SHOW EXPERIMENTAL_RANGES

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 AT statement 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

Examples

The examples in this section operate on a hypothetical "user credit information" table filled with dummy 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

• SPLIT AT
• CREATE TABLE
• CREATE INDEX
• Indexes
• Follow-the-Workload
• Architecture Overview

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