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Warning:
As of April 30, 2020, CockroachDB v2.1 is no longer supported. For more details, refer to the Release Support Policy.
The SHOW EXPERIMENTAL_RANGES statement shows information about the ranges that make up a specific table's data, including:
- The start and end keys for the range(s)
- The range ID(s)
- Which nodes contain the range replicas
- Which node contains the range that is the leaseholder
This information is useful for verifying that:
- The "follow-the-workload" feature is operating as expected.
- Range splits specified by the
SPLIT ATstatement were created as expected.
Warning:
This is an experimental feature. The interface and output are subject to change.
Synopsis
Required privileges
The user must have the SELECT privilege on the target table.
Parameters
| Parameter | Description |
|---|---|
table_name |
The name of the table you want range information about. |
table_name_with_index |
The name of the index you want range information about. |
Examples
The examples in this section operate on a hypothetical "user credit information" table filled with placeholder data, running on a 5-node cluster.
> CREATE TABLE credit_users (
id INT PRIMARY KEY,
area_code INTEGER NOT NULL,
name STRING UNIQUE NOT NULL,
address STRING NOT NULL,
zip_code INTEGER NOT NULL,
credit_score INTEGER NOT NULL
);
We added a secondary index to the table on the area_code column:
> CREATE INDEX areaCode on credit_users(area_code);
Next, we ran a couple of SPLIT ATs on the table and the index:
> ALTER TABLE credit_users SPLIT AT VALUES (5), (10), (15);
> ALTER INDEX credit_users@areaCode SPLIT AT VALUES (400), (600), (999);
Note:
In the example output below, a NULL in the Start Key column means "beginning of table".
A NULL in the End Key column means "end of table".
Show ranges for a table (primary index)
> SHOW EXPERIMENTAL_RANGES FROM TABLE credit_users;
+-----------+---------+----------+----------+--------------+
| start_key | end_key | range_id | replicas | lease_holder |
+-----------+---------+----------+----------+--------------+
| NULL | /5 | 158 | {2,3,5} | 5 |
| /5 | /10 | 159 | {3,4,5} | 5 |
| /10 | /15 | 160 | {2,4,5} | 5 |
| /15 | NULL | 161 | {2,3,5} | 5 |
+-----------+---------+----------+----------+--------------+
(4 rows)
Show ranges for an index
> SHOW EXPERIMENTAL_RANGES FROM INDEX credit_users@areaCode;
+-----------+---------+----------+-----------+--------------+
| start_key | end_key | range_id | replicas | lease_holder |
+-----------+---------+----------+-----------+--------------+
| NULL | /400 | 135 | {2,4,5} | 2 |
| /400 | /600 | 136 | {2,4,5} | 4 |
| /600 | /999 | 137 | {1,3,4,5} | 3 |
| /999 | NULL | 72 | {2,3,4,5} | 4 |
+-----------+---------+----------+-----------+--------------+
(4 rows)
See also
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