semi-consistent read
A type of read operation used for UPDATE
statements, that is a combination of read committed and consistent read. When an UPDATE
statement examines a row that is already locked, InnoDB returns the latest committed version to MariaDB so that MariaDB can determine whether the row matches the WHERE
condition of the UPDATE
. If the row matches (must be updated), MariaDB reads the row again, and this time InnoDB either locks it or waits for a lock on it. This type of read operation can only happen when the transaction has the read committed isolation level, or when the innodb-locks-unsafe_for_binlog
option is enabled.
See also consistent read.
See also isolation level.
See also READ COMMITTED.