This parameter specifies the interval (in seconds) at which Oracle collects operating statistics. Statistics are only collected when a request is made from the client to the server, or when a request completes.
Version | Type | Default | Session Modifiable |
System Modifiable |
8.0.4 | Integer | 0 | Yes | Immediate |
8.0.5 | Integer | 0 | Yes | Immediate |
8.0.6 | Integer | 0 | Yes | Immediate |
8.1.5 | Integer | 0 | Yes | Immediate |
8.1.6 | Integer | 0 | Yes | Immediate |
8.1.7 | Integer | 0 | Yes | Immediate |
9.0.1 | Integer | 0 | Yes | Immediate |
9.2.0 | Integer | 0 | Yes | Immediate |
When TIMED_OS_STATISTICS is enabled statistics are collected as follows:
The default value of zero specifies that operating system statistics are not gathered.
On older systems gathering operating system statistics was very expensive and Oracle recommended:
The parameter can be set in the initialisation file e.g.
timed_os_statistics = 30
This parameter can be set at system level e.g.
ALTER SYSTEM SET timed_os_statistics = 30
This parameter can be set at session level e.g.
ALTER SESSION SET timed_os_statistics = 0
This parameter is apparently not supported on Windows NT or Windows 2000.
Operating system (OS) statistics belong to statistics class 16 (see V$STATNAME.CLASS)
In Oracle 8.0.4 and above the value of TIMED_OS_STATISTICS is the number of seconds
In Oracle 7.3.4 and below, TIMED_OS_STATISTICS can take one of the following values
Value | Description |
OFF | Do not gather operating system statistics. This is the default value |
CALL | Gather statistics at every push or pop call. This option has significant overhead |
LOGOFF | Gather statistics when the user logs off from an Oracle session |
Statistics affected by enabling TIMED_OS_STATISTICS include:
OS User level CPU time |
OS System call CPU time |
OS Other system trap CPU time |
OS Text page fault sleep time |
OS Data page fault sleep time |
OS Kernel page fault sleep time |
OS User lock wait sleep time |
OS All other sleep time |
OS Wait-cpu (latency) time |
OS Minor page faults |
OS Major page faults |
OS Swaps |
OS Input blocks |
OS Output blocks |
OS Messages sent |
OS Messages received |
OS Signals received |
OS Voluntary context switches |
OS Involuntary context switches |
OS System calls |
OS Chars read and written |
OS Process heap size |
OS Process stack size |
The statistics collected may vary by platform and release. The above table represents statistics collected for Oracle 9.2 on Solaris