Flush the state before switching to live

Safety net for HAF, which is about to start long running CREATE INDEX.
In case  of interruption that would break state, so flush it just in
case.

Author: Krzysztof Leśniak

libraries/chain/database.cpp

@@ -976,6 +976,8 @@ void database::notify_comment_reward(const comment_reward_notification& note)
 
 void database::notify_end_of_syncing()
 {
+  chainbase::database::flush();
+  get_comments_handler().flush();
   HIVE_TRY_NOTIFY(_end_of_syncing_signal)
 }
 

libraries/chain/external_storage/memory_comment_archive.cpp

@@ -110,5 +110,10 @@ void memory_comment_archive::wipe()
   // since storage is part of SHM, database::wipe clears it, nothing extra to do here
 }
 
+void memory_comment_archive::flush()
+{
+  // nothing extra to do here
+}
+
 } } // hive::chain
 

libraries/chain/external_storage/placeholder_comment_archive.cpp

@@ -63,5 +63,10 @@ void placeholder_comment_archive::wipe()
   // do nothing - there is no extra data
 }
 
+void placeholder_comment_archive::flush()
+{
+  // do nothing - there is no extra data
+}
+
 } } // hive::chain
 

libraries/chain/external_storage/rocksdb_comment_archive.cpp

@@ -203,6 +203,11 @@ void rocksdb_comment_archive::wipe()
   provider->wipeDb();
 }
 
+void rocksdb_comment_archive::flush()
+{
+  provider->flush();
+}
+
 } }
 
 HIVE_DEFINE_TYPE_REGISTRAR_REGISTER_TYPE( hive::chain::volatile_comment_index )

libraries/chain/include/hive/chain/external_storage/comments_handler.hpp

@@ -24,6 +24,7 @@ class comments_handler : public external_storage_snapshot
 
     virtual void open() = 0;
     virtual void close() = 0;
+    virtual void flush() = 0;
     virtual void wipe() = 0;
 
     static hive::utilities::benchmark_dumper::comment_archive_details_t stats; // note: times should be measured in nanoseconds

libraries/chain/include/hive/chain/external_storage/memory_comment_archive.hpp

@@ -90,6 +90,7 @@ class memory_comment_archive final : public comments_handler
 
     virtual void open() override;
     virtual void close() override;
+    virtual void flush() override;
     virtual void wipe() override;
 };
 

libraries/chain/include/hive/chain/external_storage/placeholder_comment_archive.hpp

@@ -25,6 +25,7 @@ class placeholder_comment_archive final : public comments_handler
 
     virtual void open() override;
     virtual void close() override;
+    virtual void flush() override;
     virtual void wipe() override;
 };
 

libraries/chain/include/hive/chain/external_storage/rocksdb_comment_archive.hpp

@@ -42,6 +42,7 @@ class rocksdb_comment_archive : public comments_handler
 
     void open() override;
     void close() override;
+    void flush() override;
     void wipe() override;
 };