eG Monitoring
 

Measures reported by PgRplStatTest

The process of copying data from a PostgreSQL database server to another server is called PostgreSQL Replication. The source database server is usually called the Master server, whereas the database server receiving the copied data is called the Replica server.

In a high availability environment, the replica servers should always be in sync with the master database instance. For this, the replication should always be enabled on the master and the replica servers should be connected to the master at all times. If the replication fails even for a brief period or if the replica servers are not connected to the master, the replica servers will not be upto date. To avoid this, it is essential to monitor the replication status of the master PostgreSQL database server. The PgRplStatTest test helps administrators in this regard!

This test reports whether/not the replication process is enabled on the target database server and also helps administrators figure out if the target database server is the master or not. Additionally, this test reports the count of replica servers connected to the target database server.

Outputs of the test : One set of results for the target PostgreSQL server

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Is_replication_enabled Indicates whether/not replication is enabled on the target database server.   The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Yes 1
No 0
Note:

By default, this measure reports the Measure Values listed in the table above to indicate whether/not replication is enabled on the server. The graph of this measure however, is represented using the numeric equivalents only i.e., 0 or 1.
Is_master Indicates whether/not the database server is the master.   The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Yes 1
No 0
Note:

By default, this measure reports the Measure Values listed in the table above to indicate whether/not the server is the master. The graph of this measure however, is represented using the numeric equivalents only i.e., 0 or 1.
slave_count Indicates the number of replica servers attached to the database server. Number This measure will be reported only if the Is_master measure reports a value of Yes.

If the value of this measure decreases gradually, backup data could not be replicated by the master database server and hence data could not be retrieved if the master database server crashes.