Skip to content

perf: reduce memory allocations with intelligent capacity pre-allocation #663

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 5 commits into
base: dev
Choose a base branch
from
+676 −23
Open

perf: reduce memory allocations with intelligent capacity pre-allocation #663

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
a41b4e8
fix (docs + hql + cli): updating readme, fixes for HQL, and docker fi…
xav-db Oct 8, 2025
7ce62a5
fix (core+cli): updating version (#657)
xav-db Oct 8, 2025
ca1d88a
Added Manta Graph button to README
makosst Oct 12, 2025
1a2c030
Added Manta Graph button to README (#660)
xav-db Oct 13, 2025
5adf3ca
perf: reduce memory allocations with intelligent capacity pre-allocation
am-miracle Oct 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
[![GitHub Repo stars](https://img.shields.io/github/stars/HelixDB/helix-db)](https://github.com/HelixDB/helix-db/stargazers)
[![Discord](https://img.shields.io/discord/1354148209005559819?logo=discord)](https://discord.gg/2stgMPr5BD)
[![LOC](https://img.shields.io/endpoint?url=https://ghloc.vercel.app/api/HelixDB/helix-db/badge?filter=.rs$,.sh$&style=flat&logoColor=white&label=Lines%20of%20Code)](https://github.com/HelixDB/helix-db)
[![Manta Graph](https://getmanta.ai/api/badges?text=Manta%20Graph&link=helixdb)](https://getmanta.ai/helixdb)

<a href="https://www.ycombinator.com/launches/Naz-helixdb-the-database-for-rag-ai" target="_blank"><img src="https://www.ycombinator.com/launches/Naz-helixdb-the-database-for-rag-ai/upvote_embed.svg" alt="Launch YC: HelixDB - The Database for Intelligence" style="margin-left: 12px;"/></a>

Expand Down
4 changes: 4 additions & 0 deletions helix-db/Cargo.toml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -77,3 +77,7 @@ path = "benches/bm25_benches.rs"
[[test]]
name = "hnsw_benches"
path = "benches/hnsw_benches.rs"

[[test]]
name = "capacity_optimization_benches"
path = "benches/capacity_optimization_benches.rs"
Comment on lines +80 to +83
Copy link
Contributor

@greptile-apps greptile-apps bot Oct 16, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

style: Missing newline at end of file - rustfmt typically adds one

Suggested change
[[test]]
name = "capacity_optimization_benches"
path = "benches/capacity_optimization_benches.rs"
[[test]]
name = "capacity_optimization_benches"
path = "benches/capacity_optimization_benches.rs"
Prompt To Fix With AI 
This is a comment left during a code review.
Path: helix-db/Cargo.toml
Line: 80:83

Comment:
**style:** Missing newline at end of file - `rustfmt` typically adds one

```suggestion
[[test]]
name = "capacity_optimization_benches"
path = "benches/capacity_optimization_benches.rs"
```

How can I resolve this? If you propose a fix, please make it concise.

291 changes: 291 additions & 0 deletions helix-db/benches/capacity_optimization_benches.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,291 @@
/// Performance benchmarks for Vec::with_capacity() optimizations
///
/// Run with: cargo test --test capacity_optimization_benches --release -- --nocapture
///
/// These are performance tests that measure actual execution time
/// to demonstrate the improvements from Vec::with_capacity() optimizations

#[cfg(test)]
mod tests {
use helix_db::{
helix_engine::{
bm25::bm25::BM25,
storage_core::HelixGraphStorage,
traversal_core::{
config::Config,
ops::{
g::G,
source::{add_n::AddNAdapter, n_from_type::NFromTypeAdapter},
util::{
aggregate::AggregateAdapter, group_by::GroupByAdapter,
update::UpdateAdapter,
},
},
},
},
props,
utils::id::v6_uuid,
};
use std::sync::Arc;
use std::time::Instant;
use tempfile::TempDir;

