From 28c7826032e5c0be1a5ae48620c6f0c2debfd85c Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Fri, 9 Mar 2018 16:21:23 -0800
Subject: [PATCH] ircd::db: Add txn::append optimization allowing tuple to make
 direct column deltas.

---
 include/ircd/db/txn.h | 22 ++++++++++++++++++++++
 ircd/m/dbs.cc         |  2 +-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/ircd/db/txn.h b/include/ircd/db/txn.h
index 310d7b4e7..e1d6eaa77 100644
--- a/include/ircd/db/txn.h
+++ b/include/ircd/db/txn.h
@@ -71,6 +71,7 @@ struct ircd::db::txn::append
 	append(txn &, const delta &);
 	append(txn &, const string_view &key, const json::iov &);
 	template<class... T> append(txn &, const string_view &key, const json::tuple<T...> &);
+	template<class... T> append(txn &, const string_view &key, const json::tuple<T...> &, std::array<column, sizeof...(T)> &);
 };
 
 struct ircd::db::txn::checkpoint
@@ -103,3 +104,24 @@ ircd::db::txn::append::append(txn &txn,
 		};
 	});
 }
+
+template<class... T>
+ircd::db::txn::append::append(txn &txn,
+                              const string_view &key,
+                              const json::tuple<T...> &tuple,
+                              std::array<column, sizeof...(T)> &col)
+{
+	size_t i{0};
+	for_each(tuple, [&txn, &key, &col, &i](const auto &, auto&& val)
+	{
+		if(defined(val)) append
+		{
+			txn, col.at(i), column::delta
+			{
+				key, byte_view<string_view>{val}
+			}
+		};
+
+		++i;
+	});
+}
diff --git a/ircd/m/dbs.cc b/ircd/m/dbs.cc
index b064b4700..4e3f99348 100644
--- a/ircd/m/dbs.cc
+++ b/ircd/m/dbs.cc
@@ -106,7 +106,7 @@ ircd::m::dbs::write(db::txn &txn,
 {
 	db::txn::append
 	{
-		txn, at<"event_id"_>(event), event
+		txn, at<"event_id"_>(event), event, event_column
 	};
 
 	if(defined(json::get<"state_key"_>(event)))