WIP: rebasing on master

meilisearch-http/src/index_controller/dump.rs

@@ -0,0 +1,258 @@
+use std::{
+    fs::File,
+    path::{Path, PathBuf},
+    sync::Arc,
+};
+
+use anyhow::bail;
+use heed::EnvOpenOptions;
+use log::{error, info};
+use milli::update::{IndexDocumentsMethod, UpdateBuilder, UpdateFormat};
+use serde::{Deserialize, Serialize};
+use tempfile::TempDir;
+use tokio::fs;
+use tokio::task::spawn_blocking;
+
+use super::update_actor::UpdateActorHandle;
+use super::uuid_resolver::UuidResolverHandle;
+use super::IndexMetadata;
+use crate::index::Index;
+use crate::index_controller::uuid_resolver;
+use crate::{helpers::compression, index::Settings};
+
+#[derive(Debug, Serialize, Deserialize, Copy, Clone)]
+enum DumpVersion {
+    V1,
+}
+
+impl DumpVersion {
+    const CURRENT: Self = Self::V1;
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct DumpMetadata {
+    indexes: Vec<IndexMetadata>,
+    db_version: String,
+    dump_version: DumpVersion,
+}
+
+impl DumpMetadata {
+    /// Create a DumpMetadata with the current dump version of meilisearch.
+    pub fn new(indexes: Vec<IndexMetadata>, db_version: String) -> Self {
+        DumpMetadata {
+            indexes,
+            db_version,
+            dump_version: DumpVersion::CURRENT,
+        }
+    }
+
+    /// Extract DumpMetadata from `metadata.json` file present at provided `dir_path`
+    fn from_path(dir_path: &Path) -> anyhow::Result<Self> {
+        let path = dir_path.join("metadata.json");
+        let file = File::open(path)?;
+        let reader = std::io::BufReader::new(file);
+        let metadata = serde_json::from_reader(reader)?;
+
+        Ok(metadata)
+    }
+
+    /// Write DumpMetadata in `metadata.json` file at provided `dir_path`
+    fn to_path(&self, dir_path: &Path) -> anyhow::Result<()> {
+        let path = dir_path.join("metadata.json");
+        let file = File::create(path)?;
+
+        serde_json::to_writer(file, &self)?;
+
+        Ok(())
+    }
+}
+
+pub struct DumpService<U, R> {
+    uuid_resolver_handle: R,
+    update_handle: U,
+    dump_path: PathBuf,
+    db_name: String,
+}
+
+impl<U, R> DumpService<U, R>
+where
+    U: UpdateActorHandle,
+    R: UuidResolverHandle,
+{
+    pub fn new(
+        uuid_resolver_handle: R,
+        update_handle: U,
+        dump_path: PathBuf,
+        db_name: String,
+    ) -> Self {
+        Self {
+            uuid_resolver_handle,
+            update_handle,
+            dump_path,
+            db_name,
+        }
+    }
+
+    pub async fn run(self) {
+        if let Err(e) = self.perform_dump().await {
+            error!("{}", e);
+        }
+    }
+
+    async fn perform_dump(&self) -> anyhow::Result<()> {
+        info!("Performing dump.");
+
+        let dump_dir = self.dump_path.clone();
+        fs::create_dir_all(&dump_dir).await?;
+        let temp_dump_dir = spawn_blocking(move || tempfile::tempdir_in(dump_dir)).await??;
+        let temp_dump_path = temp_dump_dir.path().to_owned();
+
+        let uuids = self
+            .uuid_resolver_handle
+            .dump(temp_dump_path.clone())
+            .await?;
+
+        if uuids.is_empty() {
+            return Ok(());
+        }
+
+        let tasks = uuids
+            .iter()
+            .map(|&uuid| self.update_handle.dump(uuid, temp_dump_path.clone()))
+            .collect::<Vec<_>>();
+
+        futures::future::try_join_all(tasks).await?;
+
+        let dump_dir = self.dump_path.clone();
+        let dump_path = self.dump_path.join(format!("{}.dump", self.db_name));
+        let dump_path = spawn_blocking(move || -> anyhow::Result<PathBuf> {
+            let temp_dump_file = tempfile::NamedTempFile::new_in(dump_dir)?;
+            let temp_dump_file_path = temp_dump_file.path().to_owned();
+            compression::to_tar_gz(temp_dump_path, temp_dump_file_path)?;
+            temp_dump_file.persist(&dump_path)?;
+            Ok(dump_path)
+        })
+        .await??;
+
+        info!("Created dump in {:?}.", dump_path);
+
+        Ok(())
+    }
+}
+
+/// Extract Settings from `settings.json` file present at provided `dir_path`
+fn settings_from_path(dir_path: &Path) -> anyhow::Result<Settings> {
+    let path = dir_path.join("settings.json");
