Dataguard apply time

Job details

Name:	Dataguard apply time
Platform:	Oracle
Category:	Cluster and Replication
Description:	Checks refresh date of scheduled jobs in refresh group(s).
Long description:
Version:	1.0
Default schedule:	10m
Requires engine install:	No
Compatibility tag:	.[type=‘instance’ & databasetype=‘oracle’]

Parameters

Name	Default value	Description
warning_delay_min	10	Warning status if redo log apply is more than x minutes delayed
alarm_delay_min	20	Alarm status if redo log apply is more than x minutes delayed

Job Summary

Purpose:
The purpose of this job is to monitor the apply time of redo logs in Oracle Data Guard standby nodes. It ensures that the data replication from the primary to the standby databases is occurring within acceptable time limits.
Why: This job is important to ensure that the standby database remains closely synchronized with the primary database. If the redo logs apply time exceeds certain thresholds, it could indicate potential issues with data consistency or availability in the event of a failover.
Manual checking: You can check this manually in the Oracle database by issuing the following SQL command:

select 60 * extract(hour from to_dsinterval(value)) + extract(minute from to_dsinterval(value)) as "Apply lag in min" from sys.v$dataguard_stats where name like 'apply lag';

Details and Configuration

“Dataguard apply time”:
The job checks the time delay in applying redo logs at the standby nodes. It calculates the delay and triggers warnings or alarms based on predefined thresholds.
“Category”: Cluster and Replication.
“Installable Conditions”: The job is automatically installable on Oracle database instances that are configured as physical standby databases and have the necessary privileges to read from v$dataguard_stats.

Threshold Settings

Warning:
A warning is triggered if the redo log apply time is more than 10 minutes delayed.
Alarm: An alarm is triggered if the redo log apply time is more than 20 minutes delayed.

Output Specifications

Report Template

“Title”:
Dataguard apply time status
“Description”: Reflects the current status of redo log apply delays at standby nodes.
“Frequency”: The status is checked and reported every 10 minutes by default.
“Details Section in Report”: The report includes a dedicated section outlining the specific details of the apply time for each monitored instance.

Detail	Description
Apply lag in min	Displays the time lag of log apply in minutes.

Notifications

Based on the javascript computations within the job:

Apply Lag (Minutes)	Status	Message
< warning_delay_min	0	“Redo apply lag is x minutes behind primary”
≥ warning_delay_min and < alarm_delay_min	1	“Redo apply lag is x minutes behind primary”
≥ alarm_delay_min	2	“Redo apply lag is x minutes behind primary”

The system dynamically adjusts the output message and status level based on measured apply time lags, ensuring system administrators receive accurate and timely feedback regarding the health of the database replication process.