Root / Assembly / ARCCore / AREnumType / DocumentationOnlyEnum / ARConcepts / _Member / DataRetention

EnumMemberAttribute

DataRetention

KeyValue
DescriptionThe concept of when to delete old data (if deemed necessary).

Because of inherent traits of the PropertyStream concept, data will never be deleted by default.

This might result in unacceptable storage requirements / low performance. Some functionality for deletion is therefore envisaged to be necessary to implement.
See NoRealDeletion for details.

TODO: Not implemented as of Mar 2020. Not decided if should be in a specific ARComponents or just part of ARCCore.
Will probably be a specific BasePKAttribute called PKRetAttribute, maybe also something added to ClassAttribute (or something added to EnumAttribute. As of Apr 2020 we have not decided where / how to tag 'entity'-classes).
Note that retention at application level is also plausible. One scenario could be a high-availability log-collector delivering log-data to more simple (cheaper) final storage nodes that are not necessarily high-availablity themselves. The log-collector only has to keep data for as long as the final storage nodes are tolerated to be offline.
EnumMemberDataRetention
EnumTypeARCCore.ARConcepts
LongDescriptionSome ideas for how to do this:
Use a concept of 'revision number' in the actual storage file (as of Apr 2020 StreamProcessor is prepared for this (see its _storage-member) but use of it is not supported).
Example: We start with file 2020-04-13 14:19.R00001.txt and after the first compacting we store a new file called 2020-04-13 14:19.R00002.txt.
As long as there are clients 'using' the old file, it can be kept on disk (in order for ClientUpdatePosition to be compatible.
OR, more probable, compact by leaving empty-lines, thereby making ClientUpdatePosition unchanged.
We can also have a cut-off of for instance a month, and just not accept ClientUpdatePosition older than this.
(A backup mechanism could also be to build a 'last Timestamp' feature into ClientUpdatePosition, and use that as a last resort when file position can not be used).

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Generated 2020-10-13 11:11:01.084 UTC