+    let file = File::open(path)?;
+    let reader = std::io::BufReader::new(file);
+    let metadata = serde_json::from_reader(reader)?;
+
+    Ok(metadata)
+}
+
+/// Write Settings in `settings.json` file at provided `dir_path`
+fn settings_to_path(settings: &Settings, dir_path: &Path) -> anyhow::Result<()> {
+    let path = dir_path.join("settings.json");
+    let file = File::create(path)?;
+
+    serde_json::to_writer(file, settings)?;
+
+    Ok(())
+}
+
+fn import_index_v1(size: usize, dump_path: &Path, index_path: &Path) -> anyhow::Result<()> {
+    std::fs::create_dir_all(&index_path)?;
+    let mut options = EnvOpenOptions::new();
+    options.map_size(size);
+    let index = milli::Index::new(options, index_path)?;
+    let index = Index(Arc::new(index));
+
+    // extract `settings.json` file and import content
+    let settings = settings_from_path(&dump_path)?;
+    let update_builder = UpdateBuilder::new(0);
+    index.update_settings(&settings, update_builder)?;
+
+    let update_builder = UpdateBuilder::new(1);
+    let file = File::open(&index_path.join("documents.jsonl"))?;
+    let reader = std::io::BufReader::new(file);
+    index.update_documents(
+        UpdateFormat::JsonStream,
+        IndexDocumentsMethod::ReplaceDocuments,
+        reader,
+        update_builder,
+        None,
+    )?;
+
+    // the last step: we extract the milli::Index and close it
+    Arc::try_unwrap(index.0)
+        .map_err(|_e| "[dumps] At this point no one is supposed to have a reference on the index")
+        .unwrap()
+        .prepare_for_closing()
+        .wait();
+
+    Ok(())
+}
+
+pub fn load_dump(
+    db_path: impl AsRef<Path>,
+    dump_path: impl AsRef<Path>,
+    size: usize,
+) -> anyhow::Result<()> {
+    info!("Importing dump from {}...", dump_path.as_ref().display());
+    let db_path = db_path.as_ref();
+    let dump_path = dump_path.as_ref();
+    let uuid_resolver = uuid_resolver::UuidResolverHandleImpl::new(&db_path)?;
+
+    // extract the dump in a temporary directory
+    let tmp_dir = TempDir::new()?;
+    let tmp_dir_path = tmp_dir.path();
+    compression::from_tar_gz(dump_path, tmp_dir_path)?;
+
+    // read dump metadata
+    let metadata = DumpMetadata::from_path(&tmp_dir_path)?;
+
+    // choose importation function from DumpVersion of metadata
+    let import_index = match metadata.dump_version {
+        DumpVersion::V1 => import_index_v1,
+    };
+
+    // remove indexes which have same `uuid` than indexes to import and create empty indexes
+    let existing_index_uids = futures::executor::block_on(uuid_resolver.list())?;
+
+    info!("Deleting indexes provided in the dump...");
+    for idx in &metadata.indexes {
+        if let Some((_, uuid)) = existing_index_uids.iter().find(|(s, _)| s == &idx.uid) {
+            // if we find the index in the `uuid_resolver` it's supposed to exist on the file system
+            // and we want to delete it
+            let path = db_path.join(&format!("indexes/index-{}", uuid));
+            info!("Deleting {}", path.display());
+            use std::io::ErrorKind::*;
+            match std::fs::remove_dir_all(path) {
+                Ok(()) => (),
+                // if an index was present in the metadata but missing of the fs we can ignore the
+                // problem because we are going to create it later
+                Err(e) if e.kind() == NotFound => (),
+                Err(e) => bail!(e),
+            }
+        } else {
+            // if the index does not exist in the `uuid_resolver` we create it
+            futures::executor::block_on(uuid_resolver.create(idx.uid.clone()))?;
+        }
+    }
+
+    // import each indexes content
+    for idx in metadata.indexes {
+        let dump_path = tmp_dir_path.join(&idx.uid);
+        let uuid = futures::executor::block_on(uuid_resolver.get(idx.uid))?;
+        let index_path = db_path.join(&format!("indexes/index-{}", uuid));
+
+        info!("Importing dump from {} into {}...", dump_path.display(), index_path.display());
+        import_index(size, &dump_path, &index_path).unwrap();
+        info!("Dump importation from {} succeed", dump_path.display());
+    }
+
+
+    info!("Dump importation from {} succeed", dump_path.display());
+    Ok(())
+}

