From 8083a5d71cb227c9cdd3a219e72f2212a9777b7a Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Thu, 26 Apr 2018 17:19:29 -0700
Subject: [PATCH] ircd::db: Add WAL fflush; move table flushes to "sort()";
 adjust interfaces.

---
 include/ircd/db/column.h            |  2 +-
 include/ircd/db/database/database.h |  5 +--
 ircd/db.cc                          | 54 +++++++++++++++++++----------
 modules/console.cc                  | 36 ++++++++++++++++++-
 4 files changed, 75 insertions(+), 22 deletions(-)

diff --git a/include/ircd/db/column.h b/include/ircd/db/column.h
index a0650d532..2cf6d413b 100644
--- a/include/ircd/db/column.h
+++ b/include/ircd/db/column.h
@@ -48,7 +48,7 @@ namespace ircd::db
 	// [SET] Other operations
 	void setopt(column &, const string_view &key, const string_view &val);
 	void compact(column &, const string_view &begin = {}, const string_view &end = {});
-	void flush(column &, const bool &blocking = false);
+	void sort(column &, const bool &blocking = false);
 }
 
 /// Columns add the ability to run multiple LevelDB's in synchrony under the same
diff --git a/include/ircd/db/database/database.h b/include/ircd/db/database/database.h
index 4f097f59b..055c0dcf4 100644
--- a/include/ircd/db/database/database.h
+++ b/include/ircd/db/database/database.h
@@ -44,10 +44,11 @@ namespace ircd::db
 
 	// Control panel
 	void setopt(database &, const string_view &key, const string_view &val);
-	void compact(database &);
 	void fdeletions(database &, const bool &enable, const bool &force = false);
 	void checkpoint(database &, const string_view &dir);
-	void flush(database &, const bool &blocking = true);
+	void compact(database &);
+	void sort(database &, const bool &blocking = true);
+	void flush(database &, const bool &sync = false);
 	void sync(database &);
 }
 
diff --git a/ircd/db.cc b/ircd/db.cc
index c66224b8c..d5224cf60 100644
--- a/ircd/db.cc
+++ b/ircd/db.cc
@@ -135,12 +135,36 @@ ircd::db::sync(database &d)
 /// each column individually.
 void
 ircd::db::flush(database &d,
-                const bool &blocking)
+                const bool &sync)
+{
+	throw_on_error
+	{
+		d.d->FlushWAL(sync)
+	};
+}
+
+/// Moves memory structures to SST files for all columns. This doesn't
+/// necessarily sort anything that wasn't previously sorted, but it may create
+/// new SST files and shouldn't be confused with a typical fflush().
+/// Note that if blocking=true, blocking may occur for each column individually.
+void
+ircd::db::sort(database &d,
+               const bool &blocking)
 {
 	for(const auto &c : d.columns)
 	{
 		db::column column{*c};
-		db::flush(column, blocking);
+		db::sort(column, blocking);
+	}
+}
+
+void
+ircd::db::compact(database &d)
+{
+	for(const auto &c : d.columns)
+	{
+		db::column column{*c};
+		compact(column, string_view{}, string_view{});
 	}
 }
 
@@ -190,16 +214,6 @@ ircd::db::fdeletions(database &d,
 	};
 }
 
-void
-ircd::db::compact(database &d)
-{
-	for(const auto &c : d.columns)
-	{
-		db::column column{*c};
-		compact(column, string_view{}, string_view{});
-	}
-}
-
 void
 ircd::db::setopt(database &d,
                  const string_view &key,
@@ -628,12 +642,16 @@ noexcept try
 	         path);
 
 	rocksdb::CancelAllBackgroundWork(d.get(), true); // true = blocking
-	this->checkpoint.reset(nullptr);
-	this->columns.clear();
-	log.debug("'%s': closed columns; background_errors: %lu; synchronizing...",
+	log.debug("'%s': background_errors: %lu; flushing...",
 	          name,
 	          property<uint64_t>(*this, rocksdb::DB::Properties::kBackgroundErrors));
 
+	flush(*this);
+	this->checkpoint.reset(nullptr);
+	this->columns.clear();
+	log.debug("'%s': closed columns; synchronizing...",
+	          name);
+
 	sync(*this);
 	log.debug("'%s': synchronized with hardware.",
 	          name);
@@ -3944,14 +3962,14 @@ ircd::db::describe(const column &column)
 }
 
 void
-ircd::db::flush(column &column,
-                const bool &blocking)
+ircd::db::sort(column &column,
+               const bool &blocking)
 {
 	database::column &c(column);
 	database &d(*c.d);
 	rocksdb::FlushOptions opts;
 	opts.wait = blocking;
-	log.debug("'%s':'%s' @%lu FLUSH",
+	log.debug("'%s':'%s' @%lu FLUSH (sort)",
 	          name(d),
 	          name(c),
 	          sequence(d));
diff --git a/modules/console.cc b/modules/console.cc
index 3c89b2c97..dbf9d1e4e 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -818,6 +818,40 @@ catch(const std::out_of_range &e)
 bool
 console_cmd__db__flush(opt &out, const string_view &line)
 try
+{
+	const params param{line, " ",
+	{
+		"dbname", "[sync]"
+	}};
+
+	const auto dbname
+	{
+		param.at(0)
+	};
+
+	const auto sync
+	{
+		param.at(1, false)
+	};
+
+	auto &database
+	{
+		*db::database::dbs.at(dbname)
+	};
+
+	flush(database, sync);
+	out << "done" << std::endl;
+	return true;
+}
+catch(const std::out_of_range &e)
+{
+	out << "No open database by that name" << std::endl;
+	return true;
+}
+
+bool
+console_cmd__db__sort(opt &out, const string_view &line)
+try
 {
 	const params param{line, " ",
 	{
@@ -839,7 +873,7 @@ try
 		*db::database::dbs.at(dbname)
 	};
 
-	flush(database, blocking);
+	sort(database, blocking);
 	out << "done" << std::endl;
 	return true;
 }