LOB and LOB table space lock modes

This information describes the modes of LOB locks and LOB table space locks.

Modes of LOB locks

The following LOB lock modes are possible:

S (SHARE)

The lock owner and any concurrent processes can read, update, or delete the locked LOB. Concurrent processes can acquire an S lock on the LOB.

X (EXCLUSIVE)

The lock owner can read or change the locked LOB. Concurrent processes cannot access the LOB.

Modes of LOB table space locks

The following lock modes are possible on the LOB table space:

IS (INTENT SHARE)

The lock owner can update LOBs to null or zero-length, or read or delete LOBs in the LOB table space. Concurrent processes can both read and change LOBs in the same table space.

IX (INTENT EXCLUSIVE)

The lock owner and concurrent processes can read and change data in the LOB table space. The lock owner acquires a LOB lock on any data it accesses.

S (SHARE)

The lock owner and any concurrent processes can read and delete LOBs in the LOB table space. An S-lock is only acquired on a LOB in the case of an ISO(UR)

SIX (SHARE with INTENT EXCLUSIVE)

The lock owner can read and change data in the LOB table space. If the lock owner is inserting (INSERT or UPDATE), the lock owner obtains a LOB lock. Concurrent processes can read or delete data in the LOB table space (or update to a null or zero-length LOB).

X (EXCLUSIVE)

The lock owner can read or change LOBs in the LOB table space. The lock owner does not need LOB locks. Concurrent processes cannot access the data.