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perf: teach SegmentReader to lazily open/read its various SegmentComponents (#20)

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This overhauls `SegmentReader` to put its various components behind `OnceLock`s such that they can be opened and read on their first use, as oppoed when a SegmentReader is constructed -- which is once for every segment when an Index is opened.

This has a negative impact on some of Tantivy's expectations in that an existing SegementReader can still read from physical files that were deleted by a merge.  This isn't true now that the segment's physical files aren't opened until needed.  As such, I've `#[ignore]`'d six tests that expose this problem.

From our (pg_search's) side of things, we don't really have physical files and don't need to rely on the filesystem/kernel to allow reading unlinked files that are still open.

Overall, this cuts down a signficiant number of disk reads during pg_search's query planning.  With my test data it goes from 808 individual reads totalling 999,799 bytes, to 18 reads totalling 814,514 bytes.

This reduces the time it takes to plan a simple query from about 1.4ms to 0.436ms -- roughly a 3.2x improvement.
This commit is contained in:
Eric Ridge
2025-01-17 15:29:40 -05:00
committed by Stu Hood
parent ddd169b77c
commit 95661fba30
3 changed files with 198 additions and 98 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/searcher.rs
+22 -10
View File
@@ -1,5 +1,5 @@
use std::collections::BTreeMap;
use std::sync::Arc;
use std::sync::{Arc, OnceLock};
use std::{fmt, io};
use crate::collector::Collector;
@@ -86,7 +86,7 @@ impl Searcher {
/// The searcher uses the segment ordinal to route the
/// request to the right `Segment`.
pub fn doc<D: DocumentDeserialize>(&self, doc_address: DocAddress) -> crate::Result<D> {
let store_reader = &self.inner.store_readers[doc_address.segment_ord as usize];
let store_reader = &self.inner.store_readers()[doc_address.segment_ord as usize];
store_reader.get(doc_address.doc_id)
}
@@ -96,7 +96,7 @@ impl Searcher {
pub fn doc_store_cache_stats(&self) -> CacheStats {
let cache_stats: CacheStats = self
.inner
.store_readers
.store_readers()
.iter()
.map(|reader| reader.cache_stats())
.sum();
@@ -110,7 +110,7 @@ impl Searcher {
doc_address: DocAddress,
) -> crate::Result<D> {
let executor = self.inner.index.search_executor();
let store_reader = &self.inner.store_readers[doc_address.segment_ord as usize];
let store_reader = &self.inner.store_readers()[doc_address.segment_ord as usize];
store_reader.get_async(doc_address.doc_id, executor).await
}
@@ -259,8 +259,9 @@ impl From<Arc<SearcherInner>> for Searcher {
pub(crate) struct SearcherInner {
schema: Schema,
index: Index,
doc_store_cache_num_blocks: usize,
segment_readers: Vec<SegmentReader>,
store_readers: Vec<StoreReader>,
store_readers: OnceLock<Vec<StoreReader>>,
generation: TrackedObject<SearcherGeneration>,
}
@@ -281,19 +282,30 @@ impl SearcherInner {
generation.segments(),
"Set of segments referenced by this Searcher and its SearcherGeneration must match"
);
let store_readers: Vec<StoreReader> = segment_readers
.iter()
.map(|segment_reader| segment_reader.get_store_reader(doc_store_cache_num_blocks))
.collect::<io::Result<Vec<_>>>()?;
Ok(SearcherInner {
schema,
index,
doc_store_cache_num_blocks,
segment_readers,
store_readers,
store_readers: OnceLock::default(),
