Overview

The Federated MariaDB Enterprise Spider topology can be used to migrate tables from one MariaDB Enterprise Server node to another MariaDB Enterprise Server node:

• The MariaDB Enterprise Server node with the source table is configured as a Data Node.

• The MariaDB Enterprise Server node with the destination table is configured as a Spider Node.

• The Data Table is the source table on the Data Node.

• A Spider Table is created on the Spider Node that references the Data Table on the Data Node.

• On the Spider node, the Data Table's data is migrated to the destination table by querying the Spider Table like the following:

Follow the steps below to migrate tables using the Federated MariaDB Enterprise Spider topology.

Deploy the Federated Topology

Before you can migrate tables, the Federated MariaDB Enterprise Spider topology must be deployed.

For additional information, see "".

Create Local Tables

A local copy of the table must be created. This new table will contain the migrated data.

• On the Spider Node*, create a local copy of each table that is being migrated:

Migrate the Tables

The table data can be migrated to the local table using the Spider Tables.

• On the Spider Node*, migrate the table data to the local copy of the table using the statement:

Test Read Operations

On the Spider Node, read from the local copy of the table using a statement to confirm that the data has been migrated:

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See Also

_{This page is: Copyright © 2025 MariaDB. All rights reserved.}

Overview

When using Spider in the Federated MariaDB Enterprise Spider topology, backup and restore operations can be performed using MariaDB Backup or MariaDB Dump. These operations must be performed on the Spider Node and the Data Node.

MariaDB Backup

MariaDB Backup can be used to perform backup operations on Spider deployments.

Backup Spider with MariaDB Backup

MariaDB Backup can be used to create a physical backup of a Federated MariaDB Enterprise Spider topology. MariaDB Backup must be used to backup the Spider Node and the Data Node. The Spider Node and Data Node must be locked to guarantee that the backups of the Spider Node and Data Node are consistent.

The backup of the Spider Node contains:

• Physical backup for Spider Tables

• Physical backup for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Physical backup for any other database objects on the Spider Node

The backup of the Data Node contains:

• Physical backup for Data Tables

• Physical backup for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Physical backup for any other database objects on the Data Node

The following procedure shows how to take a consistent backup of a Spider Node and a Data Node deployed in a Spider Federated MariaDB Enterprise Spider topology.

1. On the Spider Node and on the Data Node, create a user account to perform the backup using the and statements:

1. On the Data Node, grant the user account Spider uses to operate on the Data Node sufficient privileges to lock the Data Tables using the statement.

For example, on the hq_server Data Node:

1. On the Spider Node, acquire a read lock on Spider Tables using the statement:

Keep this session open during the rest of the procedure.

The read lock will propagate to the Data Tables on the Data Node. The read locks will prevent the Data Tables from changing during the backup, so the backups of the Spider Node and the Data Node are consistent.

1. On the Data Node, perform the backup using MariaDB Backup:

1. When the Data Node backup is complete, perform the backup on the Spider Node using MariaDB Backup:

1. When the Spider Node backup is complete, release the table locks in your original session using the statement:

1. On the Spider Node and the Data Node, prepare each of the backups using MariaDB Backup:

The Spider Node and the Data Node now have a complete backup of the data directory. Backups should be tested to confirm they are complete and consistent.

Restoring Spider with MariaDB Backup

MariaDB Backup can restore a Federated MariaDB Enterprise Spider topology from a backup taken with MariaDB Backup.

1. On the Spider Node and on the Data Node, stop the MariaDB Server process:

1. On the Spider Node and on the Data Node, empty the data directory:

1. On the Spider Node and on the Data Node, restore the backup for that server using MariaDB Backup:

1. On the Spider Node and on the Data Node, confirm that the restored files are owned by the user that owns the MariaDB Server process:

1. On the Spider Node and on the Data Node, start the MariaDB Server process:

1. On the Spider Node, query a Spider Table to test it:

MariaDB Dump

generates backup files containing the SQL statements necessary to recreate the database. is included with MariaDB Enterprise Server and can be used to backup databases in Spider deployments. The MariaDB Client can then be used to restore databases from a .

