We mount now a directory to /opt/slurm that contains executables of
slurm version 17.11.13.  This version is again compatible with the version
that runs on head.cep4.

This branch contains a fix for the lofar-pipeline after the slurm upgrade
on head.cep4.

Task SW-581: Cherry Picked revision 40995 from trunk to release to have the changes in the cobalt_functions.sh in production

SW-35: minor changes after rollout. Only prevent task prescheduled->scheduled state change when not all claims are claimed. Try/except for different versions of psycopg2

Task ROHD-1323: Slight improvement of LBA delays. Note that file is resported, only LBA delays changed.

SW-44: removed timing code, and notices. minor performance improvement in get_max_resource_usage_between

SW-44: major simplification of process_new_claim_into_resource_usages and process_old_claim_outof_resource_usages using the new deltas table. Now the new test_20181108_bugfix_resource_usages passes as well, and preliminary results indicate a performance boost as well.

SW-44: moved the integration part of the rebuild_resource_usages* method into a seperate method, for later reusage in handling new/old claim.

SW-44: major refactoring/improvement of rebuild_resource_usages_from_claims_for_resource_of_status using a new resource_usage_delta table. Much simpler code, less exceptions and odd cases.

SW-44: minor tweaks in test. The test currently fails on a bug in the resource usages. For that bug I added special test test_20181108_bugfix_resource_usages to t_radb_functionality.py to prove it. First, I'll fix that resource_usage bug, and then continue on the performance improvements.

SW-44: found bug during performance testing. added special test test_20181108_bugfix_resource_usages to t_radb.py to prove it. Renamed t_radb.* to t_radb_functionality.* to make a better distinction with t_radb_performance.py

SW-44: remove obsolete claims once a task ends. This reduces the resource_claim and resource_usage tables significantly, speeding up overall performance.