System Variable Differences Between MariaDB 10.2 and MySQL 5.7

The following is a comparison of variables that either appear only in MariaDB 10.2 or MySQL 5.7, or have different default settings in MariaDB 10.2, and MySQL 5.7. MariaDB 10.2.19 and MySQL 5.7.13, with only default plugins enabled, were used for the comparison.

The most notable differences are that MariaDB includes, by default, the Aria storage engine (resulting in extra memory allocation), Galera Cluster, and has a different thread pool implementation. For this reason, a default implementation of MariaDB 10.2 will use more memory than MySQL 5.7. MariaDB 10.2 and MySQL 5.7 also have different GTID implementations.

MariaDB's extra memory usage can be handled with the following rules of thumb:

• If you are not using MyISAM and don't plan to use Aria:

  • Set key_buffer_size to something very low (16K) as it's not used.

  • Set aria_pagecache_buffer_size to what you think you need for handling internal tmp tables that didn't fit in memory.

  • Normally this is what before you had set for key_buffer_size (at least 1M).

• If you are using MyISAM and not planning to use Aria:

  • Set aria_pagecache_buffer_size to what you think you need for handling internal tmp tables that didn't fit in memory.

• If you are planning to use Aria, you should set aria_pagecache_buffer_size to something that fits a big part of your normal data + overflow temporary tables.