generation,
})
}
#[inline]
fn store_readers(&self) -> &[StoreReader] {
self.store_readers.get_or_init(|| {
self.segment_readers
.iter()
.map(|segment_reader| {
segment_reader
.get_store_reader(self.doc_store_cache_num_blocks)
.expect("should be able to get store reader")
})
.collect()
})
}
}
impl fmt::Debug for Searcher {
src/index/segment_reader.rs
+170 -88
View File
@@ -1,12 +1,15 @@
use std::collections::HashMap;
use std::sync::{Arc, RwLock};
use std::ops::BitOrAssign;
use std::path::PathBuf;
use std::sync::{Arc, OnceLock, RwLock};
use std::{fmt, io};
use common::{ByteCount, HasLen};
use fnv::FnvHashMap;
use itertools::Itertools;
use crate::directory::{CompositeFile, FileSlice};
use crate::directory::error::OpenReadError;
use crate::directory::{CompositeFile, FileSlice, ManagedDirectory};
use crate::error::DataCorruption;
use crate::fastfield::{intersect_alive_bitsets, AliveBitSet, FacetReader, FastFieldReaders};
use crate::fieldnorm::{FieldNormReader, FieldNormReaders};
@@ -16,7 +19,7 @@ use crate::schema::{Field, IndexRecordOption, Schema, Type};
use crate::space_usage::SegmentSpaceUsage;
use crate::store::StoreReader;
use crate::termdict::TermDictionary;
use crate::{DocId, Opstamp};
use crate::{Directory, DocId, Index, Opstamp, SegmentMeta};
/// Entry point to access all of the datastructures of the `Segment`
///
@@ -30,22 +33,25 @@ use crate::{DocId, Opstamp};
/// as close to all of the memory data is mmapped.
#[derive(Clone)]
pub struct SegmentReader {
inv_idx_reader_cache: Arc<RwLock<HashMap<Field, Arc<InvertedIndexReader>>>>,
index: Index,
segment_id: SegmentId,
custom_alive_bitset: Option<AliveBitSet>,
inv_idx_reader_cache: Arc<RwLock<HashMap<Field, Arc<InvertedIndexReader>>>>,
delete_opstamp: Option<Opstamp>,
max_doc: DocId,
num_docs: DocId,
num_docs: Arc<OnceLock<DocId>>,
termdict_composite: CompositeFile,
postings_composite: CompositeFile,
positions_composite: CompositeFile,
fast_fields_readers: FastFieldReaders,
fieldnorm_readers: FieldNormReaders,
termdict_composite: Arc<OnceLock<CompositeFile>>,
postings_composite: Arc<OnceLock<CompositeFile>>,
positions_composite: Arc<OnceLock<CompositeFile>>,
fast_fields_readers: Arc<OnceLock<FastFieldReaders>>,
fieldnorm_readers: Arc<OnceLock<FieldNormReaders>>,
store_file: FileSlice,
alive_bitset_opt: Option<AliveBitSet>,
store_file: Arc<OnceLock<FileSlice>>,
has_deletes: bool,
alive_bitset_opt: Arc<OnceLock<Option<AliveBitSet>>>,
schema: Schema,
}
@@ -59,7 +65,12 @@ impl SegmentReader {
/// Returns the number of alive documents.
/// Deleted documents are not counted.
pub fn num_docs(&self) -> DocId {
self.num_docs
*self.num_docs.get_or_init(|| {
self.alive_bitset_opt()
.as_ref()
.map(|alive_bitset| alive_bitset.num_alive_docs() as u32)
.unwrap_or(self.max_doc)
})
}
/// Returns the schema of the index this segment belongs to.
@@ -70,7 +81,7 @@ impl SegmentReader {
/// Return the number of documents that have been
/// deleted in the segment.
pub fn num_deleted_docs(&self) -> DocId {
self.max_doc - self.num_docs
self.max_doc - self.num_docs()
}
/// Returns true if some of the documents of the segment have been deleted.
@@ -89,7 +100,7 @@ impl SegmentReader {
/// # Panics
/// May panic if the index is corrupted.
pub fn fast_fields(&self) -> &FastFieldReaders {
&self.fast_fields_readers
self.fast_fields_readers()
}
/// Accessor to the `FacetReader` associated with a given `Field`.
