feat: Implement Scheduler Reference Architecture

This change implements the parts of the Datacenter Scheduling Reference
Architecture as published in SC18.

This commit consists of changes to the database schema such as:

- **Removal of `parallelizability` column in `Task`**
  This field was not used by the simulator and we opted to use a field
  describing the amount of cores the task can run on instead.
- **Removal of `task_id` column in `MachineState`**
  This field did not make sense anymore now that a machine can run
  multiple tasks. Fortunately, this field is not used in the frontend.

2 files changed, 75 insertions, 54 deletions

diff --git a/database/schema.sql b/database/schema.sql
index 7f0d5879..15dbf043 100644
--- a/database/schema.sql
+++ b/database/schema.sql
@@ -63,7 +63,7 @@ INSERT INTO authorization_levels (level) VALUES ('VIEW');
 *       -   DD is the two-digit day of the month (1-31)
 *       -   HH is the two-digit hours part (0-23)
 *       -   MM is the two-digit minutes part (0-59)
-*       -   SS is the two-digit secodns part (0-59)
+*       -   SS is the two-digit seconds part (0-59)
 */
 
 -- Simulation
@@ -146,9 +146,18 @@ DROP TABLE IF EXISTS schedulers;
 CREATE TABLE schedulers (
   name VARCHAR(50) PRIMARY KEY        NOT NULL
 );
-INSERT INTO schedulers (name) VALUES ('DEFAULT');
-INSERT INTO schedulers (name) VALUES ('SRTF');
-INSERT INTO schedulers (name) VALUES ('FIFO');
+INSERT INTO schedulers (name) VALUES ('FIFO-FIRSTFIT');
+INSERT INTO schedulers (name) VALUES ('FIFO-BESTFIT');
+INSERT INTO schedulers (name) VALUES ('FIFO-WORSTFIT');
+INSERT INTO schedulers (name) VALUES ('FIFO-RANDOM');
+INSERT INTO schedulers (name) VALUES ('SRTF-FIRSTFIT');
+INSERT INTO schedulers (name) VALUES ('SRTF-BESTFIT');
+INSERT INTO schedulers (name) VALUES ('SRTF-WORSTFIT');
+INSERT INTO schedulers (name) VALUES ('SRTF-RANDOM');
+INSERT INTO schedulers (name) VALUES ('RANDOM-FIRSTFIT');
+INSERT INTO schedulers (name) VALUES ('RANDOM-BESTFIT');
+INSERT INTO schedulers (name) VALUES ('RANDOM-WORSTFIT');
+INSERT INTO schedulers (name) VALUES ('RANDOM-RANDOM');
 
 /*
 *   Each simulation has a single trace. A trace contains tasks and their start times.
@@ -180,13 +189,24 @@ CREATE TABLE tasks (
   start_tick         INTEGER                 NOT NULL CHECK (start_tick >= 0),
   total_flop_count   INTEGER                 NOT NULL,
   job_id             INTEGER                 NOT NULL,
-  task_dependency_id INTEGER                 NULL,
   parallelizability  VARCHAR(50)             NOT NULL,
 
   FOREIGN KEY (job_id) REFERENCES jobs (id)
     ON DELETE CASCADE
+    ON UPDATE CASCADE
+);
+
+-- A dependency between two tasks.
+DROP TABLE IF EXISTS task_dependencies;
+CREATE TABLE task_dependencies (
+  first_task_id  INTEGER NOT NULL,
+  second_task_id INTEGER NOT NULL,
+
+  PRIMARY KEY (first_task_id, second_task_id),
+  FOREIGN KEY (first_task_id) REFERENCES tasks (id)
+    ON DELETE CASCADE
     ON UPDATE CASCADE,
-  FOREIGN KEY (task_dependency_id) REFERENCES tasks (id)
+  FOREIGN KEY (second_task_id) REFERENCES tasks (id)
     ON DELETE CASCADE
     ON UPDATE CASCADE
 );
@@ -318,8 +338,9 @@ DELIMITER //
 -- and tiles in a room are connected.
 DROP TRIGGER IF EXISTS before_insert_tiles_check_existence;
 CREATE TRIGGER before_insert_tiles_check_existence
-BEFORE INSERT ON tiles
-FOR EACH ROW
+  BEFORE INSERT
+  ON tiles
+  FOR EACH ROW
   BEGIN
     -- checking tile overlap
     -- a tile already exists such that..
@@ -416,8 +437,9 @@ DELIMITER //
 -- Make sure objects are added to tiles in rooms they're allowed to be in.
 DROP TRIGGER IF EXISTS before_update_tiles;
 CREATE TRIGGER before_update_tiles
-BEFORE UPDATE ON tiles
-FOR EACH ROW
+  BEFORE UPDATE
+  ON tiles
+  FOR EACH ROW
   BEGIN
 