meilisearch-http/src/index_controller/index_actor/actor.rs

@@ -36,6 +36,9 @@ impl<S: IndexStore + Sync + Send> IndexActor<S> {
         Ok(Self { receiver, update_handler, store })
     }
 
+    /// `run` poll the write_receiver and read_receiver concurrently, but while messages send
+    /// through the read channel are processed concurrently, the messages sent through the write
+    /// channel are processed one at a time.
     pub async fn run(mut self) {
         let mut receiver = self
             .receiver
@@ -119,6 +122,9 @@ impl<S: IndexStore + Sync + Send> IndexActor<S> {
             Snapshot { uuid, path, ret } => {
                 let _ = ret.send(self.handle_snapshot(uuid, path).await);
             }
+            Dump { uuid, path, ret } => {
+                let _ = ret.send(self.handle_dump(uuid, path).await);
+            }
             GetStats { uuid, ret } => {
                 let _ = ret.send(self.handle_get_stats(uuid).await);
             }
@@ -306,7 +312,35 @@ impl<S: IndexStore + Sync + Send> IndexActor<S> {
         Ok(())
     }
 
-    async fn handle_get_stats(&self, uuid: Uuid) -> IndexResult<IndexStats> {
+    async fn handle_dump(&self, uuid: Uuid, mut path: PathBuf) -> Result<()> {
+        use tokio::fs::create_dir_all;
+
+        path.push("indexes");
+        create_dir_all(&path)
+            .await
+            .map_err(|e| IndexError::Error(e.into()))?;
+
+        if let Some(index) = self.store.get(uuid).await? {
+            let mut index_path = path.join(format!("index-{}", uuid));
+            create_dir_all(&index_path)
+                .await
+                .map_err(|e| IndexError::Error(e.into()))?;
+            index_path.push("data.mdb");
+            spawn_blocking(move || -> anyhow::Result<()> {
+                // Get write txn to wait for ongoing write transaction before dump.
+                let _txn = index.write_txn()?;
+                index.env.copy_to_path(index_path, CompactionOption::Enabled)?;
+                Ok(())
+            })
+            .await
+            .map_err(|e| IndexError::Error(e.into()))?
+            .map_err(IndexError::Error)?;
+        }
+
+        Ok(())
+    }
+
+    async fn handle_get_stats(&self, uuid: Uuid) -> Result<IndexStats> {
         let index = self
             .store
             .get(uuid)

meilisearch-http/src/index_controller/index_actor/handle_impl.rs

@@ -136,7 +136,14 @@ impl IndexActorHandle for IndexActorHandleImpl {
         Ok(receiver.await.expect("IndexActor has been killed")?)
     }
 
