PG_LOCKS¶
PG_LOCKS displays information about the locks held by open transactions.
Column | Type | Reference | Description |
---|---|---|---|
locktype | Text | N/A | Type of the locked object: relation, extend, page, tuple, transactionid, virtualxid, object, userlock, and advisory |
database | OID | PG_DATABASE.oid | OID of the database in which the locked target exists
|
relation | OID | PG_CLASS.oid | OID of the relationship targeted by the lock. The value is NULL if the object is neither a relationship nor part of a relationship. |
page | Integer | N/A | Page number targeted by the lock within the relationship. If the object is neither a relation page nor row page, the value is NULL. |
tuple | Smallint | N/A | Row number targeted by the lock within the page. If the object is not a row, the value is NULL. |
virtualxid | Text | N/A | Virtual ID of the transaction targeted by the lock. If the object is not a virtual transaction ID, the value is NULL. |
transactionid | Xid | N/A | ID of the transaction targeted by the lock. If the object is not a transaction ID, the value is NULL. |
classid | OID | PG_CLASS.oid | OID of the system table that contains the object. If the object is not a general database object, the value is NULL. |
objid | OID | N/A | OID of the lock target within its system table. If the target is not a general database object, the value is NULL. |
objsubid | Smallint | N/A | Column number for a column in the table. The value is 0 if the target is some other object type. If the object is not a general database object, the value is NULL. |
virtualtransaction | Text | N/A | Virtual ID of the transaction holding or awaiting this lock |
pid | Bigint | N/A | Logical ID of the server thread holding or awaiting this lock. This is NULL if the lock is held by a prepared transaction. |
mode | Text | N/A | Lock mode held or desired by this thread For more information about lock modes, see "LOCK" in the Data Warehouse Service (DWS) SQL Syntax Reference. |
granted | boolean | N/A |
|
fastpath | boolean | N/A | Whether the lock is obtained through fast-path (true) or main lock table (false) |
waittime | Timestamp with time zone | N/A | Timestamp when the lock wait starts. This column is available only in clusters of version 9.1.0.200 or later. |
holdtime | Timestamp with time zone | N/A | Timestamp when the lock starts to be held. This column is available only in clusters of version 9.1.0.200 or later. |