V$SESSION_WAIT displays the resources or events for which active sessions are waiting.

The following are tuning considerations:

  • P1RAW, P2RAW, and P3RAW display the same values as the P1, P2, and P3 columns, except that the numbers are displayed in hexadecimal.

  • The WAIT_TIME column contains a value of -2 on platforms that do not support a fast timing mechanism. If you are running on one of these platforms and you want this column to reflect true wait times, then you must set the TIMED_STATISTICS initialization parameter to true. Remember that doing this has a small negative effect on system performance.

    In previous releases, the WAIT_TIME column contained an arbitrarily large value instead of a negative value to indicate the platform did not have a fast timing mechanism.

  • The STATE column interprets the value of WAIT_TIME and describes the state of the current or most recent wait.

Column Datatype Description
SID NUMBER Session identifier
SEQ# NUMBER Sequence number that uniquely identifies this wait. Incremented for each wait.
EVENT VARCHAR2(64) Resource or event for which the session is waiting

See Also: Appendix C, "Oracle Wait Events"

P1TEXT VARCHAR2(64) Description of the first additional parameter
P1 NUMBER First additional parameter
P1RAW RAW(4) First additional parameter
P2TEXT VARCHAR2(64) Description of the second additional parameter
P2 NUMBER Second additional parameter
P2RAW RAW(4) Second additional parameter
P3TEXT VARCHAR2(64) Description of the third additional parameter
P3 NUMBER Third additional parameter
P3RAW RAW(4) Third additional parameter
WAIT_CLASS_ID NUMBER Identifier of the wait class
WAIT_CLASS# NUMBER Number of the wait class
WAIT_CLASS VARCHAR2(64) Name of the wait class
WAIT_TIME NUMBER A nonzero value is the session's last wait time. A zero value means the session is currently waiting.
SECONDS_IN_WAIT NUMBER If WAIT_TIME = 0, then SECONDS_IN_WAIT is the seconds spent in the current wait condition. If WAIT_TIME > 0, then SECONDS_IN_WAIT is the seconds since the start of the last wait, and SECONDS_IN_WAIT - WAIT_TIME / 100 is the active seconds since the last wait ended.
STATE VARCHAR2(19) Wait state:
  • 0 - WAITING (the session is currently waiting)

  • -2 - WAITED UNKNOWN TIME (duration of last wait is unknown)

  • -1 - WAITED SHORT TIME (last wait <1/100th of a second)

  • >0 - WAITED KNOWN TIME (WAIT_TIME = duration of last wait)