Z39.50 Stress Test on Catalog of U.S. Government Publications

On December 9, 2009, a stress test was conducted on the U.S. Government Printing Office's Aleph production server. The primary function of the test was to monitor and analyze the impact (if any) what a 10,000 record limit in z39.50 would have on the system.


External users from five depository libraries conducted searches that would return large results sets, near or over the 10,000 limit, for the duration of the test using a z39.50 client of their choice. Meanwhile, sixteen GPO staff performed tasks in Aleph that they would engage in as part of their normal workday.


The group searching the CGP was the hardest hit in terms of reduced functionality, a concern since the CGP has replaced the print Monthly Catalog as the access point for the public to Federal publications cataloged for the FDLP and the Cataloging and Indexing Program. CGP searchers mainly experienced slow response times that continued to slow down as the end of the test period approached for actions including connecting to PURLs, searching, retrieving results sets and navigating through results, and some failed searches.

Next Steps for Z 39.50 Testing and Access (March 2010-September 2010)

  • New ILS hardware will be installed and tested (March 2010-May 2010). The goal is to increase capacity and improve ability of depository libraries to access CGP records via Z39.50.
  • Aleph version 20 software upgrade (completion projected for July 2010);
  • From March 2010-September 2010:
    • Maintain access only by password to Z39.50 so that only depository libraries continue to have access,
    • Maintain Z39.50 limit of 10,000 records per session while carefully monitoring server loads to ensure other ILS functionality is not compromised;
  • After ILS hardware installation and software upgrade completed, conduct another Z39.50 stress test (August 2010);
    • Evaluate test results and plan for expansion of record limit access for z39.50 access to the Aleph ILS
  • Continue to keep the FDLP community informed of z39.50 plans and developments via the FDLP Desktop

View the complete stress test summary.

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