-    async fn get_index_stats(&self, uuid: Uuid) -> IndexResult<IndexStats> {
+    async fn dump(&self, uuid: Uuid, path: PathBuf) -> Result<()> {
+        let (ret, receiver) = oneshot::channel();
+        let msg = IndexMsg::Dump { uuid, path, ret };
+        let _ = self.read_sender.send(msg).await;
+        Ok(receiver.await.expect("IndexActor has been killed")?)
+    }
+
+    async fn get_index_stats(&self, uuid: Uuid) -> Result<IndexStats> {
         let (ret, receiver) = oneshot::channel();
         let msg = IndexMsg::GetStats { uuid, ret };
         let _ = self.sender.send(msg).await;

meilisearch-http/src/index_controller/index_actor/message.rs

@@ -60,6 +60,11 @@ pub enum IndexMsg {
         path: PathBuf,
         ret: oneshot::Sender<IndexResult<()>>,
     },
+    Dump {
+        uuid: Uuid,
+        path: PathBuf,
+        ret: oneshot::Sender<Result<()>>,
+    },
     GetStats {
         uuid: Uuid,
         ret: oneshot::Sender<IndexResult<IndexStats>>,

meilisearch-http/src/index_controller/index_actor/mod.rs

@@ -180,5 +180,4 @@ mod test {
         async fn get_index_stats(&self, uuid: Uuid) -> IndexResult<IndexStats> {
             self.as_ref().get_index_stats(uuid).await
         }
-    }
 }

meilisearch-http/src/index_controller/mod.rs

@@ -5,7 +5,6 @@ use std::time::Duration;
 
 use actix_web::web::{Bytes, Payload};
 use anyhow::bail;
-use chrono::{DateTime, Utc};
 use futures::stream::StreamExt;
 use log::info;
 use milli::FieldsDistribution;
@@ -25,6 +24,7 @@ use crate::option::Opt;
 
 mod index_actor;
 mod snapshot;
+mod dump;
 mod update_actor;
 mod update_handler;
 mod updates;
@@ -87,6 +87,13 @@ impl IndexController {
                 options.ignore_snapshot_if_db_exists,
                 options.ignore_missing_snapshot,
             )?;
+        } else if let Some(ref path) = options.import_dump {
+            load_dump(
+                &options.db_path,
+                path,
+                index_size,
+            );
+
         }
 
         std::fs::create_dir_all(&path)?;

meilisearch-http/src/index_controller/update_actor/actor.rs

@@ -71,11 +71,16 @@ where
                 Some(Delete { uuid, ret }) => {
                     let _ = ret.send(self.handle_delete(uuid).await);
                 }
-                Some(Snapshot { uuids, path, ret }) => {
-                    let _ = ret.send(self.handle_snapshot(uuids, path).await);
+                Some(Snapshot { uuid, path, ret }) => {
+                    let _ = ret.send(self.handle_snapshot(uuid, path).await);
+                }
+                Some(Dump { uuid, path, ret }) => {
+                    let _ = ret.send(self.handle_dump(uuid, path).await);
                 }
                 Some(GetInfo { ret }) => {
                     let _ = ret.send(self.handle_get_info().await);
+                Some(GetSize { uuid, ret }) => {
+                    let _ = ret.send(self.handle_get_size(uuid).await);
                 }
                 None => break,
             }
@@ -194,9 +199,51 @@ where
     }
 
     async fn handle_delete(&self, uuid: Uuid) -> Result<()> {
-        let store = self.store.clone();
+        let store = self.store.delete(uuid).await?;
 
