---
title: "Limitations"
id: textsearch-limitations
pg_version: "20devel"
---

<a id="textsearch-limitations"></a>

## 12.11. Limitations

The current limitations of PostgreSQL's text search features are: 
- The length of each lexeme must be less than 2 kilobytes
- The length of a `tsvector` (lexemes + positions) must be less than 1 megabyte
- Position values in `tsvector` must be greater than 0 and no more than 16,383
- The match distance in a `<N>` (FOLLOWED BY) `tsquery` operator cannot be more than 16,384
- No more than 256 positions per lexeme
- The number of nodes (lexemes + operators) in a `tsquery` must be less than 32,768

 

For comparison, the PostgreSQL 8.1 documentation contained 10,441 unique words, a total of 335,420 words, and the most frequent word "postgresql" was mentioned 6,127 times in 655 documents. 

Another example — the PostgreSQL mailing list archives contained 910,989 unique words with 57,491,343 lexemes in 461,020 messages.