diff --git a/Cargo.lock b/Cargo.lock
index 98f06f53ad0..c18ee2f44dd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -619,7 +619,8 @@ dependencies = [
  "ra_syntax 0.1.0",
  "rayon 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "relative-path 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "salsa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "salsa 0.4.1 (git+https://github.com/salsa-rs/salsa?rev=20c9fbf)",
  "test_utils 0.1.0",
 ]
 
@@ -845,13 +846,14 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "salsa"
 version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
+source = "git+https://github.com/salsa-rs/salsa?rev=20c9fbf#20c9fbf45c0201e39cfeda4c939160ad1c35132c"
 dependencies = [
  "derive-new 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "indexmap 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1350,7 +1352,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum ryu 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7153dd96dade874ab973e098cb62fcdbb89a03682e46b144fd09550998d4a4a7"
 "checksum safemem 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8dca453248a96cb0749e36ccdfe2b0b4e54a61bfef89fb97ec621eb8e0a93dd9"
-"checksum salsa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b7a4bcb8e4e81d092709a98130025666d255c8821970dcb9347d05f928e3d505"
+"checksum salsa 0.4.1 (git+https://github.com/salsa-rs/salsa?rev=20c9fbf)" = "<none>"
 "checksum same-file 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "10f7794e2fda7f594866840e95f5c5962e886e228e68b6505885811a94dd728c"
 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
diff --git a/crates/ra_analysis/Cargo.toml b/crates/ra_analysis/Cargo.toml
index 4481e98d64e..233f34e34b0 100644
--- a/crates/ra_analysis/Cargo.toml
+++ b/crates/ra_analysis/Cargo.toml
@@ -15,7 +15,8 @@ fst = "0.3.1"
 im = "12.0.0"
 ra_syntax = { path = "../ra_syntax" }
 ra_editor = { path = "../ra_editor" }
-salsa = "0.4.1"
+salsa = { git = "https://github.com/salsa-rs/salsa", rev = "20c9fbf" }
+rustc-hash = "1.0"
 
 [dev-dependencies]
 test_utils = { path = "../test_utils" }
diff --git a/crates/ra_analysis/src/db/mod.rs b/crates/ra_analysis/src/db/mod.rs
index c54d502529b..c84bfa7a887 100644
--- a/crates/ra_analysis/src/db/mod.rs
+++ b/crates/ra_analysis/src/db/mod.rs
@@ -2,9 +2,9 @@ use std::{
     fmt,
     sync::Arc,
     hash::{Hash, Hasher},
-    collections::HashSet,
 };
 use salsa;
+use rustc_hash::FxHashSet;
 use ra_syntax::File;
 use ra_editor::{LineIndex};
 use crate::{
@@ -63,7 +63,7 @@ salsa::query_group! {
 
 #[derive(Default, Debug)]
 pub(crate) struct FileSet {
-    pub(crate) files: HashSet<FileId>,
+    pub(crate) files: FxHashSet<FileId>,
     pub(crate) resolver: FileResolverImp,
 }
 
diff --git a/crates/ra_analysis/src/roots.rs b/crates/ra_analysis/src/roots.rs
index 908f49b0a52..692a07ccd83 100644
--- a/crates/ra_analysis/src/roots.rs
+++ b/crates/ra_analysis/src/roots.rs
@@ -1,5 +1,4 @@
 use std::{
-    collections::{HashMap, HashSet},
     sync::Arc,
     panic,
 };
@@ -8,6 +7,7 @@ use parking_lot::RwLock;
 use once_cell::sync::OnceCell;
 use rayon::prelude::*;
 use salsa::Database;
+use rustc_hash::{FxHashMap, FxHashSet};
 use ra_editor::LineIndex;
 use ra_syntax::File;
 
@@ -40,8 +40,8 @@ impl WritableSourceRoot {
         file_resolver: Option<FileResolverImp>,
     ) -> WritableSourceRoot {
         let db = self.db.write();
-        let mut changed = HashSet::new();
-        let mut removed = HashSet::new();
+        let mut changed = FxHashSet::default();
+        let mut removed = FxHashSet::default();
         for (file_id, text) in changes {
             match text {
                 None => {
@@ -55,7 +55,7 @@ impl WritableSourceRoot {
             }
         }
         let file_set = db.file_set(());
-        let mut files: HashSet<FileId> = file_set
+        let mut files: FxHashSet<FileId> = file_set
             .files
             .clone();
         for file_id in removed {