PropertyIndex handle large deletions : Possible optimization

[Chetan Mehrotra <ch...@gmail.com>]

Hi Team,

Currently in case large deletion are performed i.e. deleting big subtree
where multiple property indexes are configured for nodes in that deleted
tree then deletion is found to be very slow (at least for DocumentMK).

Looking at the code it seems that if a deletion is detected the editor
still traverses the deleted sub tree completely and updates the backing
index on per node basis. Instead of that if it utilizes the fact that index
is also managed as a tree i.e. at least for ContentMirrorStoreStrategy it
can just delete the index tree at that path for various values.

LuceneIndexEditor takes a similar approach [1] by issuing a PrefixQuery to
drop all Lucene documents under that path

Chetan Mehrotra
[1]
https://github.com/apache/jackrabbit-oak/blob/trunk/oak-lucene/src/main/java/org/apache/jackrabbit/oak/plugins/index/lucene/LuceneIndexEditor.java#L230-255