diff --git a/src/ripple/app/ledger/impl/LedgerMaster.cpp b/src/ripple/app/ledger/impl/LedgerMaster.cpp
index db1b57121..500eefa6b 100644
--- a/src/ripple/app/ledger/impl/LedgerMaster.cpp
+++ b/src/ripple/app/ledger/impl/LedgerMaster.cpp
@@ -1560,12 +1560,15 @@ LedgerMaster::shouldAcquire (
     std::uint32_t const ledgerHistoryIndex,
     std::uint32_t const candidateLedger) const
 {
-    // If the ledger could be the current ledger acquire it.
-    // Otherwise, acquire it only if it's within our range of
-    // desired history and we wouldn't delete it if we had it.
-    bool ret = (candidateLedger >= currentLedger) ||
-        ((candidateLedger >= ledgerHistoryIndex) &&
-        ((currentLedger - candidateLedger) <= ledgerHistory));
+
+    // Fetch ledger if it might be the current ledger,
+    // is requested by the advisory delete setting, or
+    // is within our configured history range
+
+    bool ret (candidateLedger >= currentLedger ||
+        ((ledgerHistoryIndex > 0) &&
+            (candidateLedger > ledgerHistoryIndex)) ||
+        (currentLedger - candidateLedger) <= ledgerHistory);
 
     JLOG (m_journal.trace())
         << "Missing ledger "
diff --git a/src/ripple/app/misc/SHAMapStoreImp.h b/src/ripple/app/misc/SHAMapStoreImp.h
index 89e34dec3..f4cb75a02 100644
--- a/src/ripple/app/misc/SHAMapStoreImp.h
+++ b/src/ripple/app/misc/SHAMapStoreImp.h
@@ -150,12 +150,16 @@ public:
         return setup_.advisoryDelete;
     }
 
+    // All ledgers prior to this one are eligible
+    // for deletion in the next rotation
     LedgerIndex
     getLastRotated() override
     {
         return state_db_.getState().lastRotated;
     }
 
+    // All ledgers before and including this are unprotected
+    // and online delete may delete them if appropriate
     LedgerIndex
     getCanDelete() override
     {