diff --git a/src/logging/WriterBackend.cc b/src/logging/WriterBackend.cc
index 095490edc4..7c9c1d10ca 100644
--- a/src/logging/WriterBackend.cc
+++ b/src/logging/WriterBackend.cc
@@ -31,13 +31,13 @@ private:
         bool terminating;
 };
 
-class DisableMessage : public threading::OutputMessage<WriterFrontend>
+class FlushWriteBufferMessage : public threading::OutputMessage<WriterFrontend>
 {
 public:
-        DisableMessage(WriterFrontend* writer)
-		: threading::OutputMessage<WriterFrontend>("Disable", writer)	{}
+        FlushWriteBufferMessage(WriterFrontend* writer)
+		: threading::OutputMessage<WriterFrontend>("FlushWriteBuffer", writer)	{}
 
-	virtual bool Process()	{ Object()->SetDisable(); return true; }
+	virtual bool Process()	{ Object()->FlushWriteBuffer(); return true; }
 };
 
 }
@@ -65,25 +65,31 @@ WriterBackend::~WriterBackend()
 		}
 	}
 
-void WriterBackend::DeleteVals(Value** vals)
+void WriterBackend::DeleteVals(int num_writes, Value*** vals)
 	{
-	// Note this code is duplicated in Manager::DeleteVals().
-	for ( int i = 0; i < num_fields; i++ )
-		delete vals[i];
+	for ( int j = 0; j < num_writes; ++j )
+		{
+		// Note this code is duplicated in Manager::DeleteVals().
+		for ( int i = 0; i < num_fields; i++ )
+			delete vals[j][i];
+
+		delete [] vals[j];
+		}
 
 	delete [] vals;
 	}
 
-bool WriterBackend::FinishedRotation(WriterFrontend* writer, string new_name, string old_name,
+bool WriterBackend::FinishedRotation(string new_name, string old_name,
 				     double open, double close, bool terminating)
 	{
-	SendOut(new RotationFinishedMessage(writer, new_name, old_name, open, close, terminating));
+	SendOut(new RotationFinishedMessage(frontend, new_name, old_name, open, close, terminating));
 	return true;
 	}
 
-bool WriterBackend::Init(string arg_path, int arg_num_fields,
-		     const Field* const * arg_fields)
+bool WriterBackend::Init(WriterFrontend* arg_frontend, string arg_path, int arg_num_fields,
+			 const Field* const * arg_fields)
 	{
+	frontend = arg_frontend;
 	path = arg_path;
 	num_fields = arg_num_fields;
 	fields = arg_fields;
@@ -94,7 +100,7 @@ bool WriterBackend::Init(string arg_path, int arg_num_fields,
 	return true;
 	}
 
-bool WriterBackend::Write(int arg_num_fields, Value** vals)
+bool WriterBackend::Write(int arg_num_fields, int num_writes, Value*** vals)
 	{
 	// Double-check that the arguments match. If we get this from remote,
 	// something might be mixed up.
@@ -107,30 +113,42 @@ bool WriterBackend::Write(int arg_num_fields, Value** vals)
 		Debug(DBG_LOGGING, msg);
 #endif
 
-		DeleteVals(vals);
+		DeleteVals(num_writes, vals);
 		return false;
 		}
 
-	for ( int i = 0; i < num_fields; ++i )
-		{
-		if ( vals[i]->type != fields[i]->type )
-			{
 #ifdef DEBUG
-			const char* msg = Fmt("Field type doesn't match in WriterBackend::Write() (%d vs. %d)",
-					      vals[i]->type, fields[i]->type);
-			Debug(DBG_LOGGING, msg);
-#endif
+	// Double-check all the types match.
+	for ( int j = 0; j < num_writes; j++ )
+		{
+		for ( int i = 0; i < num_fields; ++i )
+			{
+			if ( vals[j][i]->type != fields[i]->type )
+				{
+				const char* msg = Fmt("Field type doesn't match in WriterBackend::Write() (%d vs. %d)",
+						      vals[j][i]->type, fields[i]->type);
+				Debug(DBG_LOGGING, msg);
 
-			DeleteVals(vals);
-			return false;
+				DeleteVals(num_writes, vals);
+				return false;
+				}
 			}
 		}
+#endif
 