-        tokio::task::spawn_blocking(move || store.delete_all(uuid))
+        if let Some(store) = store {
+            tokio::task::spawn(async move {
+                let store = get_arc_ownership_blocking(store).await;
+                tokio::task::spawn_blocking(move || {
+                    store.prepare_for_closing().wait();
+                    info!("Update store {} was closed.", uuid);
+                });
+            });
+        }
+
+        Ok(())
+    }
+
+    async fn handle_create(&self, uuid: Uuid) -> Result<()> {
+        let _ = self.store.get_or_create(uuid).await?;
+        Ok(())
+    }
+
+        Ok(())
+    }
+
+    async fn handle_create(&self, uuid: Uuid) -> Result<()> {
+        let _ = self.store.get_or_create(uuid).await?;
+        Ok(())
+    }
+
+    async fn handle_snapshot(&self, uuid: Uuid, path: PathBuf) -> Result<()> {
+        let index_handle = self.index_handle.clone();
+        if let Some(update_store) = self.store.get(uuid).await? {
+            tokio::task::spawn_blocking(move || -> anyhow::Result<()> {
+                // acquire write lock to prevent further writes during snapshot
+                // the update lock must be acquired BEFORE the write lock to prevent dead lock
+                let _lock = update_store.update_lock.lock();
+                let mut txn = update_store.env.write_txn()?;
+
+                // create db snapshot
+                update_store.snapshot(&mut txn, &path, uuid)?;
+
+                futures::executor::block_on(
+                    async move { index_handle.snapshot(uuid, path).await },
+                )?;
+                Ok(())
+            })
             .await
             .map_err(|e| UpdateError::Error(e.into()))?
             .map_err(|e| UpdateError::Error(e.into()))?;
@@ -245,4 +292,42 @@ where
 
         Ok(info)
     }
+
+    async fn handle_dump(&self, uuid: Uuid, path: PathBuf) -> Result<()> {
+        let index_handle = self.index_handle.clone();
+        if let Some(update_store) = self.store.get(uuid).await? {
+            tokio::task::spawn_blocking(move || -> anyhow::Result<()> {
+                // acquire write lock to prevent further writes during the dump
+                // the update lock must be acquired BEFORE the write lock to prevent dead lock
+                let _lock = update_store.update_lock.lock();
+                let mut txn = update_store.env.write_txn()?;
+
+                // create db dump
+                update_store.dump(&mut txn, &path, uuid)?;
+
+                futures::executor::block_on(
+                    async move { index_handle.dump(uuid, path).await },
+                )?;
+                Ok(())
+            })
+            .await
+            .map_err(|e| UpdateError::Error(e.into()))?
+            .map_err(|e| UpdateError::Error(e.into()))?;
+        }
+
+        Ok(())
+    }
+
+    async fn handle_get_size(&self, uuid: Uuid) -> Result<u64> {
+        let size = match self.store.get(uuid).await? {
+            Some(update_store) => tokio::task::spawn_blocking(move || -> anyhow::Result<u64> {
+                let txn = update_store.env.read_txn()?;
+
+                update_store.get_size(&txn)
+            })
+            .await
+            .map_err(|e| UpdateError::Error(e.into()))?
+            .map_err(|e| UpdateError::Error(e.into()))?,
+            None => 0,
+        };
 }

meilisearch-http/src/index_controller/update_actor/handle_impl.rs

@@ -78,6 +78,20 @@ where
         receiver.await.expect("update actor killed.")
     }
 
+    async fn dump(&self, uuid: Uuid, path: PathBuf) -> Result<()> {
+        let (ret, receiver) = oneshot::channel();
+        let msg = UpdateMsg::Dump { uuid, path, ret };
+        let _ = self.sender.send(msg).await;
+        receiver.await.expect("update actor killed.")
+    }
+
+    async fn get_size(&self, uuid: Uuid) -> Result<u64> {
+        let (ret, receiver) = oneshot::channel();
+        let msg = UpdateMsg::GetSize { uuid, ret };
+        let _ = self.sender.send(msg).await;
+        receiver.await.expect("update actor killed.")
+    }
+
     async fn update(
         &self,
         meta: UpdateMeta,

meilisearch-http/src/index_controller/update_actor/message.rs

@@ -31,7 +31,16 @@ pub enum UpdateMsg<D> {
         path: PathBuf,
         ret: oneshot::Sender<Result<()>>,
     },
+    Dump {
+        uuid: Uuid,
+        path: PathBuf,
+        ret: oneshot::Sender<Result<()>>,
+    },
     GetInfo {
         ret: oneshot::Sender<Result<UpdateStoreInfo>>,
     },
+    GetSize {
+        uuid: Uuid,
+        ret: oneshot::Sender<Result<u64>>,
+    },
 }

