diff --git a/Cargo.lock b/Cargo.lock
index 480dc782e..2d44ca380 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -391,6 +391,24 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96d30a06541fbafbc7f82ed10c06164cfbd2c401138f6addd8404629c4b16711"
 
+[[package]]
+name = "arroy"
+version = "0.5.0"
+dependencies = [
+ "bytemuck",
+ "byteorder",
+ "heed 0.21.0",
+ "log",
+ "memmap2",
+ "nohash",
+ "ordered-float",
+ "rand",
+ "rayon",
+ "roaring",
+ "tempfile",
+ "thiserror 2.0.9",
+]
+
 [[package]]
 name = "arroy"
 version = "0.5.0"
@@ -399,7 +417,7 @@ checksum = "dfc5f272f38fa063bbff0a7ab5219404e221493de005e2b4078c62d626ef567e"
 dependencies = [
  "bytemuck",
  "byteorder",
- "heed",
+ "heed 0.20.5",
  "log",
  "memmap2",
  "nohash",
@@ -418,7 +436,7 @@ source = "git+https://github.com/meilisearch/arroy/?tag=DO-NOT-DELETE-upgrade-v0
 dependencies = [
  "bytemuck",
  "byteorder",
- "heed",
+ "heed 0.20.5",
  "log",
  "memmap2",
  "nohash",
@@ -944,13 +962,13 @@ checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
 
 [[package]]
 name = "cc"
-version = "1.0.104"
+version = "1.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74b6a57f98764a267ff415d50a25e6e166f3831a5071af4995296ea97d210490"
+checksum = "be714c154be609ec7f5dad223a33bf1482fff90472de28f7362806e6d4832b8c"
 dependencies = [
  "jobserver",
  "libc",
- "once_cell",
+ "shlex",
 ]
 
 [[package]]
@@ -2403,16 +2421,37 @@ checksum = "7d4f449bab7320c56003d37732a917e18798e2f1709d80263face2b4f9436ddb"
 dependencies = [
  "bitflags 2.6.0",
  "byteorder",
- "heed-traits",
- "heed-types",
+ "heed-traits 0.20.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heed-types 0.20.1",
  "libc",
- "lmdb-master-sys",
+ "lmdb-master-sys 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "once_cell",
+ "page_size",
+ "serde",
+ "synchronoise",
+ "url",
+]
+
+[[package]]
+name = "heed"
+version = "0.21.0"
+dependencies = [
+ "bitflags 2.6.0",
+ "byteorder",
+ "heed-traits 0.20.0",
+ "heed-types 0.21.0",
+ "libc",
+ "lmdb-master-sys 0.2.4",
  "once_cell",
  "page_size",
  "synchronoise",
  "url",
 ]
 
+[[package]]
+name = "heed-traits"
+version = "0.20.0"
+
 [[package]]
 name = "heed-traits"
 version = "0.20.0"
@@ -2427,7 +2466,18 @@ checksum = "9d3f528b053a6d700b2734eabcd0fd49cb8230647aa72958467527b0b7917114"
 dependencies = [
  "bincode",
  "byteorder",
- "heed-traits",
+ "heed-traits 0.20.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "heed-types"
+version = "0.21.0"
+dependencies = [
+ "bincode",
+ "byteorder",
+ "heed-traits 0.20.0",
  "serde",
  "serde_json",
 ]
@@ -3466,6 +3516,15 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ee93343901ab17bd981295f2cf0026d4ad018c7c31ba84549a4ddbb47a45104"
 
+[[package]]
+name = "lmdb-master-sys"
+version = "0.2.4"
+dependencies = [
+ "cc",
+ "doxygen-rs",
+ "libc",
+]
+
 [[package]]
 name = "lmdb-master-sys"
 version = "0.2.4"
@@ -3513,9 +3572,9 @@ checksum = "9374ef4228402d4b7e403e5838cb880d9ee663314b0a900d5a6aabf0c213552e"
 
 [[package]]
 name = "log"
-version = "0.4.21"
+version = "0.4.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
+checksum = "30bde2b3dc3671ae49d8e2e9f044c7c005836e7a023ee57cffa25ab82764bb9e"
 
 [[package]]
 name = "lzma-rs"
@@ -3730,6 +3789,7 @@ dependencies = [
  "clap",
  "dump",
  "file-store",
+ "heed 0.20.5",
  "indexmap",
  "meilisearch-auth",
  "meilisearch-types",
@@ -3761,7 +3821,7 @@ name = "milli"
 version = "1.13.1"
 dependencies = [
  "allocator-api2",
- "arroy 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arroy 0.5.0",
  "bbqueue",
  "big_s",
  "bimap",
@@ -3790,7 +3850,7 @@ dependencies = [
  "geoutils",
  "grenad",
  "hashbrown 0.15.2",
- "heed",
+ "heed 0.21.0",
  "hf-hub",
  "indexmap",
  "insta",
diff --git a/crates/benchmarks/benches/indexing.rs b/crates/benchmarks/benches/indexing.rs
index 4bd5315ff..32f11a459 100644
--- a/crates/benchmarks/benches/indexing.rs
+++ b/crates/benchmarks/benches/indexing.rs
@@ -35,7 +35,7 @@ fn setup_dir(path: impl AsRef<Path>) {
 fn setup_index() -> Index {
     let path = "benches.mmdb";
     setup_dir(path);
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(100 * 1024 * 1024 * 1024); // 100 GB
     options.max_readers(100);
     Index::new(options, path, true).unwrap()
diff --git a/crates/benchmarks/benches/utils.rs b/crates/benchmarks/benches/utils.rs
index 5baeca869..f5d54c585 100644
--- a/crates/benchmarks/benches/utils.rs
+++ b/crates/benchmarks/benches/utils.rs
@@ -65,7 +65,7 @@ pub fn base_setup(conf: &Conf) -> Index {
     }
     create_dir_all(conf.database_name).unwrap();
 
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(100 * 1024 * 1024 * 1024); // 100 GB
     options.max_readers(100);
     let index = Index::new(options, conf.database_name, true).unwrap();
diff --git a/crates/fuzzers/src/bin/fuzz-indexing.rs b/crates/fuzzers/src/bin/fuzz-indexing.rs
index e26303010..dee19a77c 100644
--- a/crates/fuzzers/src/bin/fuzz-indexing.rs
+++ b/crates/fuzzers/src/bin/fuzz-indexing.rs
@@ -57,7 +57,7 @@ fn main() {
         let opt = opt.clone();
 
         let handle = std::thread::spawn(move || {
-            let mut options = EnvOpenOptions::new();
+            let mut options = EnvOpenOptions::new().read_txn_without_tls();
             options.map_size(1024 * 1024 * 1024 * 1024);
             let tempdir = match opt.path {
                 Some(path) => TempDir::new_in(path).unwrap(),
diff --git a/crates/index-scheduler/src/features.rs b/crates/index-scheduler/src/features.rs
index 394e6518f..bf78794ce 100644
--- a/crates/index-scheduler/src/features.rs
+++ b/crates/index-scheduler/src/features.rs
@@ -2,7 +2,7 @@ use std::sync::{Arc, RwLock};
 