     IF ((NEW.object_id IS NOT NULL) AND (
@@ -543,8 +565,9 @@ DELIMITER //
 -- Make sure a machine is not inserted at a position that does not exist for its rack.
 DROP TRIGGER IF EXISTS before_insert_machine;
 CREATE TRIGGER before_insert_machine
-BEFORE INSERT ON machines
-FOR EACH ROW
+  BEFORE INSERT
+  ON machines
+  FOR EACH ROW
   BEGIN
     IF (
       NEW.position > (SELECT capacity
diff --git a/database/test.sql b/database/test.sql
index fa7fb8aa..a2c6d165 100644
--- a/database/test.sql
+++ b/database/test.sql
@@ -43,8 +43,9 @@ INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALU
 INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (25, 10000, 1, 'PARALLEL');
 INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (25, 10000, 1, 'PARALLEL');
 INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (26, 10000, 1, 'PARALLEL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (80, 200000, 1, 1, 'PARALLEL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (80, 200000, 1, 'PARALLEL');
+
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (1, 5);
 
 -- Image Processing Trace
 INSERT INTO traces (name) VALUES ('Image Processing');
@@ -121,38 +122,39 @@ INSERT INTO traces (name) VALUES ('Path planning');
 INSERT INTO jobs (name, trace_id) VALUES ('Path planning', 3);
 
 INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (0, 1000000, 3, 'PARALLEL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (11, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (12, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (13, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (14, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (11, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (12, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (13, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (14, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (11, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (12, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (13, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (14, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (11, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (12, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (13, 200000, 3, 66, 'SEQUENTIAL');
-INSERT INTO tasks (start_tick, total_flop_count, job_id, task_dependency_id, parallelizability)
-VALUES (14, 200000, 3, 66, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (11, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (12, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (13, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (14, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (11, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (12, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (13, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (14, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (11, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (12, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (13, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (14, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (11, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (12, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (13, 200000, 3, 'SEQUENTIAL');
+INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALUES (14, 200000, 3, 'SEQUENTIAL');
+
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 67);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 68);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 69);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 70);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 71);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 72);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 73);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 74);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 75);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 76);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 77);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 78);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 79);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 80);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 81);
+INSERT INTO task_dependencies (first_task_id, second_task_id) VALUES (66, 82);
 
 -- Parallelizable Trace
 INSERT INTO traces (name) VALUES ('Parallel heavy trace');
@@ -174,17 +176,13 @@ INSERT INTO tasks (start_tick, total_flop_count, job_id, parallelizability) VALU
 
 -- Experiments
 INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 1, 'SRTF', 'Default trace, SRTF', 'QUEUED', 110);
-INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 2, 'SRTF', 'Image processing trace, SRTF', 'QUEUED', 0);
-INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 3, 'SRTF', 'Path planning trace, FIFI', 'QUEUED', 0);
+VALUES (1, 1, 3, 'fifo-bestfit', 'Path planning trace, FIFO', 'QUEUED', 0);
 INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 1, 'FIFO', 'Default trace, SRTF', 'QUEUED', 0);
+VALUES (1, 1, 1, 'srtf-firstfit', 'Default trace, SRTF', 'QUEUED', 0);
 INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 2, 'FIFO', 'Image processing trace, SRTF', 'QUEUED', 0);
+VALUES (1, 1, 2, 'srtf-firstfit', 'Image processing trace, SRTF', 'QUEUED', 0);
 INSERT INTO experiments (simulation_id, path_id, trace_id, scheduler_name, name, state, last_simulated_tick)
-VALUES (1, 1, 3, 'FIFO', 'Path planning trace, FIFO', 'QUEUED', 0);
+VALUES (1, 1, 3, 'fifo-firstfit', 'Path planning trace, FIFO', 'QUEUED', 0);
 
 -- Rooms
 INSERT INTO rooms (name, datacenter_id, type) VALUES ('room 1', 1, 'SERVER');