Which system stores index information in the database?

The correct answer is that Solr is the system that stores index information in the database. Solr is a powerful search platform built on Apache Lucene, which is designed for handling large volumes of data and providing fast search capabilities. When documents are indexed in Solr, the indexed data is stored in a specialized format that allows for efficient retrieval. This means that when a search query is made, Solr can quickly access the relevant information because it has already organized and stored the index data in a way that optimizes performance.

In contrast, while a Database Indexer generally refers to mechanisms that improve database query performance by creating indexes on database tables, it is not a standalone system like Solr. A Data Repository is more focused on the storage and management of data rather than specifically dealing with indexing for search functionality. Similarly, a Search Engine typically encompasses a wider range of technologies and processes for crawling, indexing, and retrieving information, but Solr specifically outlines the indexing part and is well-regarded for this capability.

Thus, Solr’s role as an indexing and searching solution within the database context makes it the most appropriate choice for the question regarding which system stores index information.