 use meilisearch_types::features::{InstanceTogglableFeatures, Network, RuntimeTogglableFeatures};
 use meilisearch_types::heed::types::{SerdeJson, Str};
-use meilisearch_types::heed::{Database, Env, RwTxn};
+use meilisearch_types::heed::{Database, Env, RwTxn, WithoutTls};
 
 use crate::error::FeatureNotEnabledError;
 use crate::Result;
@@ -126,7 +126,7 @@ impl FeatureData {
     }
 
     pub fn new(
-        env: &Env,
+        env: &Env<WithoutTls>,
         wtxn: &mut RwTxn,
         instance_features: InstanceTogglableFeatures,
     ) -> Result<Self> {
diff --git a/crates/index-scheduler/src/index_mapper/index_map.rs b/crates/index-scheduler/src/index_mapper/index_map.rs
index e4eb9bfb8..99daf478e 100644
--- a/crates/index-scheduler/src/index_mapper/index_map.rs
+++ b/crates/index-scheduler/src/index_mapper/index_map.rs
@@ -304,7 +304,7 @@ fn create_or_open_index(
     map_size: usize,
     creation: bool,
 ) -> Result<Index> {
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(clamp_to_page_size(map_size));
 
     // You can find more details about this experimental
@@ -333,7 +333,7 @@ fn create_or_open_index(
 #[cfg(test)]
 mod tests {
 
-    use meilisearch_types::heed::Env;
+    use meilisearch_types::heed::{Env, WithoutTls};
     use meilisearch_types::Index;
     use uuid::Uuid;
 
@@ -343,7 +343,7 @@ mod tests {
     use crate::IndexScheduler;
 
     impl IndexMapper {
-        fn test() -> (Self, Env, IndexSchedulerHandle) {
+        fn test() -> (Self, Env<WithoutTls>, IndexSchedulerHandle) {
             let (index_scheduler, handle) = IndexScheduler::test(true, vec![]);
             (index_scheduler.index_mapper, index_scheduler.env, handle)
         }
diff --git a/crates/index-scheduler/src/index_mapper/mod.rs b/crates/index-scheduler/src/index_mapper/mod.rs
index 48e29508f..aa7337534 100644
--- a/crates/index-scheduler/src/index_mapper/mod.rs
+++ b/crates/index-scheduler/src/index_mapper/mod.rs
@@ -4,7 +4,7 @@ use std::time::Duration;
 use std::{fs, thread};
 
 use meilisearch_types::heed::types::{SerdeJson, Str};
-use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn};
+use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn, WithoutTls};
 use meilisearch_types::milli;
 use meilisearch_types::milli::database_stats::DatabaseStats;
 use meilisearch_types::milli::update::IndexerConfig;
@@ -159,7 +159,7 @@ impl IndexMapper {
     }
 
     pub fn new(
-        env: &Env,
+        env: &Env<WithoutTls>,
         wtxn: &mut RwTxn,
         options: &IndexSchedulerOptions,
         budget: IndexBudget,
diff --git a/crates/index-scheduler/src/lib.rs b/crates/index-scheduler/src/lib.rs
index 3b61b5dc4..97abd04e7 100644
--- a/crates/index-scheduler/src/lib.rs
+++ b/crates/index-scheduler/src/lib.rs
@@ -40,6 +40,7 @@ pub type TaskId = u32;
 
 use std::collections::{BTreeMap, HashMap};
 use std::io::{self, BufReader, Read};
+use std::ops::Deref as _;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, RwLock};
@@ -54,7 +55,7 @@ use meilisearch_types::batches::Batch;
 use meilisearch_types::features::{InstanceTogglableFeatures, Network, RuntimeTogglableFeatures};
 use meilisearch_types::heed::byteorder::BE;
 use meilisearch_types::heed::types::I128;
-use meilisearch_types::heed::{self, Env, RoTxn};
+use meilisearch_types::heed::{self, Env, RoTxn, WithoutTls};
 use meilisearch_types::milli::index::IndexEmbeddingConfig;
 use meilisearch_types::milli::update::IndexerConfig;
 use meilisearch_types::milli::vector::{Embedder, EmbedderOptions, EmbeddingConfigs};
@@ -131,7 +132,7 @@ pub struct IndexSchedulerOptions {
 /// to be performed on them.
 pub struct IndexScheduler {
     /// The LMDB environment which the DBs are associated with.
-    pub(crate) env: Env,
+    pub(crate) env: Env<WithoutTls>,
 
     /// The list of tasks currently processing
     pub(crate) processing_tasks: Arc<RwLock<ProcessingTasks>>,
@@ -241,6 +242,7 @@ impl IndexScheduler {
 
         let env = unsafe {
             heed::EnvOpenOptions::new()
+                .read_txn_without_tls()
                 .max_dbs(Self::nb_db())
                 .map_size(budget.task_db_size)
                 .open(&options.tasks_path)
@@ -358,7 +360,7 @@ impl IndexScheduler {
         }
     }
 
-    pub fn read_txn(&self) -> Result<RoTxn> {
+    pub fn read_txn(&self) -> Result<RoTxn<WithoutTls>> {
         self.env.read_txn().map_err(|e| e.into())
     }
 
@@ -427,12 +429,12 @@ impl IndexScheduler {
     /// If you need to fetch information from or perform an action on all indexes,
     /// see the `try_for_each_index` function.
     pub fn index(&self, name: &str) -> Result<Index> {
-        self.index_mapper.index(&self.env.read_txn()?, name)
+        self.index_mapper.index(self.env.read_txn()?.deref(), name)
     }
 
     /// Return the boolean referring if index exists.
     pub fn index_exists(&self, name: &str) -> Result<bool> {
-        self.index_mapper.index_exists(&self.env.read_txn()?, name)
+        self.index_mapper.index_exists(self.env.read_txn()?.deref(), name)
     }
 
     /// Return the name of all indexes without opening them.
@@ -507,7 +509,7 @@ impl IndexScheduler {
     /// 2. The name of the specific data related to the property can be `enqueued` for the `statuses`, `settingsUpdate` for the `types`, or the name of the index for the `indexes`, for example.
     /// 3. The number of times the properties appeared.
     pub fn get_stats(&self) -> Result<BTreeMap<String, BTreeMap<String, u64>>> {
-        self.queue.get_stats(&self.read_txn()?, &self.processing_tasks.read().unwrap())
+        self.queue.get_stats(self.read_txn()?.deref(), &self.processing_tasks.read().unwrap())
     }
 
