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TDSQL Boundless

DokumentasiTDSQL BoundlessGeneral ReferenceSQL ReferenceData DictionaryINFORMATION_SCHEMATDSTORE_TIERED_STORAGE_USAGE

TDSTORE_TIERED_STORAGE_USAGE

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Terakhir diperbarui: 2026-07-17 16:08:46

Function

TDSQL Boundless divides the data of cold tables into two storage tiers under the Tiered Storage feature:
cacheDB: the local cache tier, which hosts caches for recently written and hot data and resides on local node disks.
durableDB: the remote persistent tier, which hosts uploaded cold data and resides in COS.
The system view information_schema.TDSTORE_TIERED_STORAGE_USAGE is used to view the capacity usage of cold tables in cacheDB and durableDB. It displays the approximate data volume for each table/index/partition at the granularity of (TINDEX_ID, REPLICATION_GROUP_ID). Querying from any SQL node allows you to obtain the capacity distribution of cold tables across the entire cluster. This is commonly used for capacity planning, upload progress assessment, and resource optimization.
Note:
This view displays only the data of cold tables that have entered tiered storage. Hot tables (regular tables) are not within the scope of this view.

Field Description

Column Name
Data Type
Nullable or Not
Description
TINDEX_ID
BIGINT UNSIGNED
No
TDStore internal data object ID, which uniquely identifies a table, index, or partition.
REPLICATION_GROUP_ID
BIGINT UNSIGNED
No
ID of the RG where the data resides. A single object can be distributed across multiple RGs, with each RG displayed in a separate row.
TABLE_SCHEMA
VARCHAR(64)
Yes
Name of the database to which the data belongs (schema).
TABLE_NAME
VARCHAR(64)
Yes
Name of the primary table to which the data belongs. For a partition table, the primary table name is always displayed.
PARTITION_NAME
VARCHAR(64)
Yes
Partition name. For a non-partition table, this column is NULL.
INDEX_NAME
VARCHAR(64)
Yes
Index name. A primary key is uniformly displayed as PRIMARY.
INDEX_TYPE
VARCHAR(64)
Yes
Index type. Valid values: PRIMARY, UNIQUE, MULTIPLE, FULLTEXT, SPATIAL.
CACHE_DB_SIZE
BIGINT UNSIGNED
No
Approximate data size of the index/partition in cacheDB, in bytes.
DURABLE_DB_SIZE
BIGINT UNSIGNED
No
Approximate data size of the index/partition in durableDB, in bytes.
TOTAL_SIZE
BIGINT UNSIGNED
No
Total data size, which equals CACHE_DB_SIZE + DURABLE_DB_SIZE.

Relevant parameters

The data retrieval method for the view is controlled by the system variable tdstore_tiered_storage_usage_view_mode:
Parameter Name
Scope
Default Value
Value Range
Description
tdstore_tiered_storage_usage_view_mode
GLOBAL
1
0,1,2
Controls the data source mode for the view:
0: Disables the view feature and returns an error upon query.
1: Aggregates heartbeat data through the MC (Meta Cluster), with low I/O overhead. Recommended for use in production environments.
2: Initiates RPC queries to TDStore nodes in real time, providing more real-time data but with higher overhead.

Use Limits

Limit
Description
Data Range
Only displays cold table data that has entered tiered storage. Regular tables (hot tables) are not within the view's scope.
Permission Requirements
To query this view, you must have the permission to access information_schema.
Data Precision
All SIZE columns are approximate estimates based on metadata, primarily used for observing resource usage and are not suitable as a basis for precise billing.
The arithmetic relationship CACHE_DB_SIZE + DURABLE_DB_SIZE = TOTAL_SIZE always holds precisely.
DDL Concurrency
If a DROP TABLE or DROP INDEX operation is executed concurrently during a query, the deleted objects are skipped from the results, and the query does not fail.
Query Frequency
The view is a low-frequency Ops interface. It is recommended to query it on demand in scenarios such as capacity assessment and inspection, and it is not advisable to continuously poll it in high-frequency business paths.
Version Requirement
TDSQL Boundless version V21.6.3.0 or later.