Comparison Table

Variable	MariaDB 10.2	MySQL 5.7	Notes	Variable	MariaDB 10.2	MySQL 5.7	Notes
Variable	MariaDB 10.2	MySQL 5.7	Notes
aria_*	*	-	The Aria storage engine is only available in MariaDB.
avoid_temporal_upgrade	-	OFF	MySQL-only variable for determining whether ALTER TABLE implicitly upgrades temporal columns.
bind_address	-	127.0.0.1	MySQL has the value of the bind-address option as a variable.
binlog-annotate-row-events	ON	-	Introduced in MariaDB 5.3 for replicating between MariaDB 5.3 and MySQL/MariaDB 5.1.
binlog_commit_wait_count	0	-	For use in MariaDB's parallel replication.
binlog_commit_wait_usec	100000	-	For use in MariaDB's parallel replication.
binlog_error_action		ABORT_SERVER	MySQL-only variable for controlling what happens when the server cannot write to the binary log.
binlog_format	MIXED	ROW	MariaDB and MySQL have differing binary log formats.
binlog_group_commit_sync_delay		0	MySQL-only variable for controlling the wait time before synchronizing the binary log file to disk.
binlog_group_commit_sync_no_delay_count		0	MySQL-only variable for setting the maximum number of transactions to wait for before aborting the current binlog_group_commit_sync_delay delay.
binlog_gtid_simple_recovery	-	ON	MySQL-only GTID variable. MariaDB's GTID implementation is different.
binlog_max_flush_queue_time	-	0	MySQL-only variable specifying a timeout for reading transactions from the flush queue before continuing with group commit and syncing log to disk.
binlog_optimize_thread_scheduling	ON	-	For optimized kernel thread scheduling.
binlog_order_commits	-	ON	MySQL-only variable for determining whether transactions may be committed in parallel.
binlog_rows_query_log_events	-	OFF	MySQL-only variable for logging extra information in row-based logging.
block_encryption_mode	-	aes-128-ecb	MySQL-only variable for controlling the block encryption mode for block-based algorithms.
check_constraint_checks	ON	-	Permits disabling constraint checks, for example when loading a table that violates some constraints that you plan to fix later.
check_proxy_users		OFF	MySQL-only variable for controlling whether the server performs proxy user mapping for authentication plugins.
deadlock_search_depth_long	15	-	The Aria storage engine is only available in MariaDB.
deadlock_search_depth_short	4	-	The Aria storage engine is only available in MariaDB.
deadlock_timeout_long	50000000	-	The Aria storage engine is only available in MariaDB.
deadlock_timeout_short	10000	-	The Aria storage engine is only available in MariaDB.
debug_no_thread_alarm	OFF	-	Disable system thread alarm calls, for debugging or testing.
default_authentication_plugin		mysql_native_password	MySQL's default authentication plugin.
default_master_connection	empty	-	For use with MariaDB's multi-source replication.
default_password_lifetime		360	MySQL-only variable determining how long passwords are valid for before expiring.
default_regex_flags	empty	-	For handling incompatibilities between MariaDB's PCRE and the old regex library.
default_tmp_storage_engine	empty	InnoDB	Default storage engine used for tables created with CREATE TEMPORARY TABLE.
disabled_storage_engines		empty	MySQL-only variable for disabling specific storage engines.
disconnect_on_expired_password	-	ON	MySQL permits passwords to be expired.
encrypt_binlog	OFF	-	MariaDB enables table and tablespace encryption.
encrypt_tmp_files	OFF	-	MariaDB enables table and tablespace encryption.
encrypt_tmp_disk_tables	OFF	-	MariaDB enables table and tablespace encryption.
end_markers_in_json	-	OFF	MySQL-only variable for adding end markers to JSON output.
enforce_gtid_consistency	-	OFF	MariaDB and MySQL have different GTID implementations.
enforce_storage_engine	none		Forces the use of a particular storage engine for new tables.
eq_range_index_dive_limit	0	200	For tuning when the optimizer should switch from using index dives to index statistics for qualifying rows estimation.
expensive_subquery_limit	100	-	Used for determining expensive queries for optimization.
extra_max_connections	1	-	Introduced in the MariaDB 5.1 threadpool.
extra_port	0	-	Introduced in the MariaDB 5.1 threadpool.
group_concat_max_len	1048576	1024	MariaDB increases the maximum length for a GROUP_CONCAT() result from 1K to 1M.
gtid_binlog_pos	empty	-	MariaDB and MySQL have different GTID implementations.
gtid_binlog_state	empty	-	MariaDB and MySQL have different GTID implementations.
gtid_current_pos	empty	-	MariaDB and MySQL have different GTID implementations.
gtid_domain_id	0	-	MariaDB and MySQL have different GTID implementations.
gtid_executed	-	empty	MariaDB and MySQL have different GTID implementations.
gtid_executed_compression_period	-	1000	MariaDB and MySQL have different GTID implementations.
gtid_ignore_duplicates	OFF	-	MariaDB and MySQL have different GTID implementations.