-	bool result = DoWrite(num_fields, fields, vals);
+	bool success = true;
 
-	DeleteVals(vals);
+	for ( int j = 0; j < num_writes; j++ )
+		{
+		success = DoWrite(num_fields, fields, vals[j]);
 
-	return result;
+		if ( ! success )
+			break;
+		}
+
+	DeleteVals(num_writes, vals);
+
+	return success;
 	}
 
 bool WriterBackend::SetBuf(bool enabled)
@@ -144,10 +162,10 @@ bool WriterBackend::SetBuf(bool enabled)
 	return DoSetBuf(enabled);
 	}
 
-bool WriterBackend::Rotate(WriterFrontend* writer, string rotated_path,
-			   double open, double close, bool terminating)
+bool WriterBackend::Rotate(string rotated_path, double open,
+			   double close, bool terminating)
 	{
-	return DoRotate(writer, rotated_path, open, close, terminating);
+	return DoRotate(rotated_path, open, close, terminating);
 	}
 
 bool WriterBackend::Flush()
@@ -159,3 +177,11 @@ bool WriterBackend::Finish()
 	{
 	return DoFinish();
 	}
+
+bool WriterBackend::DoHeartbeat(double network_time, double current_time)
+	{
+	SendOut(new FlushWriteBufferMessage(frontend));
+	return true;
+	}
+
+
diff --git a/src/logging/WriterBackend.h b/src/logging/WriterBackend.h
index d1e4634e6d..27f4fe45a5 100644
--- a/src/logging/WriterBackend.h
+++ b/src/logging/WriterBackend.h
@@ -19,6 +19,12 @@ public:
 	virtual ~WriterBackend();
 
 	// One-time initialization of the writer to define the logged fields.
+	//
+	// "frontend" is the frontend writer that created this backend. The
+	// *only* purpose of this value is to be passed back via messages as
+	// a argument to callbacks. One must not otherwise access the
+	// frontend, it's running in a different thread.
+	//
 	// Interpretation of "path" is left to the writer, and will be
 	// corresponding the value configured on the script-level.
 	// 
@@ -27,7 +33,7 @@ public:
 	//
 	// The new instance takes ownership of "fields", and will delete them
 	// when done.
-	bool Init(string path, int num_fields, const Field* const * fields);
+	bool Init(WriterFrontend* frontend, string path, int num_fields, const Field* const * fields);
 
 	// Writes one log entry. The method takes ownership of "vals" and
 	// will return immediately after queueing the write request, which is
@@ -38,7 +44,7 @@ public:
 	//
 	// Returns false if an error occured, in which case the writer must
 	// not be used any further.
-	bool Write(int num_fields, Value** vals);
+	bool Write(int num_fields, int num_writes, Value*** vals);
 
 	// Sets the buffering status for the writer, if the writer supports
 	// that. (If not, it will be ignored).
@@ -50,7 +56,7 @@ public:
 
 	// Triggers rotation, if the writer supports that. (If not, it will
 	// be ignored).
-	bool Rotate(WriterFrontend* writer, string rotated_path, double open, double close, bool terminating);
+	bool Rotate(string rotated_path, double open, double close, bool terminating);
 
 	// Finishes writing to this logger regularly. Must not be called if
 	// an error has been indicated earlier. After calling this, no
@@ -81,9 +87,10 @@ public:
 	//
 	// terminating: True if rotation request occured due to the main Bro
 	// process shutting down.
-	bool FinishedRotation(WriterFrontend* writer, string new_name, string old_name,
+	bool FinishedRotation(string new_name, string old_name,
 			      double open, double close, bool terminating);
 
+
 protected:
 	// Methods for writers to override. If any of these returs false, it
 	// will be assumed that a fatal error has occured that prevents the
@@ -128,11 +135,6 @@ protected:
 	// RotationDone() to signal the log manager that potential
 	// postprocessors can now run.
 	//
-	// "writer" is the frontend writer that triggered the rotation. The
-	// *only* purpose of this value is to be passed into
-	// FinishedRotation() once done. You must not otherwise access the
-	// frontend, it's running in a different thread.
-	//
 	// "rotate_path" reflects the path to where the rotated output is to
 	// be moved, with specifics depending on the writer. It should
 	// generally be interpreted in a way consistent with that of "path"
@@ -149,8 +151,8 @@ protected:
 	//
 	// A writer may ignore rotation requests if it doesn't fit with its
 	// semantics (but must still return true in that case).
-	virtual bool DoRotate(WriterFrontend* writer, string rotated_path,
-			      double open, double close, bool terminating) = 0;
+	virtual bool DoRotate(string rotated_path, double open, double close,
+			      bool terminating) = 0;
 
