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Compressing an ArcSDE geodatabase licensed under ArcGIS Server Enterprise

Compressing an ArcSDE geodatabase licensed under ArcGIS Server Enterprise

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About compressing the geodatabase

Note:This topic was updated for 9.3.1.

NOTE: Applies to geodatabases created with an ArcGIS Server Enterprise license only

As a geodatabase is edited over time, delta tables increase in size and the number of states increases. The larger the tables and the more states, the more data ArcGIS must process every time you display or query a version. Therefore, the greatest impact on performance is not the number of versions but the amount of change contained in the adds (A) and deletes (D) tables for each version. As a result, versions can have different query response times.

To maintain database performance, the ArcSDE administrator must periodically run the ArcCatalog Compress command to remove unused data. Only the ArcSDE administrator can run a compress operation. Compressing performs two key tasks:

When a large volume of uncompressed changes have accumulated, compressing the database can take hours. To avoid this, compress on a regular basis. It is a good idea to compress at the end of every day or after a period of high database activity such as data loading.

During a compress, users can stay connected to the geodatabase. If any user is editing a version, the branch for that state is locked and will not take part in the compression. It's best, therefore, to have all users disconnect before starting to ensure the entire state tree can compress. It is not necessary to disconnect sessions that are read-only such as an ArcIMS session.

If you ever find yourself waiting for compress to complete because you need the computer for something else, you can end the compress at any time. This will not leave the database in an inconsistent state. You can continue compressing at a later time.

It is important to update statistics for every versioned feature class and table in the geodatabase both before and after compressing. After edits and a database compress have taken place, database statistics are no longer accurate. This hurts query performance. To learn how to update statistics, see Updating statistics on a geodatabase licensed under ArcGIS Server Enterprise.

For more information on delta tables, states, and the compress operation, read the white paper entitled Versioning. Go to http://support.esri.com and click the White Papers link on the Knowledge Base tab.

Tip

How to compress the geodatabase

Adding the Compress command to ArcCatalog

  1. In ArcCatalog, click View, click Toolbars, and click Customize.
  2. Check the Context Menus check box in the list of toolbars. This will open the Context Menus dialog box.
  3. Expand the Context Menus list.
  4. Click the arrow next to the Remote Database Context Menu. You may have to scroll down to see this.
  5. Click the Commands tab in the Customize dialog box.
  6. In the Categories window, click Geodatabase tools.
  7. Click and drag the Compress Database command from the Commands list and drop it on the context menu. The command appears in the context menu.
  8. Click Close on the Customize dialog box.

Compressing the database in ArcCatalog

  1. In ArcCatalog, create a new database connection as the ArcSDE administrative user. (This would be the schema owner for a geodatabase stored in a user's schema in an ArcSDE geodatabase for Oracle.)
  2. Add the Compress command to ArcCatalog (see "Adding the Compress command to ArcCatalog" above).
  3. Right-click the new database connection and click Compress Database.

See Also

  • About compressing a geodatabase