@@ -116,7 +127,7 @@ impl SegmentReader {
/// They are simply stored as a fast field, serialized in
/// the `.fieldnorm` file of the segment.
pub fn get_fieldnorms_reader(&self, field: Field) -> crate::Result<FieldNormReader> {
self.fieldnorm_readers.get_field(field)?.ok_or_else(|| {
self.fieldnorm_readers().get_field(field)?.ok_or_else(|| {
let field_name = self.schema.get_field_name(field);
let err_msg = format!(
"Field norm not found for field {field_name:?}. Was the field set to record norm \
@@ -128,7 +139,7 @@ impl SegmentReader {
#[doc(hidden)]
pub fn fieldnorms_readers(&self) -> &FieldNormReaders {
&self.fieldnorm_readers
self.fieldnorm_readers()
}
/// Accessor to the segment's [`StoreReader`](crate::store::StoreReader).
@@ -136,7 +147,7 @@ impl SegmentReader {
/// `cache_num_blocks` sets the number of decompressed blocks to be cached in an LRU.
/// The size of blocks is configurable, this should be reflexted in the
pub fn get_store_reader(&self, cache_num_blocks: usize) -> io::Result<StoreReader> {
StoreReader::open(self.store_file.clone(), cache_num_blocks)
StoreReader::open(self.store_file().clone(), cache_num_blocks)
}
/// Open a new segment for reading.
@@ -149,61 +160,27 @@ impl SegmentReader {
segment: &Segment,
custom_bitset: Option<AliveBitSet>,
) -> crate::Result<SegmentReader> {
let termdict_file = segment.open_read(SegmentComponent::Terms)?;
let termdict_composite = CompositeFile::open(&termdict_file)?;
let store_file = segment.open_read(SegmentComponent::Store)?;
crate::fail_point!("SegmentReader::open#middle");
let postings_file = segment.open_read(SegmentComponent::Postings)?;
let postings_composite = CompositeFile::open(&postings_file)?;
let positions_composite = {
if let Ok(positions_file) = segment.open_read(SegmentComponent::Positions) {
CompositeFile::open(&positions_file)?
} else {
CompositeFile::empty()
}
};
let schema = segment.schema();
let fast_fields_data = segment.open_read(SegmentComponent::FastFields)?;
let fast_fields_readers = FastFieldReaders::open(fast_fields_data, schema.clone())?;
let fieldnorm_data = segment.open_read(SegmentComponent::FieldNorms)?;
let fieldnorm_readers = FieldNormReaders::open(fieldnorm_data)?;
let original_bitset = if segment.meta().has_deletes() {
let alive_doc_file_slice = segment.open_read(SegmentComponent::Delete)?;
let alive_doc_data = alive_doc_file_slice.read_bytes()?;
Some(AliveBitSet::open(alive_doc_data))
} else {
None
};
let alive_bitset_opt = intersect_alive_bitset(original_bitset, custom_bitset);
let max_doc = segment.meta().max_doc();
let num_docs = alive_bitset_opt
.as_ref()
.map(|alive_bitset| alive_bitset.num_alive_docs() as u32)
.unwrap_or(max_doc);
Ok(SegmentReader {
inv_idx_reader_cache: Default::default(),
num_docs,
max_doc,
termdict_composite,
postings_composite,
fast_fields_readers,
fieldnorm_readers,
index: segment.index().clone(),
segment_id: segment.id(),
custom_alive_bitset: custom_bitset,
inv_idx_reader_cache: Default::default(),
delete_opstamp: segment.meta().delete_opstamp(),
store_file,
alive_bitset_opt,
positions_composite,
schema,
max_doc: segment.meta().max_doc(),
num_docs: Default::default(),
termdict_composite: Default::default(),
postings_composite: Default::default(),
positions_composite: Default::default(),
fast_fields_readers: Default::default(),
fieldnorm_readers: Default::default(),
store_file: Default::default(),
has_deletes: segment.meta().has_deletes(),
alive_bitset_opt: Default::default(),
schema: segment.schema(),
})
}
@@ -236,7 +213,7 @@ impl SegmentReader {
warn!("Field {:?} does not seem indexed.", field_entry.name());
}
let postings_file_opt = self.postings_composite.open_read(field);
let postings_file_opt = self.postings_composite().open_read(field);
if postings_file_opt.is_none() || record_option_opt.is_none() {
// no documents in the segment contained this field.
