From 5df10173dd0eb2cdf8bda541b4b5efb674310756 Mon Sep 17 00:00:00 2001
From: Yueh-Hsuan Chiang <93241502+yhchiang-sol@users.noreply.github.com>
Date: Thu, 13 Oct 2022 11:41:58 -0700
Subject: [PATCH] Add comment block for BankHash ledger column (#28357)

Add comment block for BankHash ledger column.
---
 ledger/src/blockstore_db.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/ledger/src/blockstore_db.rs b/ledger/src/blockstore_db.rs
index 6bc426f169..8174966cbb 100644
--- a/ledger/src/blockstore_db.rs
+++ b/ledger/src/blockstore_db.rs
@@ -169,7 +169,15 @@ pub mod columns {
     pub struct ErasureMeta;
 
     #[derive(Debug)]
-    /// The bank hash column
+    /// The bank hash column.
+    ///
+    /// This column family persists the bank hash of a given slot.  Note that
+    /// not every slot has a bank hash (e.g., a dead slot.)
+    ///
+    /// The bank hash of a slot is derived from hashing the delta state of all
+    /// the accounts in a slot combined with the bank hash of its parent slot.
+    /// A bank hash of a slot essentially represents all the account states at
+    /// that slot.
     ///
     /// index type: u64 (see `SlotColumn`)
     /// value type: `blockstore_meta::FrozenHashVersioned`