return the on disk size actually used by meilisearch

index-scheduler/src/index_mapper/mod.rs

@@ -90,6 +90,8 @@ pub struct IndexStats {
     pub number_of_documents: u64,
     /// Size of the index' DB, in bytes.
     pub database_size: u64,
+    /// Size of the index' DB, in bytes.
+    pub used_database_size: u64,
     /// Association of every field name with the number of times it occurs in the documents.
     pub field_distribution: FieldDistribution,
     /// Creation date of the index.
@@ -105,10 +107,10 @@ impl IndexStats {
     ///
     /// - rtxn: a RO transaction for the index, obtained from `Index::read_txn()`.
     pub fn new(index: &Index, rtxn: &RoTxn) -> Result<Self> {
-        let database_size = index.on_disk_size()?;
         Ok(IndexStats {
             number_of_documents: index.number_of_documents(rtxn)?,
-            database_size,
+            database_size: index.on_disk_size()?,
+            used_database_size: index.used_size()?,
             field_distribution: index.field_distribution(rtxn)?,
             created_at: index.created_at(rtxn)?,
             updated_at: index.updated_at(rtxn)?,

index-scheduler/src/lib.rs

@@ -554,10 +554,16 @@ impl IndexScheduler {
         &self.index_mapper.indexer_config
     }
 
+    /// Return the real database size (i.e.: The size **with** the free pages)
     pub fn size(&self) -> Result<u64> {
         Ok(self.env.real_disk_size()?)
     }
 
+    /// Return the used database size (i.e.: The size **without** the free pages)
+    pub fn used_size(&self) -> Result<u64> {
+        Ok(self.env.non_free_pages_size()?)
+    }
+
     /// Return the index corresponding to the name.
     ///
     /// * If the index wasn't opened before, the index will be opened.