535: Reintroduce the max values by facet limit r=ManyTheFish a=Kerollmops

This PR reintroduces the max values by facet limit this is related to https://github.com/meilisearch/meilisearch/issues/2349.

~I would like some help in deciding on whether I keep the default 100 max values in milli and set up the `FacetDistribution` settings in Meilisearch to use 1000 as the new value, I expose the `max_values_by_facet` for this purpose.~

I changed the default value to 1000 and the max to 10000, thank you `@ManyTheFish` for the help!

Co-authored-by: Kerollmops <clement@meilisearch.com>
This commit is contained in:
bors[bot] 2022-06-01 14:30:50 +00:00 committed by GitHub
commit 74d1914a64
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@ -1,6 +1,6 @@
use std::collections::{BTreeMap, HashSet}; use std::collections::{BTreeMap, HashSet};
use std::ops::Bound::Unbounded; use std::ops::Bound::Unbounded;
use std::{fmt, mem}; use std::{cmp, fmt, mem};
use heed::types::ByteSlice; use heed::types::ByteSlice;
use roaring::RoaringBitmap; use roaring::RoaringBitmap;
@ -13,6 +13,14 @@ use crate::heed_codec::facet::{
use crate::search::facet::{FacetNumberIter, FacetNumberRange, FacetStringIter}; use crate::search::facet::{FacetNumberIter, FacetNumberRange, FacetStringIter};
use crate::{FieldId, Index, Result}; use crate::{FieldId, Index, Result};
/// The default number of values by facets that will
/// be fetched from the key-value store.
const DEFAULT_VALUES_BY_FACET: usize = 1000;
/// The hard limit in the number of values by facets that will be fetched from
/// the key-value store. Searching for more values could slow down the engine.
const MAX_VALUES_BY_FACET: usize = 10000;
/// Threshold on the number of candidates that will make /// Threshold on the number of candidates that will make
/// the system to choose between one algorithm or another. /// the system to choose between one algorithm or another.
const CANDIDATES_THRESHOLD: u64 = 3000; const CANDIDATES_THRESHOLD: u64 = 3000;
@ -20,13 +28,20 @@ const CANDIDATES_THRESHOLD: u64 = 3000;
pub struct FacetDistribution<'a> { pub struct FacetDistribution<'a> {
facets: Option<HashSet<String>>, facets: Option<HashSet<String>>,
candidates: Option<RoaringBitmap>, candidates: Option<RoaringBitmap>,
max_values_by_facet: usize,
rtxn: &'a heed::RoTxn<'a>, rtxn: &'a heed::RoTxn<'a>,
index: &'a Index, index: &'a Index,
} }
impl<'a> FacetDistribution<'a> { impl<'a> FacetDistribution<'a> {
pub fn new(rtxn: &'a heed::RoTxn, index: &'a Index) -> FacetDistribution<'a> { pub fn new(rtxn: &'a heed::RoTxn, index: &'a Index) -> FacetDistribution<'a> {
FacetDistribution { facets: None, candidates: None, rtxn, index } FacetDistribution {
facets: None,
candidates: None,
max_values_by_facet: DEFAULT_VALUES_BY_FACET,
rtxn,
index,
}
} }
pub fn facets<I: IntoIterator<Item = A>, A: AsRef<str>>(&mut self, names: I) -> &mut Self { pub fn facets<I: IntoIterator<Item = A>, A: AsRef<str>>(&mut self, names: I) -> &mut Self {
@ -34,6 +49,11 @@ impl<'a> FacetDistribution<'a> {
self self
} }
pub fn max_values_by_facet(&mut self, max: usize) -> &mut Self {
self.max_values_by_facet = cmp::min(max, MAX_VALUES_BY_FACET);
self
}
pub fn candidates(&mut self, candidates: RoaringBitmap) -> &mut Self { pub fn candidates(&mut self, candidates: RoaringBitmap) -> &mut Self {
self.candidates = Some(candidates); self.candidates = Some(candidates);
self self
@ -52,6 +72,7 @@ impl<'a> FacetDistribution<'a> {
FacetType::Number => { FacetType::Number => {
let mut key_buffer: Vec<_> = field_id.to_be_bytes().iter().copied().collect(); let mut key_buffer: Vec<_> = field_id.to_be_bytes().iter().copied().collect();
let distribution_prelength = distribution.len();
let db = self.index.field_id_docid_facet_f64s; let db = self.index.field_id_docid_facet_f64s;
for docid in candidates.into_iter() { for docid in candidates.into_iter() {
key_buffer.truncate(mem::size_of::<FieldId>()); key_buffer.truncate(mem::size_of::<FieldId>());
@ -64,6 +85,10 @@ impl<'a> FacetDistribution<'a> {
for result in iter { for result in iter {
let ((_, _, value), ()) = result?; let ((_, _, value), ()) = result?;
*distribution.entry(value.to_string()).or_insert(0) += 1; *distribution.entry(value.to_string()).or_insert(0) += 1;
if distribution.len() - distribution_prelength == self.max_values_by_facet {
break;
}
} }
} }
} }
@ -86,6 +111,10 @@ impl<'a> FacetDistribution<'a> {
.entry(normalized_value) .entry(normalized_value)
.or_insert_with(|| (original_value, 0)); .or_insert_with(|| (original_value, 0));
*count += 1; *count += 1;
if normalized_distribution.len() == self.max_values_by_facet {
break;
}
} }
} }
@ -116,6 +145,9 @@ impl<'a> FacetDistribution<'a> {
if !docids.is_empty() { if !docids.is_empty() {
distribution.insert(value.to_string(), docids.len()); distribution.insert(value.to_string(), docids.len());
} }
if distribution.len() == self.max_values_by_facet {
break;
}
} }
Ok(()) Ok(())
@ -136,6 +168,9 @@ impl<'a> FacetDistribution<'a> {
if !docids.is_empty() { if !docids.is_empty() {
distribution.insert(original.to_string(), docids.len()); distribution.insert(original.to_string(), docids.len());
} }
if distribution.len() == self.max_values_by_facet {
break;
}
} }
Ok(()) Ok(())
@ -155,6 +190,9 @@ impl<'a> FacetDistribution<'a> {
for result in range { for result in range {
let ((_, _, value, _), docids) = result?; let ((_, _, value, _), docids) = result?;
distribution.insert(value.to_string(), docids.len()); distribution.insert(value.to_string(), docids.len());
if distribution.len() == self.max_values_by_facet {
break;
}
} }
let iter = self let iter = self
@ -168,6 +206,9 @@ impl<'a> FacetDistribution<'a> {
for result in iter { for result in iter {
let ((_, normalized_value), (original_value, docids)) = result?; let ((_, normalized_value), (original_value, docids)) = result?;
normalized_distribution.insert(normalized_value, (original_value, docids.len())); normalized_distribution.insert(normalized_value, (original_value, docids.len()));
if normalized_distribution.len() == self.max_values_by_facet {
break;
}
} }
let iter = normalized_distribution let iter = normalized_distribution
@ -253,11 +294,12 @@ impl<'a> FacetDistribution<'a> {
impl fmt::Debug for FacetDistribution<'_> { impl fmt::Debug for FacetDistribution<'_> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let FacetDistribution { facets, candidates, rtxn: _, index: _ } = self; let FacetDistribution { facets, candidates, max_values_by_facet, rtxn: _, index: _ } = self;
f.debug_struct("FacetDistribution") f.debug_struct("FacetDistribution")
.field("facets", facets) .field("facets", facets)
.field("candidates", candidates) .field("candidates", candidates)
.field("max_values_by_facet", max_values_by_facet)
.finish() .finish()
} }
} }