     // Return true if there is at least one task that is processing.
diff --git a/crates/index-scheduler/src/queue/batches.rs b/crates/index-scheduler/src/queue/batches.rs
index 970e41110..785d24931 100644
--- a/crates/index-scheduler/src/queue/batches.rs
+++ b/crates/index-scheduler/src/queue/batches.rs
@@ -3,7 +3,7 @@ use std::ops::{Bound, RangeBounds};
 
 use meilisearch_types::batches::{Batch, BatchId};
 use meilisearch_types::heed::types::{DecodeIgnore, SerdeBincode, SerdeJson, Str};
-use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn};
+use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn, WithoutTls};
 use meilisearch_types::milli::{CboRoaringBitmapCodec, RoaringBitmapCodec, BEU32};
 use meilisearch_types::tasks::{Kind, Status};
 use roaring::{MultiOps, RoaringBitmap};
@@ -66,7 +66,7 @@ impl BatchQueue {
         NUMBER_OF_DATABASES
     }
 
-    pub(super) fn new(env: &Env, wtxn: &mut RwTxn) -> Result<Self> {
+    pub(super) fn new(env: &Env<WithoutTls>, wtxn: &mut RwTxn) -> Result<Self> {
         Ok(Self {
             all_batches: env.create_database(wtxn, Some(db_name::ALL_BATCHES))?,
             status: env.create_database(wtxn, Some(db_name::BATCH_STATUS))?,
diff --git a/crates/index-scheduler/src/queue/mod.rs b/crates/index-scheduler/src/queue/mod.rs
index 8850eb8fa..b13e3ffe2 100644
--- a/crates/index-scheduler/src/queue/mod.rs
+++ b/crates/index-scheduler/src/queue/mod.rs
@@ -13,7 +13,7 @@ use std::time::Duration;
 
 use file_store::FileStore;
 use meilisearch_types::batches::BatchId;
-use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn};
+use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn, WithoutTls};
 use meilisearch_types::milli::{CboRoaringBitmapCodec, BEU32};
 use meilisearch_types::tasks::{Kind, KindWithContent, Status, Task};
 use roaring::RoaringBitmap;
@@ -157,7 +157,7 @@ impl Queue {
 
     /// Create an index scheduler and start its run loop.
     pub(crate) fn new(
-        env: &Env,
+        env: &Env<WithoutTls>,
         wtxn: &mut RwTxn,
         options: &IndexSchedulerOptions,
     ) -> Result<Self> {
diff --git a/crates/index-scheduler/src/queue/tasks.rs b/crates/index-scheduler/src/queue/tasks.rs
index 913ebcb30..afe510955 100644
--- a/crates/index-scheduler/src/queue/tasks.rs
+++ b/crates/index-scheduler/src/queue/tasks.rs
@@ -1,7 +1,7 @@
 use std::ops::{Bound, RangeBounds};
 
 use meilisearch_types::heed::types::{DecodeIgnore, SerdeBincode, SerdeJson, Str};
-use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn};
+use meilisearch_types::heed::{Database, Env, RoTxn, RwTxn, WithoutTls};
 use meilisearch_types::milli::{CboRoaringBitmapCodec, RoaringBitmapCodec, BEU32};
 use meilisearch_types::tasks::{Kind, Status, Task};
 use roaring::{MultiOps, RoaringBitmap};
@@ -68,7 +68,7 @@ impl TaskQueue {
         NUMBER_OF_DATABASES
     }
 
-    pub(crate) fn new(env: &Env, wtxn: &mut RwTxn) -> Result<Self> {
+    pub(crate) fn new(env: &Env<WithoutTls>, wtxn: &mut RwTxn) -> Result<Self> {
         Ok(Self {
             all_tasks: env.create_database(wtxn, Some(db_name::ALL_TASKS))?,
             status: env.create_database(wtxn, Some(db_name::STATUS))?,
diff --git a/crates/index-scheduler/src/scheduler/process_snapshot_creation.rs b/crates/index-scheduler/src/scheduler/process_snapshot_creation.rs
index 3e1a63ce3..e14ed6942 100644
--- a/crates/index-scheduler/src/scheduler/process_snapshot_creation.rs
+++ b/crates/index-scheduler/src/scheduler/process_snapshot_creation.rs
@@ -42,7 +42,8 @@ impl IndexScheduler {
         progress.update_progress(SnapshotCreationProgress::SnapshotTheIndexScheduler);
         let dst = temp_snapshot_dir.path().join("tasks");
         fs::create_dir_all(&dst)?;
-        self.env.copy_to_file(dst.join("data.mdb"), CompactionOption::Enabled)?;
+        let mut file = std::fs::File::create(dst.join("data.mdb"))?;
+        self.env.copy_to_file(&mut file, CompactionOption::Enabled)?;
 
         // 2.2 Create a read transaction on the index-scheduler
         let rtxn = self.env.read_txn()?;
@@ -98,7 +99,8 @@ impl IndexScheduler {
                 .max_dbs(2)
                 .open(&self.scheduler.auth_path)
         }?;
-        auth.copy_to_file(dst.join("data.mdb"), CompactionOption::Enabled)?;
+        let mut file = std::fs::File::create(dst.join("data.mdb"))?;
+        auth.copy_to_file(&mut file, CompactionOption::Enabled)?;
 
         // 5. Copy and tarball the flat snapshot
         progress.update_progress(SnapshotCreationProgress::CreateTheTarball);
diff --git a/crates/index-scheduler/src/upgrade/mod.rs b/crates/index-scheduler/src/upgrade/mod.rs
index cfc351b09..c66434a49 100644
--- a/crates/index-scheduler/src/upgrade/mod.rs
+++ b/crates/index-scheduler/src/upgrade/mod.rs
@@ -1,5 +1,5 @@
 use anyhow::bail;
-use meilisearch_types::heed::{Env, RwTxn};
+use meilisearch_types::heed::{Env, RwTxn, WithoutTls};
 use meilisearch_types::tasks::{Details, KindWithContent, Status, Task};
 use meilisearch_types::versioning::{VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH};
 use time::OffsetDateTime;
@@ -9,13 +9,17 @@ use crate::queue::TaskQueue;
 use crate::versioning::Versioning;
 
 trait UpgradeIndexScheduler {
-    fn upgrade(&self, env: &Env, wtxn: &mut RwTxn, original: (u32, u32, u32))
-        -> anyhow::Result<()>;
+    fn upgrade(
+        &self,
+        env: &Env<WithoutTls>,
+        wtxn: &mut RwTxn,
+        original: (u32, u32, u32),
+    ) -> anyhow::Result<()>;
     fn target_version(&self) -> (u32, u32, u32);
 }
 
 pub fn upgrade_index_scheduler(
-    env: &Env,
+    env: &Env<WithoutTls>,
     versioning: &Versioning,
     from: (u32, u32, u32),
     to: (u32, u32, u32),
@@ -90,7 +94,7 @@ struct V1_12_ToCurrent {}
 impl UpgradeIndexScheduler for V1_12_ToCurrent {
     fn upgrade(
         &self,
-        _env: &Env,
+        _env: &Env<WithoutTls>,
         _wtxn: &mut RwTxn,
         _original: (u32, u32, u32),
     ) -> anyhow::Result<()> {
diff --git a/crates/index-scheduler/src/versioning.rs b/crates/index-scheduler/src/versioning.rs
index 22132bf5f..107b8e0ba 100644
--- a/crates/index-scheduler/src/versioning.rs
+++ b/crates/index-scheduler/src/versioning.rs
@@ -1,5 +1,5 @@
 use meilisearch_types::heed::types::Str;
-use meilisearch_types::heed::{self, Database, Env, RoTxn, RwTxn};
+use meilisearch_types::heed::{self, Database, Env, RoTxn, RwTxn, WithoutTls};
 use meilisearch_types::milli::heed_codec::version::VersionCodec;
 use meilisearch_types::versioning;
 
