Exception Alarms

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Last updated: 2021-04-09 10:42:46

The exception alarms feature displays the information overview of exception alarms (exceptions detected by "24/7 Exception Diagnosis") generated by database instances connected to DBbrain under your account.

Note：
Currently, the exception alarms feature is only supported for TencentDB for MySQL (excluding the basic single-node instance).

Exception Alarm List

Log in to the DBbrain console, select Monitoring & Alarm > Exception Alarm on the left sidebar, and select a database type at the top.

The exception alarm list displays the basic information of the database instance, risk level, diagnosis items, duration, and operations. In the search bar, you can search instances by instance ID, instance name, diagnosis item, etc. You can also filter instances by region and time.

Risk levels include notice, warning, severe, and fatal. You can filter, aggregate, and search for alarms by field. You can also click Details to view specific information about the exception and the optimization suggestion for the exception.
There are over 30 diagnosis items for exception diagnosis, such as slow SQL, primary-secondary switch, deadlock, uncommitted transaction, and OOM. You can filter, aggregate, and search for items by field. You can also sort them by duration.

Ignoring/Unignoring an Alarm

You can ignore or unignore diagnosis item alarms that are not generated by health checks to filter exception alarms.

In the exception alarm list, locate an alarm and click Ignore in the Operation column to ignore it. By doing so, other diagnosis item alarms of the instance generated by the same root cause will also be ignored.
In the exception alarm list, an ignored alarm will be grayed out. You can click Unignore to unignore it and other diagnosis item alarms generated by the same root cause.

Detailed Description of Diagnosis Items

A diagnosis item is an item diagnosed intelligently, which can be divided into four categories: performance, availability, reliability, and maintainability. Each diagnosis item belongs to only one category.

Diagnosis Item Name	Category	Description
Connectivity check	Availability	Unable to connect to the database
Slow insertion, update, or deletion	Performance	There is a thread pending for a long time
Slow SQL	Performance	There is a thread that is in the status of temp table creation, temp table replication, result sorting, etc.
Row lock wait	Performance	There is a transaction with lock wait
Uncommitted transaction	Performance	There is a thread in sleep status for a long time
DDL statement metadata lock wait	Performance	There is a thread running DDL statements with metadata lock wait
INSERT, UPDATE, and DELETE statement metadata lock wait	Performance	There is a thread running IUD statements with metadata lock wait
SELECT statement metadata lock wait	Performance	There is a thread running SELECT statements with metadata lock wait
Deadlock	Reliability	A deadlock is detected in the monitoring data, and the deadlock information exists in `INNODB STATUS`
Read-only lock	Performance	There is a thread with global read-only lock wait
SQL statement metadata lock wait	Performance	There is a thread running DDL statements with metadata lock wait
Waiting for flush tables	Performance	There is a thread waiting for flush table
High number of active sessions	Performance	The number of active sessions exceeds three times the CPU specification of the database instance
High disk utilization	Reliability	The disk utilization is too high
Memory utilization	Reliability	The memory utilization is too high
High CPU utilization	Performance	The CPU utilization is too high
Low hit rate of table open cache	Performance	The hit rate of the table open cache is low
High-risk account	Maintainability	There are anonymous or password-free accounts
Big table	Maintainability	The size of a single table exceeds 10% of the instance disk specification
I/O replication thread interruption	Reliability	A replication monitoring metric is exceptional and triggers diagnosis, and there is an I/O thread exception in `SHOW SLAVE STUTAS`
SQL replication thread interruption	Reliability	A replication monitoring metric is exceptional and triggers diagnosis, and there is an SQL thread exception in `SHOW SLAVE STUTAS`
Replication delay caused by DDL	Reliability	A replication monitoring metric is exceptional and triggers diagnosis, and there is a thread running DDL statements with metadata lock wait
Replication delay caused by transaction	Reliability	A replication monitoring metric is exceptional and triggers diagnosis, and there is a thread in sleep status with metadata lock wait
Replication delay caused by read-only lock	Reliability	A replication monitoring metric is exceptional and triggers diagnosis, and there is a thread with global read-only lock wait
Primary-secondary switch	Availability	The primary-secondary switch monitoring metric is exceptional
Instance migration caused by server failure	Availability	The monitoring metric of instance migration is exceptional due to server failure
Read-only instance removal	Availability	The read-only instance removal monitoring metric is exceptional
Disk limit exceeded	Availability	The disk limit monitoring metric is exceptional
Memory limit exceeded	Availability	The memory limit monitoring metric is exceptional
OOM	Availability	The database memory is overloaded

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