Backing Up Spider with MariaDB Dump

MariaDB Dump can be used to create a logical backup of a Federated MariaDB Enterprise Spider topology. MariaDB Dump must be used to backup the Spider Node and the Data Node. The Spider Node and Data Node must be locked to guarantee that the backups of the Spider Node and Data Node are consistent.

The backup of the Spider Node contains:

• Table definitions for Spider Tables

• Table definitions for all tables

• Table data for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Definitions for any other user accounts, privileges, views, and triggers on the Spider Node

The backup of the Data Node contains:

• Table definitions for Data Tables

• Table definitions for all tables

• Table data for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Definitions for any other user accounts, privileges, views, and triggers on the Data Node

The following procedure shows how to take a consistent backup of a Spider Node and a Data Node deployed in a Federated MariaDB Enterprise Spider topology.

1. On the Spider Node and on the Data Node, create a user account to perform the backup using the and statements:

1. On the Data Node, grant the user account Spider uses to operate on the Data Node sufficient privileges to lock the Data Tables using the GRANT statement.

For example, on the hq_server Data Node:

1. On the Spider Node, acquire a read lock on Spider Tables using the LOCK TABLES statement:

Keep this session open during the rest of the procedure.

The read lock will propagate to the Data Tables on the Data Node. The read locks will prevent the Data Tables from receiving any changes during the backup, which ensures the backups of the Spider Node and the Data Node are consistent.

1. On the Data Node, perform the backup using MariaDB Dump:

1. When the Data Node has been backed up, perform the backup on the Spider Node using MariaDB Dump:

1. When the Spider Node backup is complete, release the table locks in your original session using the UNLOCK TABLES statement:

The Spider Node and the Data Node now each have a mariadb_dump.sql backup file. This backup file contains the SQL statements needed to recreate the schema on the Spider Node and the schema and data on the Data Node. Backups should be tested to confirm they are complete and consistent.

Restoring Spider from MariaDB Dump

MariaDB Client can restore a Federated MariaDB Enterprise Spider topology from a backup taken with MariaDB Dump backup.

1. Stop all traffic to the Spider Node and the Data Node.

2. On the Spider Node, restore the backup for that server using MariaDB Client:

1. On the Data Node, restore the backup for that server using MariaDB Client:

On the Spider Node, query a Spider Table to test it:

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Overview

Choose an operation for the Sharded MariaDB Enterprise Spider topology:

Update Character Sets and Collations

The character set or collation for the Spider Table can be updated or modified using the statement.

On the Spider Node, alter the Spider Table's character set and collation:

If the new character set and collation are not compatible with the character set and collation used by the Data Table, you must also alter the character set and collation for the Data Table on the Data Node.

Update Connection Options

In a Federated MariaDB Enterprise Spider topology, the connection options for a Data Node can be updated using the statement.

• On the Spider Node*, alter the table's connection details:

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Overview

Choose an operation for the Sharded MariaDB Enterprise Spider topology:

Update Character Sets and Collations

The character set or collation for the Spider Table can be updated or modified using the statement.

On the Spider Node, alter the Spider Table's character set and collation:

If the new character set and collation are not compatible with the character set and collation used by the Data Table, you must also alter the character set and collation for the Data Table on the Data Node.

Update Connection Options

In a Sharded MariaDB Enterprise Spider topology, the connection options for a Data Node can be updated using the statement.

On the Spider Node, alter the partition's connection details:

Overview

In a Sharded MariaDB Enterprise Spider topology, new shards can be added using the following procedure.

Create Spider User

Each data node requires a user account that the Spider Node uses to connect.

On the Data Node hosting the new shard, create the Spider user account for the Spider Node using the statement:

Privileges are granted to the user account in a later step.

Test Spider User

On the Spider Node, confirm that the Spider user account can connect to the Data Node using :

Configure Connection Details

The Spider Node requires connection details for each Data Node.

On the Spider Node, create a server object to configure the connection details for the Data Node hosting the new shard using the statement:

The Data Node runs MariaDB Enterprise Server, so the FOREIGN DATA WRAPPER is set to mariadb.

Using a server object for connection details is optional. Alternatively, the connection details for the Data Node can be specified in the COMMENT table option of the statement when creating the Spider Table.

Create the Data Table

When queries read and write to a Spider Table, Spider reads and writes to the Data Tables for each partition on the Data Nodes. The Data Tables must be created on the Data Nodes with the same structure as the Spider Table.