 	// Called once on termination. Not called when any of the other
 	// methods has previously signaled an error, i.e., executing this
@@ -158,7 +160,9 @@ protected:
 	virtual bool DoFinish() = 0;
 
 	// Triggered by regular heartbeat messages from the main process.
-	virtual bool DoHeartbeat(double network_time, double current_time)	{ return true; };
+	//
+	// Note when overriding, you must call WriterBackend::DoHeartbeat().
+	virtual bool DoHeartbeat(double network_time, double current_time);
 
 private:
 	friend class Manager;
@@ -169,8 +173,9 @@ private:
 	bool Disabled()	{ return disabled; }
 
 	// Deletes the values as passed into Write().
-	void DeleteVals(Value** vals);
+	void DeleteVals(int num_writes, Value*** vals);
 
+	WriterFrontend* frontend;
 	string path;
 	int num_fields;
 	const Field* const * fields;
diff --git a/src/logging/WriterFrontend.cc b/src/logging/WriterFrontend.cc
index 92c93c1c56..2f7c1d6e7e 100644
--- a/src/logging/WriterFrontend.cc
+++ b/src/logging/WriterFrontend.cc
@@ -9,13 +9,14 @@ namespace logging  {
 class InitMessage : public threading::InputMessage<WriterBackend>
 {
 public:
-	InitMessage(WriterBackend* backend, const string path, const int num_fields, const Field* const *fields)
+	InitMessage(WriterBackend* backend, WriterFrontend* frontend, const string path, const int num_fields, const Field* const *fields)
 		: threading::InputMessage<WriterBackend>("Init", backend),
 		path(path), num_fields(num_fields), fields(fields) { }
 
-	virtual bool Process() { return Object()->Init(path, num_fields, fields); }
+	virtual bool Process() { return Object()->Init(frontend, path, num_fields, fields); }
 
 private:
+	WriterFrontend* frontend;
 	const string path;
 	const int num_fields;
 	const Field * const* fields;
@@ -31,7 +32,7 @@ public:
 		rotated_path(rotated_path), open(open),
 		close(close), terminating(terminating) { }
 
-	virtual bool Process() { return Object()->Rotate(frontend, rotated_path, open, close, terminating); }
+	virtual bool Process() { return Object()->Rotate(rotated_path, open, close, terminating); }
 
 private:
 	WriterFrontend* frontend;
@@ -44,16 +45,16 @@ private:
 class WriteMessage : public threading::InputMessage<WriterBackend>
 {
 public:
-	WriteMessage(WriterBackend* backend, const int num_fields, Value **vals)
+	WriteMessage(WriterBackend* backend, int num_fields, int num_writes, Value*** vals)
 		: threading::InputMessage<WriterBackend>("Write", backend),
-		num_fields(num_fields), fields(fields), vals(vals)	{}
+		num_fields(num_fields), vals(vals)	{}
 
-	virtual bool Process() { return Object()->Write(num_fields, vals); }
+	virtual bool Process() { return Object()->Write(num_fields, num_writes, vals); }
 
 private:
 	int num_fields;
-	Field* const* fields;
-	Value **vals;
+	int num_writes;
+	Value ***vals;
 };
 
 class SetBufMessage : public threading::InputMessage<WriterBackend>
@@ -96,6 +97,8 @@ using namespace logging;
 WriterFrontend::WriterFrontend(bro_int_t type)
 	{
 	disabled = initialized = false;
+	buf = true;
+	write_buffer_pos = 0;
 	backend = log_mgr->CreateBackend(type);
 
 	assert(backend);
@@ -108,6 +111,7 @@ WriterFrontend::~WriterFrontend()
 
 void WriterFrontend::Stop()
 	{
+	FlushWriteBuffer();
 	SetDisable();
 	backend->Stop();
 	}
@@ -125,7 +129,7 @@ void WriterFrontend::Init(string arg_path, int arg_num_fields, const Field* cons
 	fields = arg_fields;
 
 	initialized = true;
-	backend->SendIn(new InitMessage(backend, arg_path, arg_num_fields, arg_fields));
+	backend->SendIn(new InitMessage(backend, this, arg_path, arg_num_fields, arg_fields));
 	}
 
 void WriterFrontend::Write(int num_fields, Value** vals)
@@ -133,7 +137,34 @@ void WriterFrontend::Write(int num_fields, Value** vals)
 	if ( disabled )
 		return;
 
