oracle lock mode

By v$lock, we could have a look at lock in every session. Lock have a lot of mode:

mode|name||desc
–|–||–
0|none|
1|null|
2|Row-S||row sharing lock: share row
3|Row-X||row exclusive lock: for modify row
4|Share||share lock: block other DML
5|S/Row-X ||shared row exclusive lock: block other transaction
6|exclusive||exclusive lock: independently access and use


lock type:

  • TM lock for parallel accessing table
  • TX transaction lock or row lock for parallel accessing row
  • MR media recover lock means database online
  • ST space transaction lock means due to bad file structure, some segments in database in increase or shrink SMON or merging free space nearby.

oracle lock mode
https://rug.al/2015/2015-01-16-oracle-lock-mode/
Author
Rugal Bernstein
Posted on
January 16, 2015
Licensed under