gtid_mode	-	OFF	MariaDB and MySQL have different GTID implementations.
gtid_next	-	AUTOMATIC	MariaDB and MySQL have different GTID implementations.
gtid_owned	-	empty	MariaDB and MySQL have different GTID implementations.
gtid_purged	-	empty	MariaDB and MySQL have different GTID implementations.
gtid_seq_no	0	-	MariaDB and MySQL have different GTID implementations.
gtid_slave_pos	empty	-	MariaDB and MySQL have different GTID implementations.
gtid_strict_mode	OFF	-	MariaDB and MySQL have different GTID implementations.
have_openssl			MariaDB's version indicates whether YaSSL or openssl was used. MySQL's is a synonym for have_ssl.
have_statement_timeout	-		MySQL's statement execution timeout feature is available.
histogram_size	0	-	MariaDB introduced Histogram-based Statistics.
histogram_type	SINGLE_PREC_HB	-	MariaDB introduced Histogram-based Statistics.
in_transaction	0	-	Set to 1 if you are in a transaction, and 0 if not.
innodb_*	*	*	The list of differences between MariaDB 10.2 and MySQL 5.7 Innodb variables is currently incomplete.
innodb_log_optimize_ddl	ON	-	Whether redo logging should be reduced when natively creating indexes or rebuilding tables
innodb_safe_truncate	ON	-	Use a backup-safe TRUNCATE TABLE implementation and crash-safe rename operations inside InnoDB.
internal_tmp_disk_storage_engine	-	INNODB	MySQL uses this variable to set the storage engine for on-disk internal temporary tables. In MariaDB, the storage engine for on-disk internal temporary tables is not configurable at run-time. Instead, it is set at compile time, and the two options are Aria or MyISAM. If Aria is used, then the value of the aria_used_for_temp_tables system variable will be ON.
join_buffer_space_limit	2097152	-	Maximum size in bytes of the query buffer. See block-based join algorithms.
join_cache_level	2	-	For determining the join algorithms. See block-based join algorithms
key_buffer_size	134217728	8388608	Size of the buffer for the index blocks used by MyISAM tables and shared for all threads.
key_cache_file_hash_size	512	-	Number of hash buckets for open and changed files.
key_cache_segments	0	-	The number of segments in a key cache. See Segmented Key Cache.
last_gtid	-	empty	MariaDB and MySQL have different GTID implementations.
lock_wait_timeout	86400	31536000	MariaDB has reduced the timeout for acquiring metadata locks.
log_bin_compress	OFF	-	MariaDB setting for whether or not the binary log can be compressed.
log_bin_compress_min_len	256	-	Minimum length of sql statement (in statement mode) or record (in row mode) that can be compressed. See Compressing Events to Reduce Size of the Binary Log.
log_bin_use_v1_row_events	-	OFF	MySQL-only variable showing whether or not MySQL's version 2 binary logging format is being used.
log_builtin_as_identified_by_password	-	OFF	MySQL variable for use with binary logging of user-management statements,
log_error_verbosity	-	3	MySQL variable for setting verbosity of error, warning, and note messages in the error log.
log_slow_admin_statements	ON	OFF	MariaDB logs slow admin statements to the slow query log by default.
log_slow_filter	admin, filesort, filesort_on_disk, full_join, full_scan, query_cache, query_cache_miss, tmp_table, tmp_table_on_disk	-	For slow query log filtering.
log_slow_rate_limit	1	-	Limits the number of queries logged to the slow query log.
log_slow_slave_statements	ON	OFF	MariaDB logs slow slave statements to the slow query log by default.
log_slow_verbosity	empty	-	Controls information to be added to the slow query log. See also Slow Query Log Extended Statistics.
log_statements_unsafe_for_binlog	-	ON	MySQL setting for controlling whether binlog warnings are written to the error log.
log_syslog*	platform-dependent	-	MySQL variables with settings for writing to syslog.
log_tc_size	24576	-	Size in bytes of the transaction coordinator log, defined in multiples of 4096.
log_throttle_queries_not_using_indexes	-	0	MySQL-only variable for limiting the number of statements without indexes written to the slow query log.
log_timestamps	-	UTC	MySQL-only variable controlling the timezone for certain logging conditions.
master_info_repository	-	FILE	MySQL-only variable determining whether the slaves log info to file or table.
max_allowed_packet	16M	4M
max_execution_time	-	0	MySQL renamed the max_statement_time variable.
max_long_data_size	16777216	-	Maximum size for parameter values sent with mysql_stmt_send_long_data(). Removed in MySQL 5.6.
max_points_in_geometry	-	65536	Maximum points_per_circle for MySQL's ST_Buffer_Strategy() function.
max_session_mem_used	9223372036854775807	-	Amount of memory a single user session is allowed to allocate.
max_recursive_iterations	4294967295	-	Maximum number of iterations when executing recursive queries.
max_relay_log_size	1073741824	0	Can be set by session in MariaDB.
