Understanding Deferred Indexing

When your library staff adds or changes MARC records, Horizon processes dozens of indexes while saving the record. Each record takes a substantial amount of time to process simply because of the number of indexes the system must update. Deferred indexing is the process of postponing a portion of the indexing when you add or change MARC records, or re-index the Horizon database for any reason. This process helps your cataloging workstation maintain good response time during indexing procedures. (For example, if during regular indexing you have many indexes configured, it may take more than 30 seconds to import a typical bib record. With deferred indexing, this time can be cut to a few seconds.) However, deferred indexing may not work for every library.

This section assumes you are familiar with and have a strong understanding of basic Horizon indexing processes.

You can use deferred indexing to improve indexing time if your library meets one or both of these criteria:

While importing, your cSee "Understanding MARC Records"ataloging workstation is heavily affected by the time it takes to save records. If saving a MARC record frequently takes more than a few seconds, you should consider using deferred indexing.
You have several dozen MARC indexes on your system. If you have fewer indexes, deferred indexing cannot improve your system’s indexing time.

This table illustrates how deferred indexing can help speed up your Cataloging processing:

Type of Indexing

Total number of MARC indexes

Processed immediately

Processing deferred

Typical time to save or import one record

Regular indexing

80

80

0

38 seconds

Deferred indexing

80

12

68

2 seconds

You use deferred indexing by setting up queues. A queue is a list of records and indexes that are waiting for Horizon to process them. Usually, you need to set up only one queue. However, if you set up and use one queue for deferred indexing and your indexing is still slow, you can set up multiple deferred queues.

To use deferred indexing, you should set up a dedicated network workstation, or one that is rarely used for other tasks, to run the deferred indexing utility. You can set up Horizon to start deferred indexing whenever this workstation is booted or from a menu option.

Deferred indexing will not resolve such issues as network bandwidth problems, insufficient RAM on the workstation, and so forth. Make sure your network, workstation, and Horizon system are working efficiently before you choose to set up deferred indexing.

This section explains these topics:

 


© 1998-2017 Sirsi Corporation