Renames some sview variables for better clarity and put some node
  fields into alphabetic order

This commit adds support for free_mem as part of the sinfo
command using the key 'e' ('f' and 'F' are already taken).

This commit adds information about the free memory to the
output created by slurm_sprint_node_table(). The unit of
FreeMem is MiB like RealMemory.

This commit adds a new field free_mem to the node_info struct
and augments the 15.08 RPC protocol to exchange this information
as part of the ping and registration status messages. The
free memory is taken from the sysinfo() information on systems
that support this function. Overall, the implementation sticks
to the way cpu_load (the 5 min load average) is handled.

note the change and remove the new time limit if the job is requeued.

and give different error codes for different limits violated.

A job being considered for backfill scheduling can have its time
  limit altered to the partition limit, job minimum time limit,
  etc. This fixes two places where the backfill scheduler could
  leave the job in a pending state with a time limit different
  from it's original value.

add more startup/initialization logic
fix some locking issues
fix some issues related to persistent buffers

argument "size" to _print_topo_record() could be zero, resulting in
  invalid array size specification of zero.
Dead assignment to "len" in second call to _print_topo_record().

Add accounting for persistent buffer space
Fixes for data structure removal

Add "job_process" function.
Minor clean-up from code review.

Add logic to purge persistent burst buffers.
Create dummy job script as needed for buffer teardown
Multiple persistent buffer create/destroy calls in single job working

Bug 1819

Composite indexes search left to right. E.g. an index of (inx1, inx2, inx3) will search from left to right. inx2 can't be used in a where statement by itself, it requires inx1 to be present (inx3 can be optional). For the rollup index having time_end first speeds up the below query. The actual rollup queries still benefit from the original rollup index.

sacct -S 07/22-09:41:36 -E 07/22-09:42:37 -i 1-4 -ojobid,start,end,nnodes,nodelist -n -a:
mysql> explain select t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_alloc, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user from compy_job_table as t1 left join compy_assoc_table as t2 on t1.id_assoc=t2.id_assoc left join compy_resv_table as t3  on t1.id_resv=t3.id_resv  where ((t1.nodes_alloc between 1 and 4)) && ((t1.time_eligible < 1437550957 && (t1.time_end >= 1437550896 || t1.time_end = 0))) group by id_job, time_submit desc;
+----+-------------+-------+--------+---------------+---------+---------+------------------------+--------+----------------------------------------------+
| id | select_type | table | type   | possible_keys | key     | key_len | ref                    | rows   | Extra                                        |
+----+-------------+-------+--------+---------------+---------+---------+------------------------+--------+----------------------------------------------+
|  1 | SIMPLE      | t1    | ALL    | id_job,rollup | NULL    | NULL    | NULL                   | 120953 | Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY       | PRIMARY | 4       | slurm_1412.t1.id_assoc |      1 | Using where                                  |
|  1 | SIMPLE      | t3    | ref    | PRIMARY       | PRIMARY | 4       | slurm_1412.t1.id_resv  |      1 | NULL                                         |
+----+-------------+-------+--------+---------------+---------+---------+------------------------+--------+----------------------------------------------+
3 rows in set (0.00 sec)

mysql> explain select t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_alloc, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user from compy_job_table as t1 left join compy_assoc_table as t2 on t1.id_assoc=t2.id_assoc left join compy_resv_table as t3  on t1.id_resv=t3.id_resv  where ((t1.nodes_alloc between 1 and 4)) && ((t1.time_eligible < 1437550957 && (t1.time_end >= 1437550896 || t1.time_end = 0))) group by id_job, time_submit desc;
+----+-------------+-------+--------+-----------------------+---------+---------+------------------------+------+---------------------------------------------------------------------+
| id | select_type | table | type   | possible_keys         | key     | key_len | ref                    | rows | Extra                                                               |
+----+-------------+-------+--------+-----------------------+---------+---------+------------------------+------+---------------------------------------------------------------------+
|  1 | SIMPLE      | t1    | range  | id_job,rollup,rollup2 | rollup2 | 8       | NULL                   |    6 | Using index condition; Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY               | PRIMARY | 4       | slurm_1412.t1.id_assoc |    1 | Using where                                                         |
|  1 | SIMPLE      | t3    | ref    | PRIMARY               | PRIMARY | 4       | slurm_1412.t1.id_resv  |    1 | NULL                                                                |
+----+-------------+-------+--------+-----------------------+---------+---------+------------------------+------+---------------------------------------------------------------------+
3 rows in set (0.00 sec)