@@ -46,12 +46,12 @@ impl Versioning {
     }
 
     /// Return `Self` without checking anything about the version
-    pub fn raw_new(env: &Env, wtxn: &mut RwTxn) -> Result<Self, heed::Error> {
+    pub fn raw_new(env: &Env<WithoutTls>, wtxn: &mut RwTxn) -> Result<Self, heed::Error> {
         let version = env.create_database(wtxn, Some(db_name::VERSION))?;
         Ok(Self { version })
     }
 
-    pub(crate) fn new(env: &Env, db_version: (u32, u32, u32)) -> Result<Self> {
+    pub(crate) fn new(env: &Env<WithoutTls>, db_version: (u32, u32, u32)) -> Result<Self> {
         let mut wtxn = env.write_txn()?;
         let this = Self::raw_new(env, &mut wtxn)?;
         let from = match this.get_version(&wtxn)? {
diff --git a/crates/meilisearch-auth/src/store.rs b/crates/meilisearch-auth/src/store.rs
index ef992e836..bee5aef58 100644
--- a/crates/meilisearch-auth/src/store.rs
+++ b/crates/meilisearch-auth/src/store.rs
@@ -9,7 +9,7 @@ use std::str::FromStr;
 use std::sync::Arc;
 
 use hmac::{Hmac, Mac};
-use meilisearch_types::heed::BoxedError;
+use meilisearch_types::heed::{BoxedError, WithoutTls};
 use meilisearch_types::index_uid_pattern::IndexUidPattern;
 use meilisearch_types::keys::KeyId;
 use meilisearch_types::milli;
@@ -31,7 +31,7 @@ const KEY_ID_ACTION_INDEX_EXPIRATION_DB_NAME: &str = "keyid-action-index-expirat
 
 #[derive(Clone)]
 pub struct HeedAuthStore {
-    env: Arc<Env>,
+    env: Arc<Env<WithoutTls>>,
     keys: Database<Bytes, SerdeJson<Key>>,
     action_keyid_index_expiration: Database<KeyIdActionCodec, SerdeJson<Option<OffsetDateTime>>>,
     should_close_on_drop: bool,
@@ -45,8 +45,8 @@ impl Drop for HeedAuthStore {
     }
 }
 
-pub fn open_auth_store_env(path: &Path) -> milli::heed::Result<milli::heed::Env> {
-    let mut options = EnvOpenOptions::new();
+pub fn open_auth_store_env(path: &Path) -> milli::heed::Result<milli::heed::Env<WithoutTls>> {
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(AUTH_STORE_SIZE); // 1GB
     options.max_dbs(2);
     unsafe { options.open(path) }
diff --git a/crates/meilisearch-types/src/error.rs b/crates/meilisearch-types/src/error.rs
index f64301b8c..b6ca21644 100644
--- a/crates/meilisearch-types/src/error.rs
+++ b/crates/meilisearch-types/src/error.rs
@@ -500,8 +500,7 @@ impl ErrorCode for HeedError {
             HeedError::Mdb(_)
             | HeedError::Encoding(_)
             | HeedError::Decoding(_)
-            | HeedError::DatabaseClosing
-            | HeedError::BadOpenOptions { .. } => Code::Internal,
+            | HeedError::EnvAlreadyOpened => Code::Internal,
         }
     }
 }
diff --git a/crates/meilisearch/src/lib.rs b/crates/meilisearch/src/lib.rs
index e22b6dff3..554de4323 100644
--- a/crates/meilisearch/src/lib.rs
+++ b/crates/meilisearch/src/lib.rs
@@ -420,6 +420,7 @@ pub fn update_version_file_for_dumpless_upgrade(
     if from_major == 1 && from_minor == 12 {
         let env = unsafe {
             heed::EnvOpenOptions::new()
+                .read_txn_without_tls()
                 .max_dbs(Versioning::nb_db())
                 .map_size(index_scheduler_opt.task_db_size)
                 .open(&index_scheduler_opt.tasks_path)
diff --git a/crates/meilisearch/src/search/mod.rs b/crates/meilisearch/src/search/mod.rs
index 2091047fc..16a2b829d 100644
--- a/crates/meilisearch/src/search/mod.rs
+++ b/crates/meilisearch/src/search/mod.rs
@@ -1,6 +1,7 @@
 use core::fmt;
 use std::cmp::min;
 use std::collections::{BTreeMap, BTreeSet, HashSet};
+use std::ops::Deref as _;
 use std::str::FromStr;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
@@ -340,7 +341,7 @@ impl SearchKind {
         vector_len: Option<usize>,
         route: Route,
     ) -> Result<(String, Arc<Embedder>, bool), ResponseError> {
-        let embedder_configs = index.embedding_configs(&index.read_txn()?)?;
+        let embedder_configs = index.embedding_configs(index.read_txn()?.deref())?;
         let embedders = index_scheduler.embedders(index_uid, embedder_configs)?;
 
         let (embedder, _, quantized) = embedders
diff --git a/crates/meilitool/Cargo.toml b/crates/meilitool/Cargo.toml
index ffd13da34..cbbf375c6 100644
--- a/crates/meilitool/Cargo.toml
+++ b/crates/meilitool/Cargo.toml
@@ -11,6 +11,7 @@ license.workspace = true
 [dependencies]
 anyhow = "1.0.95"
 arroy_v04_to_v05 = { package = "arroy", git = "https://github.com/meilisearch/arroy/", tag = "DO-NOT-DELETE-upgrade-v04-to-v05" }
+heed_arroy_v04_to_v05 = { package = "heed", version = "0.20.5" }
 clap = { version = "4.5.24", features = ["derive"] }
 dump = { path = "../dump" }
 file-store = { path = "../file-store" }
diff --git a/crates/meilitool/src/main.rs b/crates/meilitool/src/main.rs
index 8a8b774b8..49e81d927 100644
--- a/crates/meilitool/src/main.rs
+++ b/crates/meilitool/src/main.rs
@@ -11,7 +11,7 @@ use meilisearch_auth::AuthController;
 use meilisearch_types::batches::Batch;
 use meilisearch_types::heed::types::{Bytes, SerdeJson, Str};
 use meilisearch_types::heed::{
-    CompactionOption, Database, Env, EnvOpenOptions, RoTxn, RwTxn, Unspecified,
+    CompactionOption, Database, Env, EnvOpenOptions, RoTxn, RwTxn, Unspecified, WithoutTls,
 };
 use meilisearch_types::milli::constants::RESERVED_VECTORS_FIELD_NAME;
 use meilisearch_types::milli::documents::{obkv_to_object, DocumentsBatchReader};
@@ -172,7 +172,7 @@ fn main() -> anyhow::Result<()> {
 /// Clears the task queue located at `db_path`.
 fn clear_task_queue(db_path: PathBuf) -> anyhow::Result<()> {
     let path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&path) }
+    let env = unsafe { EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&path) }
         .with_context(|| format!("While trying to open {:?}", path.display()))?;
 
