Replica property names

Property names allow a replica database to be labeled. Replica databases that are labeled can be grouped, which is important when using the START AFTER COMMIT statement, see START AFTER COMMIT. For example, you might have some replica databases that are related to the bicycle industry and others that are related to the surfboard industry, and you might want to update each of those groups of replica databases separately. You can use property names to group these replica databases. All members of a group have the same value for the property name.

Property names and values can be almost any arbitrary names and literals. For example:

Property name	Possible values
Region	north, south, east, west
Color	red, yellow, green, blue, rainbow, transparent
Mood	upbeat, blue
Philosophy	realist, nihilist, purple

If you have multiple property names, the properties can have overlapping values. If you decide that "blue" is both a useful color and a useful mood, then you can use it as a value for both properties. (A server categorized as having a blue mood will NOT fall into the same category as servers having a blue color; properties are completely independent.)

A server can have more than one property, and therefore can belong to more than one group. Also, a server does not have to have a setting for every possible property.

For examples of using properties, see START AFTER COMMIT.

Replica property names can be added at any time, and new replica databases can also be added at any time. By using property names to group your replica databases, you avoid having to rewrite the logic on the master database to call remote stored procedures on replica databases.

Note Every replica database has an implicit property called "name", which is the server name that is assigned to the replica database when it is registered.

Either the master database or the replica database can set a property for the replica database. If the replica database sets the property, then replica database must notify the master database of that property and value. The master database can set properties for a named replica database with the SET SYNC PROPERTY statement. The replica database can send its properties to the master database by using messages that include SAVE SET SYNC PROPERTY. For more information, see SET SYNC PROPERTY.