If your Data Tables already exist, grant privileges on the tables to the Spider user.

On the Data Node hosting the new shard, create the Data Tables:

The Spider Node reads and writes to the Data Table using the server and user account configured previously. The user account must have privileges on the table.

Grant Privileges

The Spider Node connects to the Data Nodes with the user account configured previously.

On the Data Node hosting the new shard, grant the Spider user sufficient privileges to operate on the Data Table:

Privileges for Spider BKA Mode

By default, the Spider user also requires the privilege on the database containing the Data Table. The privilege is required, because Spider uses temporary tables to optimize read queries when Spider BKA Mode is 1.

Spider BKA Mode is configured using the following methods:

• The session value is configured by setting the system variable on the Spider Node. The default value is -1. When the session value is -1, the value for each Spider Table is used.

• The value for each Spider Table is configured by setting the option in the COMMENT table option. When the bka_mode option is not set, the implicit value is 1.

The default spider_bka_mode value is -1, and the implicit Spider Table value is 1, so the default is 1.

On the Data Node hosting the new shard, grant the Spider user the privilege on the database:

Alter the Spider Table

A partition for the new shard must be added to the Spider Table on the Spider Node.

On the Spider Node, alter the Spider Table to add the partition and reference the name of the Data Node hosting the new shard in the COMMENT partition option:

Test Read Operations

On the Spider Node, read from the Spider Table using a statement:

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Overview

This article describes how to use Spider ODBC to connect to Oracle. This can make it easier to migrate, by not requiring a wholesale cutover, but instead enabling a piecemeal approach.

The setup looks as shown in this figure:

Prerequisites

In MariaDB,

• The Spider storage engine must be installed.

• The Spider storage engine plugin must be installed in MariaDB Enterprise Server. This is described in the instructions below.

• An ODBC driver manager, unixODBC, must be installed.

In Oracle Database,

• The ODBC driver must be installed.

• The Oracle Basic Client must be installed. This is a prerequisite for installing the ODBC driver.

Instructions

Notes

• Spider ODBC to Oracle tables does not support INSERT SELECT statements, where the Spider table is the source of the data. (MENT-1588).

• If the version of MariaDB does not have the variable, you aren't able to use a few aggregate functions on their own. (MENT-1558).

• If you get the following error message: Error from ODBC 0 01004 [Oracle][ODBC]String data, right truncated., you need to set a larger value for the variable

See Also

• Blog post by Anders Karlsson, January 2024 - 13 minute read

_{This page is: Copyright © 2025 MariaDB. All rights reserved.}

Overview

When using Spider in the Sharded MariaDB Enterprise Spider topology, backup and restore operations can be performed using MariaDB Backup or MariaDB Dump. These operations must be performed on the Spider Node as well as on each Data Node.

MariaDB Backup

MariaDB Backup can be used to perform backup operations on Spider deployments.

Backup Spider with MariaDB Backup

can be used to create a physical backup of a Sharded MariaDB Enterprise Spider topology. MariaDB Backup must be used to backup the Spider Node and all Data Nodes. The Spider Node and Data Nodes must be locked to guarantee that the backups of the Spider Node and Data Nodes are consistent.

The backup of the Spider Node contains:

• Physical backup for Spider Tables

• Physical backup for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Physical backup for any other database objects on the Spider Node

The backups of the Data Nodes contain:

• Physical backup for Data Tables

• Physical backup for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Physical backup for any other database objects on the Data Node

The following procedure shows how to take a consistent backup of a Spider Node and Data Nodes deployed in a Sharded MariaDB Enterprise Spider topology.

1. On the Spider Node and on each Data Node, create a user account to perform the backup using the and statements.

For MariaDB Enterprise Server 10.5 and later:

1. On each Data Node, grant the user account Spider uses when operating on Data Nodes sufficient privileges to lock any Data Tables using the statement.

For example, on the hq_server Data Node:

On the eastern_server Data Node:

On the western_server Data Node:

1. On the Spider Node, acquire a read lock on Spider Tables using the LOCK TABLES statement:

Keep this session open during the rest of the procedure.

The read lock will propagate to the Data Tables on each Data Node as well. The read locks will prevent the Data Tables from changing during the backup, so the backups on the Spider Node and Data Nodes are consistent.

