[FOLLOWUP][BUGFIX] keep options array for TableGarbageCollectionTask
[Packages/TYPO3.CMS.git] / typo3 / sysext / scheduler / Documentation / AppendixA / Index.rst
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10 .. _technical-background:
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12 Appendix A – Technical Background
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15 This section aims to give some more in-depth information about what
16 happens behind the scene in the Scheduler.
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18 When a task is registered with the Scheduler, an instance of the task
19 class is created and stored in a database record as a serialized
20 object. The database record itself contains additional information
21 about the registration, mostly about past and future executions. The
22 theory is that all the information that is really proper to the task
23 should be defined as member variables of the task class and is thus
24 encapsulated inside the task object. The information which relates to
25 executing a registered task is stored in the Scheduler's database
26 table.
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28 That being said, a task also contains information about its execution.
29 Indeed each task class has an instance of
30 :code:`tx_scheduler_Execution` as a member variable, which contains
31 information such as start and end date and is used to calculate the
32 next execution date.
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34 When a task is running, its start time is stored into an array, which
35 is serialized and stored in the corresponding database record. If
36 several executions are running at the same time, the array will
37 contain several timestamps. Thus the "serialized\_executions" field
38 actually contains an array of integers and not serialized instances of
39 :code:`tx_scheduler_Execution` objects.
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