rollup:
mysql> explain select job.job_db_inx, job.id_job, job.id_assoc, job.id_wckey, job.array_task_pending, job.time_eligible, job.time_start, job.time_end, job.time_suspended, job.cpus_alloc, job.cpus_req, job.id_resv, SUM(step.consumed_energy) from compy_job_table as job left outer join compy_step_table as step on job.job_db_inx=step.job_db_inx and (step.id_step>=0) where (job.time_eligible < 1420102800 && (job.time_end >= 1420099200 || job.time_end = 0)) group by job.job_db_inx order by job.id_assoc, job.time_eligible;
+----+-------------+-------+-------+--------------------------------------------------------------------------------+---------+---------+---------------------------+------+--------------------------------------------------------+
| id | select_type | table | type  | possible_keys                                                                  | key     | key_len | ref                       | rows | Extra                                                  |
+----+-------------+-------+-------+--------------------------------------------------------------------------------+---------+---------+---------------------------+------+--------------------------------------------------------+
|  1 | SIMPLE      | job   | range | PRIMARY,id_job,rollup,rollup2,wckey,qos,association,array_job,reserv,sacct_def | rollup  | 4       | NULL                      |    1 | Using index condition; Using temporary; Using filesort |
|  1 | SIMPLE      | step  | ref   | PRIMARY                                                                        | PRIMARY | 4       | slurm_1412.job.job_db_inx |    1 | Using where                                            |
+----+-------------+-------+-------+--------------------------------------------------------------------------------+---------+---------+---------------------------+------+--------------------------------------------------------+
2 rows in set (0.01 sec)

A plain sacct is sped up by moving time_end into the middle of the index (ex. id_user, time_end, time_eligible). sacct_def is for sacct calls with a state specified, sacct_def2 is for a plain sacct call.

plain sacct:
mysql> explain select t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_alloc, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user from compy_job_table as t1 left join compy_assoc_table as t2 on t1.id_assoc=t2.id_assoc left join compy_resv_table as t3  on t1.id_resv=t3.id_resv  where (t1.id_user='1003') && ((t1.time_end >= 1437548400 || t1.time_end = 0)) group by id_job, time_submit desc;
+----+-------------+-------+--------+------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
| id | select_type | table | type   | possible_keys    | key       | key_len | ref                    | rows  | Extra                                                               |
+----+-------------+-------+--------+------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
|  1 | SIMPLE      | t1    | ref    | id_job,sacct_def | sacct_def | 4       | const                  | 60476 | Using index condition; Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY          | PRIMARY   | 4       | slurm_1412.t1.id_assoc |     1 | Using where                                                         |
|  1 | SIMPLE      | t3    | ref    | PRIMARY          | PRIMARY   | 4       | slurm_1412.t1.id_resv  |     1 | NULL                                                                |
+----+-------------+-------+--------+------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
3 rows in set (0.00 sec)o

mysql> explain select t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_alloc, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user from compy_job_table as t1 left join compy_assoc_table as t2 on t1.id_assoc=t2.id_assoc left join compy_resv_table as t3  on t1.id_resv=t3.id_resv  where (t1.id_user='1003') && ((t1.time_end >= 1437548400 || t1.time_end = 0)) group by id_job, time_submit desc;
+----+-------------+-------+--------+-------------------------------------+------------+---------+------------------------+------+--------------------------------------------------------+
| id | select_type | table | type   | possible_keys                       | key        | key_len | ref                    | rows | Extra                                                  |
+----+-------------+-------+--------+-------------------------------------+------------+---------+------------------------+------+--------------------------------------------------------+
|  1 | SIMPLE      | t1    | range  | id_job,rollup2,sacct_def,sacct_def2 | sacct_def2 | 8       | NULL                   |   68 | Using index condition; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY                             | PRIMARY    | 4       | slurm_1412.t1.id_assoc |    1 | Using where                                            |
|  1 | SIMPLE      | t3    | ref    | PRIMARY                             | PRIMARY    | 4       | slurm_1412.t1.id_resv  |    1 | NULL                                                   |
+----+-------------+-------+--------+-------------------------------------+------------+---------+------------------------+------+--------------------------------------------------------+
3 rows in set (0.00 sec)

Adding the sacct_def2 index order didn't affect other queries:

sacct -s CA,CD,F,R:
mysql> explain select t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_alloc, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user from compy_job_table as t1 left join compy_assoc_table as t2 on t1.id_assoc=t2.id_assoc left join compy_resv_table as t3  on t1.id_resv=t3.id_resv  where (t1.id_user='1003') && ((t1.state='4' && (t1.time_end && (t1.time_end >= 1438028802))) || (t1.state='3' && (t1.time_end && (t1.time_end >= 1438028802))) || (t1.state='5' && (t1.time_end && (t1.time_end >= 1438028802))) || (t1.time_start && ((!t1.time_end && t1.state=1) || (1438028802 between t1.time_start and t1.time_end)))) group by id_job, time_submit desc;
+----+-------------+-------+--------+-------------------------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
| id | select_type | table | type   | possible_keys                       | key       | key_len | ref                    | rows  | Extra                                                               |
+----+-------------+-------+--------+-------------------------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
|  1 | SIMPLE      | t1    | ref    | id_job,rollup2,sacct_def,sacct_def2 | sacct_def | 4       | const                  | 60513 | Using index condition; Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY                             | PRIMARY   | 4       | slurm_1412.t1.id_assoc |     1 | Using where                                                         |
|  1 | SIMPLE      | t3    | ref    | PRIMARY                             | PRIMARY   | 4       | slurm_1412.t1.id_resv  |     1 | NULL                                                                |
+----+-------------+-------+--------+-------------------------------------+-----------+---------+------------------------+-------+---------------------------------------------------------------------+
3 rows in set (0.00 sec)

