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Parameter Template and Instance Purchase Process Optimization

Last updated: 2022-11-07 17:53:31

    Starting from December 8, 2021, TencentDB for MySQL has optimized parameter-related features and instance delivery process, including creating and applying parameter templates, comparing parameters, modifying modifiable parameters, and purchasing instances.


    Parameter capabilities are applicable only to two-node and three-node TencentDB for MySQL 5.6, 5.7, and 8.0.

    Instance Purchase Process Optimization

    As compared with the original instance purchase process, the initialization step is canceled, and you can select the character set, configure the table name case sensitivity, and enter the databases access port and root password on the instance purchase page.

    For more information, see Creating MySQL Instance.

    Parameter Optimization

    Parameter application

    Certain parameters can be defined in a formula to change along with the specification, ensuring that the database always runs with the optimal configuration.
    Expression syntax is supported as follows:

    Supported Type Description Sample
  • DBinitMemory: Memory size of instance specification, which is an integer. For example, if the memory size of the instance specification is 4,000 MB, the value of DBinitMemory will be 4000.
  • DBInitCpu: Number of CPU cores of instance specification, which is an integer. Note that the value of the innodb_buffer_pool_size parameter in TencentDB for MySQL must be between 50% and 90% of the memory size. If the configured value is above 90% or below 50%, it will be automatically configured to 90% or 50% respectively.
  • {DBinitMemory * 786432}: DBinitMemory * percentage (75% by default) * 1024 * 1024 (unit conversion).
    Operator Formula syntax: It should be enclosed in braces ({}).
  • Division operator (/): It divides the dividend by the divisor and returns an integer quotient. If the calculation result is a decimal number, only the integer part will be retained. Decimal numbers are not supported; for example, {MIN(DBInitMemory/4+500,1000000)} instead of {MIN(DBInitMemory\*0.25+500,1000000)} is supported.
  • Multiplication operator (*): It multiplies two numbers and returns an integer product. If the calculation result is a decimal number, only the integer part will be retained. Decimal number calculation is not supported.
  • -
  • MAX(): It returns the greatest value in an integer or parameter formula list.
  • MIN(): It returns the smallest value in an integer or parameter formula list.
  • {MAX(DBInitCpu/2,4)}

    For detailed parameter settings, see Setting Instance Parameters.

    Parameter template creation

    For parameter template creation, the original one parameter template type is changed to two types (high-performance template and high-stability template), and the referenced template type option is added.

    Comparison of parameters between template types:

    Changed Parameter Default Template High-Performance Template High-Stability Template
    innodb_read_io_threads 12 {MAX(DBInitCpu/2,4)} {MAX(DBInitCpu/2,4)}
    innodb_write_io_threads 12 {MAX(DBInitCpu/2,4)} {MAX(DBInitCpu/2,4)}
    max_connections 800 {MIN(DBInitMemory/4+500,100000)} {MIN(DBInitMemory/4+500,100000)}
    table_definition_cache 768 {MAX(DBInitMemory*512/1000,2048)} {MAX(DBInitMemory*512/1000,2048)}
    table_open_cache 2000 {MAX(DBInitMemory*512/1000,2048)} {MAX(DBInitMemory*512/1000,2048)}
    table_open_cache_instances 16 {MIN(DBInitMemory/1000,16)} {MIN(DBInitMemory/1000,16)}
    innodb_disable_sort_file_cache OFF OFF ON
    innodb_log_compressed_pages ON OFF ON
    innodb_print_all_deadlocks OFF OFF ON
    sync_binlog 0 1000 1
    thread_handling one-thread-per-connection pool-of-threads one-thread-per-connection
    innodb_flush_redo_using_fdatasync FALSE TRUE FALSE
    innodb_fast_ahi_cleanup_for_drop_table FALSE TRUE FALSE
    innodb_adaptive_hash_index FALSE TRUE FALSE
    innodb_table_drop_mode SYNC_DROP ASYNC_DROP SYNC_DROP
    innodb_flush_log_at_trx_commit 2 2 1

    For more information on template parameters, see Managing Parameter Template.

    New modifiable parameters

    Parameter TencentDB for MySQL 5.6 TencentDB for MySQL 5.7 TencentDB for MySQL 8.0
    character_set_client - -
    default_password_lifetime -
    innodb_alter_table_default_algorithm - -
    innodb_async_truncate_size -
    innodb_async_truncate_work_enabled - -
    innodb_default_row_format -
    innodb_fast_ahi_cleanup_for_drop_table - -
    innodb_flush_redo_using_fdatasync -
    innodb_page_cleaners -
    innodb_table_drop_mode - -
    innodb_temp_tablespace_fast_cleanup - -
    internal_tmp_mem_storage_engine - -
    slave_net_timeout -
    slave_parallel_type - -
    sort_buffer_size - -
    temptable_use_mmap - -
    thread_handling_switch_mode - -
    thread_pool_size -
    tx_isolation -

    Performance test on template types

    The test results are as shown below:

    For detailed performance test data, see Performance Comparison of Parameter Templates.

    Retaining the default parameter template

    After the new parameter system is released, the original default parameter template will be replaced by the high-performance and high-stability parameter templates. Before then, you still can retain the default parameter template settings by creating a parameter template. For more information, see Managing Parameter Template.

    Parameter comparison

    The parameter comparison feature allows you to compare the parameters of different templates.

    Click Compare on the parameter template page and select the templates to be compared in the pop-up window. Only templates for databases on the same version can be compared.

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