The index might get bigger, because all synonyms must be indexed.
Search scoring, which relies on term statistics, might suffer because synonyms are also counted, and the statistics for less common words become skewed.
Synonym rules can’t be changed for existing documents without reindexing.
...
Using synonyms in search-time analyzers on the other hand doesn’t have many of the above mentioned problems:
The index size is unaffected.
The term statistics in the corpus stay the same.
Changes in the synonym rules don’t require reindexing of documents.
And:
Starting with Elasticsearch 7.3, this reopening of indices in order to see changes in synonym files is no longer needed.
We must:
provide a new "search time" config
write a better documentation for updating synonyms in production
Reading https://www.elastic.co/blog/boosting-the-power-of-elasticsearch-with-synonyms - we quickly see Emoji Search can benefit from the new
POST /synonym_test/_reload_search_analyzers
API.And:
We must: