Merge #3651

3651: Use the writemap flag to reduce the memory usage r=irevoire a=Kerollmops

This draft PR is showing some stats about the memory usage of Meilisearch when [the LMDB `MDB_WRITEMAP` flag](3947014aed/libraries/liblmdb/lmdb.h (L573-L581)) is enabled and when it is not. As you can see there is a reduction of about 50% of the memory usage pick. The dataset used was [the Wikipedia one](https://www.notion.so/meilisearch/Wikipedia-8b1486e4b17547c5bda485d2d97767a0) with the first 30 000 first CSV documents without settings. This PR depends on https://github.com/meilisearch/heed/pull/168.

I just [opened a discussion](https://github.com/meilisearch/product/discussions/652) for people to understand the tradeoffs and give their feedback.

- [x] Create an experiment flag `--experimental-reduce-indexing-memory-usage`.
- [x] Add it to the config file.
- [x] Explain the tradeoff and copy/link the LMDB documentation in the help message.
- [x] Add analytics about the experimental flag.
- [x] Document that this flag cannot be used on Windows, ~~or hide it~~.

<details>
  <summary>The command I used to run the tests</summary>

#### Sign the binary to be able to use Instruments / xcrun
```sh
codesign -s - -f --entitlements ~/ent.plist target/release/meilisearch
```

where `ent.plist` contains:
```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>com.apple.security.get-task-allow</key>
        <true/>
    </dict>
</plist>
```

#### Run Meilisearch in measure-mode
```sh
xcrun xctrace record --template 'Allocations' --launch -- target/release/meilisearch --max-indexing-memory 0MiB
```

#### Send the wiki dataset available on notion.so / Public
```sh
for f in 0.csv 15000.csv; do echo sending $f; xh 'localhost:7700/indexes/wiki/documents' 'content-type:text/csv' `@$f;` done
```

#### Wait for the task to finish
```sh
watch --color xh --pretty all 'localhost:7700/tasks?statuses=processing'
```
</details>

Keep in mind that I tested that with the Instruments Apple tools on an iMac 5k 2019. More benchmarks must be done, especially on the indexation speed, as the flag is told to slow down writing into databases bigger that the amount of memory.

On the left Meilisearch is running without the flag. On the right, it is running with the flag.

<p align="center">
<img align="left" width="45%" alt="Instrument showing the memory usage of Meilisearch without the MDB_WRITEMAP flag" src="https://user-images.githubusercontent.com/3610253/234299524-7607f1df-6fc1-45d3-bd3d-4f9388002857.png">
<img align="right" width="45%" alt="Instrument showing the memory usage of Meilisearch with the MDB_WRITEMAP flag" src="https://user-images.githubusercontent.com/3610253/234299534-6cc3ae58-8bd9-426c-aa79-4c78f9e88b94.png">
</p>

Co-authored-by: Kerollmops <clement@meilisearch.com>
Co-authored-by: Clément Renault <clement@meilisearch.com>

Cargo.lock

@@ -1794,7 +1794,7 @@ checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
 [[package]]
 name = "heed"
 version = "0.12.5"
-source = "git+https://github.com/meilisearch/heed?tag=v0.12.5#4158a6c484752afaaf9e2530a6ee0e7ab0f24ee8"
+source = "git+https://github.com/meilisearch/heed?tag=v0.12.6#8c5b94225fc949c02bb7b900cc50ffaf6b584b1e"
 dependencies = [
  "byteorder",
  "heed-traits",
@@ -1811,12 +1811,12 @@ dependencies = [
 [[package]]
 name = "heed-traits"
 version = "0.7.0"
-source = "git+https://github.com/meilisearch/heed?tag=v0.12.5#4158a6c484752afaaf9e2530a6ee0e7ab0f24ee8"
+source = "git+https://github.com/meilisearch/heed?tag=v0.12.6#8c5b94225fc949c02bb7b900cc50ffaf6b584b1e"
 
 [[package]]
 name = "heed-types"
 version = "0.7.2"
-source = "git+https://github.com/meilisearch/heed?tag=v0.12.5#4158a6c484752afaaf9e2530a6ee0e7ab0f24ee8"
+source = "git+https://github.com/meilisearch/heed?tag=v0.12.6#8c5b94225fc949c02bb7b900cc50ffaf6b584b1e"
 dependencies = [
  "bincode",
  "heed-traits",

config.toml

@@ -126,3 +126,6 @@ ssl_tickets = false
 experimental_enable_metrics = false
 # Experimental metrics feature. For more information, see: <https://github.com/meilisearch/meilisearch/discussions/3518>
 # Enables the Prometheus metrics on the `GET /metrics` endpoint.
+
+experimental_reduce_indexing_memory_usage = false
+# Experimental RAM reduction during indexing, do not use in production, see: <https://github.com/meilisearch/product/discussions/652>

index-scheduler/src/index_mapper/index_map.rs

@@ -5,6 +5,7 @@ use std::collections::BTreeMap;
 use std::path::Path;
 use std::time::Duration;
 
+use meilisearch_types::heed::flags::Flags;
 use meilisearch_types::heed::{EnvClosingEvent, EnvOpenOptions};
 use meilisearch_types::milli::Index;
 use time::OffsetDateTime;
@@ -53,6 +54,7 @@ pub struct IndexMap {
 pub struct ClosingIndex {
     uuid: Uuid,
     closing_event: EnvClosingEvent,
+    enable_mdb_writemap: bool,
     map_size: usize,
     generation: usize,
 }
@@ -68,6 +70,7 @@ impl ClosingIndex {
     pub fn wait_timeout(self, timeout: Duration) -> Option<ReopenableIndex> {
         self.closing_event.wait_timeout(timeout).then_some(ReopenableIndex {
             uuid: self.uuid,
+            enable_mdb_writemap: self.enable_mdb_writemap,
             map_size: self.map_size,
             generation: self.generation,
         })
@@ -76,6 +79,7 @@ impl ClosingIndex {
 
 pub struct ReopenableIndex {
     uuid: Uuid,
+    enable_mdb_writemap: bool,
     map_size: usize,
     generation: usize,
 }
@@ -103,7 +107,7 @@ impl ReopenableIndex {
                 return Ok(());
             }
             map.unavailable.remove(&self.uuid);
-            map.create(&self.uuid, path, None, self.map_size)?;
+            map.create(&self.uuid, path, None, self.enable_mdb_writemap, self.map_size)?;
         }
         Ok(())
     }
@@ -170,16 +174,17 @@ impl IndexMap {
         uuid: &Uuid,
         path: &Path,
         date: Option<(OffsetDateTime, OffsetDateTime)>,
+        enable_mdb_writemap: bool,
         map_size: usize,
     ) -> Result<Index> {
         if !matches!(self.get_unavailable(uuid), Missing) {
             panic!("Attempt to open an index that was unavailable");
         }
-        let index = create_or_open_index(path, date, map_size)?;
+        let index = create_or_open_index(path, date, enable_mdb_writemap, map_size)?;
         match self.available.insert(*uuid, index.clone()) {
             InsertionOutcome::InsertedNew => (),
             InsertionOutcome::Evicted(evicted_uuid, evicted_index) => {
-                self.close(evicted_uuid, evicted_index, 0);
+                self.close(evicted_uuid, evicted_index, enable_mdb_writemap, 0);
             }
             InsertionOutcome::Replaced(_) => {
                 panic!("Attempt to open an index that was already opened")
@@ -212,17 +217,30 @@ impl IndexMap {
     /// | Closing         | Closing       |
     /// | Available       | Closing       |
     ///
-    pub fn close_for_resize(&mut self, uuid: &Uuid, map_size_growth: usize) {
+    pub fn close_for_resize(
+        &mut self,
+        uuid: &Uuid,
+        enable_mdb_writemap: bool,
+        map_size_growth: usize,
+    ) {
         let Some(index) = self.available.remove(uuid) else { return; };
-        self.close(*uuid, index, map_size_growth);
+        self.close(*uuid, index, enable_mdb_writemap, map_size_growth);
     }
 
-    fn close(&mut self, uuid: Uuid, index: Index, map_size_growth: usize) {
+    fn close(
+        &mut self,
+        uuid: Uuid,
+        index: Index,
+        enable_mdb_writemap: bool,
+        map_size_growth: usize,
+    ) {
         let map_size = index.map_size().unwrap_or(DEFAULT_MAP_SIZE) + map_size_growth;
         let closing_event = index.prepare_for_closing();
         let generation = self.next_generation();
-        self.unavailable
-            .insert(uuid, Some(ClosingIndex { uuid, closing_event, map_size, generation }));
+        self.unavailable.insert(
+            uuid,
+            Some(ClosingIndex { uuid, closing_event, enable_mdb_writemap, map_size, generation }),
+        );
     }
 
     /// Attempts to delete and index.
@@ -282,11 +300,15 @@ impl IndexMap {
 fn create_or_open_index(
     path: &Path,
     date: Option<(OffsetDateTime, OffsetDateTime)>,
+    enable_mdb_writemap: bool,
     map_size: usize,
 ) -> Result<Index> {
     let mut options = EnvOpenOptions::new();
     options.map_size(clamp_to_page_size(map_size));
     options.max_readers(1024);
+    if enable_mdb_writemap {
+        unsafe { options.flag(Flags::MdbWriteMap) };
+    }
 
     if let Some((created, updated)) = date {
         Ok(Index::new_with_creation_dates(options, path, created, updated)?)

index-scheduler/src/index_mapper/mod.rs

@@ -66,6 +66,8 @@ pub struct IndexMapper {
     index_base_map_size: usize,
     /// The quantity by which the map size of an index is incremented upon reopening, in bytes.
     index_growth_amount: usize,
+    /// Whether we open a meilisearch index with the MDB_WRITEMAP option or not.
+    enable_mdb_writemap: bool,
     pub indexer_config: Arc<IndexerConfig>,
 }
 
@@ -123,15 +125,22 @@ impl IndexMapper {
         index_base_map_size: usize,
         index_growth_amount: usize,
         index_count: usize,
+        enable_mdb_writemap: bool,
         indexer_config: IndexerConfig,
     ) -> Result<Self> {
+        let mut wtxn = env.write_txn()?;
+        let index_mapping = env.create_database(&mut wtxn, Some(INDEX_MAPPING))?;
+        let index_stats = env.create_database(&mut wtxn, Some(INDEX_STATS))?;
+        wtxn.commit()?;
+
         Ok(Self {
             index_map: Arc::new(RwLock::new(IndexMap::new(index_count))),
-            index_mapping: env.create_database(Some(INDEX_MAPPING))?,
-            index_stats: env.create_database(Some(INDEX_STATS))?,
+            index_mapping,
+            index_stats,
             base_path,
             index_base_map_size,
             index_growth_amount,
+            enable_mdb_writemap,
             indexer_config: Arc::new(indexer_config),
         })
     }
@@ -162,6 +171,7 @@ impl IndexMapper {
                     &uuid,
                     &index_path,
                     date,
+                    self.enable_mdb_writemap,
                     self.index_base_map_size,
                 )?;
 
@@ -273,7 +283,11 @@ impl IndexMapper {
             .ok_or_else(|| Error::IndexNotFound(name.to_string()))?;
 
         // We remove the index from the in-memory index map.
-        self.index_map.write().unwrap().close_for_resize(&uuid, self.index_growth_amount);
+        self.index_map.write().unwrap().close_for_resize(
+            &uuid,
+            self.enable_mdb_writemap,
+            self.index_growth_amount,
+        );
 
         Ok(())
     }
@@ -338,6 +352,7 @@ impl IndexMapper {
                                 &uuid,
                                 &index_path,
                                 None,
+                                self.enable_mdb_writemap,
                                 self.index_base_map_size,
                             )?;
                         }

index-scheduler/src/lib.rs

@@ -233,6 +233,8 @@ pub struct IndexSchedulerOptions {
     pub task_db_size: usize,
     /// The size, in bytes, with which a meilisearch index is opened the first time of each meilisearch index.
     pub index_base_map_size: usize,
+    /// Whether we open a meilisearch index with the MDB_WRITEMAP option or not.
+    pub enable_mdb_writemap: bool,
     /// The size, in bytes, by which the map size of an index is increased when it resized due to being full.
     pub index_growth_amount: usize,
     /// The number of indexes that can be concurrently opened in memory.
@@ -374,6 +376,11 @@ impl IndexScheduler {
         std::fs::create_dir_all(&options.indexes_path)?;
         std::fs::create_dir_all(&options.dumps_path)?;
 
+        if cfg!(windows) && options.enable_mdb_writemap {
+            // programmer error if this happens: in normal use passing the option on Windows is an error in main
+            panic!("Windows doesn't support the MDB_WRITEMAP LMDB option");
+        }
+
         let task_db_size = clamp_to_page_size(options.task_db_size);
         let budget = if options.indexer_config.skip_index_budget {
             IndexBudget {
@@ -396,25 +403,37 @@ impl IndexScheduler {
             .open(options.tasks_path)?;
         let file_store = FileStore::new(&options.update_file_path)?;
 
+        let mut wtxn = env.write_txn()?;
+        let all_tasks = env.create_database(&mut wtxn, Some(db_name::ALL_TASKS))?;
+        let status = env.create_database(&mut wtxn, Some(db_name::STATUS))?;
+        let kind = env.create_database(&mut wtxn, Some(db_name::KIND))?;
+        let index_tasks = env.create_database(&mut wtxn, Some(db_name::INDEX_TASKS))?;
+        let canceled_by = env.create_database(&mut wtxn, Some(db_name::CANCELED_BY))?;
+        let enqueued_at = env.create_database(&mut wtxn, Some(db_name::ENQUEUED_AT))?;
+        let started_at = env.create_database(&mut wtxn, Some(db_name::STARTED_AT))?;
+        let finished_at = env.create_database(&mut wtxn, Some(db_name::FINISHED_AT))?;
+        wtxn.commit()?;
+
         // allow unreachable_code to get rids of the warning in the case of a test build.
         let this = Self {
             must_stop_processing: MustStopProcessing::default(),
             processing_tasks: Arc::new(RwLock::new(ProcessingTasks::new())),
             file_store,
-            all_tasks: env.create_database(Some(db_name::ALL_TASKS))?,
-            status: env.create_database(Some(db_name::STATUS))?,
-            kind: env.create_database(Some(db_name::KIND))?,
-            index_tasks: env.create_database(Some(db_name::INDEX_TASKS))?,
-            canceled_by: env.create_database(Some(db_name::CANCELED_BY))?,
-            enqueued_at: env.create_database(Some(db_name::ENQUEUED_AT))?,
-            started_at: env.create_database(Some(db_name::STARTED_AT))?,
-            finished_at: env.create_database(Some(db_name::FINISHED_AT))?,
+            all_tasks,
+            status,
+            kind,
+            index_tasks,
+            canceled_by,
+            enqueued_at,
+            started_at,
+            finished_at,
             index_mapper: IndexMapper::new(
                 &env,
                 options.indexes_path,
                 budget.map_size,
                 options.index_growth_amount,
                 budget.index_count,
+                options.enable_mdb_writemap,
                 options.indexer_config,
             )?,
             env,
@@ -1471,6 +1490,7 @@ mod tests {
                 dumps_path: tempdir.path().join("dumps"),
                 task_db_size: 1000 * 1000, // 1 MB, we don't use MiB on purpose.
                 index_base_map_size: 1000 * 1000, // 1 MB, we don't use MiB on purpose.
+                enable_mdb_writemap: false,
                 index_growth_amount: 1000 * 1000, // 1 MB
                 index_count: 5,
                 indexer_config,

meilisearch-auth/src/store.rs

@@ -55,9 +55,11 @@ impl HeedAuthStore {
         let path = path.as_ref().join(AUTH_DB_PATH);
         create_dir_all(&path)?;
         let env = Arc::new(open_auth_store_env(path.as_ref())?);
-        let keys = env.create_database(Some(KEY_DB_NAME))?;
+        let mut wtxn = env.write_txn()?;
+        let keys = env.create_database(&mut wtxn, Some(KEY_DB_NAME))?;
         let action_keyid_index_expiration =
-            env.create_database(Some(KEY_ID_ACTION_INDEX_EXPIRATION_DB_NAME))?;
+            env.create_database(&mut wtxn, Some(KEY_ID_ACTION_INDEX_EXPIRATION_DB_NAME))?;
+        wtxn.commit()?;
         Ok(Self { env, keys, action_keyid_index_expiration, should_close_on_drop: true })
     }
 

meilisearch/src/analytics/segment_analytics.rs

@@ -225,6 +225,7 @@ impl super::Analytics for SegmentAnalytics {
 struct Infos {
     env: String,
     experimental_enable_metrics: bool,
+    experimental_reduce_indexing_memory_usage: bool,
     db_path: bool,
     import_dump: bool,
     dump_dir: bool,
@@ -258,6 +259,7 @@ impl From<Opt> for Infos {
         let Opt {
             db_path,
             experimental_enable_metrics,
+            experimental_reduce_indexing_memory_usage,
             http_addr,
             master_key: _,
             env,
@@ -300,6 +302,7 @@ impl From<Opt> for Infos {
         Self {
             env,
             experimental_enable_metrics,
+            experimental_reduce_indexing_memory_usage,
             db_path: db_path != PathBuf::from("./data.ms"),
             import_dump: import_dump.is_some(),
             dump_dir: dump_dir != PathBuf::from("dumps/"),

meilisearch/src/lib.rs

@@ -232,6 +232,7 @@ fn open_or_create_database_unchecked(
             dumps_path: opt.dump_dir.clone(),
             task_db_size: opt.max_task_db_size.get_bytes() as usize,
             index_base_map_size: opt.max_index_size.get_bytes() as usize,
+            enable_mdb_writemap: opt.experimental_reduce_indexing_memory_usage,
             indexer_config: (&opt.indexer_options).try_into()?,
             autobatching_enabled: true,
             max_number_of_tasks: 1_000_000,

meilisearch/src/main.rs

@@ -29,6 +29,11 @@ fn setup(opt: &Opt) -> anyhow::Result<()> {
 async fn main() -> anyhow::Result<()> {
     let (opt, config_read_from) = Opt::try_build()?;
 
+    anyhow::ensure!(
+        !(cfg!(windows) && opt.experimental_reduce_indexing_memory_usage),
+        "The `experimental-reduce-indexing-memory-usage` flag is not supported on Windows"
+    );
+
     setup(&opt)?;
 
     match (opt.env.as_ref(), &opt.master_key) {

meilisearch/src/option.rs

@@ -48,6 +48,8 @@ const MEILI_IGNORE_DUMP_IF_DB_EXISTS: &str = "MEILI_IGNORE_DUMP_IF_DB_EXISTS";
 const MEILI_DUMP_DIR: &str = "MEILI_DUMP_DIR";
 const MEILI_LOG_LEVEL: &str = "MEILI_LOG_LEVEL";
 const MEILI_EXPERIMENTAL_ENABLE_METRICS: &str = "MEILI_EXPERIMENTAL_ENABLE_METRICS";
+const MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE: &str =
+    "MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE";
 
 const DEFAULT_CONFIG_FILE_PATH: &str = "./config.toml";
 const DEFAULT_DB_PATH: &str = "./data.ms";
@@ -293,6 +295,11 @@ pub struct Opt {
     #[serde(default)]
     pub experimental_enable_metrics: bool,
 
+    /// Experimental RAM reduction during indexing, do not use in production, see: <https://github.com/meilisearch/product/discussions/652>
+    #[clap(long, env = MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE)]
+    #[serde(default)]
+    pub experimental_reduce_indexing_memory_usage: bool,
+
     #[serde(flatten)]
     #[clap(flatten)]
     pub indexer_options: IndexerOpts,
@@ -385,6 +392,7 @@ impl Opt {
             #[cfg(all(not(debug_assertions), feature = "analytics"))]
             no_analytics,
             experimental_enable_metrics: enable_metrics_route,
+            experimental_reduce_indexing_memory_usage: reduce_indexing_memory_usage,
         } = self;
         export_to_env_if_not_present(MEILI_DB_PATH, db_path);
         export_to_env_if_not_present(MEILI_HTTP_ADDR, http_addr);
@@ -426,6 +434,10 @@ impl Opt {
             MEILI_EXPERIMENTAL_ENABLE_METRICS,
             enable_metrics_route.to_string(),
         );
+        export_to_env_if_not_present(
+            MEILI_EXPERIMENTAL_REDUCE_INDEXING_MEMORY_USAGE,
+            reduce_indexing_memory_usage.to_string(),
+        );
         indexer_options.export_to_env();
     }
 