     eprintln!("Deleting tasks from the database...");
@@ -225,8 +225,8 @@ fn clear_task_queue(db_path: PathBuf) -> anyhow::Result<()> {
 }
 
 fn try_opening_database<KC: 'static, DC: 'static>(
-    env: &Env,
-    rtxn: &RoTxn,
+    env: &Env<WithoutTls>,
+    rtxn: &RoTxn<WithoutTls>,
     db_name: &str,
 ) -> anyhow::Result<Database<KC, DC>> {
     env.open_database(rtxn, Some(db_name))
@@ -235,8 +235,8 @@ fn try_opening_database<KC: 'static, DC: 'static>(
 }
 
 fn try_opening_poly_database(
-    env: &Env,
-    rtxn: &RoTxn,
+    env: &Env<WithoutTls>,
+    rtxn: &RoTxn<WithoutTls>,
     db_name: &str,
 ) -> anyhow::Result<Database<Unspecified, Unspecified>> {
     env.database_options()
@@ -246,6 +246,23 @@ fn try_opening_poly_database(
         .with_context(|| format!("Missing the {db_name:?} poly database"))
 }
 
+fn try_opening_poly_database_arroy_v04_to_v05(
+    env: &heed_arroy_v04_to_v05::Env,
+    rtxn: &heed_arroy_v04_to_v05::RoTxn,
+    db_name: &str,
+) -> anyhow::Result<
+    heed_arroy_v04_to_v05::Database<
+        heed_arroy_v04_to_v05::Unspecified,
+        heed_arroy_v04_to_v05::Unspecified,
+    >,
+> {
+    env.database_options()
+        .name(db_name)
+        .open(rtxn)
+        .with_context(|| format!("While opening the {db_name:?} poly database"))?
+        .with_context(|| format!("Missing the {db_name:?} poly database"))
+}
+
 fn try_clearing_poly_database(
     wtxn: &mut RwTxn,
     database: Database<Unspecified, Unspecified>,
@@ -284,8 +301,10 @@ fn export_a_dump(
         FileStore::new(db_path.join("update_files")).context("While opening the FileStore")?;
 
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     eprintln!("Dumping the keys...");
 
@@ -386,9 +405,10 @@ fn export_a_dump(
     for result in index_mapping.iter(&rtxn)? {
         let (uid, uuid) = result?;
         let index_path = db_path.join("indexes").join(uuid.to_string());
-        let index = Index::new(EnvOpenOptions::new(), &index_path, false).with_context(|| {
-            format!("While trying to open the index at path {:?}", index_path.display())
-        })?;
+        let index = Index::new(EnvOpenOptions::new().read_txn_without_tls(), &index_path, false)
+            .with_context(|| {
+                format!("While trying to open the index at path {:?}", index_path.display())
+            })?;
 
         let rtxn = index.read_txn()?;
         let metadata = IndexMetadata {
@@ -438,8 +458,10 @@ fn export_a_dump(
 
 fn compact_index(db_path: PathBuf, index_name: &str) -> anyhow::Result<()> {
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     let rtxn = env.read_txn()?;
     let index_mapping: Database<Str, UuidCodec> =
@@ -456,9 +478,10 @@ fn compact_index(db_path: PathBuf, index_name: &str) -> anyhow::Result<()> {
         }
 
         let index_path = db_path.join("indexes").join(uuid.to_string());
-        let index = Index::new(EnvOpenOptions::new(), &index_path, false).with_context(|| {
-            format!("While trying to open the index at path {:?}", index_path.display())
-        })?;
+        let index = Index::new(EnvOpenOptions::new().read_txn_without_tls(), &index_path, false)
+            .with_context(|| {
+                format!("While trying to open the index at path {:?}", index_path.display())
+            })?;
 
         eprintln!("Awaiting for a mutable transaction...");
         let _wtxn = index.write_txn().context("While awaiting for a write transaction")?;
@@ -514,8 +537,10 @@ fn export_documents(
     offset: Option<usize>,
 ) -> anyhow::Result<()> {
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     let rtxn = env.read_txn()?;
     let index_mapping: Database<Str, UuidCodec> =
@@ -526,9 +551,10 @@ fn export_documents(
         if uid == index_name {
             let index_path = db_path.join("indexes").join(uuid.to_string());
             let index =
-                Index::new(EnvOpenOptions::new(), &index_path, false).with_context(|| {
-                    format!("While trying to open the index at path {:?}", index_path.display())
-                })?;
+                Index::new(EnvOpenOptions::new().read_txn_without_tls(), &index_path, false)
+                    .with_context(|| {
+                        format!("While trying to open the index at path {:?}", index_path.display())
+                    })?;
 
             let rtxn = index.read_txn()?;
             let fields_ids_map = index.fields_ids_map(&rtxn)?;
@@ -616,8 +642,10 @@ fn hair_dryer(
     index_parts: &[IndexPart],
 ) -> anyhow::Result<()> {
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     eprintln!("Trying to get a read transaction on the index scheduler...");
 
@@ -630,9 +658,10 @@ fn hair_dryer(
         if index_names.iter().any(|i| i == uid) {
             let index_path = db_path.join("indexes").join(uuid.to_string());
             let index =
-                Index::new(EnvOpenOptions::new(), &index_path, false).with_context(|| {
-                    format!("While trying to open the index at path {:?}", index_path.display())
-                })?;
+                Index::new(EnvOpenOptions::new().read_txn_without_tls(), &index_path, false)
+                    .with_context(|| {
+                        format!("While trying to open the index at path {:?}", index_path.display())
+                    })?;
 
             eprintln!("Trying to get a read transaction on the {uid} index...");
 
diff --git a/crates/meilitool/src/upgrade/v1_10.rs b/crates/meilitool/src/upgrade/v1_10.rs
index 043520e82..ec0d6fda3 100644
--- a/crates/meilitool/src/upgrade/v1_10.rs
+++ b/crates/meilitool/src/upgrade/v1_10.rs
@@ -2,7 +2,9 @@ use std::path::Path;
 
 use anyhow::{bail, Context};
 use meilisearch_types::heed::types::{SerdeJson, Str};
-use meilisearch_types::heed::{Database, Env, EnvOpenOptions, RoTxn, RwTxn, Unspecified};
+use meilisearch_types::heed::{
+    Database, Env, EnvOpenOptions, RoTxn, RwTxn, Unspecified, WithoutTls,
+};
 use meilisearch_types::milli::index::{db_name, main_key};
 