fn setup_test_db() -> (Arc<HelixGraphStorage>, TempDir) {
let temp_dir = TempDir::new().unwrap();
let db_path = temp_dir.path().to_str().unwrap();

let mut config = Config::default();
config.bm25 = Some(true);

let storage = HelixGraphStorage::new(db_path, config, Default::default()).unwrap();
(Arc::new(storage), temp_dir)
}

fn setup_db_with_nodes(count: usize) -> (Arc<HelixGraphStorage>, TempDir) {
let (storage, temp_dir) = setup_test_db();
let mut txn = storage.graph_env.write_txn().unwrap();

for i in 0..count {
let _ = G::new_mut(Arc::clone(&storage), &mut txn)
.add_n(
"User",
Some(props! {
"name" => format!("User{}", i),
"age" => (20 + (i % 50)) as i64,
"department" => format!("Dept{}", i % 5),
"city" => format!("City{}", i % 10),
"role" => format!("Role{}", i % 3),
"score" => (i % 100) as i64,
}),
None,
)
.collect_to_obj();
}

txn.commit().unwrap();
(storage, temp_dir)
}

#[test]
fn bench_aggregate_small() {
println!("\n=== Aggregate Performance (100 rows) ===");

for prop_count in [1, 3, 5] {
let (storage, _temp_dir) = setup_db_with_nodes(100);

let properties: Vec<String> = match prop_count {
1 => vec!["department".to_string()],
3 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
],
5 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
"role".to_string(),
"score".to_string(),
],
_ => vec![],
};

let start = Instant::now();
let txn = storage.graph_env.read_txn().unwrap();
let _result = G::new(Arc::clone(&storage), &txn)
.n_from_type("User")
.aggregate_by(&properties, false);
let elapsed = start.elapsed();

println!(" {} properties: {:?}", prop_count, elapsed);
}
}

#[test]
fn bench_aggregate_medium() {
println!("\n=== Aggregate Performance (1,000 rows) ===");

for prop_count in [1, 3, 5] {
let (storage, _temp_dir) = setup_db_with_nodes(1000);

let properties: Vec<String> = match prop_count {
1 => vec!["department".to_string()],
3 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
],
5 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
"role".to_string(),
"score".to_string(),
],
_ => vec![],
};

let start = Instant::now();
let txn = storage.graph_env.read_txn().unwrap();
let _result = G::new(Arc::clone(&storage), &txn)
.n_from_type("User")
.aggregate_by(&properties, false);
let elapsed = start.elapsed();

println!(" {} properties: {:?}", prop_count, elapsed);
}
}

#[test]
fn bench_aggregate_large() {
println!("\n=== Aggregate Performance (10,000 rows) ===");

let (storage, _temp_dir) = setup_db_with_nodes(10000);

for prop_count in [1, 3, 5] {
let properties: Vec<String> = match prop_count {
1 => vec!["department".to_string()],
3 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
],
5 => vec![
"department".to_string(),
"age".to_string(),
"city".to_string(),
"role".to_string(),
"score".to_string(),
],
_ => vec![],
};

let start = Instant::now();
let txn = storage.graph_env.read_txn().unwrap();
let _result = G::new(Arc::clone(&storage), &txn)
.n_from_type("User")
.aggregate_by(&properties, false);
let elapsed = start.elapsed();

println!(" {} properties: {:?}", prop_count, elapsed);
}
}

#[test]
fn bench_group_by() {
println!("\n=== Group By Performance ===");

for size in [100, 1000] {
let (storage, _temp_dir) = setup_db_with_nodes(size);
let properties = vec!["department".to_string(), "city".to_string()];

let start = Instant::now();
let txn = storage.graph_env.read_txn().unwrap();
let _result = G::new(Arc::clone(&storage), &txn)
.n_from_type("User")
.group_by(&properties, false);
let elapsed = start.elapsed();

println!(" {} rows: {:?}", size, elapsed);
}
}

#[test]
fn bench_update_operations() {
println!("\n=== Update Performance ===");

for size in [10, 100, 1000] {
let (storage, _temp_dir) = setup_db_with_nodes(size);
let mut txn = storage.graph_env.write_txn().unwrap();

