Increase max concurrent readers on indexes

meilisearch-lib/src/index/dump.rs

@@ -105,6 +105,7 @@ impl Index {
 
         let mut options = EnvOpenOptions::new();
         options.map_size(size);
+        options.max_readers(1024);
         let index = milli::Index::new(options, &dst_dir_path)?;
 
         let mut txn = index.write_txn()?;

meilisearch-lib/src/index/index.rs

@@ -94,6 +94,7 @@ impl Index {
         create_dir_all(&path)?;
         let mut options = EnvOpenOptions::new();
         options.map_size(size);
+        options.max_readers(1024);
         let inner = Arc::new(milli::Index::new(options, &path)?);
         Ok(Index {
             inner,

meilisearch-lib/src/snapshot.rs

@@ -181,6 +181,7 @@ impl SnapshotJob {
 
             let mut options = milli::heed::EnvOpenOptions::new();
             options.map_size(self.index_size);
+            options.max_readers(1024);
             let index = milli::Index::new(options, entry.path())?;
             index.copy_to_path(dst, CompactionOption::Enabled)?;
         }