LOCKS

LOCKS displays information about locks held by each open transaction.

Table 1 LOCKS columns

Name	Type	Description
locktype	text	Type of the locked object: relation, extend, page, tuple, transactionid, virtualxid, object, userlock, or advisory
database	oid	OID of the database in which the locked object exists. The OID is 0 if the object is a shared object. The OID is NULL if the object is a transaction ID.
relation	oid	OID of the relationship targeted by the lock. The value is NULL if the object is not a relationship or part of a relationship.
page	integer	Page number targeted by the lock within the relationship. The value is NULL if the object is not a relationship page or row page.
tuple	smallint	Row number targeted by the lock within the page. The value is NULL if the object is not a row.
bucket	integer	Hash bucket ID.
virtualxid	text	Virtual ID of the transaction targeted by the lock. The value is NULL if the object is not a virtual transaction ID.
transactionid	xid	ID of the transaction targeted by the lock. The value is NULL if the object is not a transaction ID.
classid	oid	OID of the system catalog that contains the object. The value is NULL if the object is not a general database object.
objid	oid	OID of the locked object within its system catalog. The value is NULL if the object is not a general database object.
objsubid	smallint	Column number for a column in the table (0 if the object is of other object type and NULL if the object is not a general database object)
virtualtransaction	text	Virtual ID of the transaction holding or awaiting this lock
pid	bigint	Logical ID of the server thread holding or awaiting this lock. The value is NULL if the lock is held by a prepared transaction.
sessionid	bigint	ID of the session holding or awaiting this lock The value is NULL if the lock is held by a prepared transaction.
mode	text	Lock mode held or desired by this thread
granted	Boolean	The value is TRUE if the lock is a held lock. The value is FALSE if the lock is an awaited lock.
fastpath	Boolean	The value is TRUE if the lock is obtained through fast-path, and is FALSE if the lock is obtained through the main lock table.
locktag	text	Lock information that the session waits for. It can be parsed using the locktag_decode() function.
global_sessionid	text	Global session ID