Example
Sitecore ships with a set of standard indexes pre-configured which you can extend, or you can define your own. Of the pre-configured, sitecore_master_index & sitecore_web_index are of most interest for your site search. These are the predefined indexes for all of your Sitecore items in the tree of your master & web databases respectively, and are configured to store all of the standard fields of a Sitecore item that will be common among all templates.
You can look at this configuration of the standard web index at this location: <Your Site>\App_Config\Include\Sitecore.ContentSearch.Lucene.Index.Web.config
The main areas of importance of an index's configuration are:
- The Field Configuration - What fields should be stored in the index, and how they should be stored.
- The Strategy - How and when should the index be updated.
- The Crawler - The location where the index can get it's Sitecore data
Field Configuration
Looking in the sitecore_web_index config, you can see the following reference: <configuration ref="contentSearch/indexConfigurations/defaultLuceneIndexConfiguration" />. This refers to a shared index configuration file found here: <Your Site>\App_Config\Include\Sitecore.ContentSearch.Lucene.DefaultIndexConfiguration.config. Here you can see all of the fields that are included in the standard config.
There are basically two ways to defined a field: either the field is sourced directly from a Sitecore item field, or it's a computed field. A computed field allows you write some code to do some calculations and store the result in the field. This code will get executed when the index is built/updated not when the index is queried. This is particularly useful if the field needs to store aggregated data, such as counts etc.
Within the <fieldMap> element you'll see the elements <fieldNames hint="raw:AddFieldByFieldName"> & <fields hint="raw:AddComputedIndexField">, which contain the directly sourced fields and the computed fields respectively.
Strategy
The strategy of your index determines when your index is updated. There are the following options to choose from:
- OnPublishEndAsynchronousStrategy (onPublishEndAsync) - When an item is published, the index will be updated asynchronously.
- SynchronousStrategy (syncMaster) - When an item is saved, the index will be updated instantly and synchronously.
- IntervalAsynchronousStrategy (intervalAsyncCore/intervalAsyncMaster) - Periodically check for item updates & update the index asynchronously
- ManualStrategy - No automatic index updates. Indexes will only be updated manually (through the control panel, or programmatically)
- RebuildAfterFullPublishStrategy (rebuildAfterFullPublish) - After a publish, the index will be rebuilt in full
- RemoteRebuildStrategy (remoteRebuild) - This strategy is for multiple instances of Sitecore. For example, if a rebuild is called for from the content management server, then the remote content delivery servers will subscribed to this event and rebuild their own indexes.
By default, the master index is configured as syncMaster. This is because if you're in the experience editor saving items and rendering on the page displays the results of an index, you'll want to see changes you've made to items immediately in the results. The web index is configured as 'onPublishEndAsync', this is because the indexes of your web database only need updating when items are published from the master database to the web.
You can also combine multiple strategies. For example, if you have separate Sitecore instances for your content management (CM) & content delivery (CD), it would make sense to combine the onPublishEndAsync with remoteRebuild, so that CD indexes get updated when items are published as well as get rebuilt when a user triggers a rebuild from the control panel of the CM server.
You can choose your strategy using the following config:
<strategies hint="list:AddStrategy">
<strategy ref="contentSearch/indexConfigurations/indexUpdateStrategies/onPublishEndAsync" />
</strategies>
The Crawler
This allows you to specify the location of the Sitecore data you want to index. The web index has the following default configuration:
<locations hint="list:AddCrawler">
<crawler type="Sitecore.ContentSearch.SitecoreItemCrawler, Sitecore.ContentSearch">
<Database>web</Database>
<Root>/sitecore</Root>
</crawler>
</locations>
The two important bits are the <Database> and <Root> elements. The <Root> element allows you to specify the starting position in your Sitecore tree that the index should index. In reality, you're likely to have a 'Home' node under the content node that you'd point this at so that it only indexes actual content/pages rather than your templates etc.
