Chapter 9. GT.M Database Structure(GDS)

Revision History
Revision V7.1-002 19 September 2023
Revision V7.1-000 04 April 2023
Revision V7.0-000 12 February 2021
Revision V6.3-013 30 June 2020
Revision V6.3-008 24 April 2019
Revision V6.3-007 04 February 2019
Revision V6.3-006 26 October 2018
Revision V6.3-005 03 July 2018
Revision V6.3-001 20 March 2017
  • In “File Header Data Elements ”, removed references to OpenVMS and added the descriptions of WIP queue cache blocks, DB is auto-created, DB shares gvstats. LOCK crit sharing, AsyncIO

Revision V6.0-003/1 19 February 2014

In “File Header Data Elements ”, updated the descriptions for V6.0-003.

Revision V6.0-003 27 January 2014

In “GDS Blocks ”, corrected the description of block header fields.

Table of Contents

Database File Organization with GDS
Database File Header
File Header Data Elements
Local Bitmaps
Master Bitmap
Database Structure
Tree Organization
GDS Blocks
GDS Records
GDS Keys
Compression Count
Use of Keys
Characteristics of Keys
Global Variable Names
String Subscripts
Numeric Subscripts

GDS is an FIS proprietary internal database structure used to store global variables and lock resource names. A high-level understanding of GDS can help database administrators correctly interpret GT.M logs/error messages, and maintain database metrics. You should always consult GT.M support (gtmsupport@fisglobal.com) in the unlikely event of getting database integrity issues.

[Note] Note

This chapter provides a high-level overview of GDS components. A comprehensive description of all the components of GDS is beyond the scope of this chapter.