See Also optimizer, temporary table, temporary tablespace.  A kind of  lock  that allows other  transactions  to read the locked object, and to also acquire other shared locks on it, but not to write to it. The opposite of  exclusive lock . See Also exclusive lock, lock, transaction.  Another way of referring to the  system tablespace  or a  general tablespace . General tablespaces were introduced in MySQL 5.7. More than one table can reside in a shared tablespace. Only a single table can reside in a  file-per-table  tablespace. See Also general tablespace, system tablespace.  The process of  flushing  to disk all  dirty  buffer pool pages whose redo entries are contained in certain portion of the  redo log . Occurs before  InnoDB  reuses a portion of a log file; the log files are used in a circular fashion. Typically occurs with write-intensive  workloads . See Also dirty page, flush, redo log, workload.  The process of stopping the MySQL server. By default, this process cleans up operations for  InnoDB  tables, so InnoDB  can be  slow  to shut down, but fast to start up later. If you skip the cleanup operations, it is  fast  to shut down but the cleanup must be performed during the next restart. The shutdown mode for  InnoDB  is controlled by the  innodb_fast_shutdown  option. See Also fast shutdown, InnoDB, slow shutdown, startup. See replica.  A type of  log  used for performance tuning of SQL statements processed by the MySQL server. The log information is stored in a file. You must enable this feature to use it. You control which categories of “slow”  SQL statements are logged. For more information, see Section 5.4.5, “The Slow Query Log” . See Also general query log, log.  A type of  shutdown  that does additional  InnoDB  flushing operations before completing. Also known as a clean shutdown . Specified by the configuration parameter  innodb_fast_shutdown=0  or the command  SET GLOBAL innodb_fast_shutdown=0; . Although the shutdown itself can take longer, that time should be saved on the subsequent startup. See Also clean shutdown, fast shutdown, shutdown.  A representation of data at a particular time, which remains the same even as changes are  committed  by other transactions . Used by certain  isolation levels  to allow  consistent reads . See Also commit, consistent read, isolation level, transaction.  The buffer used for sorting data during creation of an  InnoDB  index. Sort buffer size is configured using the innodb_sort_buffer_size  configuration option.  A database server machine in a  replication  scenario that processes the initial insert, update, and delete requests for data. These changes are propagated to, and repeated on, other servers known as  replicas . See Also replica, replication. 6187 source sort buffer snapshot slow shutdown slow query log slave shutdown sharp checkpoint shared tablespace shared lock