how does solr store data - Wikitechy https://www.wikitechy.com/interview-questions/tag/how-does-solr-store-data/ Interview Questions Tue, 14 Sep 2021 10:41:57 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png how does solr store data - Wikitechy https://www.wikitechy.com/interview-questions/tag/how-does-solr-store-data/ 32 32 How Solr represents data ? https://www.wikitechy.com/interview-questions/apache-solr/how-solr-represents-data/ https://www.wikitechy.com/interview-questions/apache-solr/how-solr-represents-data/#respond Mon, 12 Jul 2021 13:57:33 +0000 https://www.wikitechy.com/interview-questions/?p=238

Solr represents data

  • In Apache Solr, a Document is the part of search as well as index.
  • Index consists of one or more Documents and then Document consists of one or more Fields.
  • In database terminology,a Document corresponds to a row of the table, and a Field corresponds to a column of the table.
apache solr with hadoop

Schema

  • Before adding documents to Solr, you need to specify the schema, represented in a file called schema.xml.
  • It is not suitable to modify the schema after documents has added to the index.

The schema declares:

  1. what kinds of fields there are
  2. which field should be used as the unique/primary key
  3. which fields are required
  4. how to index and search each field

Field Types

  • In Solr, every field has a type.
  • Apache Solr expands the variety of field types offered in Lucene.

Examples of basic field types available in Solr include:

  1. float
  2. long
  3. double
  4. date
  5. text
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Apache Solr works

Indexing

  • Apache Solr is capable to get quick search responses because, as a replacement for searching the text directly, it searches an index instead.
  • It stores index in a directory called index in the data directory.
how apache solr works

Working:

  • The Apache Solr creates inverted index of the documents that are posted in to its collection or core.
  • Core or collection is just part entity which can be used to post documents and running queries on that set of documents.
  • Inverted index is a main term in the domain of Information Retrieval and Natural Language Processing.
  • Now take a document, note down all the unique words appearing in that document as well as note the frequency of the words. Hence the inverted index is ready.
  • Solr creates similar inverted index of the documents posted to its core using a defined schema.
  • Schema is a blue print which helps Solr in creating inverted index of the documents by giving a set of predefined fields in the schema.xml file.
  • Once Solr completes indexing the documents posted to its core or collection it can be used to run queries.
solr work
  • Now a user can query Solr for related documents using its query parser or admin panel.
  • When a query is given to Solr, it breaks the query into different chunks or entities and matches it with the inverted index of the documents created previous.
  • The documents obtained accordingly of a Solr search is based on the same class and other constraints defined in its schema.xml and solr.config file.
]]> https://www.wikitechy.com/interview-questions/apache-solr/how-does-the-apache-solr-works/feed/ 0 Where does the Apache Solr store the actual data ? https://www.wikitechy.com/interview-questions/apache-solr/where-does-the-apache-solr-store-the-actual-data/ https://www.wikitechy.com/interview-questions/apache-solr/where-does-the-apache-solr-store-the-actual-data/#respond Mon, 12 Jul 2021 11:58:00 +0000 https://www.wikitechy.com/interview-questions/?p=234 Apache Solr store the actual data
  • Apache Solr creates an index of its own and stores it in inverted index format.
  • While generating these indexes you can use different tokens and analyzers so that your search becomes easier.
  • The purpose of Apache Solr is to search and then the purpose of NoSQL is to use it as WORM (Write Once Read Many).
  • In the event you want to create search engine and store in NoSQL then you can create index in search and while indexing you can also write to NoSQL Systems.
  • Care needs to be taken to make certain consistency in Apache Solr as well as NoSQL systems.
  • There are new tools these days that can transfer from NoSQL to Solr.
  • The Apache Solr index is a particularly designed data structure, stored on the file system as a set of index files.
  • The index is designed with capable data structures to maximize performance and to minimize resource usage.
Apache Solr Store Data
]]> https://www.wikitechy.com/interview-questions/apache-solr/where-does-the-apache-solr-store-the-actual-data/feed/ 0 What is the difference between Apache Solr and MongoDB ? https://www.wikitechy.com/interview-questions/apache-solr/what-is-the-difference-between-apache-solr-and-mongodb/ https://www.wikitechy.com/interview-questions/apache-solr/what-is-the-difference-between-apache-solr-and-mongodb/#respond Mon, 12 Jul 2021 11:39:50 +0000 https://www.wikitechy.com/interview-questions/?p=228 Difference between Apache Solr and MongoDB:
  • Here,Some of the examples of document oriented database is MongoDB, Cassandra, and CouchBD.
Name Apache Solr MongoDB
Description A widely used enterprise
search engine based on Apache Lucene.		 One of the most popular document stores
Developer Apache Software Foundation MongoDB, Inc.
Cloud-based No No
Server operating systems All OS with a Java VM
and a servlet container		 Linux OS X Solaris Windows
Data scheme Yes schema-free
Implementation language Java C++
Secondary indexes Yes Yes
SQL No No
]]> https://www.wikitechy.com/interview-questions/apache-solr/what-is-the-difference-between-apache-solr-and-mongodb/feed/ 0 What is the most ideal approach to use Apache Solr for relational JOIN ? https://www.wikitechy.com/interview-questions/apache-solr/what-is-the-most-ideal-approach-to-use-apache-solr-for-relational-join/ https://www.wikitechy.com/interview-questions/apache-solr/what-is-the-most-ideal-approach-to-use-apache-solr-for-relational-join/#respond Mon, 12 Jul 2021 09:28:47 +0000 https://www.wikitechy.com/interview-questions/?p=224

Apache Solr for relational JOIN:

  • Run a single-use script that do the joins on the SOLR index (file) to replace the author_id and author_name, or include the field if you need both. Updating 10,000,000+ documents will get a while, however it is definitely achievable.
  • After that you can have new documents indexed with both fields, doing the JOIN one at a time.
  • In common, SOLR works with entirely denormalized information.
  • If it is more than just authors’ names, you could still denormalize the information, repeating your documents for every one of the related author documents.
  • Another technique is SOLR 4 has “JOIN” ability.
  • You’d first need to at least contain a pipeline wherever author information is indexed into SOLR in real-time.
  • Utilize Elastic Search to simply deal with the complex SOLR queries involving JOIN-like operations.
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