Tablespace Size

Tablespace Size is a screen for monitoring and managing the usage of database tablespaces. You can quickly check the size change trend of each tablespace using a line chart, and detect space shortages in advance through daily changes and Remaining Day.

• Tablespace Size Trend: Use the line chart to track the capacity change trend of major tablespaces.

• Disk Usage: View disk usage and remaining days per mount point. Available when the XOS agent is installed.

• Tablespace Size Detail: Analyze the latest usage, daily changes, and remaining days for individual tablespaces.

Prerequisites

To display data on the Tablespace Size screen, DB Configuration and Agent Configuration are required.

DB Configuration

Grant permissions to the monitoring account so the agent can query tablespace and segment information.

GRANT SELECT ANY DICTIONARY TO whatap;

Or grant permissions to individual views.

GRANT SELECT ON dba_segments TO whatap;

Agent Configuration

This configuration is for collecting segment size (TOP 50) data. Based on the conditions below, the agent collects segment size data once a day at the configured time. Data may not be collected due to conditions such as segments_min_size. Without this configuration, segment size information will not be available.

Option	Type	Default	Description
segments	boolean	true	Enable/disable segment information collection
segments_hour	int	5	Time to collect segment information. Default is 5, which starts collection at 5 AM.
segments_min_size	int	10	Minimum segment size (MB) for collection
segments_exclude_sys	int	1	Exclude sys account segments (1: exclude, 0: include)
segments_max_count	int	50	Number of segments to collect per tablespace

Tablespace size collection options

Depending on the DB environment, performance issues may occur during tablespace size collection. Use the following options to adjust the collection method and interval.

Option	Type	Default	Description
tablespace	int	1	Select the tablespace size collection method - 0: Disable collection - 1: Query based on dba_free_space (most common) - 2: Query based on free_blocks for LMT (Locally Managed Tablespace) - 3: Query based on tablespace_usage_metrics view (per-datafile query not available, no Auto Ext info)
tablespace_split	boolean	false	Applied when the tablespace option is 1 - true: First retrieves the list of datafiles, then queries free space for each file individually to distribute the load. Use this when collection query load is high in large datafile environments.
tablespace_interval	int	60	Tablespace size collection interval (minutes) - Default: 60 minutes (1 hour)

Tip

If collection is not smooth due to large DB size, try setting tablespace=1 with tablespace_split=true to distribute the load, or switch to tablespace=2.

Tablespace Size

Basic Options

In the top filter area of the Tablespace Size screen, you can select the time range and target database to query.

• Time: Select the query time range. Up to 3 weeks can be queried; queries over 3 days are displayed as daily averages.

• Instance: Select the target DB instance to query.

• Data Unit: Select from MiB/GiB/TiB. All table size values are displayed in the selected unit.

• Database: Select the target database to query.

Tablespace Size Trend

Displays the size change of each tablespace as a line chart. Each tablespace is color-coded and can be identified in the legend at the bottom.

• Hover over the chart to see detailed values by time period.

Item	Description
Top 5 / 10 / 15 / 20	Select the number of top tablespaces to display on the chart
Size / Used	Switch between Size (total size) and Used (usage)

Disk Usage

Note

Available when the XOS agent is installed.

Displays disk usage per mount point. The Latest Data section shows the most recently collected data within the query range selected in the time selector. You can check the size, Usage (%), Increase AVG, and Remaining Day at that point in time.

Latest Data

Column	Description
Mount Point	Disk mount path
Size	Total disk size
Used	Used size
Free Size	Remaining free space
Usage(%)	Usage rate (visualized as a progress bar)
Increase AVG	Average daily increase over the query period
Remaining Day	Remaining available days based on the current growth rate

Daily Columns

Displays Size and daily change (Inc) for each date in the query period.

• Search: Filter by Label or Path.

• CSV: Export in CSV format.

In an ASM environment, both the Disk Usage tab and the ASM Disk Usage tab are displayed together.

ASM Disk Usage

The daily columns, search, and CSV features are the same as Disk Usage.

Column	Description
Label	ASM disk label
Path	ASM disk path
Size	Total disk size
Used	Used size
Free Size	Remaining free space
Usage(%)	Usage rate (visualized as a progress bar)
Increase AVG	Average daily increase over the query period
Remaining Day	Remaining available days based on the current growth rate

Tablespace Size Detail

Displays detailed usage for individual tablespaces. The TOTAL row at the top shows the overall total. The Latest Data section shows the most recently collected data within the query range selected in the time selector. You can check the size, Usage (%), Increase AVG, and Remaining Day at that point in time.

