While migrating large repositories say having 3 M docs (250k PDF) Lucene indexing takes long time to complete (at time 4 days!). Currently the text extraction logic is coupled with Lucene indexing and hence is performed in a single threaded mode which slows down the indexing process. Further if the reindexing has to be triggered it has to be done all over again.
To speed up the Lucene indexing we can decouple the text extraction
from actual indexing. It is partly based on discussion on OAK-2787
- Introduce a new ExtractedTextProvider which can provide extracted text for a given Blob instance
- In oak-run introduce a new indexer mode - This would take a path in repository and would then traverse the repository and look for existing binaries and extract text from that
So before or after migration is done one can run this oak-run tool to create this store which has the text already extracted. Then post startup we need to wire up the ExtractedTextProvider instance (which is backed by the BlobStore populated before) and indexing logic can just get content from that. This would avoid performing expensive text extraction in the indexing thread.
See discussion thread http://markmail.org/thread/ndlfpkwfgpey6o66