Upgrade to Lucene to 9.x

[lfcnassif]

We are using a very old 4.9 version. A lot of Lucene APIs changed and it will need some work. This is a sensible upgrade and will break back compatibility. At least Lucene query performance and memory usage evolved a lot in 2018 and 2019: https://home.apache.org/~mikemccand/lucenebench/

TermQueries increased from 40/s to 1k/s !

[lfcnassif]

migrated to lucene-5.5.5 as a first step in 17babcd

[lfcnassif]

Migration to lucene-6.6.6 c5a44db merged in master.

Now we can use multidimensional points.

[lfcnassif]

I'm resuming this work. It's harder than expected, because DocValues, used in lots of places, are not random accessible anymore since Lucene 7.0:
https://issues.apache.org/jira/browse/LUCENE-7407

[lfcnassif]

Lucene 9.0.0 was recently released: https://lucene.apache.org/core/corenews.html#apache-lucenetm-900-available
I highlight Support for indexing high-dimensionality numeric vectors to perform nearest-neighbor search, using the Hierarchical Navigable Small World graph algorithm
It is a state-of-the-art algorithm that could be used in photoDNA, similar images, similar faces and future vector based features look up.
But Lucene 9.0 requires JDK 11 or newer.

What other devs think about setting JDK 11 as minimum version for IPED, as it will use by default the embedded JDK 11 at processing and analysis time? Users won't have issues if they use the *.exe files and will receive a warning before exit if they execute the *.jar files with an older JDK version.
I'm +1.

[fmpfeifer]

I think that JDK 11 as minimum requirement is almost mandatory now.
Supporting JDK 8 is already holding us back.
my 2p.

[lfcnassif]

Supporting JDK 8 is already holding us back.

What JDK 11 feature/library would you like to use?