When comparing Solr vs Algolia, the Slant community recommends Solr for most people. In the question“What are the best search engines for web applications?” Solr is ranked 2nd while Algolia is ranked 6th. The most important reason people chose Solr is:
A key differentiator of Solr is the level of customizability the [SearchComponent](http://wiki.apache.org/solr/SearchComponent) feature provides. >SearchComponent provides the developer astonishing flexibility in the way search queries are assembled and executed. At the time of writing, there does not appear to be a ElasticSearch equivalent of SearchComponent. [source](http://www.elasticsearchtutorial.com/elasticsearch-vs-solr.html) Whilst ElasticSearch has a number of plugin-points there doesn't appear to be an equivalent of Solr's SearchComponent that enables you to modify the workflow of existing API endpoints.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Customizablity
A key differentiator of Solr is the level of customizability the SearchComponent feature provides.
SearchComponent provides the developer astonishing flexibility in the way search queries are assembled and executed. At the time of writing, there does not appear to be a ElasticSearch equivalent of SearchComponent. source
Whilst ElasticSearch has a number of plugin-points there doesn't appear to be an equivalent of Solr's SearchComponent that enables you to modify the workflow of existing API endpoints.
Pro Open source
Pro Stats component
Solr allows to view average, standard deviation, maximum, minimum, sum of squares of a particular numeric field. It also allows faceting of that numeric field based on the value(s) of other fields.
Pro Results grouping
Solr allows you to group search results. Results can be grouped by:
- Field Value
- Query
- Function Query
You can also collapse multiple results with the same field value down to a single result.
Pro Decision tree faceting
Solr has a faceting feature called pivot facets or 'decision tree facets'. Pivot facets enable you to calculate facets inside a parents facet, for example pivoting on 'size' than 'color' returns 'color' facet counts for each 'size' facet
Pro Local params
Solr has a great feature that enables you to use LocalParams to perform more advanced faceting. They provide a way to "localize" information about a specific argument that is being sent to Solr. In other words, LocalParams provide a way to add meta-data to certain argument types such as query strings. From the Solr Wiki:
LocalParams are expressed as prefixes to arguments to be sent to Solr. For example:
Assume we have the existing query parameter
q=solr rocks
We can prefix this query string with LocalParams to provide more information to the query parser, for example changing the default operator type to "AND" and the default field to "title" for the lucene query parser:
q={!q.op=AND df=title}solr rocks
Pro SpellChecker
Solr allows has the functionality to check and correct spelling mistakes in search queries. The three main implementations are:
- IndexBasedSpellChecker
- WordBreadkSolrSpellChecker
- DirectSolrSpellChecker
Pro Very fast and reliable
API replies in few milliseconds and they have datacenters all around the world.
Pro As a hosted service it reduces required maintenance work
Algolia provides worldwide hosting, meaning you can scale up search worldwide at the click of a button.
Pro Optimized UX for autocomplete and find-as-you-type results
Their InstantSearch.js library and accompanying native mobile UX tools make it easy to build beautiful search experiences.
Pro Free Hacker Plan: 10K records and 100K monthly operations
In addition to their 14-day free trial, Algolia supports their Community with a free plan as well as discounts for non-profits, students and the open source community.
Pro Search-as-you-type is built-in
Designed to natively search for prefixes (enables auto-complete menu search OOTB).
Pro Very easy to configure
The configuration is based on tie breaks which makes reasoning about the search easier.
Pro 100% customizable
Pro Language-agnostic & typo tolerance
Algolia's engine has been built in such a way that you can index and search any language, or even several languages at the same time.
The engine is also typo tolerant, and will allow for up to two typos in each words of the search query.
This typo tolerance feature is also language agnostic, as it relies on optimized data structures and "fuzzy" tree traversals (implementing a Damarau-Levenshtein distance algorithm) instead of using dictionaries.
Pro Unique ranking formula combining full-text and business relevance
Their Tie-Breaking Algorithm gives you powerful relevance from day one that you can customize as much as you want by integrating the business metrics that matter most.
Cons
Con General missing features
Solr is currently missing the following general features:
- Per-doc/query analyzer chain
- Support for nested documents
- Support for multiple document types per schema
- Ability to modify document scores with custom scripts
- Equivalent to Elasticsearch's percolation
Con Missing some useful features for cloud distribution
Solr is currently missing the following features that are useful when managing a distributed system:
- Automatic shard rebalancing
- Ability to re-locate shards and replicas on demand
- Ability to change the schema without restarting the server
- Ability to search across multiple indexes.
Con Commercial
There is a Free tier limited to 10k records that can only do 100k operations.