 use super::v1_9;
@@ -92,7 +94,7 @@ fn update_index_stats(
 
 fn update_date_format(
     index_uid: &str,
-    index_env: &Env,
+    index_env: &Env<WithoutTls>,
     index_wtxn: &mut RwTxn,
 ) -> anyhow::Result<()> {
     let main = try_opening_poly_database(index_env, index_wtxn, db_name::MAIN)
@@ -106,8 +108,8 @@ fn update_date_format(
 
 fn find_rest_embedders(
     index_uid: &str,
-    index_env: &Env,
-    index_txn: &RoTxn,
+    index_env: &Env<WithoutTls>,
+    index_txn: &RoTxn<WithoutTls>,
 ) -> anyhow::Result<Vec<String>> {
     let main = try_opening_poly_database(index_env, index_txn, db_name::MAIN)
         .with_context(|| format!("while checking REST embedders for index `{index_uid}`"))?;
@@ -164,8 +166,10 @@ pub fn v1_9_to_v1_10(
     // 2. REST embedders. We don't support this case right now, so bail
 
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     let mut sched_wtxn = env.write_txn()?;
 
@@ -205,9 +209,13 @@ pub fn v1_9_to_v1_10(
 
         let index_env = unsafe {
             // FIXME: fetch the 25 magic number from the index file
-            EnvOpenOptions::new().max_dbs(25).open(&index_path).with_context(|| {
-                format!("while opening index {uid} at '{}'", index_path.display())
-            })?
+            EnvOpenOptions::new()
+                .read_txn_without_tls()
+                .max_dbs(25)
+                .open(&index_path)
+                .with_context(|| {
+                    format!("while opening index {uid} at '{}'", index_path.display())
+                })?
         };
 
         let index_txn = index_env.read_txn().with_context(|| {
@@ -252,9 +260,13 @@ pub fn v1_9_to_v1_10(
 
         let index_env = unsafe {
             // FIXME: fetch the 25 magic number from the index file
-            EnvOpenOptions::new().max_dbs(25).open(&index_path).with_context(|| {
-                format!("while opening index {uid} at '{}'", index_path.display())
-            })?
+            EnvOpenOptions::new()
+                .read_txn_without_tls()
+                .max_dbs(25)
+                .open(&index_path)
+                .with_context(|| {
+                    format!("while opening index {uid} at '{}'", index_path.display())
+                })?
         };
 
         let mut index_wtxn = index_env.write_txn().with_context(|| {
diff --git a/crates/meilitool/src/upgrade/v1_11.rs b/crates/meilitool/src/upgrade/v1_11.rs
index 44aeb125f..971b0c65e 100644
--- a/crates/meilitool/src/upgrade/v1_11.rs
+++ b/crates/meilitool/src/upgrade/v1_11.rs
@@ -12,7 +12,7 @@ use meilisearch_types::heed::{Database, EnvOpenOptions};
 use meilisearch_types::milli::index::db_name;
 
 use crate::uuid_codec::UuidCodec;
-use crate::{try_opening_database, try_opening_poly_database};
+use crate::{try_opening_database, try_opening_poly_database_arroy_v04_to_v05};
 
 pub fn v1_10_to_v1_11(
     db_path: &Path,
@@ -23,8 +23,10 @@ pub fn v1_10_to_v1_11(
     println!("Upgrading from v1.10.0 to v1.11.0");
 
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     let sched_rtxn = env.read_txn()?;
 
@@ -50,9 +52,12 @@ pub fn v1_10_to_v1_11(
         );
 
         let index_env = unsafe {
-            EnvOpenOptions::new().max_dbs(25).open(&index_path).with_context(|| {
-                format!("while opening index {uid} at '{}'", index_path.display())
-            })?
+            heed_arroy_v04_to_v05::EnvOpenOptions::new()
+                .max_dbs(25)
+                .open(&index_path)
+                .with_context(|| {
+                    format!("while opening index {uid} at '{}'", index_path.display())
+                })?
         };
 
         let index_rtxn = index_env.read_txn().with_context(|| {
@@ -61,9 +66,12 @@ pub fn v1_10_to_v1_11(
                 index_path.display()
             )
         })?;
-        let index_read_database =
-            try_opening_poly_database(&index_env, &index_rtxn, db_name::VECTOR_ARROY)
-                .with_context(|| format!("while updating date format for index `{uid}`"))?;
+        let index_read_database = try_opening_poly_database_arroy_v04_to_v05(
+            &index_env,
+            &index_rtxn,
+            db_name::VECTOR_ARROY,
+        )
+        .with_context(|| format!("while updating date format for index `{uid}`"))?;
 
         let mut index_wtxn = index_env.write_txn().with_context(|| {
             format!(
@@ -72,9 +80,12 @@ pub fn v1_10_to_v1_11(
             )
         })?;
 
-        let index_write_database =
-            try_opening_poly_database(&index_env, &index_wtxn, db_name::VECTOR_ARROY)
-                .with_context(|| format!("while updating date format for index `{uid}`"))?;
+        let index_write_database = try_opening_poly_database_arroy_v04_to_v05(
+            &index_env,
+            &index_wtxn,
+            db_name::VECTOR_ARROY,
+        )
+        .with_context(|| format!("while updating date format for index `{uid}`"))?;
 
         arroy_v04_to_v05::ugrade_from_prev_version(
             &index_rtxn,
diff --git a/crates/meilitool/src/upgrade/v1_12.rs b/crates/meilitool/src/upgrade/v1_12.rs
index 3ad171c31..1dd679eb9 100644
--- a/crates/meilitool/src/upgrade/v1_12.rs
+++ b/crates/meilitool/src/upgrade/v1_12.rs
@@ -115,8 +115,10 @@ fn convert_update_files(db_path: &Path) -> anyhow::Result<()> {
 /// Rebuild field distribution as it was wrongly computed in v1.12.x if x < 3
 fn rebuild_field_distribution(db_path: &Path) -> anyhow::Result<()> {
     let index_scheduler_path = db_path.join("tasks");
-    let env = unsafe { EnvOpenOptions::new().max_dbs(100).open(&index_scheduler_path) }
-        .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
+    let env = unsafe {
+        EnvOpenOptions::new().read_txn_without_tls().max_dbs(100).open(&index_scheduler_path)
+    }
+    .with_context(|| format!("While trying to open {:?}", index_scheduler_path.display()))?;
 
     let mut sched_wtxn = env.write_txn()?;
 
@@ -173,11 +175,12 @@ fn rebuild_field_distribution(db_path: &Path) -> anyhow::Result<()> {
 
             println!("\t- Rebuilding field distribution");
 