meilisearch-http/src/index_controller/update_actor/mod.rs

@@ -40,8 +40,11 @@ pub trait UpdateActorHandle {
     async fn get_all_updates_status(&self, uuid: Uuid) -> Result<Vec<UpdateStatus>>;
     async fn update_status(&self, uuid: Uuid, id: u64) -> Result<UpdateStatus>;
     async fn delete(&self, uuid: Uuid) -> Result<()>;
-    async fn snapshot(&self, uuids: HashSet<Uuid>, path: PathBuf) -> Result<()>;
+    async fn create(&self, uuid: Uuid) -> Result<()>;
+    async fn snapshot(&self, uuid: Uuid, path: PathBuf) -> Result<()>;
+    async fn dump(&self, uuid: Uuid, path: PathBuf) -> Result<()>;
     async fn get_info(&self) -> Result<UpdateStoreInfo>;
+    async fn get_size(&self, uuid: Uuid) -> Result<u64>;
     async fn update(
         &self,
         meta: UpdateMeta,

meilisearch-http/src/index_controller/update_actor/update_store.rs

@@ -499,9 +499,56 @@ impl UpdateStore {
         Ok(())
     }
 
+    pub fn dump(
+        &self,
+        txn: &mut heed::RwTxn,
+        path: impl AsRef<Path>,
+        uuid: Uuid,
+    ) -> anyhow::Result<()> {
+        let update_path = path.as_ref().join("updates");
+        create_dir_all(&update_path)?;
+
+        let mut dump_path = update_path.join(format!("update-{}", uuid));
+        // acquire write lock to prevent further writes during dump
+        create_dir_all(&dump_path)?;
+        dump_path.push("data.mdb");
+
+        // create db dump
+        self.env.copy_to_path(&dump_path, CompactionOption::Enabled)?;
+
+        let update_files_path = update_path.join("update_files");
+        create_dir_all(&update_files_path)?;
+
+        for path in self.pending.iter(&txn)? {
+            let (_, path) = path?;
+            let name = path.file_name().unwrap();
+            let to = update_files_path.join(name);
+            copy(path, to)?;
+        }
+
+        Ok(())
+    }
+
     pub fn get_info(&self) -> anyhow::Result<UpdateStoreInfo> {
         let mut size = self.env.size();
         let txn = self.env.read_txn()?;
+        for entry in self.pending_queue.iter(&txn)? {
+            let (_, pending) = entry?;
+            if let Some(path) = pending.content_path() {
+                size += File::open(path)?.metadata()?.len();
+            }
+        }
+        let processing = match *self.state.read() {
+            State::Processing(uuid, _) => Some(uuid),
+            _ => None,
+        };
+
+        Ok(UpdateStoreInfo { size, processing })
+    }
+
+    pub fn get_size(&self, txn: &heed::RoTxn) -> anyhow::Result<u64> {
+        let mut size = self.env.size();
+        let txn = self.env.read_txn()?;
 
         for entry in self.pending_queue.iter(&txn)? {
             let (_, pending) = entry?;

meilisearch-http/src/index_controller/uuid_resolver/actor.rs

@@ -41,6 +41,9 @@ impl<S: UuidStore> UuidResolverActor<S> {
                 Some(SnapshotRequest { path, ret }) => {
                     let _ = ret.send(self.handle_snapshot(path).await);
                 }
+                Some(DumpRequest { path, ret }) => {
+                    let _ = ret.send(self.handle_dump(path).await);
+                }
                 Some(GetSize { ret }) => {
                     let _ = ret.send(self.handle_get_size().await);
                 }
@@ -82,6 +85,10 @@ impl<S: UuidStore> UuidResolverActor<S> {
         self.store.snapshot(path).await
     }
 
+    async fn handle_dump(&self, path: PathBuf) -> Result<Vec<Uuid>> {
+        self.store.dump(path).await
+    }
+
     async fn handle_insert(&self, uid: String, uuid: Uuid) -> Result<()> {
         if !is_index_uid_valid(&uid) {
             return Err(UuidError::BadlyFormatted(uid));

meilisearch-http/src/index_controller/uuid_resolver/handle_impl.rs

@@ -68,6 +68,7 @@ impl UuidResolverHandle for UuidResolverHandleImpl {
             .expect("Uuid resolver actor has been killed")?)
     }
 
