Federated search: support facets

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Louis Dureuil 2024-09-12 17:51:20 +02:00
parent 7b55462610
commit 533f1d4345
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@ -9,20 +9,24 @@ use std::vec::{IntoIter, Vec};
use actix_http::StatusCode;
use index_scheduler::{IndexScheduler, RoFeatures};
use indexmap::IndexMap;
use meilisearch_types::deserr::DeserrJsonError;
use meilisearch_types::error::deserr_codes::{
InvalidMultiSearchWeight, InvalidSearchLimit, InvalidSearchOffset,
InvalidMultiSearchFacetsByIndex, InvalidMultiSearchMaxValuesPerFacet,
InvalidMultiSearchMergeFacets, InvalidMultiSearchSortFacetValuesBy, InvalidMultiSearchWeight,
InvalidSearchLimit, InvalidSearchOffset,
};
use meilisearch_types::error::ResponseError;
use meilisearch_types::index_uid::IndexUid;
use meilisearch_types::milli::score_details::{ScoreDetails, ScoreValue};
use meilisearch_types::milli::{self, DocumentId, TimeBudget};
use meilisearch_types::milli::{self, DocumentId, OrderBy, TimeBudget};
use roaring::RoaringBitmap;
use serde::Serialize;
use super::ranking_rules::{self, RankingRules};
use super::{
prepare_search, AttributesFormat, HitMaker, HitsInfo, RetrieveVectors, SearchHit, SearchKind,
SearchQuery, SearchQueryWithIndex,
compute_facet_distribution_stats, prepare_search, AttributesFormat, ComputedFacets, FacetStats,
HitMaker, HitsInfo, RetrieveVectors, SearchHit, SearchKind, SearchQuery, SearchQueryWithIndex,
};
use crate::error::MeilisearchHttpError;
use crate::routes::indexes::search::search_kind;
@ -73,6 +77,59 @@ pub struct Federation {
pub limit: usize,
#[deserr(default = super::DEFAULT_SEARCH_OFFSET(), error = DeserrJsonError<InvalidSearchOffset>)]
pub offset: usize,
#[deserr(default, error = DeserrJsonError<InvalidMultiSearchFacetsByIndex>)]
pub facets_by_index: BTreeMap<IndexUid, Option<Vec<String>>>,
#[deserr(default, error = DeserrJsonError<InvalidMultiSearchMergeFacets>)]
pub merge_facets: Option<MergeFacets>,
}
#[derive(Copy, Clone, Debug, deserr::Deserr, Default)]
#[deserr(error = DeserrJsonError<InvalidMultiSearchMergeFacets>, rename_all = camelCase, deny_unknown_fields)]
pub struct MergeFacets {
#[deserr(default, error = DeserrJsonError<InvalidMultiSearchSortFacetValuesBy>)]
pub sort_facet_values_by: SortFacetValuesBy,
#[deserr(default, error = DeserrJsonError<InvalidMultiSearchMaxValuesPerFacet>)]
pub max_values_per_facet: Option<usize>,
}
impl MergeFacets {
pub fn to_components(this: Option<Self>) -> (Option<OrderBy>, Option<usize>) {
match this {
Some(MergeFacets { sort_facet_values_by, max_values_per_facet }) => {
(sort_facet_values_by.into(), max_values_per_facet)
}
None => (None, None),
}
}
}
#[derive(Debug, deserr::Deserr, Default, Clone, Copy)]
#[deserr(rename_all = camelCase, deny_unknown_fields)]
pub enum SortFacetValuesBy {
#[default]
IndexSettings,
/// By lexicographic order...
Alpha,
/// Or by number of docids in common?
