Spectacu.la Advanced Search

Once the index is live you should be able to tick the enable button. Now we get to choose from up to 5 different modes of search:

1. 08Default mode: This will find posts containing any of the term, the more of the terms there are in a post the higher relevance score it receives and thus the higher in the results it will appear (presuming sorting by rank). If two or more terms are searched for but only one can be found then posts matching that one will be returned. Terms matched in titles count as one and a half as much as those in the content.
2. 09Boolean mode: Very much the same as default mode but you get several extra operators that can alter a query. Adding + or – to the head of a term will either make it so that you return posts that must have the term or must not have the term. > or < will increase or decrease the importance of a word. So for example (phone >droid) would find all phone post and droid post but droid posts would be considered more important. A full explanation of the operators can be found here.
3. 10With query expansion: This kind of search can find posts related to your search terms but don’t necessarily contain any of the terms entered. So search for “android” for example and it will use posts that contain the word android to find words that are related to it. So it may deem that you want posts about robots too or it may also figure you want post relating to Google’s phone OS it really depends upon your sites content. For this mode you’ll need to tweak the relevance limit bases on what has been returned for your content otherwise it can end up returning all posts on your site. Not too big a problem if ordered by relevance but if ordered by date your results will make no sense at all.
4. 11In natural language mode: If you have MySQL 5.1 or better you will have two more modes available to you. First is In natural language mode which is mostly the same as default mode and in natural language more with query expansion which is functionally the same as the with query expansion.

If your server works with wp_cron then you can set up a periodic table optimise that will help keep your table index in order. If your site changes rarely then you can set it to run infrequently or not at all and just use the “optimise table” button to do it as and when you want/need to. The more accurate your index is the better your search results will be and the lower the load on the db. All good basically. The optimise will kick in after the time it is set to run but wp-cron requires a visitor to kick off the job. So if you set it to start at 3:00am and you don’t get an activity on your site until 10am the next day the job won’t start until 10am. This shouldn’t be a problem as most optimisations apply very little load and take only a few second to run.