Adding nodes_alloc index speeds up quries with queries like: sacct -i 2-10000

mysql> EXPLAIN SELECT t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user FROM compy_job_table AS t1 LEFT JOIN compy_assoc_table AS t2 ON t1.id_assoc = t2.id_assoc LEFT JOIN compy_resv_table AS t3 ON t1.id_resv = t3.id_resv WHERE ((t1.nodes_alloc between 2 and 10000)) && ((t1.time_start && ((1434384740 BETWEEN t1.time_start AND t1.time_end) || (t1.time_start BETWEEN 1434384740 AND 1434384741)))) GROUP BY id_job , time_submit DESC;
+----+-------------+-------+--------+----------------+---------+---------+-------------------------+--------+----------------------------------------------+
| id | select_type | table | type   | possible_keys  | key     | key_len | ref                     | rows   | Extra                                        |
+----+-------------+-------+--------+----------------+---------+---------+-------------------------+--------+----------------------------------------------+
|  1 | SIMPLE      | t1    | ALL    | id_job,rollup2 | NULL    | NULL    | NULL                    | 117549 | Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY        | PRIMARY | 4       | 1411_master.t1.id_assoc |      1 | NULL                                         |
|  1 | SIMPLE      | t3    | ref    | PRIMARY        | PRIMARY | 4       | 1411_master.t1.id_resv  |      1 | NULL                                         |
+----+-------------+-------+--------+----------------+---------+---------+-------------------------+--------+----------------------------------------------+
3 rows in set (0.00 sec)

mysql> EXPLAIN SELECT t1.account, t1.array_max_tasks, t1.array_task_str, t1.cpus_req, t1.derived_ec, t1.derived_es, t1.exit_code, t1.id_array_job, t1.id_array_task, t1.id_assoc, t1.id_block, t1.id_group, t1.id_job, t1.id_qos, t1.id_resv, t3.resv_name, t1.id_user, t1.id_wckey, t1.job_db_inx, t1.job_name, t1.kill_requid, t1.mem_req, t1.node_inx, t1.nodelist, t1.nodes_alloc, t1.partition, t1.priority, t1.state, t1.time_eligible, t1.time_end, t1.time_start, t1.time_submit, t1.time_suspended, t1.timelimit, t1.track_steps, t1.wckey, t1.gres_alloc, t1.gres_req, t1.gres_used, t2.acct, t2.lft, t2.user FROM compy_job_table AS t1 LEFT JOIN compy_assoc_table AS t2 ON t1.id_assoc = t2.id_assoc LEFT JOIN compy_resv_table AS t3 ON t1.id_resv = t3.id_resv WHERE ((t1.nodes_alloc between 2 and 10000)) && ((t1.time_start && ((1434384740 BETWEEN t1.time_start AND t1.time_end) || (t1.time_start BETWEEN 1434384740 AND 1434384741)))) GROUP BY id_job , time_submit DESC;
+----+-------------+-------+--------+----------------------------+-------------+---------+-------------------------+------+---------------------------------------------------------------------+
| id | select_type | table | type   | possible_keys              | key         | key_len | ref                     | rows | Extra                                                               |
+----+-------------+-------+--------+----------------------------+-------------+---------+-------------------------+------+---------------------------------------------------------------------+
|  1 | SIMPLE      | t1    | range  | id_job,rollup2,nodes_alloc | nodes_alloc | 4       | NULL                    |  720 | Using index condition; Using where; Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | eq_ref | PRIMARY                    | PRIMARY     | 4       | 1411_master.t1.id_assoc |    1 | NULL                                                                |
|  1 | SIMPLE      | t3    | ref    | PRIMARY                    | PRIMARY     | 4       | 1411_master.t1.id_resv  |    1 | NULL                                                                |
+----+-------------+-------+--------+----------------------------+-------------+---------+-------------------------+------+---------------------------------------------------------------------+
3 rows in set (0.00 sec)

No change in functionality

If node definitions in slurm.conf are spread across multiple lines
and topology/tree is configured, then sub-optimal node selection can
occur.
bug 1645

This also adds the ability to display allocated memory on a node
bug 1804

Conflicts:
	slurm/slurm.h.in
	src/slurmctld/job_scheduler.c
	src/slurmd/slurmstepd/task.c

Rather than generating loads of log messages about too much time
being used to build the job queue every few seconds, log it only
every 10 minutes.
bug 1827

Log the number of job-partition pairs added to the queue for job
scheduling.
bug 1827

Minor updates to web page document
Minor improvements to error message logic

Improve logging
Disable stage-in/out if only persistent buffers used
End-to-end with persistent buffer works
Improve user error information

Also, use first pool as default if none configured
Several changes for updated API calls