mysql 默認設置

甲骨文MySQL部門副總裁 Tomas Ulin在MySQL Connect 2012大會上稱，甲骨文已經對MySQL Server 5.6中的默認設置進行了更改，主要如下： 

設置	舊值	新值
back_log	50	50 + ( max_connections / 5 ) 上限爲900
binlog_checksum	NONE	CRC32
binlog-row-event-max-size	1k	8k
flush_time	1800	Windows平臺從1800改爲0
host_cache_size	128	128 + 1 for each of the first 500 max_connections + 1 for every 20 max_connections over 500, capped at 2000
innodb_autoextend_increment	8	64
innodb_buffer_pool_instances	0	8。在32位Windows中，如果innodb_buffer_pool_size大於1300M，默認值爲innodb_buffer_pool_size / 128M
innodb_concurrency_tickets	500	5000
innodb_file_per_table	0	1
innodb_log_file_size	5M	48M
innodb_old_blocks_time	0	1000
innodb_open_files	300	300。如果innodb_file_per_table爲ON，則爲更高的table_open_cache值或300
innodb_purge_batch_size	20	300
innodb_purge_threads	0	1
innodb_stats_on_metadata	on	off
join_buffer_size	128k	256k
max_allowed_packet	1M	4M
max_connect_errors	10	100
open_files_limit	0	5000
query_cache_size	0	1M
query_cache_type	ON/1	OFF/0
sort_buffer_size	2M	256k
sql_mode	none	NO_ENGINE_SUBSTITUTION
sync_master_info	0	10000
sync_relay_log	0	10000
sync_relay_log_info	0	10000
table_definition_cache	400	400 + table_open_cache / 2, capped at 2000
table_open_cache	400	2000
thread_cache_size	0	8 + max_connections/100, capped at 100