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MySQL sync settings

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MySQL sync settings affect the performance of the database cluster. When creating a MySQL sync database cluster, the values for all settings are set automatically. The values are selected to ensure high cluster performance and vary depending on the cluster configuration and MySQL sync version.

If the automatic values are not suitable for your tasks, set your own values when creating the cluster or change the settings in an already created cluster.

For your information

We recommend that you change the settings only when necessary — incorrect values can reduce cluster performance. When scaling the cluster, some settings are automatically replaced with valid values.

View list of settings

Look for a detailed description of the settings in the official MySQL documentation.

You can view a list of settings available for modification when creating a cluster or changing settings.

If you have changed settings, you can see a list of all changes.

  1. In the Dashboard, on the top menu, click Products and select Cloud Databases.
  2. Open the Active tab.
  3. Open the cluster page → Settings tab.
  4. The DBMS Settings block displays the previously changed settings — name and value.

Change settings

For your information

Changing some parameters in the settings causes the databases in the cluster to reboot — the cluster may be unavailable during this time. These settings depend on the MySQL sync version — see their list.

  1. In the Dashboard, on the top menu, click Products and select Cloud Databases.
  2. Open the Active tab.
  3. Open the cluster page → Settings tab.
  4. In the DBMS Settings block, click Change and specify the new values.
  5. Click Save.

List of settings that require a reboot

  • innodb_adaptive_hash_index_parts;
  • innodb_autoinc_lock_mode;
  • innodb_buffer_pool_instances;
  • innodb_buffer_pool_pool_load_at_startup;
  • innodb_commit_concurrency;
  • innodb_flush_method;
  • innodb_ft_cache_size;
  • innodb_ft_max_token_size;
  • innodb_ft_min_token_size;
  • innodb_ft_total_cache_size;
  • innodb_ft_sort_pll_degree;
  • innodb_log_buffer_size (except MySQL sync 8);
  • innodb_log_file_size;
  • innodb_page_cleaners;
  • innodb_purge_threads;
  • innodb_read_io_threads;
  • innodb_rollback_on_timeout;
  • innodb_sort_buffer_size;
  • innodb_sync_array_size;
  • innodb_write_io_threads;
  • max_digest_length;
  • table_open_cache_instances;
  • thread_pool_size;
  • thread_stack.

Settings when scaling a cluster

Any DBMS parameter has limits of acceptable values. When scaling the cluster (changing the configuration), the values of some settings are automatically changed to the allowable values so that the cluster can work.

When the cluster is scaled and moves to ACTIVE status, you can set new values — change the settings.

A list of settings that change values when the cluster is scaled:

innodb_buffer_pool_size, innodb_log_file_size, innodb_buffer_pool_instances, thread_pool_size, max_heap_table_size, tmp_table_size, temptable_max_ram

CHARSET and COLLATION

MySQL sync uses utf8mb4 as the encoding (CHARSET).

The sorting algorithm (COLLATION) is used as a sorting algorithm:

  • in MySQL sync — utf8mb4_general_ci
  • in MySQL sync — utf8mb4_0900_ai_ci

You can change the CHARSET and COLLATION values when creating objects.