Simple Topic But useful and good to know .
V$SESSION_WAIT
Displays the current or last wait for each session. or its displays the events for which sessions have just completed waiting or are currently waiting.
V$SESSION_EVENT
Lists information on waits for an event by a session or Its similar to V$SYSTEM_EVENT, but displays all waits for each session.
Means, a session is running and waiting to acquire a resource. Because V$SESSION_WAIT is a current state view, it also contains a finer-granularity of information than V$SESSION_EVENT or V$SYSTEM_EVENT. It includes additional identifying data for the current event in three parameter columns: P1, P2, and P3.
For example, V$SESSION_EVENT can show that session 124 (SID=124) had many waits on the db file scattered read event, but it does not show which file and block number. However, V$SESSION_WAIT shows the file number in P1, the block number read in P2, and the number of blocks read in P3 (P1 and P2 let you determine for which segments the wait event is occurring).
V$SESSION_WAIT
Displays the current or last wait for each session. or its displays the events for which sessions have just completed waiting or are currently waiting.
V$SESSION_EVENT
Lists information on waits for an event by a session or Its similar to V$SYSTEM_EVENT, but displays all waits for each session.
For example, V$SESSION_EVENT can show that session 124 (SID=124) had many waits on the db file scattered read event, but it does not show which file and block number. However, V$SESSION_WAIT shows the file number in P1, the block number read in P2, and the number of blocks read in P3 (P1 and P2 let you determine for which segments the wait event is occurring).
No comments:
Post a Comment