Count,
}
impl From<SortFacetValuesBy> for Option<OrderBy> {
fn from(value: SortFacetValuesBy) -> Self {
match value {
SortFacetValuesBy::Alpha => Some(OrderBy::Lexicographic),
SortFacetValuesBy::Count => Some(OrderBy::Count),
SortFacetValuesBy::IndexSettings => None,
}
}
}
#[derive(Debug, deserr::Deserr, Default)]
#[deserr(rename_all = camelCase, deny_unknown_fields)]
pub enum GroupFacetsBy {
Facet,
#[default]
Index,
}
#[derive(Debug, deserr::Deserr)]
@ -82,7 +139,7 @@ pub struct FederatedSearch {
#[deserr(default)]
pub federation: Option<Federation>,
}
#[derive(Serialize, Clone, PartialEq)]
#[derive(Serialize, Clone)]
#[serde(rename_all = "camelCase")]
pub struct FederatedSearchResult {
pub hits: Vec<SearchHit>,
@ -93,6 +150,13 @@ pub struct FederatedSearchResult {
#[serde(skip_serializing_if = "Option::is_none")]
pub semantic_hit_count: Option<u32>,
#[serde(skip_serializing_if = "Option::is_none")]
pub facet_distribution: Option<BTreeMap<String, IndexMap<String, u64>>>,
#[serde(skip_serializing_if = "Option::is_none")]
pub facet_stats: Option<BTreeMap<String, FacetStats>>,
#[serde(skip_serializing_if = "FederatedFacets::is_empty")]
pub facets_by_index: FederatedFacets,
// These fields are only used for analytics purposes
#[serde(skip)]
pub degraded: bool,
@ -109,6 +173,9 @@ impl fmt::Debug for FederatedSearchResult {
semantic_hit_count,
degraded,
used_negative_operator,
facet_distribution,
facet_stats,
facets_by_index,
} = self;
let mut debug = f.debug_struct("SearchResult");
@ -122,9 +189,18 @@ impl fmt::Debug for FederatedSearchResult {
if *degraded {
debug.field("degraded", degraded);
}
if let Some(facet_distribution) = facet_distribution {
debug.field("facet_distribution", &facet_distribution);
}
if let Some(facet_stats) = facet_stats {
debug.field("facet_stats", &facet_stats);
}
if let Some(semantic_hit_count) = semantic_hit_count {
debug.field("semantic_hit_count", &semantic_hit_count);
}
if !facets_by_index.is_empty() {
debug.field("facets_by_index", &facets_by_index);
}
debug.finish()
}
@ -313,16 +389,111 @@ struct SearchHitByIndex {
}
struct SearchResultByIndex {
index: String,
hits: Vec<SearchHitByIndex>,
candidates: RoaringBitmap,
estimated_total_hits: usize,
degraded: bool,
used_negative_operator: bool,
facets: Option<ComputedFacets>,
}
#[derive(Debug, Clone, Default, Serialize)]
pub struct FederatedFacets(pub BTreeMap<String, ComputedFacets>);
impl FederatedFacets {
pub fn insert(&mut self, index: String, facets: Option<ComputedFacets>) {
if let Some(facets) = facets {
self.0.insert(index, facets);
}
}
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
pub fn merge(
self,
MergeFacets { sort_facet_values_by, max_values_per_facet }: MergeFacets,
facet_order: Option<BTreeMap<String, (String, OrderBy)>>,
) -> Option<ComputedFacets> {
if self.is_empty() {
return None;
}
let mut distribution: BTreeMap<String, _> = Default::default();
let mut stats: BTreeMap<String, FacetStats> = Default::default();
for facets_by_index in self.0.into_values() {
for (facet, index_distribution) in facets_by_index.distribution {
match distribution.entry(facet) {
std::collections::btree_map::Entry::Vacant(entry) => {
entry.insert(index_distribution);
}
std::collections::btree_map::Entry::Occupied(mut entry) => {
let distribution = entry.get_mut();
for (value, index_count) in index_distribution {
distribution
.entry(value)
.and_modify(|count| *count += index_count)
.or_insert(index_count);
}
}
}
}
for (facet, index_stats) in facets_by_index.stats {
match stats.entry(facet) {
std::collections::btree_map::Entry::Vacant(entry) => {
entry.insert(index_stats);
}
std::collections::btree_map::Entry::Occupied(mut entry) => {
let stats = entry.get_mut();
stats.min =
if stats.min <= index_stats.min { stats.min } else { index_stats.min };
stats.max =
if stats.max >= index_stats.max { stats.max } else { index_stats.max };
}
}
}
}
// fixup order
for (facet, values) in &mut distribution {
let order_by = Option::<OrderBy>::from(sort_facet_values_by)
.or_else(|| match &facet_order {
Some(facet_order) => facet_order.get(facet).map(|(_, order)| *order),
None => None,
})
.unwrap_or_default();