1. On each Data Node, perform the backup using .

With MariaDB Backup 10.5 and later, use the mariadb-backup command:

1. On the Spider Node, after backing up each Data Node, perform a backup with .

With MariaDB Backup 10.5 and later, use the mariadb-backup command:

1. On the Spider Node, after the backup is complete, in your original session, use the statement to release the table locks:

1. On the Spider Node and each of the Data Nodes, prepare each of the backups using MariaDB Backup.

With MariaDB Backup 10.5 and later, use the mariadb-backup command:

The Spider Node and Data Nodes now each have a complete backup of the data directory. Backups should be tested to confirm they are complete and consistent.

Restore Spider with MariaDB Backup

can restore a Sharded MariaDB Enterprise Spider topology from a backup taken with MariaDB Backup.

1. On the Spider Node and on each Data Node, stop the MariaDB Server process:

1. On the Spider Node and on each Data Node, empty the data directory:

1. On the Spider Node and on each Data Node, restore the backup for that server using MariaDB Backup.

With MariaDB Backup 10.5 and later, use the mariadb-backup command:

1. On the Spider Node and on each Data Node, confirm that the restored files are owned by the user that owns the MariaDB Server process:

1. On the Spider Node and on each Data Node, start the MariaDB Server process:

1. On the Spider Node, query a Spider Table to test it:

MariaDB Dump

generates backup files containing the SQL statements necessary to recreate the database. MariaDB Dump is included with MariaDB Server and can be used to backup databases in Spider deployments. The MariaDB Client can then be used to restore databases from a MariaDB Dump backup.

Backup Spider with MariaDB Dump

can be used to create a logical backup of a Sharded MariaDB Enterprise Spider topology. MariaDB Dump must be used to backup the Spider Node and all Data Nodes. The Spider Node and Data Nodes must be locked to guarantee that the backups of the Spider Node and Data Nodes are consistent.

The backup of the Spider Node contains:

• Table definitions for Spider Tables

• Table definitions for all tables

• Table data for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Definitions for any other user accounts, privileges, views, and triggers on the Spider Node

The backups of the Data Nodes contain:

• Table definitions for Data Tables

• Table definitions for all tables

• Table data for tables that use InnoDB, Aria, MyISAM, and MyRocks

• Definitions for any other user accounts, privileges, views, and triggers on the Data Node

The following procedure shows how to take a consistent backup of a Spider Node and Data Nodes deployed in a Sharded MariaDB Enterprise Spider topology.

1. On the Spider Node and on each Data Node, create a user account to perform the backup using the and statements:

1. On each Data Node, grant the user account Spider uses to operate on the Data Nodes sufficient privileges to lock any Data Tables using the GRANT statement.

For example, on the hq_server Data Node:

On the eastern_server Data Node:

On the western_server Data Node:

1. On the Spider Node, acquire a read lock on Spider Tables using the statement:

Keep this session open during the rest of the procedure.

The read lock will propagate to the Data Tables on each Data Node as well. The read locks will prevent the Data Tables from changing during the backup, so the backups of the Spider Node and Data Nodes are consistent.

1. On each Data Node, perform the backup using MariaDB Dump. With MariaDB Dump 10.5 and later, use the mariadb-dump command:

1. On the Spider Node, once the Data Nodes are backed up, perform a backup using MariaDB Dump.

With MariaDB Dump 10.5 and later, use the mariadb-dump command:

1. On the Spider Node, after the backups are complete, in your original session use the statement to release the table locks:

The Spider Node and the Data Node now each have a mariadb_dump.sql backup file. This backup file contains the SQL statements needed to recreate the schema on the Spider Node and the schema and data on the Data Nodes. Backups should be tested to confirm they are complete and consistent.

Restore Spider from MariaDB Dump

MariaDB Client can restore a Sharded MariaDB Enterprise Spider topology from a backup taken with backup.

1. Stop all traffic to the Spider Node and each Data Node.

2. On the Spider Node, restore the backup for that server using MariaDB Client.

With MariaDB Client 10.5 and later, use the mariadb command:

1. On the Data Node, restore the backup for that server using MariaDB Client.

With MariaDB Client 10.5 and later, use the mariadb command:

1. On the Spider Node, query a Spider Table to test it:

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