-	backend->SendIn(new WriteMessage(backend, num_fields, vals));
+	if ( ! write_buffer )
+		{
+		// Need new buffer.
+		write_buffer = new Value**[WRITER_BUFFER_SIZE];
+		write_buffer_pos = 0;
+		}
+
+	if ( write_buffer_pos >= WRITER_BUFFER_SIZE )
+		// Buffer full.
+		FlushWriteBuffer();
+
+	write_buffer[write_buffer_pos++] = vals;
+
+	if ( ! buf )
+		// Send out immediately if we don't want buffering.
+		FlushWriteBuffer();
+	}
+
+void WriterFrontend::FlushWriteBuffer()
+	{
+	if ( ! write_buffer_pos )
+		// Nothing to do.
+		return;
+
+	backend->SendIn(new WriteMessage(backend, num_fields, write_buffer_pos, write_buffer));
+
+	// Clear buffer (no delete, we pass ownership to child thread.)
+	write_buffer = 0;
 	}
 
 void WriterFrontend::SetBuf(bool enabled)
@@ -141,7 +172,13 @@ void WriterFrontend::SetBuf(bool enabled)
 	if ( disabled )
 		return;
 
+	buf = enabled;
+
 	backend->SendIn(new SetBufMessage(backend, enabled));
+
+	if ( ! buf )
+		// Make sure no longer buffer any still queued data.
+		FlushWriteBuffer();
 	}
 
 void WriterFrontend::Flush()
@@ -149,6 +186,7 @@ void WriterFrontend::Flush()
 	if ( disabled )
 		return;
 
+	FlushWriteBuffer();
 	backend->SendIn(new FlushMessage(backend));
 	}
 
@@ -157,6 +195,7 @@ void WriterFrontend::Rotate(string rotated_path, double open, double close, bool
 	if ( disabled )
 		return;
 
+	FlushWriteBuffer();
 	backend->SendIn(new RotateMessage(backend, this, rotated_path, open, close, terminating));
 	}
 
@@ -165,6 +204,7 @@ void WriterFrontend::Finish()
 	if ( disabled )
 		return;
 
+	FlushWriteBuffer();
 	backend->SendIn(new FinishMessage(backend));
 	}
 
diff --git a/src/logging/WriterFrontend.h b/src/logging/WriterFrontend.h
index 1998429d38..ed1a674842 100644
--- a/src/logging/WriterFrontend.h
+++ b/src/logging/WriterFrontend.h
@@ -34,6 +34,7 @@ public:
 	void Write(int num_fields, Value** vals);
 	void SetBuf(bool enabled);
 	void Flush();
+	void FlushWriteBuffer();
 	void Rotate(string rotated_path, double open, double close, bool terminating);
 	void Finish();
 
@@ -49,18 +50,22 @@ public:
 protected:
 	friend class Manager;
 
-
 	WriterBackend* backend;
 	bool disabled;
 	bool initialized;
+	bool buf;
 
 	string path;
 	int num_fields;
 	const Field* const * fields;
+
+	// Buffer for bulk writes.
+	static const int WRITER_BUFFER_SIZE = 50;
+
+	int write_buffer_pos;
+	Value*** write_buffer;
 };
 
 }
 
-
-
 #endif
diff --git a/src/logging/writers/Ascii.cc b/src/logging/writers/Ascii.cc
index 70f513be3b..a1ceb6e217 100644
--- a/src/logging/writers/Ascii.cc
+++ b/src/logging/writers/Ascii.cc
@@ -317,8 +317,7 @@ bool Ascii::DoWrite(int num_fields, const Field* const * fields,
 	return true;
 	}
 
