80+ TOP Apache Solr Interview Questions and Answers [UPDATED]

  • Question: What Is Apache Solr?

    Answer :

    Apache Solr is a standalone full-text search platform to perform searches on multiple websites and index documents using XML and HTTP. Built on a Java Library called Lucence, Solr supports a rich schema specification for a wide range and offers flexibility in dealing with different document fields. It also consists of an extensive search plugin API for developing custom search behavior.

  • Question: What Is Apache Lucene?

    Answer :

    Supported by Apache Software Foundation, Apache Lucene is a free, open-source, high-performance text search engine library written in Java by Doug Cutting. Lucence facilitates full-featured searching, highlighting, indexing and spellchecking of documents in various formats like MS Office docs, HTML, PDF, text docs and others.

  • Question: What Is Highlighting?

    Answer :

    Highlighting refers to the fragmentation of documents matching the user’s query included in the query response. These fragments are then highlighted and placed in a special section, which is used by clients and users to present the snippets. Solr consists of a number of highlighting utilities having control over different fields. The highlighting utilities can be called by Request Handlers and reused with standard query parsers.

  • Question: What Is The Use Of Tokenizer?

    Answer :

    It is used to split a stream of text into a series of tokens, where each token is a subsequence of characters in the text. The token produced are then passed through Token Filters that can add, remove or update the tokens. Later,that field is indexed by the resulting token stream.

  • Question: What Is Copying Field?

    Answer :

    It is used to describe how to populate fields with data copied from another field.

  • Question: How To Install Solr?

    Answer :

    The three steps of Installation are:

    1. Server-related files, e.g. Tomcat or start.jar (Jetty).
    2. Solr webapp as a .war.
    3. Solr Home which comprises the data directory and configuration files.
  • Question: What Are The Advantages And Disadvantages Of Standard Query Parser?

    Answer :

    Also known as Lucence Parser, the Solr standard query parser enables users to specify precise queries through a robust syntax. However, the parser’s syntax is vulnerable to many syntax errors unlike other error-free query parsers like DisMax parser.

  • Question: Explain Faceting In Solr.?

    Answer :

    As the name suggests, Faceting is the arrangement and categorization of all search results based on their index terms. The process of faceting makes the searching task smoother as users can look for the exact results.

  • Question: What File Contains Definition Of The Field Types And Fields Of Documents?

    Answer :

    schema.xml file contains definition of the field types and fields of documents.

  • Question: What Command Is Used To See How To Use The Bin/solr Script?

    Answer :

    Execute $ bin/Solr –helpto see how to use the bin/Solr script.

  • Question: Define Dynamic Fields?

    Answer :

    Dynamic Fields are a useful feature if users by any chance forget to define one or more fields. They allow excellent flexibility to index fields that have not been explicitly defined in the schema.

  • Question: Give The Syntax To Start The Server.?

    Answer :

    $ bin/solr start is used to start the server.

  • Question: Which Command Is Used To Start Solr In Foreground?

    Answer :

    $ bin/solr start –f is used to start Solr in foreground.

  • Question: How To Shut Down Apache Solr?

    Answer :

    Solr is shut down from the same terminal where it was launched. Click Ctrl+C to shut it down.

  • Question: What Is Field Analyzer?

    Answer :

    Working with textual data in Solr, Field Analyzer reviews and checks the filed text and generates a token stream. The pre-process of analyzing of input text is performed at the time of searching or indexing and at query time. Most Solr applications use Custom Analyzers defined by users. Remember, each Analyzer has only one Tokenizer.

  • Question: What File Contains Configuration For Data Directory?

    Answer :

    Solrconfig.xml file contains configuration for data directory.

  • Question: Name The Basic Field Types In Solr?

    Answer :

    • date.
    • long
    • double
    • text
    • float
  • Question: What Is The Use Of Stats.field?

    Answer :

    It is used to generate statistics over the results of arbitrary numeric functions.

  • Question: Name Different Types Of Highlighters?

    Answer :

    There are 3 highlighters in Solr:

    Standard Highlighter : provides precise matches even for advanced queryparsers.

    FastVector Highlighter : Though less advanced than Standard Highlighter, it works better for more languages and supports Unicode breakiterators.

    Postings Highlighter : Much more precise, efficient and compact than the above vector one but inappropriate for a more number of query terms.

  • Question: What Are The Features Of Apache Solr?

    Answer :

    1. Allows Scalable, high performance indexing Near real-time indexing.
    2. Standards-based open interfaces like XML, JSON and HTTP.
    3. Flexible and adaptable faceting.
    4. Advanced and Accurate full-text search.
    5. Linearly scalable, auto index replication, auto failover and recovery.
    6. Allows concurrent searching and updating.
    7. Comprehensive HTML administration interfaces.
    8. Provides cross-platform solutions that are index-compatibleFind out how Apache Solr works perfectly with Hadoop in this blog post.
  • Question: What Is Request Handler?

    Answer :

    When a user runs a search in Solr, the search query is processed by a request handler. SolrRequestHandler is a Solr Plugin, which illustrates the logic to be executed for any request.Solrconfig.xml file comprises several handlers (containing a number of instances of the same SolrRequestHandler class having different configurations).

  • Question: What Is Phonetic Filter?

    Answer :

    Phonetic filter creates tokens using one of the phonetic encoding algorithms in the org.apache.commons.codec.language package.

  • Question: What Are The Important Configuration Files Of Solr?

    Answer :

    Solr supports two important configuration files:

    1. solrconfig.xml.
    2. schema.xml
  • Question: What Is The Use Of Field Type?

    Answer :

    Field type defines how Solr would interpret data in a field and how that field can be queried.

  • Question: What Are The Most Common Elements In Solrconfig.xml?

    Answer :

    • Search components
    • Cache parameters
    • Data directory location
    • Request handlers
  • Question: What Data Is Specified By Schema?

    Answer :

    Schema declares:

    • how to index and search each field?
    • what kinds of fields are available?
    • what fields are required?
    • what field should be used as the unique/primary key?
  • Question: What All Information Is Specified In Field Type?

    Answer :

    A field type includes four types of information:

    1. Name of field type.
    2. Field attributes.
    3. An implementation class name.
    4. If the field type is Text Field , a description of the field analysis for the field type.
  • Question: What Is Solrcloud?

    Answer :

    Apache Solr facilitates fault-tolerant, high-scalable searching capabilities that enable users to set up a highly-available cluster of Solr servers. These capabilities are well revered as SolrCloud.

  • Question: Which Syntax Is Used To Stop Solr?

    Answer :

    $ bin/solr stop -p 8983 is used to stop Solr.

  • Question: What Syntax Is Used To Check Whether Solr Is Currently Running Or Not?

    Answer :

    $ bin/solr status is used to check Solr running status.

  • Apache Solr Questions and Answers for Interview

    Preparing for Apache Solr job interview and whether you’re experienced or fresher & don’t know what kind of questions will be asked in Apache Solr interview, then go through the above 80+ Top Apache Solr Interview Questions and Answers to crack your job interview.