bors[bot] 758b4acea7
Merge #776
776: Reduce incremental indexing time of `words_prefix_position_docids` DB r=curquiza a=loiclec

Fixes partially https://github.com/meilisearch/milli/issues/605

The `words_prefix_position_docids` can easily contain millions of entries. Thus, iterating
over it can be very expensive. But we do so needlessly for every document addition tasks.

It can sometimes cause indexing performance issues when :
- a user sends many `documentAdditionOrUpdate` tasks that cannot be all batched together (for example if they are interspersed with `documentDeletion` tasks)
- the documents contain long, diverse text fields, thus increasing the number of entries in `words_prefix_position_docids`
- the index has accumulated many soft-deleted documents, further increasing the size of `words_prefix_position_docids`
- the machine running Meilisearch does not have great IO performance (e.g. slow SSD, or quota-limited by the cloud provider)

Note, before approving  the PR: the only changed file should be `milli/src/update/words_prefix_position_docids.rs`.

Co-authored-by: Loïc Lecrenier <loic.lecrenier@me.com>
2023-01-31 15:52:28 +00:00
..
2023-01-31 11:12:59 +01:00