validation: flush state after initial sync

src/init.cpp

@@ -82,6 +82,9 @@ static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;
 // Dump addresses to banlist.dat every 15 minutes (900s)
 static constexpr int DUMP_BANS_INTERVAL = 60 * 15;
 
+//! Check if initial sync is done and no change in block height every 30s
+static constexpr int SYNC_CHECK_INTERVAL = 30;
+
 std::unique_ptr<CConnman> g_connman;
 std::unique_ptr<PeerLogicValidation> peerLogic;
 std::unique_ptr<BanMan> g_banman;
@@ -1250,6 +1253,28 @@ bool AppInitLockDataDirectory()
     return true;
 }
 
+/**
+ * Once initial sync is finished, flush state to protect against data loss
+ */
+static void FlushAfterSync()
+{
+    if (IsInitialBlockDownload()) {
+        scheduler.scheduleFromNow(FlushAfterSync, SYNC_CHECK_INTERVAL * 1000);
+        return;
+    }
+
+    static int last_chain_height = -1;
+    LOCK(cs_main);
+    int current_height = chainActive.Height();
+    if (last_chain_height == -1 || last_chain_height != current_height) {
+        last_chain_height = current_height;
+        scheduler.scheduleFromNow(FlushAfterSync, SYNC_CHECK_INTERVAL * 1000);
+        return;
+    }
+
+    FlushStateToDisk();
+}
+
 bool AppInitMain(InitInterfaces& interfaces)
 {
     const CChainParams& chainparams = Params();
@@ -1858,5 +1883,7 @@ bool AppInitMain(InitInterfaces& interfaces)
         g_banman->DumpBanlist();
     }, DUMP_BANS_INTERVAL * 1000);
 
+    scheduler.scheduleFromNow(FlushAfterSync, SYNC_CHECK_INTERVAL * 1000);
+
     return true;
 }