Test speed of Lucene 8 vs Lucene 4 id lookups using DocValuesTermsQuery.
Lucene 8
1000000 docs
Indexing start string Indexing complete string search string complete in 9.713112046 secs
Indexing start numeric Indexing complete numeric search numeric complete in 0.441230859 secs
Lucene 4
1000000 docs
Indexing start string Indexing complete string search string complete in 4.7344909 secs
Indexing start numeric Indexing complete numeric
org.opentest4j.AssertionFailedError: (Numerics dont work with Terms Filter)
Take away
Lucene 8 numeric lookups are much faster!
Lucene 8 string lookup is twice as slow as Lucene 4.