Description

Find out what the settings in the Store and Forward system mean. Each database connection has its own Store and Forward settings.

Video recorded using: Ignition 8.1

Transcript

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[00:00] Let's take a look at the settings for a store and forward engine. I'm on the Gateway and I'm in the configure section under databases and store and forward. Here you can see I already have a store and forward engine for a MySQL database. You'll notice this note down below, stating a store and forward engine is automatically created for each database connection. So as soon as I added this database, the engine was created. Now before moving on, it's important to know that many objects and subsystems and ignition utilize the store and forward system such as the alarm journal. Some of these systems also have settings to skip or completely bypass the store and forward system. Now let's take a look at some of the settings here. All created engines, will have the same settings, so don't worry if you are utilizing a different kind of database.

[01:02] I'll click on the edit button here to access those properties. The memory buffer size here dictates how many records can be held within the memory buffer. The store settings dictate when we should take records from the memory buffer and move them to the disc buffer. First, we have the disc cache enabled setting. If disabled Ignition will no longer store records onto the hard drive, and if the memory buffer becomes full, you could lose records. While the disc cache is enabled, the max records property here dictates the maximum number of records that will be saved to the hard drive. Then we have the right size and right time properties. These are used to determine when to move records from the memory buffer to the disc buffer. With the default settings, we'll wait until there are 25 records or at least 5,000 milliseconds have passed, whichever one of these two becomes true first. Finally, we have the only forward from cache option, which forces all records to go through the disc cache before being forwarded.

[02:03] Otherwise, the system will pull from either buffer or both to try to satisfy the forward right settings. If we scroll down a little bit further here, we can take a look at these forward settings. These control how often we take records from either buffer and move them to the database. We have another write size and write time, which work in a very similar fashion to the store settings above. So again, we'll wait until there are at least 25 records in a buffer or until we've had items in the buffer for at least one second. Once these are true, then the records are pushed to the database, and again, this is for both buffers. If you look down a little bit further, you can enable a schedule and then define when you want to have that schedule run. This means that Ignition will not write anything to the database until the scheduled time. This gives you an opportunity to control when you're pushing data into your database.

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