-            let index =
-                meilisearch_types::milli::Index::new(EnvOpenOptions::new(), &index_path, false)
-                    .with_context(|| {
-                        format!("while opening index {uid} at '{}'", index_path.display())
-                    })?;
+            let index = meilisearch_types::milli::Index::new(
+                EnvOpenOptions::new().read_txn_without_tls(),
+                &index_path,
+                false,
+            )
+            .with_context(|| format!("while opening index {uid} at '{}'", index_path.display()))?;
 
             let mut index_txn = index.write_txn()?;
 
diff --git a/crates/milli/Cargo.toml b/crates/milli/Cargo.toml
index 5eb89ea53..3c5b0744b 100644
--- a/crates/milli/Cargo.toml
+++ b/crates/milli/Cargo.toml
@@ -29,10 +29,9 @@ fst = "0.4.7"
 fxhash = "0.2.1"
 geoutils = "0.5.1"
 grenad = { version = "0.5.0", default-features = false, features = ["rayon", "tempfile"] }
-heed = { version = "0.20.5", default-features = false, features = [
+heed = { path = "../../../heed/heed", version = "0.21.0", default-features = false, features = [
     "serde-json",
     "serde-bincode",
-    "read-txn-no-tls",
 ] }
 indexmap = { version = "2.7.0", features = ["serde"] }
 json-depth-checker = { path = "../json-depth-checker" }
@@ -85,7 +84,7 @@ rhai = { git = "https://github.com/rhaiscript/rhai", rev = "ef3df63121d27aacd838
     "no_time",
     "sync",
 ] }
-arroy = "0.5.0"
+arroy = { version = "0.5.0", path = "../../../arroy" }
 rand = "0.8.5"
 tracing = "0.1.41"
 ureq = { version = "2.12.1", features = ["json"] }
diff --git a/crates/milli/src/documents/mod.rs b/crates/milli/src/documents/mod.rs
index 88fa38d30..5392b843e 100644
--- a/crates/milli/src/documents/mod.rs
+++ b/crates/milli/src/documents/mod.rs
@@ -75,21 +75,6 @@ impl DocumentsBatchIndex {
     pub fn id(&self, name: &str) -> Option<FieldId> {
         self.0.get_by_right(name).cloned()
     }
-
-    pub fn recreate_json(&self, document: &obkv::KvReaderU16) -> Result<Object> {
-        let mut map = Object::new();
-
-        for (k, v) in document.iter() {
-            // TODO: TAMO: update the error type
-            let key =
-                self.0.get_by_left(&k).ok_or(crate::error::InternalError::DatabaseClosing)?.clone();
-            let value = serde_json::from_slice::<serde_json::Value>(v)
-                .map_err(crate::error::InternalError::SerdeJson)?;
-            map.insert(key, value);
-        }
-
-        Ok(map)
-    }
 }
 
 impl FieldIdMapper for DocumentsBatchIndex {
diff --git a/crates/milli/src/error.rs b/crates/milli/src/error.rs
index c8ed1912f..db6220a63 100644
--- a/crates/milli/src/error.rs
+++ b/crates/milli/src/error.rs
@@ -32,8 +32,6 @@ pub enum Error {
 
 #[derive(Error, Debug)]
 pub enum InternalError {
-    #[error("{}", HeedError::DatabaseClosing)]
-    DatabaseClosing,
     #[error("missing {} in the {db_name} database", key.unwrap_or("key"))]
     DatabaseMissingEntry { db_name: &'static str, key: Option<&'static str> },
     #[error("missing {key} in the fieldids weights mapping")]
@@ -80,6 +78,9 @@ pub enum InternalError {
     ArroyError(#[from] arroy::Error),
     #[error(transparent)]
     VectorEmbeddingError(#[from] crate::vector::Error),
+
+    #[error("{}", HeedError::EnvAlreadyOpened)]
+    EnvAlreadyOpened,
 }
 
 #[derive(Error, Debug)]
@@ -471,8 +472,7 @@ impl From<HeedError> for Error {
             // TODO use the encoding
             HeedError::Encoding(_) => InternalError(Serialization(Encoding { db_name: None })),
             HeedError::Decoding(_) => InternalError(Serialization(Decoding { db_name: None })),
-            HeedError::DatabaseClosing => InternalError(DatabaseClosing),
-            HeedError::BadOpenOptions { .. } => UserError(InvalidLmdbOpenOptions),
+            HeedError::EnvAlreadyOpened => InternalError(EnvAlreadyOpened),
         }
     }
 }
diff --git a/crates/milli/src/index.rs b/crates/milli/src/index.rs
index c748324ae..abcc418a7 100644
--- a/crates/milli/src/index.rs
+++ b/crates/milli/src/index.rs
@@ -5,7 +5,7 @@ use std::fs::File;
 use std::path::Path;
 
 use heed::types::*;
-use heed::{CompactionOption, Database, RoTxn, RwTxn, Unspecified};
+use heed::{CompactionOption, Database, RoTxn, RwTxn, Unspecified, WithoutTls};
 use roaring::RoaringBitmap;
 use rstar::RTree;
 use serde::{Deserialize, Serialize};
@@ -109,7 +109,7 @@ pub mod db_name {
 #[derive(Clone)]
 pub struct Index {
     /// The LMDB environment which this index is associated with.
-    pub(crate) env: heed::Env,
+    pub(crate) env: heed::Env<heed::WithoutTls>,
 
     /// Contains many different types (e.g. the fields ids map).
     pub(crate) main: Database<Unspecified, Unspecified>,
@@ -176,7 +176,7 @@ pub struct Index {
 
 impl Index {
     pub fn new_with_creation_dates<P: AsRef<Path>>(
-        mut options: heed::EnvOpenOptions,
+        mut options: heed::EnvOpenOptions<WithoutTls>,
         path: P,
         created_at: time::OffsetDateTime,
         updated_at: time::OffsetDateTime,
@@ -274,7 +274,7 @@ impl Index {
     }
 
     pub fn new<P: AsRef<Path>>(
-        options: heed::EnvOpenOptions,
+        options: heed::EnvOpenOptions<WithoutTls>,
         path: P,
         creation: bool,
     ) -> Result<Index> {
@@ -283,7 +283,7 @@ impl Index {
     }
 
     fn set_creation_dates(
-        env: &heed::Env,
+        env: &heed::Env<WithoutTls>,
         main: Database<Unspecified, Unspecified>,
         created_at: time::OffsetDateTime,
         updated_at: time::OffsetDateTime,
@@ -305,12 +305,12 @@ impl Index {
     }
 
     /// Create a read transaction to be able to read the index.
-    pub fn read_txn(&self) -> heed::Result<RoTxn<'_>> {
+    pub fn read_txn(&self) -> heed::Result<RoTxn<'_, WithoutTls>> {
         self.env.read_txn()
     }
 
     /// Create a static read transaction to be able to read the index without keeping a reference to it.
-    pub fn static_read_txn(&self) -> heed::Result<RoTxn<'static>> {
+    pub fn static_read_txn(&self) -> heed::Result<RoTxn<'static, WithoutTls>> {
         self.env.clone().static_read_txn()
     }
 
