.
SET GLOBAL innodb_flush_log_at_trx_commit=1;
BEGIN;
INSERT INTO t VALUES(0);
DELETE FROM t WHERE a=0;
COMMIT;
# restart: --innodb-force-recovery=3
disconnect con1;
SELECT * FROM t;
a
1
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
SELECT * FROM t;
a
1
UPDATE t SET a=3 WHERE a=1;
# restart: --innodb-read-only
# Starting with MariaDB 10.2, innodb_read_only implies READ UNCOMMITTED.
# In earlier versions, this would return the last committed version
# (empty table)!
SHOW VARIABLES LIKE "innodb_read_only";
Variable_name	Value
innodb_read_only	ON
SELECT * FROM t;
a
3
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
SELECT * FROM t;
a
3
SET GLOBAL innodb_max_purge_lag_wait=0;
INSERT INTO mysql.innodb_index_stats
SELECT * FROM mysql.innodb_index_stats LIMIT 0;
Test Temp tablespace truncate in read only mode
SET GLOBAL innodb_truncate_temporary_tablespace_now=1;
# restart
SELECT * FROM t;
a
3
DROP TABLE t;