match order_by {
OrderBy::Lexicographic => {
values.sort_unstable_by(|left, _, right, _| left.cmp(right))
}
OrderBy::Count => {
values.sort_unstable_by(|_, left, _, right| {
left.cmp(right)
// biggest first
.reverse()
})
}
}
if let Some(max_values_per_facet) = max_values_per_facet {
values.truncate(max_values_per_facet)
};
}
Some(ComputedFacets { distribution, stats })
}
}
pub fn perform_federated_search(
index_scheduler: &IndexScheduler,
queries: Vec<SearchQueryWithIndex>,
federation: Federation,
mut federation: Federation,
features: RoFeatures,
) -> Result<FederatedSearchResult, ResponseError> {
let before_search = std::time::Instant::now();
@ -357,13 +528,29 @@ pub fn perform_federated_search(
// 2. perform queries, merge and make hits index by index
let required_hit_count = federation.limit + federation.offset;
let (override_sort_facet_values_by, override_max_values_per_facet) =
MergeFacets::to_components(federation.merge_facets);
// In step (2), semantic_hit_count will be set to Some(0) if any search kind uses semantic
// Then in step (3), we'll update its value if there is any semantic search
let mut semantic_hit_count = None;
let mut results_by_index = Vec::with_capacity(queries_by_index.len());
let mut previous_query_data: Option<(RankingRules, usize, String)> = None;
// remember the order and name of first index for each facet when merging with index settings
// to detect if the order is inconsistent for a facet.
let mut facet_order: Option<BTreeMap<String, (String, OrderBy)>> = match federation.merge_facets
{
Some(MergeFacets { sort_facet_values_by: SortFacetValuesBy::IndexSettings, .. }) => {
Some(Default::default())
}
_ => None,
};
for (index_uid, queries) in queries_by_index {
let first_query_index = queries.first().map(|query| query.query_index);
let index = match index_scheduler.index(&index_uid) {
Ok(index) => index,
Err(err) => {
@ -371,9 +558,8 @@ pub fn perform_federated_search(
// Patch the HTTP status code to 400 as it defaults to 404 for `index_not_found`, but
// here the resource not found is not part of the URL.
err.code = StatusCode::BAD_REQUEST;
if let Some(query) = queries.first() {
err.message =
format!("Inside `.queries[{}]`: {}", query.query_index, err.message);
if let Some(query_index) = first_query_index {
err.message = format!("Inside `.queries[{}]`: {}", query_index, err.message);
}
return Err(err);
}
@ -398,6 +584,23 @@ pub fn perform_federated_search(
let mut used_negative_operator = false;
let mut candidates = RoaringBitmap::new();
let facets_by_index = federation.facets_by_index.remove(&index_uid).flatten();
// TODO: recover the max size + facets_by_index as return value of this function so as not to ask it for all queries
if let Err(mut error) =
check_facet_order(&mut facet_order, &index_uid, &facets_by_index, &index, &rtxn)
{
error.message = format!(
"Inside `.federation.facetsByIndex.{index_uid}`: {error}{}",
if let Some(query_index) = first_query_index {
format!("\n Note: index `{index_uid}` used in `.queries[{query_index}]`")
} else {
Default::default()
}
);
return Err(error);
}
// 2.1. Compute all candidates for each query in the index
let mut results_by_query = Vec::with_capacity(queries.len());
@ -566,34 +769,118 @@ pub fn perform_federated_search(
.collect();
let merged_result = merged_result?;
let estimated_total_hits = candidates.len() as usize;
let facets = facets_by_index
.map(|facets_by_index| {
compute_facet_distribution_stats(
&facets_by_index,
&index,
&rtxn,
candidates,
override_max_values_per_facet,
override_sort_facet_values_by,
)
})
.transpose()
.map_err(|mut error| {
error.message = format!(
"Inside `.federation.facetsByIndex.{index_uid}`: {}{}",
error.message,
if let Some(query_index) = first_query_index {
format!("\n Note: index `{index_uid}` used in `.queries[{query_index}]`")
} else {
Default::default()
}
);
error
})?;
results_by_index.push(SearchResultByIndex {
index: index_uid,
hits: merged_result,
candidates,
estimated_total_hits,
degraded,
used_negative_operator,
facets,
});
}
// bonus step, make sure to return an error if an index wants a non-faceted field, even if no query actually uses that index.
