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Code Issues Releases Wiki Activity

Clean up the words prefixes when deleting documents and words

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Clément Renault 2021-02-17 11:22:25 +01:00
parent 62eee9c69e
commit ea37fd821d
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GPG Key ID: 92ADA4E935E71FA4
1 changed files with 41 additions and 4 deletions
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45
milli/src/update/delete_documents.rs
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@ -159,10 +159,6 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
}
}
// FIXME we must recompute the words prefixes docids.
todo!("recompute words prefixes docids");
todo!("recompute words prefixes pairs proximity docids");
// We construct an FST set that contains the words to delete from the words FST.
let words_to_delete = words.iter().filter_map(|(word, must_remove)| {
if *must_remove { Some(word.as_ref()) } else { None }
@ -185,6 +181,47 @@ impl<'t, 'u, 'i> DeleteDocuments<'t, 'u, 'i> {
// We write the new words FST into the main database.
self.index.put_words_fst(self.wtxn, &new_words_fst)?;
// We iterate over the word prefix docids database and remove the deleted documents ids
// from every docids lists. We register the empty prefixes in an fst Set for futur deletion.
let mut prefixes_to_delete = fst::SetBuilder::memory();
let mut iter = word_prefix_docids.iter_mut(self.wtxn)?;
while let Some(result) = iter.next() {
let (prefix, mut docids) = result?;
let previous_len = docids.len();
docids.difference_with(&self.documents_ids);
if docids.is_empty() {
iter.del_current()?;
prefixes_to_delete.insert(prefix)?;
} else if docids.len() != previous_len {
iter.put_current(prefix, &docids)?;
}
}
drop(iter);
// We compute the new prefix FST and write it only if there is a change.
let prefixes_to_delete = prefixes_to_delete.into_set();
if !prefixes_to_delete.is_empty() {
let new_words_prefixes_fst = {
// We retrieve the current words prefixes FST from the database.
let words_prefixes_fst = self.index.words_prefixes_fst(self.wtxn)?;
let difference = words_prefixes_fst.op().add(&prefixes_to_delete).difference();
// We stream the new external ids that does no more contains the to-delete external ids.
let mut new_words_prefixes_fst_builder = fst::SetBuilder::memory();
new_words_prefixes_fst_builder.extend_stream(difference.into_stream())?;
// We create an words FST set from the above builder.
new_words_prefixes_fst_builder.into_set()
};
// We write the new words prefixes FST into the main database.
self.index.put_words_prefixes_fst(self.wtxn, &new_words_prefixes_fst)?;
}
// FIXME we must recompute the words prefixes docids.
todo!("recompute words prefixes pairs proximity docids");
// We delete the documents ids that are under the pairs of words,
// it is faster and use no memory to iterate over all the words pairs than
// to compute the cartesian product of every words of the deleted documents.