[ddorian43]

DuckDuckGo isn't based on lucene/solr but bing-api.

[tpayet]

my bad, my informations could be outdated.

based on http://highscalability.com/blog/2013/1/28/duckduckgo-archite...:

The fat tail queries go against PostgreSQL and the long tail queries go against Solr. For shorter queries PostgreSQL takes precedence. Long tail fills in Instance Answers where nothing else catches.

It seems that Bing is now a part of their sources indeed: https://help.duckduckgo.com/results/sources

[bmn__]

Both are used. Source: Torsten Raudssus who works for DDG as developer liaison.

[ddorian43]

You saying they do websearch in lucene/solr ? How many TB do they have in solr ?