title: Read Locks
By default, reads do not acquire a lock which makes normal reads faster. Read locks can optionally be acquired via the [withReadLock] method. For example, if tx is a transaction then tx.withReadLock().get(row,col) reads with a lock.
- Create transaction tx1
- Using tx1 set kerbalnaut0001:stat:weight to 90
- Using tx1 set kerbalnaut0002:stat:weight to 70
- Using tx1 set kerbalnaut0003:stat:weight to 80
- Commit tx1
- Create transaction tx2
- Create transaction tx3
- Create transaction tx4
- Using tx2 set flight0001:stat:weight to the read locked values of kerbalnaut0001:stat:weight plus kerbalnaut0003:stat:weight
- Using tx3 set flight0002:stat:weight to the read locked values of kerbalnaut0001:stat:weight plus kerbalnaut0002:stat:weight
- Using tx4 set kerbalnaut0001:stat:weight to 95
- Commit tx2
- Commit tx3
- Commit tx4
Both tx2 and tx3 get a read lock on kerbalnaut0001:stat:weight without interfering with each other. The read locks prevent tx4 from committing. Try reordering the commits for tx2, tx3, and tx4.
[withReadLock]: {{ site.fluo_api_static }}/{{ site.latest_fluo_release }}/org/apache/fluo/api/client/TransactionBase.html#withReadLock--