Donovan Lambright, Automation Librarian

Lately, we've had a rash of questions about record indexing and the iPac web-based catalog and it seems like a good time to explore the topic.

When bibliographic (title) records are added or updated to the Horizon database, they are indexed immediately.  Any changes or updates will show up in searches with no delay.  This is not the case with iPac.  Unlike Horizon, the iPac is a separate application with it's own server and software.  It searches the database just like Horizon does but there are a number of extra "moving parts" in the process.  Besides making the whole process more complex, this means that there is more that can go wrong.  Or just slow things down.

The iPac server has an indexing process that runs continuously in the background.  It's job is to index changes and updates in the Horizon database so they can be included in searches.  It's not an instant process; changes to the Horizon database can take anywhere from one to eight hours to show up in patron search results.

Why the wide variation?  That's a good question and, like most good questions, there is no single answer.  Indexing times can vary based on:

• how busy the server is
• the condition of the indices

The first bullet point is fairly straightforward.  If the server is busy, say in the middle of the afternoon, everything runs a little slower.

The second bullet point requires a longer explanation.  Over time, the indices in iPac degrade from use.  It's a gradual process which SirsiDynix can't really explain but is not unheard of with complex database systems.  As this degradation gets more pronounced, searches start to take longer and database updates start to take longer before showing up in searches.  The official remedy for this situation is to do a complete reindexing of the database in iPac.  When we started using Horizon, Dynix (as they were called at the time) recommended we perform a reindex every three months.  This worked pretty well for us until a few months ago when we noticed that the three-month schedule wasn't working as well as it used to.  So we now reindex every two months.

For those keeping score, we last reindexed in mid-October.  The next reindex is scheduled for November.

Please note that everything in this post pertains only to the iPac.  The Horizon staff client uses an entirely different set of indices and  is not subject to these issues.

I hope this sheds a little light on what goes on behind the iPac curtain.  As always, please don't hesitate to contact the SELCO Help Desk if you have any questions about searching behavior in iPac.