Oracle中的Parallel Execution 和有用的view


默认是parallel_max_servers是大于0的 也就是打开的

alter session enable parallel [ddl | dml | query];
alter session disable parallel [ddl | dml | query];
alter session force parallel ddl parallel 5;

用来分析DB性能的几个view.

V$PROCESS
Contains information about the currently active processes

V$SESSION
Lists session information for each current session

V$SESS_IO
Contains I/O statistics for each user session

V$SESSION_LONGOPS
Displays the status of various operations that run for longer than 6 seconds (in absolute time). These operations currently include many backup and recovery functions, statistics gathering, and query execution. More operations are added for every Oracle Database release.

V$SESSION_WAIT
Displays the current or last wait for each session

V$SESSION_WAIT_HISTORY
Lists the last ten wait events for each active session

V$WAIT_CHAINS
Displays information about blocked sessions

V$SYSSTAT
Contains session statistics

V$RESOURCE_LIMIT
Provides information about current and maximum global resource utilization for some system resources

V$SQLAREA
Contains statistics about shared SQL areas. Contains one row for each SQL string. Provides statistics about SQL statements that are in memory, parsed, and ready for execution