max_seeks_for_key	4294967295	4294967295 (32-bit) or 18446744073709547520 (64-bit)	The most key seeks required when searching with an index, regardless of the actual index cardinality. If this value is set lower than its default and maximum, indexes will tend to be preferred over table scans.
max_statement_time	0	-	Maximum time in seconds that a query can execute before being aborted. MySQL used to have a variable of this name before renaming it max_execution_time.
max_write_lock_count	4294967295	4294967295 (32-bit) or 18446744073709547520 (64-bit)	Read lock requests will be permitted for processing after this many write locks.
mrr_buffer_size	262144	-	Size of buffer to use when using multi-range read with range access. See Multi Range Read optimization.
myisam_block_size	1024	-	Block size used for MyISAM index pages.
myisam_recover_options	BACKUP,QUICK	OFF	MyISAM recovery mode.
myisam_sort_buffer_size	134216704	8388608	Size in bytes of the buffer allocated when creating or sorting indexes on a MyISAM table.
mysql56_temporal_format	ON		Causes MariaDB to use the MySQL-5.6 low level formats for TIME, DATETIME and TIMESTAMP instead of the MariaDB 5.3+ version.
mysql_native_password_proxy_users	-	OFF	Whether MySQL's authentication plugin supports proxy users. I
new	-	OFF	Used for backward-compatibility with MySQL 4.1, not present in MariaDB.
ngram_token_size	-	2	Sets the n-gram token size for MySQL's n-gram full-text parser.
offline_mode	-	OFF	MySQL settting for specifying whether the server should run in offline mode.
old_mode	Empty string	-	Used for getting MariaDB to emulate behavior from an old version of MySQL or MariaDB. See OLD Mode.
optimizer_selectivity_sampling_limit	100	-	Controls number of record samples to check condition selectivity.
optimizer_switch	See details		A series of flags for controlling the query optimizer. MariaDB has introduced a number of new settings.
optimizer_trace	-	Off by default	MySQL-only variable for optimizer tracing.
optimizer_trace_features	-	Off by default	MySQL-only variable for optimizer tracing.
optimizer_trace_limit	-	1	MySQL-only variable for optimizer tracing.
optimizer_trace_max_mem_size	-	16384	MySQL-only variable for optimizer tracing.
optimizer_trace_offset	-	-1	MySQL-only variable for optimizer tracing.
optimizer_use_condition_selectivity	1	-	Controls which statistics can be used by the optimizer when looking for the best query execution plan.
parser_max_mem_size	-	4294967295 (32-bit) or 18446744073709547520 (64-bit)	MySQL variable for limiting memory available to the parser.
performance_schema	OFF	ON	The Performance Schema is off by default in MariaDB.
performance_schema_*			Many performance schema variables are autoset in MySQL.
plugin_maturity	unknown	-	Minimum acceptable plugin maturity.
progress_report_time	5	-	Time in seconds between sending progress reports to the client for time-consuming statements.
query_alloc_block_size	16384	8192	Size in bytes of the extra blocks allocated during query parsing and execution (after query_prealloc_size is used up).
query_cache_strip_comments	OFF	-	Whether to strip any comments from the query before searching to see if it exists in the query cache.
query_prealloc_size	24576	8192	Size in bytes of the persistent buffer for query parsing and execution, allocated on connect and freed on disconnect.
range_optimizer_max_mem_size	-	1536000	MySQL-only variable setting a limit on the range optimizer's memory usage.
rbr_exec_mode	-	STRICT	MySQL-only variable for determining the handling of certain key errors.
read_binlog_speed_limit	0	-	Permits restricting the speed at which the slave reads the binlog from the master.
relay_log_info_repository	-	FILE	MySQL-only variable determining whether the slave's position in the relay logs is written to a file or table.
replicate_annotate_row_events	ON	-	Tells the slave to reproduce annotate_rows_events received from the master in its own binary log.
replicate_do_db	empty string	-	See Dynamic Replication Variables.
replicate_do_table	empty string	-	See Dynamic Replication Variables.
replicate_events_marked_for_skip	replicate	-	See Selectively skipping replication of binlog events.
replicate_ignore_db	empty string	-	See Dynamic Replication Variables.
replicate_ignore_table	empty string	-	See Dynamic Replication Variables.
replicate_wild_do_table	empty string	-	See Dynamic Replication Variables.
replicate_wild_ignore_table	empty string	-	See Dynamic Replication Variables.
require_secure_transport	-	OFF	MySQL-only variable determining whether client to server connections need to be secure.
rowid_merge_buff_size	8388608	-	See Non-semi-join subquery optimizations.
rpl_stop_slave_timeout	-	31536000	MySQL-only variable for controlling the time that STOP SLAVE waits before timing out.
server_id	1	0	0 is no longer valid in MariaDB.
server_id_bits	-	server_id	MySQL-only variable for use in MySQL Cluster.
server_uuid	-	UUID	MySQL-only variable containing the UUID.
