Clamp the databases size to the page size

Cargo.lock

@@ -1625,7 +1625,7 @@ dependencies = [
  "libc",
  "lmdb-rkv-sys",
  "once_cell",
- "page_size",
+ "page_size 0.4.2",
  "synchronoise",
  "url",
  "zerocopy",
@@ -1783,6 +1783,7 @@ dependencies = [
  "meili-snap",
  "meilisearch-types",
  "nelson",
+ "page_size 0.5.0",
  "roaring",
  "serde",
  "serde_json",
@@ -2663,6 +2664,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "page_size"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b7663cbd190cfd818d08efa8497f6cd383076688c49a391ef7c0d03cd12b561"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"

index-scheduler/Cargo.toml

@@ -13,6 +13,7 @@ enum-iterator = "1.1.3"
 file-store = { path = "../file-store" }
 log = "0.4.14"
 meilisearch-types = { path = "../meilisearch-types" }
+page_size = "0.5.0"
 roaring = { version = "0.10.0", features = ["serde"] }
 serde = { version = "1.0.136", features = ["derive"] }
 serde_json = { version = "1.0.85", features = ["preserve_order"] }

index-scheduler/src/index_mapper.rs

@@ -13,7 +13,7 @@ use uuid::Uuid;
 
 use self::IndexStatus::{Available, BeingDeleted};
 use crate::uuid_codec::UuidCodec;
-use crate::{Error, Result};
+use crate::{clamp_to_page_size, Error, Result};
 
 const INDEX_MAPPING: &str = "index-mapping";
 
@@ -68,7 +68,7 @@ impl IndexMapper {
     /// The path *must* exists or an error will be thrown.
     fn create_or_open_index(&self, path: &Path) -> Result<Index> {
         let mut options = EnvOpenOptions::new();
-        options.map_size(self.index_size);
+        options.map_size(clamp_to_page_size(self.index_size));
         options.max_readers(1024);
         Ok(Index::new(options, path)?)
     }

index-scheduler/src/lib.rs

@@ -55,7 +55,7 @@ use utils::{filter_out_references_to_newer_tasks, keep_tasks_within_datetimes, m
 use uuid::Uuid;
 
 use crate::index_mapper::IndexMapper;
-use crate::utils::check_index_swap_validity;
+use crate::utils::{check_index_swap_validity, clamp_to_page_size};
 
 pub(crate) type BEI128 =
     meilisearch_types::heed::zerocopy::I128<meilisearch_types::heed::byteorder::BE>;
@@ -362,7 +362,7 @@ impl IndexScheduler {
 
         let env = heed::EnvOpenOptions::new()
             .max_dbs(10)
-            .map_size(options.task_db_size)
+            .map_size(clamp_to_page_size(options.task_db_size))
             .open(options.tasks_path)?;
         let file_store = FileStore::new(&options.update_file_path)?;
 

index-scheduler/src/utils.rs

@@ -324,6 +324,11 @@ pub(crate) fn check_index_swap_validity(task: &Task) -> Result<()> {
     Ok(())
 }
 
+/// Clamp the provided value to be a multiple of system page size.
+pub fn clamp_to_page_size(size: usize) -> usize {
+    size / page_size::get() * page_size::get()
+}
+
 #[cfg(test)]
 impl IndexScheduler {
     /// Asserts that the index scheduler's content is internally consistent.