[Instances] Honor reserved instances

[joligario]

Logic to select next available instance id was incorrect. The correct logic selected the max id + 1 or max reserved + 1, but then it would overwrite if we enabled recycling ids. Additionally, it was incrementing the reserved ids and assigning ids to the max reserved id vice the next available. Finally, it was running the logic twice.

[joligario]

No instances:

MariaDB [eqemu]> select min(i1.id + 1) as next_available from instance_list i1 left join instance_list i2 on i1.id + 1 = i2.id  where i1.id > 30 and i2.id is null;
+----------------+
| next_available |
+----------------+
|           NULL |
+----------------+
1 row in set (0.001 sec)

MariaDB [eqemu]> SELECT IFNULL(MAX(id), 30) + 1 FROM instance_list WHERE id > 30;
+-------------------------+
| IFNULL(MAX(id), 30) + 1 |
+-------------------------+
|                      31 |
+-------------------------+
1 row in set (0.000 sec)

Some reserved instances populated. Should select 31 if not recycling, NULL if we are:

+----+------+---------+-----------+------------+----------+---------------+
| id | zone | version | is_global | start_time | duration | never_expires |
+----+------+---------+-----------+------------+----------+---------------+
|  1 |   25 |       1 |         1 |          0 |        0 |             1 |
|  2 |   25 |       2 |         1 |          0 |        0 |             1 |
|  3 |  151 |       1 |         1 |          0 |        0 |             1 |
|  4 |  114 |       1 |         1 |          0 |        0 |             1 |
|  5 |  344 |       1 |         1 |          0 |        0 |             1 |
|  6 |  202 |       0 |         1 |          0 |        0 |             1 |
+----+------+---------+-----------+------------+----------+---------------+
6 rows in set (0.000 sec)

MariaDB [eqemu]> SELECT IFNULL(MAX(id), 30) + 1 FROM instance_list WHERE id > 30;
+-------------------------+
| IFNULL(MAX(id), 30) + 1 |
+-------------------------+
|                      31 |
+-------------------------+
1 row in set (0.000 sec)

MariaDB [eqemu]> select min(i1.id + 1) as next_available from instance_list i1 left join instance_list i2 on i1.id + 1 = i2.id  where i1.id > 30 and i2.id is null;
+----------------+
| next_available |
+----------------+
|           NULL |
+----------------+
1 row in set (0.001 sec)

Some scattered instances. Should select 38 if not recycling, 34 if we are:

MariaDB [eqemu]> select * from instance_list;
+----+------+---------+-----------+------------+----------+---------------+
| id | zone | version | is_global | start_time | duration | never_expires |
+----+------+---------+-----------+------------+----------+---------------+
|  1 |   25 |       1 |         1 |          0 |        0 |             1 |
|  2 |   25 |       2 |         1 |          0 |        0 |             1 |
|  3 |  151 |       1 |         1 |          0 |        0 |             1 |
|  4 |  114 |       1 |         1 |          0 |        0 |             1 |
|  5 |  344 |       1 |         1 |          0 |        0 |             1 |
|  6 |  202 |       0 |         1 |          0 |        0 |             1 |
| 31 |  100 |       0 |         0 |          0 |        0 |             0 |
| 32 |  101 |       0 |         0 |          0 |        0 |             0 |
| 33 |  102 |       0 |         0 |          0 |        0 |             0 |
| 37 |  103 |       0 |         0 |          0 |        0 |             0 |
+----+------+---------+-----------+------------+----------+---------------+
10 rows in set (0.000 sec)

MariaDB [eqemu]> SELECT IFNULL(MAX(id), 30) + 1 FROM instance_list WHERE id > 30;
+-------------------------+
| IFNULL(MAX(id), 30) + 1 |
+-------------------------+
|                      38 |
+-------------------------+
1 row in set (0.000 sec)

MariaDB [eqemu]> select min(i1.id + 1) as next_available from instance_list i1 left join instance_list i2 on i1.id + 1 = i2.id  where i1.id > 30 and i2.id is null;
+----------------+
| next_available |
+----------------+
|             34 |
+----------------+
1 row in set (0.001 sec)

[Akkadius]

Instances:RecycleInstanceIds enabled

Instances:RecycleInstanceIds disabled