3.4.3 Estimating the size when using a Suspend/Resume Plugin

If you want to use Suspend/Resume Plugins, prepare an external storage device (such as a database) to manage the suspend information. Any external storage device can be used to manage suspend information, as long as it is separate from Navigation Platform's embedded database and it has enough space to hold the suspend information.

This section explains the management of suspend information and how to estimate the amount of suspend information, and also provides an example of performing the estimation.

Organization of this subsection

(1) Suspend information management units
(2) Procedure to estimate the size of suspend information
(3) Size estimation example

(1) Suspend information management units

You must first decide on the units for managing the suspend information that is to be saved to the external storage device.

The figure below shows an example of how individual suspend information is managed on a per-user and per-Operation Content basis. In this example, because the user IDs and the Operational Content IDs are unique, it is possible to keep track of individual suspend information for each user in each operation.

Figure 3‒6: Relationship between users and suspend information

When you have used the API provided by Navigation Platform to develop a Suspend/Resume Plugin, deletion of the suspend information is invoked at the following times.

When the user clicks the Finish button in the Operational Content Execution Window (when the operation is finished)

When the Operational Content is finished, the suspend information for the user who finished it is deleted.
When changes are made to an Operational Content shown in the Operational Content Execution Window

When an Operational Content is modified, the suspend information for all users is deleted.
When a user who is editing an Operational Content in the Operational Content Editing Window deletes it

When an Operational Content is deleted, the suspend information for all users is deleted.
When the user attempts to resume the operation in the Operational Content Execution Window and an integrity error occurs

If the Operational Content has been updated since the time suspend information was saved, an integrity error occurs. At this time, the suspend information of the user who selected the relevant Operational Content is deleted.

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(2) Procedure to estimate the size of suspend information

Use the following procedure to estimate the data size of suspend information.

Estimate the data size per unit of suspend information (average value over all Operational Contents).

Estimation formula

{(Average size of data entered by user + 350) × number of Guide Parts + 640} × number of Process Nodes + (average size of data entered by user + 560) × number of Data Store Plugin parameters + 2,700 = data size per unit of suspend information (unit: bytes)
Estimate the number of users of Operational Contents (average value over all Operational Contents).
Estimate the required data size from steps 1 and 2.

Estimation formula

Data size per unit of suspend information × number of users of Operational Contents × number of Operational Contents = Required data size (unit: bytes)

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(3) Size estimation example

The following is an example of estimating the amount of suspend information based on the conditions listed below.

Conditions for estimate (all values are averages)

Number of Operational Contents: 100
Number of Process Nodes: 30
Average size of data entered by a user: 1,000 bytes
Number of Guide Parts: 50
Number of Data Store Plugin parameters: 30
Number of users of Operational Contents: 20

Estimation example (data size per unit of suspend information)

{(1,000 + 350) × 50 + 640} × 30 + (1,000 + 560) × 30 + 2,700 = 2,093,700 bytes

Estimation example (required data size)

2,093,700 × 20 × 100 = 4,187,400,000 bytes [Figure] 3.9 GB

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