The Data Overview tab on a table's details page gives you a snapshot of the table's storage footprint and access activity. Use these metrics to identify tables that are growing quickly, sitting idle, or overdue for cleanup—without querying the data directly.
If you have enabled the data lake management feature, the tab also shows storage class distribution and file size distribution.
Metrics
| Metric | What it measures | Data source |
|---|---|---|
| Size | Total size of all data stored in the table | DLF-hosted location: Object Storage Service (OSS) statistics. Other locations: E-MapReduce (EMR) engine statistics. |
| Total Number of Tables | Total number of files stored in the table | DLF-hosted location: OSS statistics. Other locations: EMR engine statistics. |
| Number of Partitions | Total number of partitions in the table | Metadata |
| DDL Last Updated | Last time the table schema was changed using a data definition language (DDL) statement | DLF-hosted location: OSS statistics |
| Data Last Updated | Last time the table data was modified | DLF-hosted location: OSS statistics |
| File Visits within Last Day | Number of times the table was accessed in the last day | Compute engines (currently EMR only—see requirements). Refreshed daily at 00:00, with a delay of about 10 minutes. |
| File Visits within Last Seven Days | Number of times the table was accessed in the last seven days | Compute engines (currently EMR only) |
| File Visits within Last 30 Days | Number of times the table was accessed in the last 30 days | Compute engines (currently EMR only) |
Requirements for File Visits metrics
The File Visits metrics require the following:
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EMR version V3.45.1 or later, or V5.11.1 or later. For other EMR versions, upgrade the EMRHOOK component in an EMR gateway first. See Upgrade the EMRHOOK component in an EMR gateway.
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Only Spark and Hive compute engines are supported.
Use cases
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Storage optimization: Sort tables by Size to find the largest tables and prioritize them for storage-tier optimization or compaction.
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Cold archiving: Use the File Visits metrics to identify tables that have not been accessed recently. Tables with low or zero visits over 30 days are candidates for cold archive storage.
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Stale data cleanup: Sort by Data Last Updated to locate tables that have not been updated for an extended period. Review these tables to decide whether to clean or remove them.
View data overview for a table
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Log on to the DLF console.
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In the left-side navigation pane, choose Metadata > Metadata.
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Click the Table tab. Set the Catalog List and Database Name parameters, then enter the table name to search for.
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Click the table name to open its details page.
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Click the Data Overview tab.