@@ -340,7 +340,9 @@ impl Index {
     }
 
     pub fn copy_to_file<P: AsRef<Path>>(&self, path: P, option: CompactionOption) -> Result<File> {
-        self.env.copy_to_file(path, option).map_err(Into::into)
+        let mut file = std::fs::File::create(path.as_ref())?;
+        self.env.copy_to_file(&mut file, option)?;
+        Ok(file)
     }
 
     /// Returns an `EnvClosingEvent` that can be used to wait for the closing event,
@@ -1870,7 +1872,7 @@ pub(crate) mod tests {
     impl TempIndex {
         /// Creates a temporary index
         pub fn new_with_map_size(size: usize) -> Self {
-            let mut options = EnvOpenOptions::new();
+            let mut options = EnvOpenOptions::new().read_txn_without_tls();
             options.map_size(size);
             let _tempdir = TempDir::new_in(".").unwrap();
             let inner = Index::new(options, _tempdir.path(), true).unwrap();
diff --git a/crates/milli/src/search/new/tests/integration.rs b/crates/milli/src/search/new/tests/integration.rs
index e60a09ec5..20a438492 100644
--- a/crates/milli/src/search/new/tests/integration.rs
+++ b/crates/milli/src/search/new/tests/integration.rs
@@ -15,7 +15,7 @@ use crate::constants::RESERVED_GEO_FIELD_NAME;
 
 pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     let path = tempfile::tempdir().unwrap();
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(10 * 1024 * 1024); // 10 MB
     let index = Index::new(options, &path, true).unwrap();
 
diff --git a/crates/milli/src/update/facet/mod.rs b/crates/milli/src/update/facet/mod.rs
index dbacf6248..9f7e1056b 100644
--- a/crates/milli/src/update/facet/mod.rs
+++ b/crates/milli/src/update/facet/mod.rs
@@ -301,7 +301,7 @@ pub(crate) mod test_helpers {
 
     use grenad::MergerBuilder;
     use heed::types::Bytes;
-    use heed::{BytesDecode, BytesEncode, Env, RoTxn, RwTxn};
+    use heed::{BytesDecode, BytesEncode, Env, RoTxn, RwTxn, WithoutTls};
     use roaring::RoaringBitmap;
 
     use super::bulk::FacetsUpdateBulkInner;
@@ -339,7 +339,7 @@ pub(crate) mod test_helpers {
         for<'a> BoundCodec:
             BytesEncode<'a> + BytesDecode<'a, DItem = <BoundCodec as BytesEncode<'a>>::EItem>,
     {
-        pub env: Env,
+        pub env: Env<WithoutTls>,
         pub content: heed::Database<FacetGroupKeyCodec<BytesRefCodec>, FacetGroupValueCodec>,
         pub group_size: Cell<u8>,
         pub min_level_size: Cell<u8>,
@@ -361,7 +361,7 @@ pub(crate) mod test_helpers {
             let group_size = group_size.clamp(2, 127);
             let max_group_size = std::cmp::min(127, std::cmp::max(group_size * 2, max_group_size)); // 2*group_size <= x <= 127
             let min_level_size = std::cmp::max(1, min_level_size); // 1 <= x <= inf
-            let mut options = heed::EnvOpenOptions::new();
+            let mut options = heed::EnvOpenOptions::new().read_txn_without_tls();
             let options = options.map_size(4096 * 4 * 1000 * 100);
             let tempdir = tempfile::TempDir::new().unwrap();
             let env = unsafe { options.open(tempdir.path()) }.unwrap();
diff --git a/crates/milli/src/update/new/indexer/document_changes.rs b/crates/milli/src/update/new/indexer/document_changes.rs
index f77ac7658..a2388a662 100644
--- a/crates/milli/src/update/new/indexer/document_changes.rs
+++ b/crates/milli/src/update/new/indexer/document_changes.rs
@@ -3,7 +3,7 @@ use std::sync::atomic::Ordering;
 use std::sync::{Arc, RwLock};
 
 use bumpalo::Bump;
-use heed::RoTxn;
+use heed::{RoTxn, WithoutTls};
 use rayon::iter::IndexedParallelIterator;
 
 use super::super::document_change::DocumentChange;
@@ -28,7 +28,7 @@ pub struct DocumentChangeContext<
     /// inside of the DB.
     pub db_fields_ids_map: &'indexer FieldsIdsMap,
     /// A transaction providing data from the DB before all indexing operations
-    pub rtxn: RoTxn<'indexer>,
+    pub rtxn: RoTxn<'indexer, WithoutTls>,
 
     /// Global field id map that is up to date with the current state of the indexing process.
     ///
diff --git a/crates/milli/tests/search/facet_distribution.rs b/crates/milli/tests/search/facet_distribution.rs
index 4d8bf324c..da4aa93a6 100644
--- a/crates/milli/tests/search/facet_distribution.rs
+++ b/crates/milli/tests/search/facet_distribution.rs
@@ -13,7 +13,7 @@ use serde_json::{from_value, json};
 #[test]
 fn test_facet_distribution_with_no_facet_values() {
     let path = tempfile::tempdir().unwrap();
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(10 * 1024 * 1024); // 10 MB
     let index = Index::new(options, &path, true).unwrap();
 
diff --git a/crates/milli/tests/search/mod.rs b/crates/milli/tests/search/mod.rs
index 337a4c88c..661b8285e 100644
--- a/crates/milli/tests/search/mod.rs
+++ b/crates/milli/tests/search/mod.rs
@@ -32,7 +32,7 @@ pub const CONTENT: &str = include_str!("../assets/test_set.ndjson");
 
 pub fn setup_search_index_with_criteria(criteria: &[Criterion]) -> Index {
     let path = tempfile::tempdir().unwrap();
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(10 * 1024 * 1024); // 10 MB
     let index = Index::new(options, &path, true).unwrap();
 
diff --git a/crates/milli/tests/search/query_criteria.rs b/crates/milli/tests/search/query_criteria.rs
index 3cc747f06..89708461d 100644
--- a/crates/milli/tests/search/query_criteria.rs
+++ b/crates/milli/tests/search/query_criteria.rs
@@ -262,7 +262,7 @@ fn criteria_mixup() {
 #[test]
 fn criteria_ascdesc() {
     let path = tempfile::tempdir().unwrap();
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(12 * 1024 * 1024); // 10 MB
     let index = Index::new(options, &path, true).unwrap();
 
diff --git a/crates/milli/tests/search/typo_tolerance.rs b/crates/milli/tests/search/typo_tolerance.rs
index 837b5e6b2..f239df3a4 100644
--- a/crates/milli/tests/search/typo_tolerance.rs
+++ b/crates/milli/tests/search/typo_tolerance.rs
@@ -108,7 +108,7 @@ fn test_typo_tolerance_two_typo() {
 #[test]
 fn test_typo_disabled_on_word() {
     let tmp = tempdir().unwrap();
-    let mut options = EnvOpenOptions::new();
+    let mut options = EnvOpenOptions::new().read_txn_without_tls();
     options.map_size(4096 * 100);
     let index = Index::new(options, tmp.path(), true).unwrap();