Full Text Search in MongoDB not yielding the expected result for “@@@”

Question

So I have a document in a collection with on of the fields having a value \"@@@\" I indexed the collection and tried running the query:

db.getCollection(\'TestColl

Answer 1

Text search is designed to index strings based on language heuristics. Text indexing involves two general steps: tokenizing (converting a string into individual terms of interest) followed by stemming (converting each term into a root form for indexing based on language-specific rules).

During the tokenizing step certain characters (for example, punctuation symbols such as @) are classified as word separators (aka delimiters) rather than text input and used to separate the original string into terms. Language-specific stop words (common words such as "the", "is", or "on" in English) are also excluded from a text index.

Since your search phrase of @@@ consists entirely of delimiters, there is no corresponding entry in the text index.

If you want to match generic string patterns, you should use regular expressions rather than text search. For example: db.getCollection('TestCollection').find({field2:/@@@/}). However, please note the caveats on index usage for regular expressions.