@@ -251,7 +228,7 @@ impl SegmentReader {
let postings_file = postings_file_opt.unwrap();
let termdict_file: FileSlice =
self.termdict_composite.open_read(field).ok_or_else(|| {
self.termdict_composite().open_read(field).ok_or_else(|| {
DataCorruption::comment_only(format!(
"Failed to open field {:?}'s term dictionary in the composite file. Has the \
schema been modified?",
@@ -259,7 +236,7 @@ impl SegmentReader {
))
})?;
let positions_file = self.positions_composite.open_read(field).ok_or_else(|| {
let positions_file = self.positions_composite().open_read(field).ok_or_else(|| {
let error_msg = format!(
"Failed to open field {:?}'s positions in the composite file. Has the schema been \
modified?",
@@ -431,7 +408,7 @@ impl SegmentReader {
/// Returns the bitset representing the alive `DocId`s.
pub fn alive_bitset(&self) -> Option<&AliveBitSet> {
self.alive_bitset_opt.as_ref()
self.alive_bitset_opt().as_ref()
}
/// Returns true if the `doc` is marked
@@ -444,7 +421,7 @@ impl SegmentReader {
/// Returns an iterator that will iterate over the alive document ids
pub fn doc_ids_alive(&self) -> Box<dyn Iterator<Item = DocId> + Send + '_> {
if let Some(alive_bitset) = &self.alive_bitset_opt {
if let Some(alive_bitset) = self.alive_bitset_opt() {
Box::new(alive_bitset.iter_alive())
} else {
Box::new(0u32..self.max_doc)
@@ -455,30 +432,135 @@ impl SegmentReader {
pub fn space_usage(&self) -> io::Result<SegmentSpaceUsage> {
Ok(SegmentSpaceUsage::new(
self.num_docs(),
self.termdict_composite.space_usage(self.schema()),
self.postings_composite.space_usage(self.schema()),
self.positions_composite.space_usage(self.schema()),
self.fast_fields_readers.space_usage()?,
self.fieldnorm_readers.space_usage(self.schema()),
self.termdict_composite().space_usage(self.schema()),
self.postings_composite().space_usage(self.schema()),
self.positions_composite().space_usage(self.schema()),
self.fast_fields_readers().space_usage()?,
self.fieldnorm_readers().space_usage(self.schema()),
self.get_store_reader(0)?.space_usage(),
self.alive_bitset_opt
self.alive_bitset_opt()
.as_ref()
.map(AliveBitSet::space_usage)
.unwrap_or_default(),
))
}
fn relative_path(&self, component: SegmentComponent) -> PathBuf {
let mut path = self.segment_id().uuid_string();
path.push_str(&match component {
SegmentComponent::Postings => ".idx".to_string(),
SegmentComponent::Positions => ".pos".to_string(),
SegmentComponent::Terms => ".term".to_string(),
SegmentComponent::Store => ".store".to_string(),
SegmentComponent::TempStore => ".store.temp".to_string(),
SegmentComponent::FastFields => ".fast".to_string(),
SegmentComponent::FieldNorms => ".fieldnorm".to_string(),
SegmentComponent::Delete => format!(".{}.del", self.delete_opstamp().unwrap_or(0)),
});
PathBuf::from(path)
}
fn open_read(&self, component: SegmentComponent) -> Result<FileSlice, OpenReadError> {
let path = self.relative_path(component);
self.index.directory().open_read(&path)
}
#[inline]
fn store_file(&self) -> &FileSlice {
self.store_file.get_or_init(move || {
self.open_read(SegmentComponent::Store)
.expect("should be able to open store segment component")
})
}
#[inline]
fn termdict_composite(&self) -> &CompositeFile {
self.termdict_composite.get_or_init(move || {
CompositeFile::open(
&self
.open_read(SegmentComponent::Terms)
.expect("should be able to open termdict segment component"),
)
.expect("should be able to open termdict composite file")
})
}
#[inline]
fn postings_composite(&self) -> &CompositeFile {
self.postings_composite.get_or_init(move || {
CompositeFile::open(
&self
.open_read(SegmentComponent::Postings)
.expect("should be able to open postings segment component"),
)
.expect("should be able to open postings composite file")