milli/Cargo.toml

@@ -25,8 +25,13 @@ flatten-serde-json = { path = "../flatten-serde-json" }
 fst = "0.4.7"
 fxhash = "0.2.1"
 geoutils = "0.5.1"
-grenad = { version = "0.4.4", default-features = false, features = ["tempfile"] }
-heed = { git = "https://github.com/meilisearch/heed", tag = "v0.12.5", default-features = false, features = ["lmdb", "sync-read-txn"] }
+grenad = { version = "0.4.4", default-features = false, features = [
+    "tempfile",
+] }
+heed = { git = "https://github.com/meilisearch/heed", tag = "v0.12.6", default-features = false, features = [
+    "lmdb",
+    "sync-read-txn",
+] }
 json-depth-checker = { path = "../json-depth-checker" }
 levenshtein_automata = { version = "0.2.1", features = ["fst_automaton"] }
 memmap2 = "0.5.10"
@@ -44,7 +49,12 @@ smallvec = "1.10.0"
 smartstring = "1.0.1"
 tempfile = "3.5.0"
 thiserror = "1.0.40"
-time = { version = "0.3.20", features = ["serde-well-known", "formatting", "parsing", "macros"] }
+time = { version = "0.3.20", features = [
+    "serde-well-known",
+    "formatting",
+    "parsing",
+    "macros",
+] }
 uuid = { version = "1.3.1", features = ["v4"] }
 
 filter-parser = { path = "../filter-parser" }
@@ -63,13 +73,13 @@ big_s = "1.0.2"
 insta = "1.29.0"
 maplit = "1.0.2"
 md5 = "0.7.0"
-rand = {version = "0.8.5", features = ["small_rng"] }
+rand = { version = "0.8.5", features = ["small_rng"] }
 
 [target.'cfg(fuzzing)'.dev-dependencies]
 fuzzcheck = "0.12.1"
 
 [features]
-all-tokenizations = [ "charabia/default" ]
+all-tokenizations = ["charabia/default"]
 
 # Use POSIX semaphores instead of SysV semaphores in LMDB
 # For more information on this feature, see heed's Cargo.toml

milli/src/index.rs

@@ -170,33 +170,46 @@ impl Index {
         unsafe { options.flag(Flags::MdbAlwaysFreePages) };
 