// Get nodes to update
let update_tr = {
let rtxn = storage.graph_env.read_txn().unwrap();
G::new(Arc::clone(&storage), &rtxn)
.n_from_type("User")
.collect_to::<Vec<_>>()
};

let start = Instant::now();
let _result = G::new_mut_from(Arc::clone(&storage), &mut txn, update_tr)
.update(Some(vec![("score".to_string(), 999.into())]))
.collect_to::<Vec<_>>();
let elapsed = start.elapsed();

txn.commit().unwrap();
println!(" {} nodes: {:?}", size, elapsed);
}
}

#[test]
fn bench_bm25_search() {
println!("\n=== BM25 Search Performance ===");

let (storage, _temp_dir) = setup_test_db();
let mut wtxn = storage.graph_env.write_txn().unwrap();

let bm25 = storage.bm25.as_ref().expect("BM25 should be enabled");

// Insert 10,000 documents
for i in 0..10000 {
let doc = format!(
"Document {} contains various search terms keywords database performance optimization testing benchmark",
i
);
bm25.insert_doc(&mut wtxn, v6_uuid(), &doc).unwrap();
}

wtxn.commit().unwrap();

let rtxn = storage.graph_env.read_txn().unwrap();

for limit in [10, 100, 1000] {
let start = Instant::now();
let _results = bm25.search(&rtxn, "database optimization performance", limit);
let elapsed = start.elapsed();

println!(" limit={}: {:?}", limit, elapsed);
}
}

#[test]
fn bench_vector_allocation_patterns() {
println!("\n=== Vector Allocation Patterns ===");

// Pattern 1: Vec::new() in loop (old way - slow)
let start = Instant::now();
for _ in 0..1000 {
let properties_count = 5;
for _ in 0..100 {
let mut vec1 = Vec::new();
let mut vec2 = Vec::new();
for i in 0..properties_count {
vec1.push(i);
vec2.push(format!("value_{}", i));
}
}
}
let vec_new_time = start.elapsed();
println!(" Vec::new() in loop: {:?}", vec_new_time);

// Pattern 2: Vec::with_capacity() in loop (new way - fast)
let start = Instant::now();
for _ in 0..1000 {
let properties_count = 5;
for _ in 0..100 {
let mut vec1 = Vec::with_capacity(properties_count);
let mut vec2 = Vec::with_capacity(properties_count);
for i in 0..properties_count {
vec1.push(i);
vec2.push(format!("value_{}", i));
}
}
}
let vec_capacity_time = start.elapsed();
println!(" Vec::with_capacity() in loop: {:?}", vec_capacity_time);

let improvement =
(1.0 - (vec_capacity_time.as_secs_f64() / vec_new_time.as_secs_f64())) * 100.0;
println!(" Improvement: {:.1}% faster", improvement);
}
}
8 changes: 6 additions & 2 deletions helix-db/src/helix_engine/bm25/bm25.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -370,7 +370,9 @@ impl BM25 for HBM25Config {
}

// Sort by score and return top results
let mut results: Vec<(u128, f32)> = doc_scores.into_iter().collect();
// Pre-allocate with exact capacity to avoid reallocation during collection
let mut results: Vec<(u128, f32)> = Vec::with_capacity(doc_scores.len());
results.extend(doc_scores);
results.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
results.truncate(limit);

Expand Down Expand Up @@ -450,7 +452,9 @@ impl HybridSearch for HelixGraphStorage {
}
}

let mut results = combined_scores.into_iter().collect::<Vec<(u128, f32)>>();
// Pre-allocate with exact capacity to avoid reallocation during collection
let mut results = Vec::with_capacity(combined_scores.len());
results.extend(combined_scores);
results.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
results.truncate(limit);

Expand Down
Loading