-bool Ascii::DoRotate(WriterFrontend* writer, string rotated_path, double open,
-		     double close, bool terminating)
+bool Ascii::DoRotate(string rotated_path, double open, double close, bool terminating)
 	{
 	// Don't rotate special files or if there's not one currently open.
 	if ( ! file || IsSpecial(Path()) )
@@ -330,7 +329,7 @@ bool Ascii::DoRotate(WriterFrontend* writer, string rotated_path, double open,
 	string nname = rotated_path + "." + LogExt();
 	rename(fname.c_str(), nname.c_str());
 
-	if ( ! FinishedRotation(writer, nname, fname, open, close, terminating) )
+	if ( ! FinishedRotation(nname, fname, open, close, terminating) )
 		{
 		Error(Fmt("error rotating %s to %s", fname.c_str(), nname.c_str()));
 		return false;
diff --git a/src/logging/writers/Ascii.h b/src/logging/writers/Ascii.h
index 37fcfef267..0c627c68e9 100644
--- a/src/logging/writers/Ascii.h
+++ b/src/logging/writers/Ascii.h
@@ -23,8 +23,8 @@ protected:
 	virtual bool DoWrite(int num_fields, const Field* const * fields,
 			     Value** vals);
 	virtual bool DoSetBuf(bool enabled);
-	virtual bool DoRotate(WriterFrontend* writer, string rotated_path,
-			      double open, double close, bool terminating);
+	virtual bool DoRotate(string rotated_path, double open,
+			      double close, bool terminating);
 	virtual bool DoFlush();
 	virtual bool DoFinish();
 
diff --git a/src/logging/writers/None.cc b/src/logging/writers/None.cc
index e419d88a6b..a9a7872f85 100644
--- a/src/logging/writers/None.cc
+++ b/src/logging/writers/None.cc
@@ -4,10 +4,9 @@
 using namespace logging;
 using namespace writer;
 
-bool None::DoRotate(WriterFrontend* writer, string rotated_path,
-		    double open, double close, bool terminating)
+bool None::DoRotate(string rotated_path, double open, double close, bool terminating)
 	{
-	if ( ! FinishedRotation(writer, string("/dev/null"), Path(), open, close, terminating))
+	if ( ! FinishedRotation(string("/dev/null"), Path(), open, close, terminating))
 		{
 		Error(Fmt("error rotating %s", Path().c_str()));
 		return false;
diff --git a/src/logging/writers/None.h b/src/logging/writers/None.h
index 9b2ab6c698..9360ef44f6 100644
--- a/src/logging/writers/None.h
+++ b/src/logging/writers/None.h
@@ -23,8 +23,8 @@ protected:
 	virtual bool DoWrite(int num_fields, const Field* const * fields,
 			     Value** vals)	{ return true; }
 	virtual bool DoSetBuf(bool enabled)	{ return true; }
-	virtual bool DoRotate(WriterFrontend* writer, string rotated_path,
-			      double open, double close, bool terminating);
+	virtual bool DoRotate(string rotated_path, double open,
+			      double close, bool terminating);
 	virtual bool DoFlush()	{ return true; }
 	virtual bool DoFinish()	{ return true; }
 };
diff --git a/src/threading/MsgThread.h b/src/threading/MsgThread.h
index 8f37041bb6..ec249e90ad 100644
--- a/src/threading/MsgThread.h
+++ b/src/threading/MsgThread.h
@@ -184,8 +184,11 @@ protected:
 	 * Triggers a heartbeat message being sent to the client thread.
 	 *
 	 * This is method is called regularly by the threading::Manager.
+	 *
+	 * Can be overriden in derived classed to hook into the heart beat,
+	 * but must call the parent implementation.
 	 */
-	void Heartbeat();
+	virtual void Heartbeat();
 
 	/**
 	 * Overriden from BasicThread.
@@ -194,6 +197,17 @@ protected:
 	virtual void Run();
 	virtual void OnStop();
 
+	/**
+	 * Regulatly triggered for execution in the child thread.
+	 *
+	 * When overriding, one must call the parent class' implementation.
+	 *
+	 * network_time: The network_time when the heartbeat was trigger by
+	 * the main thread.
+	 *
+	 * current_time: Wall clock when the heartbeat was trigger by the
+	 * main thread.
+	 */
 	virtual bool DoHeartbeat(double network_time, double current_time)	{ return true; }
 
 private: