See Also change buffer, change buffering.  The technique of storing changes to secondary index pages, resulting from  INSERT  operations, in the  change buffer  rather than writing the changes immediately, so that the physical writes can be performed to minimize random I/O. It is one of the types of  change buffering ; the others are  delete buffering  and  purge buffering . Insert buffering is not used if the secondary index is  unique , because the uniqueness of new values cannot be verified before the new entries are written out. Other kinds of change buffering do work for unique indexes. See Also change buffer, change buffering, delete buffering, insert buffer, purge buffering, unique index.  A type of  gap lock  that is set by  INSERT  operations prior to row insertion. This type of  lock  signals the intent to insert in such a way that multiple transactions inserting into the same index gap need not wait for each other if they are not inserting at the same position within the gap. For more information, see Section 15.7.1, “InnoDB Locking” . See Also gap lock, lock, next-key lock.  A single  mysqld  daemon managing a  data directory  representing one or more  databases  with a set of  tables . It is common in development, testing, and some  replication  scenarios to have multiple instances on the same server  machine, each managing its own data directory and listening on its own port or socket. With one instance running a  disk-bound  workload, the server might still have extra CPU and memory capacity to run additional instances. See Also data directory, database, disk-bound, mysqld, replication, server, table.  Modifications at the source code level to collect performance data for tuning and debugging. In MySQL, data collected by instrumentation is exposed through an SQL interface using the  INFORMATION_SCHEMA  and PERFORMANCE_SCHEMA  databases. See Also INFORMATION_SCHEMA, Performance Schema. See intention lock.  A kind of  lock  that applies to the table, used to indicate the kind of lock the  transaction  intends to acquire on rows in the table. Different transactions can acquire different kinds of intention locks on the same table, but the first transaction to acquire an  intention exclusive  (IX) lock on a table prevents other transactions from acquiring any S or X locks on the table. Conversely, the first transaction to acquire an  intention shared  (IS) lock on a table prevents other transactions from acquiring any X locks on the table. The two-phase process allows the lock requests to be resolved in order, without blocking locks and corresponding operations that are compatible. For more information about this locking mechanism, see Section 15.7.1, “InnoDB Locking” . See Also lock, lock mode, locking, transaction. See intention lock.  Code for instrumenting or debugging some aspect of an application, which can be enabled without recompiling or changing the source of the application itself. See Also command interceptor, Connector/J, Connector/NET, exception interceptor.  An optimized internal  InnoDB  temporary table used by the  optimizer . See Also optimizer. 6161 insert buffering insert intention lock instance instrumentation intention exclusive lock intention lock intention shared lock interceptor intrinsic temporary table