Monitor elements

Monitor elements are data structures used to store information about a particular aspect of the database system status. For example, the monitor element direct_reads reflects the number of read operations that take place that are performed directly from disk, rather than from any buffer pool.

Each monitor element reflects one of the following types of data:
Counters track the number of times something happens. For example, the deadlocks monitor element records the total number of deadlocks that have occurred. Other examples of counters include commit_sql_stmts (commit statements attempted), rows_deleted and total_sorts.
Gauges reflect a measurement of how much of something is happening or is used. For example, time-spent monitor elements, such as total_section_proc_time or total_sort_time are measures of how much time is used in different phases of processing. Other examples of gauges include: locks_held, num_extent_moved, and sort_heap_allocated. Compared to counters, which can only increase over time, the values in gauges might go up or down, depending on what is happening in the database.
Watermarks reflect the highest value reached for a given measurement. For example, uow_total_time_top shows the lifetime of the longest-running unit of work since the database was activated. Other examples of watermarks include: pkg_cache_size_top, and sort_heap_top.
Many monitor elements report text values. For example, stmt_text contains the text of an SQL statement. Other examples of text monitor elements include: table_name, tablespace_type, and db_storage_path_state.
Timestamp monitor elements show the time that something happened. For example, conn_time shows the time that a connection was made to a database. Other examples of timestamp monitor elements include: lock_wait_start_time stmt_first_use_time, and uow_stop_time. Compared to gauges that measure elapsed time, timestamps measure the exact point in time that something begins or ends.

You can examine monitor elements by using monitoring interfaces such as table functions or event monitors.