add --limit_load_slot_count_from_snapshot to ledger-tool (#17417)

runtime/src/accounts_db.rs

@@ -5123,12 +5123,15 @@ impl AccountsDb {
     }
 
     #[allow(clippy::needless_collect)]
-    pub fn generate_index(&self) {
+    pub fn generate_index(&self, limit_load_slot_count_from_snapshot: Option<usize>) {
         type AccountsMap<'a> =
             HashMap<Pubkey, (StoredMetaWriteVersion, AppendVecId, StoredAccountMeta<'a>)>;
         let mut slots = self.storage.all_slots();
         #[allow(clippy::stable_sort_primitive)]
         slots.sort();
+        if let Some(limit) = limit_load_slot_count_from_snapshot {
+            slots.truncate(limit); // get rid of the newer slots and keep just the older
+        }
         let total_processed_slots_across_all_threads = AtomicU64::new(0);
         let outer_slots_len = slots.len();
         let chunk_size = (outer_slots_len / 7) + 1; // approximately 400k slots in a snapshot

runtime/src/serde_snapshot.rs

@@ -135,6 +135,7 @@ pub(crate) fn bank_from_stream<R>(
     additional_builtins: Option<&Builtins>,
     account_indexes: AccountSecondaryIndexes,
     caching_enabled: bool,
+    limit_load_slot_count_from_snapshot: Option<usize>,
 ) -> std::result::Result<Bank, Error>
 where
     R: Read,
@@ -154,6 +155,7 @@ where
                 additional_builtins,
                 account_indexes,
                 caching_enabled,
+                limit_load_slot_count_from_snapshot,
             )?;
             Ok(bank)
         }};
@@ -243,6 +245,7 @@ fn reconstruct_bank_from_fields<E>(
     additional_builtins: Option<&Builtins>,
     account_indexes: AccountSecondaryIndexes,
     caching_enabled: bool,
+    limit_load_slot_count_from_snapshot: Option<usize>,
 ) -> Result<Bank, Error>
 where
     E: SerializableStorage,
@@ -254,6 +257,7 @@ where
         &genesis_config.cluster_type,
         account_indexes,
         caching_enabled,
+        limit_load_slot_count_from_snapshot,
     )?;
     accounts_db.freeze_accounts(
         &Ancestors::from(&bank_fields.ancestors),
@@ -279,6 +283,7 @@ fn reconstruct_accountsdb_from_fields<E>(
     cluster_type: &ClusterType,
     account_indexes: AccountSecondaryIndexes,
     caching_enabled: bool,
+    limit_load_slot_count_from_snapshot: Option<usize>,
 ) -> Result<AccountsDb, Error>
 where
     E: SerializableStorage,
@@ -371,6 +376,6 @@ where
     accounts_db
         .write_version
         .fetch_add(version, Ordering::Relaxed);
-    accounts_db.generate_index();
+    accounts_db.generate_index(limit_load_slot_count_from_snapshot);
     Ok(accounts_db)
 }

runtime/src/serde_snapshot/tests.rs

@@ -73,6 +73,7 @@ where
         &ClusterType::Development,
         AccountSecondaryIndexes::default(),
         false,
+        None,
     )
 }
 
@@ -226,6 +227,7 @@ fn test_bank_serialize_style(serde_style: SerdeStyle) {
         None,
         AccountSecondaryIndexes::default(),
         false,
+        None,
     )
     .unwrap();
     dbank.src = ref_sc;

runtime/src/snapshot_utils.rs

@@ -603,6 +603,7 @@ pub fn bank_from_archive<P: AsRef<Path>>(
     additional_builtins: Option<&Builtins>,
     account_indexes: AccountSecondaryIndexes,
     accounts_db_caching_enabled: bool,
+    limit_load_slot_count_from_snapshot: Option<usize>,
 ) -> Result<Bank> {
     let unpack_dir = tempfile::Builder::new()
         .prefix(TMP_SNAPSHOT_PREFIX)
@@ -633,6 +634,7 @@ pub fn bank_from_archive<P: AsRef<Path>>(
         additional_builtins,
         account_indexes,
         accounts_db_caching_enabled,
+        limit_load_slot_count_from_snapshot,
     )?;
 
     if !bank.verify_snapshot_bank() {
@@ -791,6 +793,7 @@ fn rebuild_bank_from_snapshots(
     additional_builtins: Option<&Builtins>,
     account_indexes: AccountSecondaryIndexes,
     accounts_db_caching_enabled: bool,
+    limit_load_slot_count_from_snapshot: Option<usize>,
 ) -> Result<Bank> {
     info!("snapshot version: {}", snapshot_version);
 
@@ -826,6 +829,7 @@ fn rebuild_bank_from_snapshots(
                 additional_builtins,
                 account_indexes,
                 accounts_db_caching_enabled,
+                limit_load_slot_count_from_snapshot,
             ),
         }?)
     })?;