--- /dev/null
+Did You Mean? Single word search suggestions
+^^^^^^^^^^^^^
+This feature is the first in the series to add native search suggestions
+to the Evergreen search logic. A significant portion of the code is
+dedicated to infrastructure that will be used in later enhancements to
+the functionality.
+
+Overview
+++++++++
+When searching the OPAC or staff catalog in a single search class (title,
+author, subject, series, identifier, or keyword) with a single search term
+users can be presented with alternate search terms. Depending on how the
+instance has been configured, suggestions may be provided for only
+misspelled words (as defined by existance in the bibliographic corpus),
+terms that are spelled properly but occur very few times, or on every
+single-term search.
+
+Upgrading
++++++++++++++++++++
+This feature requires the addition of new perl module dependencies. Please
+run the app server and database server dependency Makefiles before applying
+the database and code updates.
+
+At the end of the database upgrade script, the administrator is presented
+with a set of instructions necessary to precompute the suggestion
+dictionary based on the current bibliographic database. The first half
+of this procedure can be started even before the upgrade begins, as soon
+as the Evergreen database is no longer accessible to users that might
+cause changes to bibliographic records. For very large instances, this
+dictionary generation can take several hours and needs to be run on a
+server with significant RAM and CPU resources. Please look at the upgrade
+script before beginning an upgrade and plan this dictinoary creation as
+part of the overall upgrade procedure.
+
+Given a server, such as a database server with 64G of RAM, you should
+be able to run all six of the shell commands in parallel in screen
+sessions or with a tool such as GNU parallel.
+
+These commands invoke a script that will generate a class-specific sub-
+set of the dictionary, and can be used to recreate the dictionary if
+necessary in the future.
+