})
}
#[inline]
fn positions_composite(&self) -> &CompositeFile {
self.positions_composite.get_or_init(move || {
if let Ok(positions_file) = &self.open_read(SegmentComponent::Positions) {
CompositeFile::open(&positions_file)
.expect("should be able to open positions composite component")
} else {
CompositeFile::empty()
}
})
}
#[inline]
fn fast_fields_readers(&self) -> &FastFieldReaders {
self.fast_fields_readers.get_or_init(move || {
FastFieldReaders::open(
self.open_read(SegmentComponent::FastFields)
.expect("should be able to open fast fields segment component"),
self.schema.clone(),
)
.expect("should be able to open fast fields readers")
})
}
#[inline]
fn fieldnorm_readers(&self) -> &FieldNormReaders {
self.fieldnorm_readers.get_or_init(move || {
FieldNormReaders::open(
self.open_read(SegmentComponent::FieldNorms)
.expect("should be able to open field norms segment component"),
)
.expect("should be able to open field norms readers")
})
}
#[inline]
fn alive_bitset_opt(&self) -> &Option<AliveBitSet> {
self.alive_bitset_opt.get_or_init(move || {
let physical_alive_bitset = if self.has_deletes {
Some(AliveBitSet::open(
self.open_read(SegmentComponent::Delete)
.expect("should be able to open deletes segment component")
.read_bytes()
.expect("should be able to read deletes segment component"),
))
} else {
None
};
intersect_alive_bitset(physical_alive_bitset, self.custom_alive_bitset.clone())
})
}
}
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
/// FieldMetadata
pub struct FieldMetadata {
/// The field name
// Notice: Don't reorder the declaration of 1.field_name 2.typ, as it is used for ordering by
// field_name then typ.
/// Notice: Don't reorder the declaration of 1.field_name 2.typ, as it is used for ordering by
/// field_name then typ.
pub field_name: String,
/// The field type
// Notice: Don't reorder the declaration of 1.field_name 2.typ, as it is used for ordering by
// field_name then typ.
/// Notice: Don't reorder the declaration of 1.field_name 2.typ, as it is used for ordering by
/// field_name then typ.
pub typ: Type,
/// Is the field stored in the doc store
pub stored: bool,
@@ -577,8 +659,8 @@ fn intersect_alive_bitset(
}
impl fmt::Debug for SegmentReader {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "SegmentReader({:?})", self.segment_id)
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "SegmentReader({:?})", self.segment_id())
}
}
src/indexer/index_writer.rs
+6
View File
@@ -2257,6 +2257,7 @@ mod tests {
}
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_ff_num_ips_regression() {
assert!(test_operation_strategy(
&[
@@ -2298,27 +2299,32 @@ mod tests {
#![proptest_config(ProptestConfig::with_cases(20))]
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_delete_proptest_adding(ops in proptest::collection::vec(adding_operation_strategy(), 1..100)) {
assert!(test_operation_strategy(&ops[..], false).is_ok());
}
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_delete_proptest_with_merge_adding(ops in proptest::collection::vec(adding_operation_strategy(), 1..100)) {
assert!(test_operation_strategy(&ops[..], true).is_ok());
}
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_delete_proptest(ops in proptest::collection::vec(balanced_operation_strategy(), 1..10)) {
assert!(test_operation_strategy(&ops[..], false).is_ok());
}
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_delete_proptest_with_merge(ops in proptest::collection::vec(balanced_operation_strategy(), 1..100)) {
assert!(test_operation_strategy(&ops[..], true).is_ok());
}
}
#[test]
#[ignore = "doesn't work with deferred segment loading"]
fn test_delete_bug_reproduction_ip_addr() {
use IndexingOp::*;
let ops = &[