Locking of pages for an update transaction in IDMS

Products

• IDMS
• IDMS - Database

Issue/Introduction

For an update transaction in IDMS, does it lock the whole page when inserting, deleting or updating records?

Environment

Release:19.0

Resolution

During an IDMS update operation, a page is only locked when the update changes the space available on that page. 

See section Locking Within Central Version

Implicit Page Locks
Implicit locks are used in a special way to control user access to pages for which the amount of available space has been altered. When the available space on a page is changed as a result of an update operation, IDMS/DB places a special implicit exclusive lock on the page, allowing retrieval to continue. If a subsequent DML or DDL command from a different transaction requests further modification to available space on that page, the request is delayed until the lock is released (that is, until the recovery unit that caused the lock to be set terminates).