Latest Data

Column	Description
Container	Container (PDB) name. Displayed only in CDB environments; hidden in Non-CDB environments.
Tablespace	Tablespace name
Auto Ext	Auto extension status (YES/NO). Column visibility can be toggled in settings.
Inc By	Increment unit for auto extension. Column visibility can be toggled in settings.
Max Size	Maximum size limit. Column visibility can be toggled in settings.
Total Size	Total tablespace size
Used Size	Used size
Free Size	Remaining free space
Usage(%)	Usage rate (visualized as a progress bar)
Increase AVG	Average daily increase over the query period
Remaining Day	Remaining days based on current growth rate, calculated as Free Size ÷ Increase AVG

Daily Columns

Displays Size and daily change (Inc) for each date in the query period. Increases are shown as positive values and decreases as negative values, color-coded for distinction.

Additional Features

• Magnifier icon: Displays a popup of the top 50 segments by space usage in the tablespace.

• ▼ Expand: Expand the list of data files belonging to the tablespace.

• Search: Filter by container or tablespace.

• CSV Download: Export in CSV format. When downloading, you can select Tablespace or Datafile unit.

Table Settings

Click the Settings button in the top right to configure table display options.

Item	Description
Column: Auto Ext / Inc By / Max Size	Toggle the display of Auto Ext, Inc By, and Max Size columns.
Warning(%)	Usage rate (%) for warning level; displayed in orange when exceeded. Default: 80
Critical(%)	Usage rate (%) for critical level; displayed in red when exceeded. Default: 100
Reset Settings	Reset all settings to default values

Segment Size (TOP 50)

Click the magnifier icon in the tablespace row to display a popup showing the top 50 segments occupying the most space in that tablespace.

Click the Download button at the top right of the popup to export the list shown in the popup to a CSV file. The column configuration and display format visible on the screen are reflected in the file as they are, and the saved file name is table_size_top50.csv.

Note

The segments option must be enabled in the Agent configuration. The agent collects segment size data once a day, and without this configuration, data will not be available.

Column	Description
Tablespace Name	Tablespace the segment belongs to
Owner	Schema that owns the segment
Segment Name	Segment name. Click to view object details in the Object Detail popup.
Segment Type	Segment type (TABLE, INDEX, LOBSEGMENT, etc.)
Partition Name	Partition name (if a partitioned table)
Size	Segment size. Size changes can be tracked via date columns.

Object Detail

Click a segment name in the Segment Size (TOP 50) popup to send a real-time query request to the agent and display detailed information about that object.

• Object Basic Info: owner, table_name, num_rows, blocks, avg_row_len, tablespace_name, partitioned, last_analyzed, compression, status, etc.

• Column/Index: Column list (column_id, column_name, nullable, data_type, data_default, num_distinct, num_buckets) and index information.

Data Interpretation Guide

Key Checkpoints

• Tablespace with high Usage(%)

  Risk of space shortage → Consider cleaning up unnecessary data or expanding the tablespace.

• Tablespace with high Increase AVG

  Rapidly growing → Check Remaining Day and take proactive action.

• Short Remaining Day

  Available space will be exhausted soon based on current growth rate → Immediate action required.

• Tablespace with Auto Ext set to NO

  Auto extension is disabled; errors may occur when space is exhausted → If usage is high, consider manual expansion or enabling Auto Ext.

• Sudden change in daily Inc value

  Large-scale data load or deletion occurred on a specific date → Investigate the cause.

• Check disk Usage(%) and tablespace Usage(%) together

  Even if a tablespace has free space, expansion is not possible if the disk is full.

Practical Use Scenarios

Scenario 1. Proactive Space Shortage Detection

1. Sort by Usage(%) in descending order in Tablespace Size Detail

2. Check Remaining Day for tablespaces with high usage

3. If remaining days are few, expand the tablespace or clean up unnecessary data

Scenario 2. Capacity Surge Root Cause Analysis

1. Check for rapidly increasing tablespaces in the Tablespace Size Trend chart

2. Identify the date when the increase occurred in the daily Inc column of that tablespace

3. Click the 🔍 magnifier icon for that tablespace to analyze segments occupying the most space

4. Review segment details for unnecessary indexes or ways to reduce data size; if none found, consider disk expansion

Scenario 3. Disk Capacity Management

1. Check mount points with high Usage(%) in Disk Usage

2. Use Remaining Day to estimate when the disk will be full

3. Compare with Tablespace Size Detail to identify which tablespaces are consuming the most disk space

Scenario 4. Auto Extension Configuration Check

1. Enable Auto Ext / Inc By / Max Size columns in settings

2. Among tablespaces with Auto Ext set to NO, check those with high Usage(%)

3. If necessary, enable auto extension or manually expand the tablespace