Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/13197
The patch adds initial support for backing FAISS's inverted file based indices with data stored in RocksDB. It introduces a `SecondaryIndex` implementation called `FaissIVFIndex` which takes ownership of a `faiss::IndexIVF` object. During indexing, `FaissIVFIndex` treats the original value of the specified primary column as an embedding vector, and passes it to the provided FAISS index object to perform quantization. It replaces the original embedding vector with the result of the coarse quantizer (i.e. the inverted list id), and puts the result of the fine quantizer (if any) into the secondary index value. Note that this patch is only one half of the equation; it provides a way of storing FAISS inverted lists in RocksDB but there is currently no retrieval/search support (this will be a follow-up change). Also, the integration currently works only with our internal Buck build. I plan to add support for `cmake` / `make` based builds similarly to how we handle Folly.
Reviewed By: jowlyzhang
Differential Revision: D66907065
fbshipit-source-id: 63fdf29895d5feeffc230254a7ddfb0aac050967
b339d089ed