We just noticed a very strange problem with Solr 6.4.2 QueryParser. The QueryParser changes the query by itself from time to time. This happens if doing a search request reload several times at higher rate.
Good example: ... <str name="q">textth:waffenhandel</str> <result name="response" numFound="85" start="0"> ... <str name="rawquerystring">textth:waffenhandel</str> <str name="querystring">textth:waffenhandel</str> <str name="parsedquery">+SynonymQuery(Synonym(textth:"arms sales" textth:"arms trade"... <str name="parsedquery_toString">+Synonym(textth:"arms sales" textth:"arms trade"... Bad example: ... <str name="q">textth:waffenhandel</str> <result name="response" numFound="20459" start="0"> ... <str name="rawquerystring">textth:waffenhandel</str> <str name="querystring">textth:waffenhandel</str> <str name="parsedquery">+textth:rss</str> <str name="parsedquery_toString">+textth:rss</str> As you can see in the bad example after several reloads the parsedquery changed to term "rss". But the original querystring has no "rss" substring at all. That is really strange. Anyone seen this before? Single index, Solr 6.4.2. Regards Bernd