session_track_gtids	-	OFF	MySQL-only variables for tracking gtid changes. MariaDB and MySQL's gtid implementation is different.
session_track_system_variables	Empty	*	MySQL's version tracks a number of system variable by default.
session_track_transaction_info	OFF	*	For tracking changes to the transaction attributes.
sha256_password_proxy_users	-	OFF	MySQL-only variable determining whether the sha256_password plugin supports proxy users.
show_compatibility_56	-	OFF	MySQL variable for indicating status of certain compatibility traits between MySQL 5.6 and MySQL 5.7.
show_old_temporals	-	OFF	MySQL-only variable for determining whether SHOW CREATE TABLE output should include comments for old format temporal columns.
skip_parallel_replication	OFF	-	See parallel replication.
skip_replication	OFF	-	See Selectively skipping replication of binlog events.
slave_allow_batching	-	OFF	MySQL-only replication variable.
slave_checkpoint_group	-	512	MySQL-only replication variable.
slave_checkpoint_period	-	300	MySQL-only replication variable.
slave_ddl_exec_mode	IDEMPOTENT	-	Modes for how replication of DDL events should be executed.
slave_domain_parallel_threads	0	-	For configuring parallel replication.
slave_net_timeout	3600	60	MySQL 5.7 has reduced the timeout to 60s.
slave_parallel_max_queued	131072	-	For configuring parallel replication.
slave_parallel_mode	conservative	-	Controls what transactions are applied in parallel when using parallel_replication.
slave_parallel_threads	0	-	For configuring parallel replication.
slave_parallel_type	-	DATABASE	MySQL-only replication variable.
slave_pending_jobs_size_max	-	16777216	MySQL-only replication variable.
slave_preserve_commit_order	-	OFF	MySQL-only replication variable.
slave_rows_search_algorithms	-	TABLE_SCAN, INDEX_SCAN	MySQL-only replication variable.
slave_run_triggers_for_rbr	NO		See Running triggers on the slave for Row-based events for a description and use-case for this setting.
sort_buffer_size	2097152	262144	The default sort buffer allocated has been reduced in MySQL.
sql_mode	STRICT_TRANS_TABLES, ERROR_FOR_DIVISION_BY_ZERO, NO_AUTO_CREATE_USER, NO_ENGINE_SUBSTITUTION	ONLY_FULL_GROUP_BY, STRICT_TRANS_TABLES, NO_ZERO_IN_DATE, NO_ZERO_DATE, ERROR_FOR_DIVISION_BY_ZERO, NO_AUTO_CREATE_USER, NO_ENGINE_SUBSTITUTION	See SQL Mode.
standard_compliant_cte	ON	-	See Common Table Expressions.
storage_engine	InnoDB	-	Alias for default_storage_engine, removed in MySQL.
strict_password_validation	ON	-	In MariaDB, when password validation plugins are enabled, reject passwords that cannot be validated (passwords specified as a hash).
super_read_only	-	OFF	MySQL variable for prohibiting client updates from users with the SUPER privilege.
sync_binlog	0	1	MySQL 5.7 synchronizes all actions to the binary log before they are committed.
table_definition_cache	400	-1 (autosized)	Number of table definitions that can be cached.
table_open_cache_instances	8	16	Maximum number of table cache instances.
thread_cache_size	Autosized	-1 (autosized)	MariaDB uses an improved thread pool.
thread_concurrency	10	-	Removed in MySQL 5.7.
thread_pool_idle_timeout	60	-	See Using the Thread Pool.
thread_pool_max_threads	65536	-	See Using the Thread Pool.
thread_pool_min_threads	1	-	Windows-only. See Using the Thread Pool.
thread_pool_oversubscribe	3	-	See Using the Thread Pool.
thread_pool_prio_kickup	auto	-	See Using the Thread Pool.
thread_pool_priority	auto	-	See Using the Thread Pool.
thread_pool_size	Number of processors	16*	See Using the Thread Pool. *Only available in MySQL with a commercial plugin.
thread_pool_stall_limit	500	6*	See Using the Thread Pool. *Only available in MySQL with a commercial plugin.
thread_stack	299008	196608 or 262144	See Using the Thread Pool.
timed_mutexes	OFF	-	Removed in MySQL 5.7.
tls_version	-	Varies	MySQL-only variable showing the permitted tls protocols.
tmp_disk_table_size	18446744073709551615	-	Max size for data for an internal temporary on-disk MyISAM or Aria table.
tmp_memory_table_size	16777216	-	Alias for tmp_table_size.
transaction_allow_batching	-	OFF	MySQL-only variable for enabling batching of statements within the same transaction in MySQL Cluster.
transaction_write_set_extraction	-	OFF	Unused MySQL-only variable.
use_stat_tables	NEVER	-	Controls the use of engine-independent table statistics.
userstat	OFF	-	Whether to activate MariaDB's User Statistics implementation, not available in MySQL.
version_malloc_library	*	-	Version of the used malloc library.
version_ssl_library	*	-	Version of the used TLS library.
wsrep_*	*	-	Galera cluster is only available in MariaDB.
Variable	MariaDB 10.2	MySQL 5.7	Notes

See Also

• System Variable Differences Between MariaDB 10.3 and MySQL 5.7

• System Variable Differences Between MariaDB 10.2 and MySQL 5.6

• System Variable Differences Between MariaDB 10.1 and MySQL 5.7