log secondary index contents on startup (#24348)

runtime/src/accounts_db.rs

@@ -7175,6 +7175,8 @@ impl AccountsDb {
             timings.report();
         }
 
+        self.accounts_index.log_secondary_indexes();
+
         IndexGenerationInfo {
             accounts_data_len: accounts_data_len.load(Ordering::Relaxed),
         }

runtime/src/accounts_index.rs

@@ -1408,6 +1408,22 @@ impl<T: IndexValue> AccountsIndex<T> {
         }
     }
 
+    /// log any secondary index counts, if non-zero
+    pub(crate) fn log_secondary_indexes(&self) {
+        if !self.program_id_index.index.is_empty() {
+            info!("secondary index: {:?}", AccountIndex::ProgramId);
+            self.program_id_index.log_contents();
+        }
+        if !self.spl_token_mint_index.index.is_empty() {
+            info!("secondary index: {:?}", AccountIndex::SplTokenMint);
+            self.spl_token_mint_index.log_contents();
+        }
+        if !self.spl_token_owner_index.index.is_empty() {
+            info!("secondary index: {:?}", AccountIndex::SplTokenOwner);
+            self.spl_token_owner_index.log_contents();
+        }
+    }
+
     pub(crate) fn update_secondary_indexes(
         &self,
         pubkey: &Pubkey,

runtime/src/secondary_index.rs

@@ -1,5 +1,6 @@
 use {
     dashmap::{mapref::entry::Entry::Occupied, DashMap},
+    log::*,
     solana_sdk::{pubkey::Pubkey, timing::AtomicInterval},
     std::{
         collections::HashSet,
@@ -223,4 +224,19 @@ impl<SecondaryIndexEntryType: SecondaryIndexEntry + Default + Sync + Send>
             vec![]
         }
     }
+
+    /// log top 20 (owner, # accounts) in descending order of # accounts
+    pub fn log_contents(&self) {
+        let mut entries = self
+            .index
+            .iter()
+            .map(|entry| (entry.value().len(), *entry.key()))
+            .collect::<Vec<_>>();
+        entries.sort_unstable();
+        entries
+            .iter()
+            .rev()
+            .take(20)
+            .for_each(|(v, k)| info!("owner: {}, accounts: {}", k, v));
+    }
 }