         let env = options.open(path)?;
-        let main = env.create_poly_database(Some(MAIN))?;
-        let word_docids = env.create_database(Some(WORD_DOCIDS))?;
-        let exact_word_docids = env.create_database(Some(EXACT_WORD_DOCIDS))?;
-        let word_prefix_docids = env.create_database(Some(WORD_PREFIX_DOCIDS))?;
-        let exact_word_prefix_docids = env.create_database(Some(EXACT_WORD_PREFIX_DOCIDS))?;
-        let docid_word_positions = env.create_database(Some(DOCID_WORD_POSITIONS))?;
-        let word_pair_proximity_docids = env.create_database(Some(WORD_PAIR_PROXIMITY_DOCIDS))?;
-        let script_language_docids = env.create_database(Some(SCRIPT_LANGUAGE_DOCIDS))?;
+        let mut wtxn = env.write_txn()?;
+        let main = env.create_poly_database(&mut wtxn, Some(MAIN))?;
+        let word_docids = env.create_database(&mut wtxn, Some(WORD_DOCIDS))?;
+        let exact_word_docids = env.create_database(&mut wtxn, Some(EXACT_WORD_DOCIDS))?;
+        let word_prefix_docids = env.create_database(&mut wtxn, Some(WORD_PREFIX_DOCIDS))?;
+        let exact_word_prefix_docids =
+            env.create_database(&mut wtxn, Some(EXACT_WORD_PREFIX_DOCIDS))?;
+        let docid_word_positions = env.create_database(&mut wtxn, Some(DOCID_WORD_POSITIONS))?;
+        let word_pair_proximity_docids =
+            env.create_database(&mut wtxn, Some(WORD_PAIR_PROXIMITY_DOCIDS))?;
+        let script_language_docids =
+            env.create_database(&mut wtxn, Some(SCRIPT_LANGUAGE_DOCIDS))?;
         let word_prefix_pair_proximity_docids =
-            env.create_database(Some(WORD_PREFIX_PAIR_PROXIMITY_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_PAIR_PROXIMITY_DOCIDS))?;
         let prefix_word_pair_proximity_docids =
-            env.create_database(Some(PREFIX_WORD_PAIR_PROXIMITY_DOCIDS))?;
-        let word_position_docids = env.create_database(Some(WORD_POSITION_DOCIDS))?;
-        let word_fid_docids = env.create_database(Some(WORD_FIELD_ID_DOCIDS))?;
-        let field_id_word_count_docids = env.create_database(Some(FIELD_ID_WORD_COUNT_DOCIDS))?;
-        let word_prefix_position_docids = env.create_database(Some(WORD_PREFIX_POSITION_DOCIDS))?;
-        let word_prefix_fid_docids = env.create_database(Some(WORD_PREFIX_FIELD_ID_DOCIDS))?;
-        let facet_id_f64_docids = env.create_database(Some(FACET_ID_F64_DOCIDS))?;
-        let facet_id_string_docids = env.create_database(Some(FACET_ID_STRING_DOCIDS))?;
-        let facet_id_exists_docids = env.create_database(Some(FACET_ID_EXISTS_DOCIDS))?;
-        let facet_id_is_null_docids = env.create_database(Some(FACET_ID_IS_NULL_DOCIDS))?;
-        let facet_id_is_empty_docids = env.create_database(Some(FACET_ID_IS_EMPTY_DOCIDS))?;
+            env.create_database(&mut wtxn, Some(PREFIX_WORD_PAIR_PROXIMITY_DOCIDS))?;
+        let word_position_docids = env.create_database(&mut wtxn, Some(WORD_POSITION_DOCIDS))?;
+        let word_fid_docids = env.create_database(&mut wtxn, Some(WORD_FIELD_ID_DOCIDS))?;
+        let field_id_word_count_docids =
+            env.create_database(&mut wtxn, Some(FIELD_ID_WORD_COUNT_DOCIDS))?;
+        let word_prefix_position_docids =
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_POSITION_DOCIDS))?;
+        let word_prefix_fid_docids =
+            env.create_database(&mut wtxn, Some(WORD_PREFIX_FIELD_ID_DOCIDS))?;
+        let facet_id_f64_docids = env.create_database(&mut wtxn, Some(FACET_ID_F64_DOCIDS))?;
+        let facet_id_string_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_STRING_DOCIDS))?;
+        let facet_id_exists_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_EXISTS_DOCIDS))?;
+        let facet_id_is_null_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_IS_NULL_DOCIDS))?;
+        let facet_id_is_empty_docids =
+            env.create_database(&mut wtxn, Some(FACET_ID_IS_EMPTY_DOCIDS))?;
 
-        let field_id_docid_facet_f64s = env.create_database(Some(FIELD_ID_DOCID_FACET_F64S))?;
+        let field_id_docid_facet_f64s =
+            env.create_database(&mut wtxn, Some(FIELD_ID_DOCID_FACET_F64S))?;
         let field_id_docid_facet_strings =
-            env.create_database(Some(FIELD_ID_DOCID_FACET_STRINGS))?;
-        let documents = env.create_database(Some(DOCUMENTS))?;
+            env.create_database(&mut wtxn, Some(FIELD_ID_DOCID_FACET_STRINGS))?;
+        let documents = env.create_database(&mut wtxn, Some(DOCUMENTS))?;
+        wtxn.commit()?;
 
         Index::set_creation_dates(&env, main, created_at, updated_at)?;
 

milli/src/update/facet/mod.rs

@@ -261,7 +261,9 @@ pub(crate) mod test_helpers {
             let options = options.map_size(4096 * 4 * 1000 * 100);
             let tempdir = tempfile::TempDir::new().unwrap();
             let env = options.open(tempdir.path()).unwrap();
-            let content = env.create_database(None).unwrap();
+            let mut wtxn = env.write_txn().unwrap();
+            let content = env.create_database(&mut wtxn, None).unwrap();
+            wtxn.commit().unwrap();
 
             FacetIndex {
                 content,