Precise for Oracle can monitor real database performance with incredibly low overhead. In fact, we rarely even use a connection to the database, yet we still gather performance data on a sub-second . How is this possible?
For every Oracle instance, there is a structure called the System Global Area (SGA). This structure holds information about SQL statements, cached data, wait events, and other shared resources. At the operating system level, this SGA is just a multi-gigabyte block of shared memory. Processes such as Oracle listeners or other daemons, attach to this shared memory block. In a RAC environment, each Oracle instance running on its own server has its own processes and SGA.
The SGA is the key to how Precise monitors Oracle. Instead of connecting to the database and executing SQL to read tables and views, Precise is simply an operating system process that attaches to and reads a big block of shared memory. Because we understand the SGA architecture, Precise can record performance data on statements, wait events, execution plans, and other shared resources, all without connecting to the database or running a single SQL statement.
Oracle doesn’t even know we’re there. In fact, in rare cases where system tables are locked, listeners are unavailable, or other catastrophic failure, Precise will continue to collect and report on Oracle database performance. In an actual case, a user had somehow locked a system table and stopped parsing of all SQL statements, effectively locking out hundreds of real-time users. Precise, because it is only reading memory and not running SQL, quickly identified the problematic statement. The DBAs, who were using Precise as a real-time monitor of database performance, used that information to end the session, released the latch, and the database was working again all within 90 seconds. The problem was fixed so quickly that it wasn’t until minutes later that the DBAs started getting notifications from the helpdesk that the application was down.
Any other solution that required running SQL statements to gather performance data would have been locked out of the database, eventually requiring a 20+ minute reboot.
Precise for Oracle is engineered to have incredibly low overhead and impact on your database while providing a wealth of information about real users, statements, tables, statistics, and other performance data. We invite you to visit https://www.idera.com/productssolutions/oracle-database-solutions to look at our solutions. We would be happy to give you a demo and help you install Precise for Oracle in your environment for your evaluation.