US Patent 10417210 Multi-token matching scheme

A multi-token matching scheme efficiently detects multi-token keyword matches in content received by a database system. A keyword list may include multi-token keywords. Head tokens from the multi-token keywords are converted into a head hashmap. Token chains identifying tokens and delimiters in the multi-token keywords are generated and linked to the head hashmap. Tokens in the content are compared with the head hashmap. The matching tokens and following segments in the content are compared with the token chains. Portions of the content matching the token chains are identified as keyword matches. The matching scheme may use reverse delimiter tries to detect content matches for multi-token keywords with leading delimiters.