Button for 1977 Button for 1984 Button for 1990 Button for 1995 Button for MDC Button for notes Button for examples
Left Hand Pointer

OMI - Replication

1995 Version of ANSI (Equivalent to Current ISO Version) of Standard

Right Hand Pointer

4.6 Replication

Implementers of OMI may offer replication of changes to selected global variables. That is, set and kill operations are also applied to global variables of the same name in one or more other environments, some of which may reside on other OMI nodes.

Replication is often applied symmetrically to keep the databases identical, whichever one a client changes explicitly. For example, ^XX on computer A is replicated to ^XX on computer B and vice versa, so a change to either one evokes an OMI request to change the other. Then the protocol must avoid an endless series of transactions caused by mutual replication.

Requests (set, set extract, set piece, and kill) that alter variables shall include a replication flag to indicate whether the request should be replicated.

Note – Implementations of OMI are not required to perform replication. They are required to provide the replication flag in order to cooperate with implementations that do perform replication.

All agents shall originate set, set extract, set piece, and kill requests with replication enabled. Servers shall attempt the requested operation whether or not replication is enabled, subject to other considerations like authorization, and shall reply as described in 4.3.3.

An implementation that supports replication shall take further action if and only if it successfully performs a set, set extract, set piece, or kill operation with replication enabled. (The operation may have originated from an OMI request or from a local set, set extract, set piece, or kill by a process on the server's own node.) The agent on that node shall:

Button for 1977 Button for 1984 Button for 1990 Button for 1995 Button for MDC Button for notes Button for examples

Copyright © Standard Documents; 1977-2018 MUMPS Development Committee;
Copyright © Examples: 1995-2018 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2018 Ed de Moel.

This page most recently updated on 13-Sep-2014, 14:15:16 .

For comments, contact Ed de Moel (demoel@jacquardsystems.com)