+    /// TODO: we should merge this function with the dump function
     async fn snapshot(&self, path: PathBuf) -> Result<HashSet<Uuid>> {
         let (ret, receiver) = oneshot::channel();
         let msg = UuidResolveMsg::SnapshotRequest { path, ret };
@@ -77,6 +78,15 @@ impl UuidResolverHandle for UuidResolverHandleImpl {
             .expect("Uuid resolver actor has been killed")?)
     }
 
+    async fn dump(&self, path: PathBuf) -> Result<Vec<Uuid>> {
+        let (ret, receiver) = oneshot::channel();
+        let msg = UuidResolveMsg::DumpRequest { path, ret };
+        let _ = self.sender.send(msg).await;
+        Ok(receiver
+            .await
+            .expect("Uuid resolver actor has been killed")?)
+    }
+
     async fn get_size(&self) -> Result<u64> {
         let (ret, receiver) = oneshot::channel();
         let msg = UuidResolveMsg::GetSize { ret };

meilisearch-http/src/index_controller/uuid_resolver/message.rs

@@ -31,6 +31,10 @@ pub enum UuidResolveMsg {
         path: PathBuf,
         ret: oneshot::Sender<Result<HashSet<Uuid>>>,
     },
+    DumpRequest {
+        path: PathBuf,
+        ret: oneshot::Sender<Result<Vec<Uuid>>>,
+    },
     GetSize {
         ret: oneshot::Sender<Result<u64>>,
     },

meilisearch-http/src/index_controller/uuid_resolver/mod.rs

@@ -31,6 +31,7 @@ pub trait UuidResolverHandle {
     async fn delete(&self, name: String) -> anyhow::Result<Uuid>;
     async fn list(&self) -> anyhow::Result<Vec<(String, Uuid)>>;
     async fn snapshot(&self, path: PathBuf) -> Result<HashSet<Uuid>>;
+    async fn dump(&self, path: PathBuf) -> Result<Vec<Uuid>>;
     async fn get_size(&self) -> Result<u64>;
 }
 

meilisearch-http/src/index_controller/uuid_resolver/store.rs

@@ -21,6 +21,7 @@ pub trait UuidStore {
     async fn list(&self) -> Result<Vec<(String, Uuid)>>;
     async fn insert(&self, name: String, uuid: Uuid) -> Result<()>;
     async fn snapshot(&self, path: PathBuf) -> Result<HashSet<Uuid>>;
+    async fn dump(&self, path: PathBuf) -> Result<Vec<Uuid>>;
     async fn get_size(&self) -> Result<u64>;
 }
 
@@ -130,6 +131,8 @@ impl UuidStore for HeedUuidStore {
         .await?
     }
 
+    // TODO: we should merge this function and the following function for the dump. it's exactly
+    // the same code
     async fn snapshot(&self, mut path: PathBuf) -> Result<HashSet<Uuid>> {
         let env = self.env.clone();
         let db = self.db;
@@ -155,6 +158,31 @@ impl UuidStore for HeedUuidStore {
         .await?
     }
 
+    async fn dump(&self, mut path: PathBuf) -> Result<Vec<Uuid>> {
+        let env = self.env.clone();
+        let db = self.db;
+        tokio::task::spawn_blocking(move || {
+            // Write transaction to acquire a lock on the database.
+            let txn = env.write_txn()?;
+            let mut entries = Vec::new();
+            for entry in db.iter(&txn)? {
+                let (_, uuid) = entry?;
+                let uuid = Uuid::from_slice(uuid)?;
+                entries.push(uuid)
+            }
+
+            // only perform dump if there are indexes
+            if !entries.is_empty() {
+                path.push("index_uuids");
+                create_dir_all(&path).unwrap();
+                path.push("data.mdb");
+                env.copy_to_path(path, CompactionOption::Enabled)?;
+            }
+            Ok(entries)
+        })
+        .await?
+    }
+
     async fn get_size(&self) -> Result<u64> {
         Ok(self.env.size())
     }