Lock tree

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This tool analyzes the trend of locks that occurred during the day. This function allows you to visually check the tree structure of the session that generated the lock (lock holder) and the session waiting for the lock (lock waiter). You can analyze the relationship between the holder and waiter of the lock that occurred at a specific time point. Through the WhaTap's Lock Tree feature, the DB administrator can identify and resolve the DB lock issues and optimize the DB performance.

Key features are as follows:

• Lock trend analysis: The trends of locks that occurred during the set search period are traced over time and displayed in a graph. This allows you to visually check how the locks are created and resolved.

• Check lock holder and waiter: You can see the holder and waiter for each lock in a tree structure. Through this, when a specific lock occurs, you can check the relationship between the session that generated the lock and the waiting session.

• Inter-session relationship analysis: By analyzing the relationship between the session that generated the lock and the waiting session, you can identify the cause of the lock that occurred during the query execution and transaction handling.

• Visual lock trend by time: Through the 1-Min Lock Trends and Lock Wait Sessions features, the lock occurrence data can be analyzed in time zones.

Basic usage 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.

Lock Wait Sessions

The Lock Wait Sessions feature allows you to analyze the lock wait sessions. Depending on the query period, the lock wait session data is provided at 5-minute intervals when the query is for 3 hours or more, and at 5-second intervals when the query is for less than 3 hours. You can also adjust the time range by dragging the chart flexibly.

1-Min Lock Trends

If you click a specific time zone in Lock Wait Sessions, the lock occurrence status for 30 minutes, from 15 minutes before to 15 minutes after is visualized. This allows you to effectively analyze the lock occurrence trend at 30-minute intervals.

Note

Total Locks indicates the total number of locks generated in the time zone.

Viewing time

1-Min Lock Trends and Lock Tree tables are timed based on the maximum number of locks that occurred at the clicked time in Lock Wait Sessions. This allows you to find the zone with the most locks.

If you click the bar of a different time zone in the 1-Min Lock Trends chart with the Lock Wait Sessions unchanged, the time range is synced to the Lock Tree table by using the seconds with the highest number of locks for the minute. This allows you to see the information reflected in the Lock Tree table when changing the time zone.

• Viewing for 3 hours or more (using 5-minute data)

  The bar color of the 5-minute zone from the time of inquiry appears more prominent.

  When the 07:15:00 time point is clicked, the color of the 07:15:00-07:20:00 zone's bar chart appears more prominent.

  

• Viewing for less than 3 hours (using 5-minute data)

  It is useful for analyzing the locks that occur within short time intervals.

  

Column information guide

For more information about columns, see the link.

Item	Description
oname	Agent or instance name.
id	Unique ID of the session.
db_username	User name connected to the database.
elapse_time	Time elapsed since the task started.
waiter type	Type of the entity waiting for a lock.
holder type	Type of the entity holding a lock.
holder desc	Detailed description of the entity holding a lock.
waiter desc	Detailed description of the entity waiting for a lock.
query	Executed SQL query.
query_param	Parameters used for a query.