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Lucy::Index::BackgroundMerger – Apache Lucy Documentation
Apache Lucy™


Lucy::Index::BackgroundMerger - Consolidate index segments in the background.


my $bg_merger = Lucy::Index::BackgroundMerger->new(
    index  => '/path/to/index',


Adding documents to an index is usually fast, but every once in a while the index must be compacted and an update takes substantially longer to complete. See FastUpdates for how to use this class to control worst-case index update performance.

As with Indexer, see FileLocking if your index is on a shared volume.



my $bg_merger = Lucy::Index::BackgroundMerger->new(
    index   => '/path/to/index',    # required
    manager => $manager             # default: created internally

Open a new BackgroundMerger.

  • index - Either a string filepath or a Folder.
  • manager - An IndexManager. If not supplied, an IndexManager with a 10-second write lock timeout will be created.




Optimize the index for search-time performance. This may take a while, as it can involve rewriting large amounts of data.



Commit any changes made to the index. Until this is called, none of the changes made during an indexing session are permanent.

Calls prepare_commit() implicitly if it has not already been called.



Perform the expensive setup for commit() in advance, so that commit() completes quickly.

Towards the end of prepare_commit(), the BackgroundMerger attempts to re-acquire the write lock, which is then held until commit() finishes and releases it.


Lucy::Index::BackgroundMerger isa Clownfish::Obj.