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Questions tagged [inverted-index]

Inverted index is an index data structure storing a mapping from content, such as words or numbers, to its locations in a database file, or in a document or a set of documents. The purpose of an inverted index is to allow fast full text searches, at a cost of increased processing when a document is added to the database.

Inverted index (also referred to as postings file or inverted file) is an index data structure storing a mapping from content, such as words or numbers, to its locations in a database file, or in a document or a set of documents. The purpose of an inverted index is to allow fast full text searches, at a cost of increased processing when a document is added to the database. The inverted file may be the database file itself, rather than its index. It is the most popular data structure used in document retrieval systems, used on a large scale for example in search engines. Several significant general-purpose mainframe-based database management systems have used inverted list architectures, including ADABAS, DATACOM/DB, and Model 204.

There are two main variants of inverted indexes: A record level inverted index (or inverted file index or just inverted file) contains a list of references to documents for each word. A word level inverted index (or full inverted index or inverted list) additionally contains the positions of each word within a document. The latter form offers more functionality (like phrase searches), but needs more time and space to be created.

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Use of indexes for multi-word queries in full-text search (e.g. web search)

I understand that a fundamental aspect of full-text search is the use of inverted indexes. So, with an inverted index a one-word query becomes trivial to answer. Assuming the index is structured like this: some-word -> [doc385, doc211, doc39977,…
Luís Marques
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Inverting a dictionary with list values

I have this index as a dict. index = { 'Testfil2.txt': ['nisse', 'hue', 'abe', 'pind'], 'Testfil1.txt': ['hue', 'abe', 'tosse', 'svend']} I need to invert the index so it will be a dict with duplicates of values merged into one key with the…
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How do search engines merge results from an inverted index?

How do search engines merge results from an inverted index? For example, if I searched for the inverted indexes of the words "dog" and "bat", there would be two huge lists of every document which contained one of the two words. I doubt that a search…
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Lucene's algorithm

I read the paper by Doug Cutting; "Space optimizations for total ranking". Since it was written a long time ago, I wonder what algorithms lucene uses (regarding postings list traversal and score calculation, ranking). Particularly, the total ranking…
teddy teddy
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Forward Index vs Inverted index Why?

I was reading about inverted index (used by the text search engines like Solr, Elastic Search etc) and as I understand (if we take "Person" as an example): The attribute to Person relationship is inverted: John -> PersonId(1), PersonId(2),…
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Loading a large dictionary using python pickle

I have a full inverted index in form of nested python dictionary. Its structure is : {word : { doc_name : [location_list] } } For example let the dictionary be called index, then for a word " spam ", entry would look like : { spam : { doc1.txt :…
easysid
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How to optimize "text search" for inverted index and relational database?

Update 2022-08-12 I re-thought about it and realized I was overcomplicating it. I found the best way to enhance this system is by using good old information retrieval techniques ie using 'location' of a word in a sentence and 'ranking' queries to…
ccot
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Using cPickle to serialize a large dictionary causes MemoryError

I'm writing an inverted index for a search engine on a collection of documents. Right now, I'm storing the index as a dictionary of dictionaries. That is, each keyword maps to a dictionary of docIDs->positions of occurrence. The data model looks…
Stephen Poletto
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Inverted Index: Find a phrase in a set of documents

I'm implementing an inverted index structure, in particular one that allows boolean queries, and word-level granularity. I have large database of text, and I keep an index that tells me, for every word, in which file it is (IDdoc), and where in the…
Maria Ines Parnisari
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Get inverted index from SQLite FTS table

After I have implemented a full text search function in my application using Sqlite and FTS tables I would be interested in a performant way of retrieving the FULL inverted index out of my FTS table. In effect - I would need a result table including…
user625626
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Tips for creating a very large database of hashes

The question: What solution or tips would you have to deal with a very large (multi terabytes) database indexed on strong hashes with high redundancy? Some kind of inverted storage? Is there something that could be done with Postgres? I am ready…
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B Tree Index vs Inverted Index?

Here is mine understanding about both B Tree index :- It is generally used database column. It keeps the column content as key and row_id as value . It keeps the key in sorted fashion to quickly find the key and row location Inverted Index :-…
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How can I store the inverted document index on a disk?

I know this question has been asked again and again in stackoverflow and google, but I find that all the answers cannot satisfy me. Most of the solutions assume that the whole index can fit in memory, then we can store it to the disk by Java…
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Elastic Search Geo Spatial search implementation

I am trying to understand how elastic search supports Geo Spatial search internally. For the basic search, it uses the inverted index; but how does it combine with the additional search criteria like searching for a particular text within a certain…
java_geek
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Storing an inverted index

I am working on a project on Info Retrieval. I have made a Full Inverted Index using Hadoop/Python. Hadoop outputs the index as (word,documentlist) pairs which are written on the file. For a quick access, I have created a dictionary(hashtable)…
easysid
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