Examples
T1 scans R, and updates a few tuples:
- T1 gets an SIX lock on R, and occasionally upgrades to X on a tuple.
T2 uses an index to read only part of R:
- T2 gets an IS lock on R, and repeatedly gets an S lock on tuples of R.
T3 reads all of R:
- T3 gets an S lock on R.
- OR, T3 could behave like T2; can use lock escalation to decide which.