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What kind of search engine is Apache Solr?
Overview Apache Solr is a full text search engine that is built on Apache Lucene. Recently, I was looking into performance where the query had leading wildcards. There have been many questions over the years about leading wildcard queries.
How are leading wildcard queries handled in Apache Solr?
Apache Solr has a token filter called the ReversedWildcardFilterFactorythat emits reversed tokens. This can be used when constructing fieldTypes for fields that may need to handle leading wildcard queries. There is an example of this in the _defaultconfig setcalled text_general_rev.
What is the reversed token filter in Apache Solr?
Apache Solr has a token filter called the ReversedWildcardFilterFactorythat emits reversed tokens. This can be used when constructing fieldTypes for fields that may need to handle leading wildcard queries.
When to use asterick in leading wildcard query?
A leading wildcard query must iterate through all of the terms in the index to see if they match the query. For even moderately sized indices this can be time consuming. With the asterick ( *) at the beginning of the query, this means that there can be many matches throughout the index.
What is Apache Solr? Apache Solr (Searching On Lucene w/ Replication) is a free, open-source search engine based on the Apache Lucene library. An Apache Lucene subproject, it has been available since 2004 and is one of the most popular search engines available today worldwide.
How does a query handler work in Solr?
When you send a query, Solr processes it with a query request handles (or simply query handler) that works similarly to the index handler, only that is used to return documents from the Solr index instead of uploading them. NOTE: Before running the actual query, you may want to identify the fields you want to target with each keyword.
Which is the best way to analyze Solr data?
Solr has two ways of analyzing data: Facets. These are good for real-time analytics. For example, in product search, you’d break down results by brand. In log analysis, you’d look at the volume of errors per hour. Streaming aggregations.
How are metrics exposed in Apache Solr 6.4?
Solr exposes its metrics via JMX MBeans, so you can do some ad-hoc monitoring (more like spot-checking) using tools like JConsole, or JMXC. As of Solr 6.4 Solr started exposing its metrics via an HTTP API, too.
What are some examples of how Solr works?
Examples include joining results with a different data set (potentially outside Solr) and machine learning tasks such as clustering or regression. Before diving into the process of how Solr works, it’s important to understand the key terms used when working with Solr, from cores to documents, nodes, shards and more.