Make controller do a simple write-through cache without revalidating. Means you must restart if files change on disk, but will decrease I/O considerably.

1 files changed, 17 insertions, 46 deletions

diff --git a/controller/JSONDB.cpp b/controller/JSONDB.cpp
index 298ac721..9c28ddf1 100644
--- a/controller/JSONDB.cpp
+++ b/controller/JSONDB.cpp
@@ -53,8 +53,6 @@ bool JSONDB::put(const std::string &n,const nlohmann::json &obj)
 
 	_E &e = _db[n];
 	e.obj = obj;
-	e.lastModifiedOnDisk = OSUtils::getLastModified(path.c_str());
-	e.lastCheck = OSUtils::now();
 
 	return true;
 }
@@ -64,53 +62,26 @@ const nlohmann::json &JSONDB::get(const std::string &n,unsigned long maxSinceChe
 	if (!_isValidObjectName(n))
 		return _EMPTY_JSON;
 
-	const uint64_t now = OSUtils::now();
-	std::string buf;
 	std::map<std::string,_E>::iterator e(_db.find(n));
-
-	if (e != _db.end()) {
-		if ((now - e->second.lastCheck) <= (uint64_t)maxSinceCheck)
-			return e->second.obj;
-
-		const std::string path(_genPath(n,false));
-		if (!path.length()) // sanity check
-			return _EMPTY_JSON;
-
-		// We are somewhat tolerant to momentary disk failures here. This may
-		// occur over e.g. EC2's elastic filesystem (NFS).
-		const uint64_t lm = OSUtils::getLastModified(path.c_str());
-		if (e->second.lastModifiedOnDisk != lm) {
-			if (OSUtils::readFile(path.c_str(),buf)) {
-				try {
-					e->second.obj = OSUtils::jsonParse(buf);
-					e->second.lastModifiedOnDisk = lm; // don't update these if there is a parse error -- try again and again ASAP
-					e->second.lastCheck = now;
-				} catch ( ... ) {} // parse errors result in "holding pattern" behavior
-			}
-		}
-
+	if (e != _db.end())
 		return e->second.obj;
-	} else {
-		const std::string path(_genPath(n,false));
-		if (!path.length())
-			return _EMPTY_JSON;
-
-		if (!OSUtils::readFile(path.c_str(),buf))
-			return _EMPTY_JSON;
-
-		const uint64_t lm = OSUtils::getLastModified(path.c_str());
-		_E &e2 = _db[n];
-		try {
-			e2.obj = OSUtils::jsonParse(buf);
-		} catch ( ... ) {
-			e2.obj = _EMPTY_JSON;
-			buf = "{}";
-		}
-		e2.lastModifiedOnDisk = lm;
-		e2.lastCheck = now;
 
-		return e2.obj;
+	const std::string path(_genPath(n,false));
+	if (!path.length())
+		return _EMPTY_JSON;
+	std::string buf;
+	if (!OSUtils::readFile(path.c_str(),buf))
+		return _EMPTY_JSON;
+
+	_E &e2 = _db[n];
+	try {
+		e2.obj = OSUtils::jsonParse(buf);
+	} catch ( ... ) {
+		e2.obj = _EMPTY_JSON;
+		buf = "{}";
 	}
+
+	return e2.obj;
 }
 
 void JSONDB::erase(const std::string &n)
@@ -131,7 +102,7 @@ void JSONDB::_reload(const std::string &p,const std::string &b)
 	std::vector<std::string> dl(OSUtils::listDirectory(p.c_str()));
 	for(std::vector<std::string>::const_iterator di(dl.begin());di!=dl.end();++di) {
 		if ((di->length() > 5)&&(di->substr(di->length() - 5) == ".json")) {
-			this->get(b + di->substr(0,di->length() - 5),0);
+			this->get(b + di->substr(0,di->length() - 5));
 		} else {
 			this->_reload((p + ZT_PATH_SEPARATOR + *di),(b + *di + ZT_PATH_SEPARATOR));
 		}