LOCALTRANSACTIONALLOCKS System Table Description

Description

A pseudo table generated to show information about all transactional locks known to the local Transaction Engine (TE). This table shows all local SHARED locks and all distributed EXCLUSIVE locks. SHARED locks on remote TEs will not be part of the pseudo table.

The SOURCENODE column in this table specifies the TE from where this lock held is being reported, but not necessarily the TE where the transaction is executing.

The NODEID column in this table specifies the TE on which the transaction owning the lock is currently running. This value for a given transaction does not change.

Caution: Client applications should never contain code that accesses SYSTEM pseudo tables as they are subject to, and furthermore likely to, change from release to release.

Fields

Field Type Description
OBJECTID integer A unique ID identifying the database object.
TRANSACTIONID bigint The identifier of the transaction owning the lock.
NODEID integer

The Identifier of the TE where this transaction is running.

LOCKTYPE string

The type of lock to be set (EXCLUSIVE or SHARED).

Note: At the time of writing, NuoDB 3.2.2 does not support the acquiring of SHARED locks.

SOURCENODE integer The NODEID from which this particular row in the table has originated. If there are multiple TEs running in the domain, a row is generated in this table for each transaction for each TE. SOURCENODE identifies the TE reporting on this transaction. To identify the actual TE where this transaction is running, see NODEID.

Indexes

None

Example

When connected to TE1, SELECT * FROM system.localtransactionallocks;
==================================== Row #1 ====================================
OBJECTID: 72
TRANSID: 2050
NODEID: 2
LOCKTYPE: Shared
SOURCENODE: 2
==================================== Row #2 ====================================
OBJECTID: 70
TRANSID: 898
NODEID: 2
LOCKTYPE: Exclusive
SOURCENODE: 2
			
When connected to TE2, SELECT * FROM system.localtransactionallocks;
==================================== Row #1 ====================================
OBJECTID: 70
TRANSID: 898
NODEID: 2
LOCKTYPE: Exclusive
SOURCENODE: 3