MeiliSearch/milli/src/update/word_prefix_docids.rs

132 lines
4.7 KiB
Rust
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use std::collections::{HashMap, HashSet};
use grenad::{CompressionType, MergerBuilder};
use heed::types::ByteSlice;
use crate::update::index_documents::{
create_sorter, merge_roaring_bitmaps, sorter_into_lmdb_database, CursorClonableMmap, MergeFn,
};
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use crate::{Index, Result};
pub struct WordPrefixDocids<'t, 'u, 'i> {
wtxn: &'t mut heed::RwTxn<'i, 'u>,
index: &'i Index,
pub(crate) chunk_compression_type: CompressionType,
pub(crate) chunk_compression_level: Option<u32>,
pub(crate) max_nb_chunks: Option<usize>,
pub(crate) max_memory: Option<usize>,
}
impl<'t, 'u, 'i> WordPrefixDocids<'t, 'u, 'i> {
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pub fn new(
wtxn: &'t mut heed::RwTxn<'i, 'u>,
index: &'i Index,
) -> WordPrefixDocids<'t, 'u, 'i> {
WordPrefixDocids {
wtxn,
index,
chunk_compression_type: CompressionType::None,
chunk_compression_level: None,
max_nb_chunks: None,
max_memory: None,
}
}
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#[logging_timer::time("WordPrefixDocids::{}")]
pub fn execute(
self,
new_word_docids: Vec<grenad::Reader<CursorClonableMmap>>,
new_prefix_fst_words: &[String],
common_prefix_fst_words: &[&[String]],
del_prefix_fst_words: &HashSet<Vec<u8>>,
) -> Result<()> {
// It is forbidden to keep a mutable reference into the database
// and write into it at the same time, therefore we write into another file.
let mut prefix_docids_sorter = create_sorter(
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merge_roaring_bitmaps,
self.chunk_compression_type,
self.chunk_compression_level,
self.max_nb_chunks,
self.max_memory,
);
let mut word_docids_merger = MergerBuilder::new(merge_roaring_bitmaps);
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for reader in new_word_docids {
word_docids_merger.push(reader.into_cursor()?);
}
let mut word_docids_iter = word_docids_merger.build().into_stream_merger_iter()?;
let mut current_prefixes: Option<&&[String]> = None;
let mut prefixes_cache = HashMap::new();
while let Some((word, data)) = word_docids_iter.next()? {
current_prefixes = match current_prefixes.take() {
Some(prefixes) if word.starts_with(&prefixes[0].as_bytes()) => Some(prefixes),
_otherwise => {
write_prefixes_in_sorter(&mut prefixes_cache, &mut prefix_docids_sorter)?;
common_prefix_fst_words
.iter()
.find(|prefixes| word.starts_with(&prefixes[0].as_bytes()))
}
};
if let Some(prefixes) = current_prefixes {
for prefix in prefixes.iter() {
if word.starts_with(prefix.as_bytes()) {
match prefixes_cache.get_mut(prefix.as_bytes()) {
Some(value) => value.push(data.to_owned()),
None => {
prefixes_cache.insert(prefix.clone().into(), vec![data.to_owned()]);
}
}
}
}
}
}
write_prefixes_in_sorter(&mut prefixes_cache, &mut prefix_docids_sorter)?;
// We fetch the docids associated to the newly added word prefix fst only.
let db = self.index.word_docids.remap_data_type::<ByteSlice>();
for prefix in new_prefix_fst_words {
let prefix = std::str::from_utf8(prefix.as_bytes())?;
for result in db.prefix_iter(self.wtxn, prefix)? {
let (_word, data) = result?;
prefix_docids_sorter.insert(prefix, data)?;
}
}
// We remove all the entries that are no more required in this word prefix docids database.
let mut iter = self.index.word_prefix_docids.iter_mut(self.wtxn)?.lazily_decode_data();
while let Some((prefix, _)) = iter.next().transpose()? {
if del_prefix_fst_words.contains(prefix.as_bytes()) {
unsafe { iter.del_current()? };
}
}
drop(iter);
// We finally write the word prefix docids into the LMDB database.
sorter_into_lmdb_database(
self.wtxn,
*self.index.word_prefix_docids.as_polymorph(),
prefix_docids_sorter,
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merge_roaring_bitmaps,
)?;
Ok(())
}
}
fn write_prefixes_in_sorter(
prefixes: &mut HashMap<Vec<u8>, Vec<Vec<u8>>>,
sorter: &mut grenad::Sorter<MergeFn>,
) -> Result<()> {
for (key, data_slices) in prefixes.drain() {
for data in data_slices {
sorter.insert(&key, data)?;
}
}
Ok(())
}