Simplify scheduler to only consider task creation and number of queries

NEWS.md

@@ -4,7 +4,7 @@
 New features:
  * Batch queries are handled per db host.
    - There is an scheduler controlling how many queries and in what order they are run.
-     - Priority is based on: # of queries already run, last execution time, and oldest user in queue.
+     - Priority is based on: number of queries already ran, and oldest user in queue.
  * Batch queries capacity: allow to configure how many jobs to run per db host.
 
 

batch/scheduler/scheduler.js

@@ -31,11 +31,6 @@ function Scheduler(capacity, taskRunner) {
             return taskEntityA.jobs - taskEntityB.jobs;
         }
 
-        // priority for entity with oldest executed job
-        if (taskEntityA.runAt !== taskEntityB.runAt) {
-            return taskEntityA.runAt - taskEntityB.runAt;
-        }
-
         // priority for oldest job
         if (taskEntityA.createdAt !== taskEntityB.createdAt) {
             return taskEntityA.createdAt - taskEntityB.createdAt;