Lock Tree & Dead Lock

You can analyze the trend of locks during the day. The session that caused a lock (Lock Holder) and the session waiting for a lock (Lock Waiter) can be checked through a tree structure. Through these functions, you can analyze queries by checking the relationship between holders and waiters for locks that occurred at specific points.

Lock tree

Home > Select Project > Analysis > Lock Tree

It provides the time series chart and lock tree for the locks occurred during the day. From the point where a lock first occurred, the structure of holders and waiters is displayed in a tree form. You can check the rock tree over time.

Basic screen guide

Select the desired date, time, and instance to view in Time and Instance. If a lock occurs at the set time, the searched data appears in Lock Wait Sessions and the Lock Tree table at the bottom of the screen.

• You can see the data for up to two weeks within a chart. If you click a specific time in the graph chart, you can check the lock information for the selected time in the table at the bottom of the screen. If you select the button in seconds, you can view the lock information in 5-second increments.

  Note

  Through the tags on the upper right of the Lock Wait Sessions chart, you can see the units to view.

• As you continuously drag (drill down) a specific time zone on the graph chart, you can see the charts and lock trees for detailed time zones.

• You can see the data in 5-second increments by dragging within 3 hours on the chart. However, the data in 5-second increments can only be viewed within the most recent month. The data earlier than one month can only be viewed as 5-minute summary data. For example, you can drag (drill down) lock tree data from 40 days ago for the 5-minute summary data, but you cannot see 5-second data.

Active session

Item	Description
Instance Name	Instance Name
id	Connection identifier
user	SQL execution account
host	Hostname that this thread is connected to.
db	Default database name. If nothing, it is NULL.
command	Running command type (Query/Sleep/Daemon, etc.)
time	Execution time of the current command (sec)
state	Current thread status (executing, updating, sending data, etc.)
query	Running statement. It displays the literal value SQL separated from Processlist.info.
query_param	Literal value separated from query
type	Thread type. FOREGROUND/BACKGROUND, etc.
connection_type	The protocol used to establish a connection. TCP/IP, SSL/TLS

Lock tree

Item	Description
holder type	Type of the holder session
lock mode	holder_mode
waiter type	Type of the waiter session
lock request	waiter_mode
state	This is the step where the current process is in progress.
table	holder_table/waiter_table
index	holder_index/waiter_index

Process information

The following items are the metrics collected if the XOS agent has been installed.

Item	Description
cputime	CPU usage time
cpuusage	CPU Utilization
elapse	Elapsed time of CPU usage
vsize	Virtual memory size (Kb)
rss	Resident Set Size (RSS) that is the number of physical pages associated with the process.
state	Process status
ioread	Actual time spent reading the block (milliseconds)
iowrite	Actual time spent writing the block (milliseconds)
pss	Process specific memory usage + Percentage of shared memory occupied by one process
uid	user id
cmd	Executing command
longcmd	Full path of cmd

Dead lock

Home > Select Project > Analysis > Dead Lock

A deadlock occurs when multiple processes or transactions block each other from processing by locking database resources (tables or rows). Frequent deadlocks cause inconvenience to end users and reduce the service quality. In the Deadlock menu, you can see the time and related data when the deadlock occurred. This information can help you identify and solve problems in the application design.

You can check information about deadlocks that have occurred in the database.

1. Set the time to search in Time.

2. Select an instance name to view in instance.

3. Select .

It provides deadlock information in the form of table.

Note

You can select a lookup time (up to 3 weeks). Select the clock display area to query a random date and time. If you click the date and time text area, the selectable options for the date and time appear.