Overview of search in SharePoint Server 2013
Published: July 16, 2012
Summary: Learn about SharePoint search architecture, SharePoint search components, SharePoint search databases, and the SharePoint search topology.
Applies to: SharePoint Server 2013
The search architecture contains search components and databases. How you structure the search architecture depends on where you intend to use search: for the enterprise or for Internet sites. When building the search architecture, you should take into account considerations such as high availability and fault tolerance, the volume of your content and the estimated amount of page views and queries per second.
For more information about search hardware requirements and scaling considerations: see Scale search for performance and availability in SharePoint Server 2013.
For more information about search topologies for different use cases: see the technical diagrams Enterprise search architectures for SharePoint Server 2013 Preview and Internet sites search architectures for SharePoint Server 2013 Preview.
In this article:
Overview of search components and search databases
The following tables show an overview of all the available search components and search databases. For more information about how search components and databases interact, see the Search architectures for SharePoint Server 2013 Preview technical diagram.
|Search component name||Description|
Crawls content sources to collect crawled properties and metadata from crawled items and sends this information to the content processing component.
Content processing component
Transforms the crawled items and sends them to the index component. This component also maps crawled properties to managed properties and interacts with the analytics processing component.
Analytics processing component
Analyzes the crawled items and how users interact with the search results. The analyses are used to improve the search relevance and to create search reports and recommendations.
Receives the processed items from the content processing component and writes them to the search index. This component also handles incoming queries, retrieves information from the search index and sends back the result set to the query processing component.
Query processing component
Analyzes incoming queries. This helps to optimize precision, recall and relevance. The queries are sent to the index component, which returns a set of search results for the query.
Search administration component
Runs the system processes for search, and adds and initializes new instances of search components.
|Search database name||Description|
Stores tracking information and details about crawled items such as documents and URLs. It also stores information such as the last crawl time, the last crawl ID and the type of update (add, update, delete) during the last crawl.
Stores unprocessed information that is extracted by the content processing component and information about search clicks. The analytics processing component analyzes this information.
Analytics reporting database
Stores the results of usage analysis, such as the number of times an item has been viewed. It also stores statistics from the different analyses. These statistics are used to create usage reports.
Search administration database
Stores settings for the Search service application, such as the topology, crawl rules, query rules and the mappings between crawled and managed properties.
About the crawl component
The crawl component crawls the content sources. You can crawl a wide variety of content sources, for example file shares, SharePoint content, line of business applications and many more. To retrieve information, the crawl component connects to the content sources by invoking the appropriate indexing connector or protocol handler. After retrieving the content, the crawl component passes crawled items to the content processing component.
For more information about crawling content sources, see Plan crawling and federation in SharePoint Server 2013.
About the content processing component
The content processing component processes crawled items and sends these items to the index component. The content processing component performs operations such as document parsing and property mapping. It also performs linguistics processing such as language detection and entity extraction. The component transforms crawled items into artifacts that are included in the search index. The content processing component also writes information about links and URLs to the link database. In turn, the analytics processing component writes information related to the relevance of these links and URLs to the search index through the content processing component.
For more information about content processing, see Plan crawling and federation in SharePoint Server 2013.
About the analytics processing component
The analytics processing component analyzes crawled items, which is referred to as search analytics, and how users interact with search, which is referred to as usage analytics. Examples of search analytics are links, anchor texts and metadata. An example of usage analytics is the number of times an item is viewed. The analytics processing component analyzes search analytics and usage analytics. Search analytics information is stored in the link database and usage analytics information in the analytics reporting database. For more information, see Overview of analytics processing in SharePoint Server 2013.
About the index component
The index component is the logical representation of an index replica. In the search topology, you have to provision one index component for each index replica. The index component receives processed items from the content processing component and writes those items to an index file. Index files are stored on a disk in an index replica.
The index component receives queries from the query processing component and returns result sets.
You can divide the search index into discrete portions, called index partitions. Each index partition holds one or more index replicas. The search index is the aggregation of all index partitions.
For more information about the search schema and the search index, see Overview of the search schema in SharePoint Server 2013.
About the query processing component
The query component analyzes and processes queries and results. When the query processing component receives a query, it analyzes and processes the query to optimize precision, recall and relevance. The processed query is submitted to the index component. The index component returns a result set based on the processed query to the query processing component, which in turn processes that result set, before returning it to the front-end.
For more information, see Plan to transform queries and order results in SharePoint 2013.
About the search administration component
The search administration component runs the system processes for search. This component performs provisioning, which is to add and initialize instances of the other search components.
About the crawl database
The crawl database stores tracking information and details about crawled items. For example, it stores information about the last crawl time, the last crawl ID and the type of update during the last crawl.
About the link database
The link database stores information extracted by the content processing component. It also stores information about the number of times people have clicked on a search result. The information is stored unprocessed; the analytics processing component performs the analysis.
About the analytics reporting database
The analytics reporting database stores the results of usage analytics and extracts information from the link database when it is required.
About the search administration database
The search administration database stores search configuration data and the access control list (ACL) for the crawl component. There can be only one search administration database per search service application.
July 16, 2012