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What is Locksize?

What is Locksize?

LOCKSIZE TABLESPACE. A process acquires no table, page, row, LOB, or XML locks within the table space. That improves performance by reducing the number of locks maintained, but greatly inhibits concurrency. LOCKSIZE TABLE.

Which process is used to promote the lock sizes of page to the lock size of table space?

In that case, the bind process issues a message warning that the lock size has been promoted as described under Lock promotion. LOCKSIZE ROW. A process acquires row locks, plus table, partition, or table space locks of modes that permit row locks (IS, IX, or SIX).

How do I resolve a Db2 issue?

Procedure

  1. Obtain information from the lock event monitor or administration notification log about all tables where agents are experiencing deadlocks.
  2. Use the information in the administration notification log to decide how to resolve the deadlock problem.

What causes Db2 deadlock?

A deadlock occurs when two or more application processes each hold locks on resources that the others need and without which they cannot proceed. After a preset time interval, Db2 can roll back the current unit of work for one of the processes or request a process to terminate.

What is Locksize in Db2?

LOCKSIZE ANY is the default for CREATE TABLESPACE. It allows Db2 to choose the lock size, and Db2 usually chooses LOCKSIZE PAGE and LOCKMAX SYSTEM for non-LOB/non-XML table spaces. For LOB table spaces, Db2 chooses LOCKSIZE LOB and LOCKMAX SYSTEM. Row-level locking might also result in more data page latch contention.

On which level we can apply the locks in Db2?

4) On which levels locks can be applied? Locking can be applied on either of Page, table and table space.

Which utility is used to restore the tablespace?

You can use the DSN1COPY utility to restore a partition or an entire table space for a partition-by-growth table space. The total number of partitions in the DSN1COPY input data set might not be consistent with the number of partitions that are defined on the current table space.

How do you find deadlocks in db2?

Detecting and managing deadlocks

  1. Right-click on the Lock icon and select Deadlock Detection.
  2. select one of the following commands from the submenu: Monitor Deadlocks. Pause Deadlock Detection. Resume Deadlock Detection. Stop Deadlock Detection. Show Deadlocks.

What are the isolation levels in db2?

The database manager supports four isolation levels.

  • Repeatable read (RR)
  • Read stability (RS)
  • Cursor stability (CS)
  • Uncommitted read (UR)

What is lock contention explain with example?

The most obvious example of contention is on a lock. If thread A has a lock and thread B wants to acquire that same lock, thread B will have to wait until thread A releases the lock.

Which is the default lock size in DB2?

LOCKSIZE ANY is the default for CREATE TABLESPACE. It allows Db2 to choose the lock size, and Db2 usually chooses LOCKSIZE PAGE and LOCKMAX SYSTEM for non-LOB/non-XML tablespaces. For LOB table spaces, Db2 chooses LOCKSIZE LOB and LOCKMAX SYSTEM. Similarly, for XML table spaces, Db2 chooses LOCKSIZE XML and LOCKMAX SYSTEM.

How to specify the size of locks for a table space?

Db2 chooses the size of the lock, usually LOCKSIZE PAGE. For LOB table spaces Db2 usually chooses LOCKSIZE LOB. If a LOB must be accessed, a process acquires LOB locks and the necessary LOB table space locks (IS or IX). This option is valid only for LOB table spaces.

How to create large table spaces in DB2?

For information about the rules and restrictions for creating table spaces in work file databases, see Table spaces in a work file database. For information about creating large object (LOB) table spaces, see CREATE LOB TABLESPACE. Db2 creates XML table spaces implicitly when you create or alter tables to add XML columns.

Which is the default buffer pool in DB2?

DSNDB04 is the default. Identifies the buffer pool to be used for the table space and determines the page size of the table space. For 4KB, 8KB, 16KB and 32KB page buffer pools, the page sizes are 4 KB, 8 KB, 16 KB, and 32 KB, respectively.