Understanding and Configuring Solr's PingRequestHandler

In this blog, we'll talk about simple yet very useful Solr handler which is PingRequestHandler. We can use Ping Request Handler…

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Solr LocalParams and Security

Local Parameters are often called as LocalParams. Using this we can “localize” information about an argument that is being sent to Solr through Solr query. its another way of adding…

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Using Solr and TikaOCR to search text inside an image.

Tesseract is probably the most accurate open source OCR engine available and with Apache Tika 1.7 you can now use the awesome Tesseract OCR parser within Tika!

Solr 5.x has support…

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Using Solr's ComplexPhraseQueryParser

ComplexPhraseQuery allows complex phrase query syntax e.g “canc* treat* “. It Performs multiple passes over Query text to parse any nested logic in PhraseQueries.

The first pass takes any PhraseQuery content…

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Measuring Search Relevance using NDCG

Normalized Discounted Cumulative Gain (NDCG) is popular method for measuring the quality of a set of search results. It asserts the following:

Very relevant results are more useful than somewhat relevant…

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Query Rescoring in Solr

Sometimes relevance requirements are very complex and creates performance issues during execution. There is a very nice feature Introduced in Solr 4.9 called “Query Reranking/Rescoring” (SOLR-6088) which allows us to…

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Understanding PhraseQuery and Slop in Solr

PhraseQuery in Lucene matches documents containing a particular sequence of terms. PhraseQuery uses positional information of the term that is stored in an index. 

The number of other words permitted between…

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Exactish Phrase Matching in Solr

Phrase match: A simple way by which we can achieve exact matching in Solr is by using the default string type. It is exact phrase matching. the string is a useful…

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Solr's mm parameter - Explanation of Min Number Should Match

This article explains the format used for specifying the “Min Number Should Match” criteria of the BooleanQuery objects built by the DisMaxRequestHandler.  Using this it is possible to specify a…

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