This topic describes the release notes for the engine parameters of PolarDB for MySQL 5.6.
2025.01.16
Category | Parameter | Level | Description |
New | loose_innodb_buffer_pool_instances | Global | The number of buffer pool instances. Valid values: 1 to 64. Default value: 8. |
2024.09.26
Category | Parameter | Level | Description |
Modified | loose_innodb_purge_batch_size | Global | The default value of the parameter is changed to match the node specifications to improve CPU utilization. |
2024.08.22
Category | Parameter | Level | Description |
Modified | default_time_zone | Global/Session | The range of valid values for the
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2024.08.15
Category | Parameter | Level | Description |
New | loose_polar_support_mdl_sync_preemption | Global/Session | Specifies whether to enable preemptive DDL.
Note This parameter is supported only for PolarDB for MySQL 5.6 whose revision version is 5.6.1.0.43 or later. |
loose_polar_mdl_sync_preempt_after_wait_second | Global | The timeout period in which the metadata lock (MDL) synchronization must be completed. If the MDL is not synchronized when the specified timeout period ends, the system starts to preempt the MDL. Valid values: 1 to 31536000. Default value: 10. Unit: seconds. | |
Modified | default_time_zone | Global/Session | The range of valid values for the
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2024.06.24
Category | Parameter | Level | Description |
Modified | innodb_purge_threads | Global | The value of the parameter is automatically changed to match the number of CPU cores on the primary node of the cluster. For example, if the primary node has four CPU cores, the value of the parameter is 4. If the primary node has eight CPU cores, the value of the parameter is 8. Valid values: 4 to 32. |
innodb_purge_batch_size | Global | The default value of the parameter is changed to 1000. | |
loose_rds_audit_max_sql_size | Global | The maximum length of a single SQL statement in the audit logs is increased to 1,048,576 characters. |
2024.03.29
Category | Parameter | Level | Description |
New | init_connect | Global | The SQL statement that is automatically executed when a new connection is established. Valid values:
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2024.03.14
Category | Parameter | Level | Description |
New | innodb_undo_log_truncate | Global | Specifies whether to enable the undo log recycling feature. Valid values:
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2023.12.25
Category | Parameter | Level | Description |
Modified | loose_innodb_primary_flush_max_lsn_lag | Global/Session | The default value of the |
2023.12.18
Category | Parameter | Level | Description |
New | max_connections | Global/Session | The maximum number of connections to the database. Valid values: 1 to 200000. Default value: 2312. |
max_user_connections | Global/Session | The maximum number of connections for a single user. Valid values: 10 to 200000. Default value: 1800. |
2023.11.09
Category | Parameter | Level | Description |
New | loose_innodb_persist_replica_enable | Global | Specifies whether read-only nodes are available when the primary node fails. Valid values:
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2023.09.26
Category | Parameter | Level | Description |
New | loose_innodb_trx_resume | Global | Specifies whether to enable the transaction resumable upload feature. Valid values:
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loose_innodb_trx_resume_persist_undo_at_stmt | Global | Specifies whether to make the undo logs recorded for each SQL statement in the transaction persistent along with the SQL statement after the transaction resumable upload feature is enabled. Valid values:
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2023.08.31
Category | Parameter | Level | Description |
Modified | loose_max_statement_time | Global/Session | You can configure this parameter on a node. |
2023.08.09
Category | Parameter | Level | Description |
New | innodb_ft_server_stopword_table | Global/Session | The stop words of the full-text index. |
2023.06.28
Category | Parameter | Level | Description |
New | sort_buffer_size | Global/Session | The size of the buffer allocated for sorting operations within each session. Valid values: 32768 to 4294967295. Default value: 1024 KB. Unit: bytes. |
2023.06.26
Category | Parameter | Level | Description |
New | loose_rds_trx_idle_timeout | Global/Session | The timeout period for the server to wait for idle transactions. Valid values: 0 to 30758400. Default value: 0. Unit: seconds. |
loose_rds_strict_trx_idle_timeout | Global/Session | The timeout period for the server in the concurrent mode to wait for idle transactions. Valid values: 0 to 30758400. Default value: 0. Unit: seconds. | |
loose_rds_trx_readonly_idle_timeout | Global/Session | The timeout period for the server to wait for read-only idle transactions. Valid values: 0 to 30758400. Default value: 0. Unit: seconds. | |
loose_rds_trx_changes_idle_timeout | Global/Session | The timeout period for the server to wait for non-read-only idle transactions. Valid values: 0 to 30758400. Default value: 0. Unit: seconds. |
2023.05.22
Category | Parameter | Level | Description |
New | loose_imci_thread_pool_size | Global | The maximum number of threads that can be used in the thread pool for in-memory column indexes (IMCIs). Valid values: 1 to 2048. The default value is calculated based on the following formula: Value of DBNodeClassCPU × 3. |
lower_case_table_names | Global/Session | Specifies whether table names are case-sensitive. Valid values:
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2023.03.23
Category | Parameter | Level | Description |
New | loose_foreign_key_checks | Global/Session | Specifies whether to check foreign key constraints. Valid values:
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2022.10.28
Category | Parameter | Level | Description |
New | loose_low_limit_check_enabled | Global | Specifies whether to use the low limit optimization method. Valid values:
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loose_prefer_ordering_index | Global | Specifies whether to use the ordering index optimization method. Valid values:
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2022.10.24
Category | Parameter | Level | Description |
Modified | loose_innodb_logical_read_ahead_threads | Global | The default number of threads for logical prefetching. |