Examples

View the view structure.
DESC information_schema.TDSTORE_TIERED_STORAGE_USAGE;
Returned results:
+----------------------+-----------------+------+-----+---------+-------+
| Field                | Type            | Null | Key | Default | Extra |
+----------------------+-----------------+------+-----+---------+-------+
| TINDEX_ID            | bigint unsigned | NO   |     | NULL    |       |
| REPLICATION_GROUP_ID | bigint unsigned | NO   |     | NULL    |       |
| TABLE_SCHEMA         | varchar(64)     | YES  |     | NULL    |       |
| TABLE_NAME           | varchar(64)     | YES  |     | NULL    |       |
| PARTITION_NAME       | varchar(64)     | YES  |     | NULL    |       |
| INDEX_NAME           | varchar(64)     | YES  |     | NULL    |       |
| INDEX_TYPE           | varchar(64)     | YES  |     | NULL    |       |
| CACHE_DB_SIZE        | bigint unsigned | NO   |     | NULL    |       |
| DURABLE_DB_SIZE      | bigint unsigned | NO   |     | NULL    |       |
| TOTAL_SIZE           | bigint unsigned | NO   |     | NULL    |       |
+----------------------+-----------------+------+-----+---------+-------+
Query the capacity distribution of non-partitioned cold tables (including secondary indexes).
SELECT TABLE_SCHEMA, TABLE_NAME, PARTITION_NAME, INDEX_NAME, INDEX_TYPE,
       CACHE_DB_SIZE, DURABLE_DB_SIZE, TOTAL_SIZE
FROM information_schema.TDSTORE_TIERED_STORAGE_USAGE
WHERE TABLE_SCHEMA = 'cold_db' AND TABLE_NAME = 't_cold_data'
ORDER BY INDEX_NAME;
Returned results:
+--------------+-------------+----------------+------------+------------+---------------+-----------------+------------+
| TABLE_SCHEMA | TABLE_NAME  | PARTITION_NAME | INDEX_NAME | INDEX_TYPE | CACHE_DB_SIZE | DURABLE_DB_SIZE | TOTAL_SIZE |
+--------------+-------------+----------------+------------+------------+---------------+-----------------+------------+
| cold_db      | t_cold_data | NULL           | idx_val    | MULTIPLE   |          1024 |            8192 |       9216 |
| cold_db      | t_cold_data | NULL           | PRIMARY    | PRIMARY    |          4096 |           32768 |      36864 |
+--------------+-------------+----------------+------------+------------+---------------+-----------------+------------+
Query the capacity distribution of partitioned cold tables.
SELECT TABLE_NAME, PARTITION_NAME, INDEX_NAME, INDEX_TYPE,
       CACHE_DB_SIZE, DURABLE_DB_SIZE, TOTAL_SIZE
FROM information_schema.TDSTORE_TIERED_STORAGE_USAGE
WHERE TABLE_SCHEMA = 'cold_db' AND TABLE_NAME = 't_cold_part'
ORDER BY PARTITION_NAME, INDEX_NAME;
Returned results (each partition of a partition table is displayed in a separate row):
+-------------+----------------+------------+------------+---------------+-----------------+------------+
| TABLE_NAME  | PARTITION_NAME | INDEX_NAME | INDEX_TYPE | CACHE_DB_SIZE | DURABLE_DB_SIZE | TOTAL_SIZE |
+-------------+----------------+------------+------------+---------------+-----------------+------------+
| t_cold_part | p0             | PRIMARY    | PRIMARY    |          2048 |           16384 |      18432 |
| t_cold_part | p1             | PRIMARY    | PRIMARY    |          2048 |           16384 |      18432 |
| t_cold_part | p2             | PRIMARY    | PRIMARY    |          2048 |           16384 |      18432 |
+-------------+----------------+------------+------------+---------------+-----------------+------------+
Summarize cold data capacity by table.
SELECT TABLE_SCHEMA,
       TABLE_NAME,
       SUM(CACHE_DB_SIZE)   AS CACHE_TOTAL,
       SUM(DURABLE_DB_SIZE) AS DURABLE_TOTAL,
       SUM(TOTAL_SIZE)      AS GRAND_TOTAL
FROM information_schema.TDSTORE_TIERED_STORAGE_USAGE
GROUP BY TABLE_SCHEMA, TABLE_NAME
ORDER BY GRAND_TOTAL DESC;
Identify indexes with an excessively high proportion in the local cache layer.
When the proportion of an index in cacheDB is significantly higher than that in durableDB, it indicates that a large amount of cold data has not been uploaded. You can investigate this by checking the progress of the upload task.
SELECT TABLE_SCHEMA, TABLE_NAME, PARTITION_NAME, INDEX_NAME,
       CACHE_DB_SIZE, DURABLE_DB_SIZE,
       ROUND(CACHE_DB_SIZE * 100.0 / NULLIF(TOTAL_SIZE, 0), 2) AS CACHE_PCT
FROM information_schema.TDSTORE_TIERED_STORAGE_USAGE
WHERE TOTAL_SIZE > 0
ORDER BY CACHE_PCT DESC
LIMIT 10;
Switch the view data source mode.
The default mode 1 aggregates data through MC with low I/O overhead. When more real-time data is required, you can temporarily switch to mode 2:
-- Switch to real-time RPC mode
SET GLOBAL tdstore_tiered_storage_usage_view_mode = 2;

-- Execute the query
SELECT * FROM information_schema.TDSTORE_TIERED_STORAGE_USAGE LIMIT 10;

-- Switch back to the default mode after the query is completed
SET GLOBAL tdstore_tiered_storage_usage_view_mode = 1;
Attention:
When tdstore_tiered_storage_usage_view_mode is set to 0, this view query will directly return an error. You must reset it to 1 or 2 for normal use.
Topik sebelumnya: TDSTORE_TIERING_COLD_RG_JOB_PROGRESSTopik selanjutnya: TDSTORE_TSO_STATUS

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