Step 3: Test Spider Sharded Topology

Overview

This page details step 3 of the 3-step procedure "Deploy Spider Sharded Topology".

This step tests MariaDB Enterprise Spider.

Interactive commands are detailed. Alternatively, the described operations can be performed using automation.

Test Enterprise Server Service

Use Systemd to test whether the MariaDB Enterprise Server service is running.

This action is performed on the Spider Node each Data Node.

Check if the MariaDB Enterprise Server service is running by executing the following:

$ systemctl status mariadb

If the service is not running on any node, start the service by executing the following on that node:

$ sudo systemctl start mariadb

Test Local Client Connections

Use MariaDB Client to test the local connection to the Enterprise Server node.

This action is performed on the Spider Node each Data Node:

$ sudo mariadb

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 38
Server version: 10.4.34-24-MariaDB-Enterprise MariaDB Enterprise Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

The sudo command is used here to connect to the Enterprise Server node using the root@localhost user account, which authenticates using the unix_socket authentication plugin. Other user accounts can be used by specifying the --user and --password command-line options.

Test Data Node Client Connections

Use MariaDB Client to test a client connection to each Data Node from the Spider Node using the Spider user.

This action is performed on the Spider Node:

$ mariadb \
   --host 192.0.2.2 \
   --user spider_user \
   --password

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 38
Server version: 10.4.34-24-MariaDB-Enterprise MariaDB Enterprise Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

The host and port of a Data Node can be provided using the --host and --port command-line options. The credentials for the Spider user can be provided using the --user and --password command-line options.

If the Spider user is unable to connect to a Data Node from the Spider Node, check the password for the Spider user account on the Data Node.

For additional information, see "Create Spider User".

Test Spider Storage Engine Plugin

Query the information_schema.PLUGINS table to confirm that the Enterprise Spider storage engine is loaded.

This action is performed on the Spider Node.

Execute the following query:

SELECT PLUGIN_NAME, PLUGIN_STATUS
FROM information_schema.PLUGINS
WHERE PLUGIN_LIBRARY LIKE 'ha_spider%';

+--------------------------+---------------+
| PLUGIN_NAME              | PLUGIN_STATUS |
+--------------------------+---------------+
| SPIDER                   | ACTIVE        |
| SPIDER_ALLOC_MEM         | ACTIVE        |
| SPIDER_WRAPPER_PROTOCOLS | ACTIVE        |
+--------------------------+---------------+

The PLUGIN_STATUS column for each Spider-related plugin should contain ACTIVE.

For additional information, see "Load the Spider Plugin".

Test Write Operations

Write to the Spider Table using an INSERT statement to test write operations.

This action is performed on the Spider Node.

Execute the following query:

INSERT INTO spider_sharded_sales.invoices
   (branch_id, invoice_id, customer_id, invoice_date, invoice_total, payment_method)
VALUES (1, 4, 1, '2021-03-10 12:45:10', 3045.73, 'CREDIT_CARD');

Test Read Operations

Read from the Spider Table using a SELECT statement to test read operations.

This action is performed on the Spider Node.

Execute the following query:

SELECT * FROM spider_sharded_sales.invoices;

+-----------+------------+-------------+----------------------------+---------------+----------------+
| branch_id | invoice_id | customer_id | invoice_date               | invoice_total | payment_method |
+-----------+------------+-------------+----------------------------+---------------+----------------+
|         1 |          1 |           1 | 2020-05-10 12:35:10.000000 |       1087.23 | CREDIT_CARD    |
|         1 |          2 |           2 | 2020-05-10 14:17:32.000000 |       1508.57 | WIRE_TRANSFER  |
|         1 |          3 |           3 | 2020-05-10 14:25:16.000000 |        227.15 | CASH           |
|         1 |          4 |           1 | 2021-03-10 12:45:10.000000 |       3045.73 | CREDIT_CARD    |
|         2 |          1 |           2 | 2020-05-10 12:31:00.000000 |       1351.04 | CREDIT_CARD    |
|         2 |          2 |           2 | 2020-05-10 12:45:27.000000 |        162.11 | WIRE_TRANSFER  |
|         2 |          3 |           4 | 2020-05-10 13:11:23.000000 |        350.00 | CASH           |
|         3 |          1 |           5 | 2020-05-10 12:31:00.000000 |        111.50 | CREDIT_CARD    |
|         3 |          2 |           8 | 2020-05-10 12:45:27.000000 |       1509.23 | WIRE_TRANSFER  |
|         3 |          3 |           3 | 2020-05-10 13:11:23.000000 |       3301.66 | CASH           |
+-----------+------------+-------------+----------------------------+---------------+----------------+

Test Sharding

Use the EXPLAIN PARTITIONS statement with a SELECT statement to determine which shards Spider will read for the query.

This action is performed on the Spider Node.

Execute the following query:

EXPLAIN PARTITIONS
SELECT * FROM spider_sharded_sales.invoices
WHERE customer_id = 4;

+------+-------------+----------+--------------------------------------------------+------+---------------+------+---------+------+------+-----------------------------------+
| id   | select_type | table    | partitions                                       | type | possible_keys | key  | key_len | ref  | rows | Extra                             |
+------+-------------+----------+--------------------------------------------------+------+---------------+------+---------+------+------+-----------------------------------+
|    1 | SIMPLE      | invoices | hq_partition,eastern_partition,western_partition | ALL  | NULL          | NULL | NULL    | NULL | 9    | Using where with pushed condition |
+------+-------------+----------+--------------------------------------------------+------+---------------+------+---------+------+------+-----------------------------------+

The specific shards read by the query are listed in the partitions column. If partition pruning does not eliminate unnecessary shards for a query with a restrictive filter, then check the partition definitions.

Next Step

Navigation in the procedure "Deploy Spider Sharded Topology":

  • This page was step 3 of 3.

  • This procedure is complete.