Start Updating lucene index

Updating lucene index

Performing lookups in batches gains some efficiency because we sort the terms in unicode order so we can do a single sequential scan through each segment's terms dictionary and postings.

It is a good analogy when you frame it in terms of searching. However, there are many differences between a Lucene index and a database.

Apache Lucene is an open source project available for free download. In this example we will see how to append to an existing lucene index. Then use our java program to create index and search.

We will see how we can update the existing index files with new data. Then we will add a new file, update the index and search again.

So you gain as much concurrency as indexing threads you are sending through .

This class is challenging to implement since it must handle so many complex and costly concurrent operations: ongoing indexing, deletes and updates; refreshing new readers; writing new segment files; committing changes to disk; merging segments and adding indexes.

This file writing takes the in-memory resolved doc ids and writes a new per-segment bitset, for deleted documents, or a whole new doc values column per field, for doc values updates.

This is typically a fast operation, except for large indices where a whole column of doc-values updates could be sizable.

We fixed that, more than 6 years ago now, yielding big indexing throughput gains on concurrent hardware.