Message Searching Options
vBulletin Options > vBulletin Options > Message Searching Options- Search Engine Enabled
Allow searching for posts and threads within the forums. This is a relatively server-intensive process so you may want to disable it if you have problems.
- Minimum Time Between Searches
The minimum time (in seconds) that must expire before the user can perform a new search.
Set this to 0 to allow users to search as frequently as they want.
- Search Results Posts Per Page
Number of successful search results to display per page.
- Maximum Search Results to Return
Any search results over this number will be discarded.
- Search Index Minimum Word Length
When using the vBulletin default search, this option limits the size of indexed words. The smaller this number is, the larger your search index, and conversely your database is going to be.When using the Fulltext search, this option limits the size of words that may be searched for. Smaller words take longer to search for as they are more common. MySQL Fulltext has its own minimum word length as well that must be changed at the server level.
- Automatic Similar Thread Search
Setting this option will cause a search for similar threads to be automatically done when a new thread is posted. These similar threads are then linked to from the newly posted thread's page. This can have an effect on performance.
- Search Result Sharing
In order to conserve resources, vBulletin will allow search results to be shared among users for one hour. The downside of this is that search results can appear out of order if a thread is updated in the interim.
- Similar Threads Relevance Threshold
For a post to be matched in a search for similar threads, it must have a score of this number or greater, per searchable word. For more information on how post scores are determined, see the Search Algorithms section.
- Words to be excluded from search
If there are special words that are very common for your forum, you may wish to remove them from being searchable. Searching for very common words on a large forum can be server intensive. Separate each word with a space.