for (index_uid, facets) in federation.facets_by_index {
let index = match index_scheduler.index(&index_uid) {
Ok(index) => index,
Err(err) => {
let mut err = ResponseError::from(err);
// Patch the HTTP status code to 400 as it defaults to 404 for `index_not_found`, but
// here the resource not found is not part of the URL.
err.code = StatusCode::BAD_REQUEST;
err.message = format!(
"Inside `.federation.facetsByIndex.{index_uid}`: {}\n Note: index `{index_uid}` is not used in queries",
err.message
);
return Err(err);
}
};
// Important: this is the only transaction we'll use for this index during this federated search
let rtxn = index.read_txn()?;
if let Err(mut error) =
check_facet_order(&mut facet_order, &index_uid, &facets, &index, &rtxn)
{
error.message = format!(
"Inside `.federation.facetsByIndex.{index_uid}`: {error}\n Note: index `{index_uid}` is not used in queries",
);
return Err(error);
}
if let Some(facets) = facets {
if let Err(mut error) = compute_facet_distribution_stats(
&facets,
&index,
&rtxn,
Default::default(),
override_max_values_per_facet,
override_sort_facet_values_by,
) {
error.message =
format!("Inside `.federation.facetsByIndex.{index_uid}`: {}\n Note: index `{index_uid}` is not used in queries", error.message);
return Err(error);
}
}
}
// 3. merge hits and metadata across indexes
// 3.1 merge metadata
let (estimated_total_hits, degraded, used_negative_operator) = {
let (estimated_total_hits, degraded, used_negative_operator, facets) = {
let mut estimated_total_hits = 0;
let mut degraded = false;
let mut used_negative_operator = false;
let mut facets: FederatedFacets = FederatedFacets::default();
for SearchResultByIndex {
index,
hits: _,
candidates,
estimated_total_hits: estimated_total_hits_by_index,
facets: facets_by_index,
degraded: degraded_by_index,
used_negative_operator: used_negative_operator_by_index,
} in &results_by_index
} in &mut results_by_index
{
estimated_total_hits += candidates.len() as usize;
estimated_total_hits += *estimated_total_hits_by_index;
degraded |= *degraded_by_index;
used_negative_operator |= *used_negative_operator_by_index;
let facets_by_index = std::mem::take(facets_by_index);
let index = std::mem::take(index);
facets.insert(index, facets_by_index);
}
(estimated_total_hits, degraded, used_negative_operator)
(estimated_total_hits, degraded, used_negative_operator, facets)
};
// 3.2 merge hits
@ -610,6 +897,18 @@ pub fn perform_federated_search(
.map(|hit| hit.hit)
.collect();
let (facet_distribution, facet_stats, facets_by_index) = match federation.merge_facets {
Some(merge_facets) => {
let facets = facets.merge(merge_facets, facet_order);
let (facet_distribution, facet_stats) =
facets.map(|ComputedFacets { distribution, stats }| (distribution, stats)).unzip();
(facet_distribution, facet_stats, FederatedFacets::default())
}
None => (None, None, facets),
};
let search_result = FederatedSearchResult {
hits: merged_hits,
processing_time_ms: before_search.elapsed().as_millis(),
@ -621,7 +920,39 @@ pub fn perform_federated_search(
semantic_hit_count,
degraded,
used_negative_operator,
facet_distribution,
facet_stats,
facets_by_index,
};
Ok(search_result)
}
fn check_facet_order(
facet_order: &mut Option<BTreeMap<String, (String, OrderBy)>>,
current_index: &str,
facets_by_index: &Option<Vec<String>>,
index: &milli::Index,
rtxn: &milli::heed::RoTxn<'_>,
) -> Result<(), ResponseError> {
if let (Some(facet_order), Some(facets_by_index)) = (facet_order, facets_by_index) {
let index_facet_order = index.sort_facet_values_by(rtxn)?;
for facet in facets_by_index {
let index_facet_order = index_facet_order.get(facet);
let (previous_index, previous_facet_order) = facet_order
.entry(facet.to_owned())
.or_insert_with(|| (current_index.to_owned(), index_facet_order));
if previous_facet_order != &index_facet_order {
return Err(MeilisearchHttpError::InconsistentFacetOrder {
facet: facet.clone(),
previous_facet_order: *previous_facet_order,
previous_uid: previous_index.clone(),
current_uid: current_index.to_owned(),
index_facet_order,
}
.into());
}
}
};
Ok(())
}