Large result sets can impact performance, but using pagination or LIMIT clauses helps optimize data retrieval. Insufficient CPU, memory, or disk I/O resources further degrade performance, causing slow queries. Locking and contention issues arise from concurrent data access, creating bottlenecks. Additio...
OPTIMIZE TABLE,以及账户管理语句 阻止:对InnoDB重做日志中没有记录的修改InnoDB文件的操作。 阻止:发出 BINARY LOGS命令 允许:只影响用户创建的临时表的DDL操作实际上,当持有备份锁时,属于用户的临时表的文件可以被创建、重命名或。 允许:创建binary log二进制日志文件。 UNLOCK INSTANCE释放当前会话持有备份...
一般来说,可以查看数据库运行峰值时间的状态值Open_tables和Opened_tables,用以判断是否需要增加table_cache的值,即如果Open_tables接近table_cache的时候,并且Opened_tables这个值在逐步增加,那就要考虑增加这个值的大小了。 external-locking = FALSE#MySQL选项可以避免外部锁定。True为开启。 max_allowed_packet =16M#...
How many deleted blocks still have reserved space. You can optimize your table to minimize this space. SeeSection 9.6.4, “MyISAM Table Optimization”. Datafile parts For dynamic-row format, this indicates how many data blocks there are. For an optimized table without fragmented rows, this is...
13.7.2.4 OPTIMIZE TABLE Statement OPTIMIZE[NO_WRITE_TO_BINLOG|LOCAL]TABLEtbl_name[,tbl_name]... OPTIMIZE TABLEreorganizes the physical storage of table data and associated index data, to reduce storage space and improve I/O efficiency when accessing the table. The exact changes made to each ...
Is there a way I get optimize to work on parent tables? 0 jago 12 years ago Addition to the above entry: I guess I should have said……….. Is there a way I can get optimize to work on a parent table *without* having to drop the FK constraints in all child tables and then...
Fixed an issue where in special cases certain slave errors are not ignored even withslave_skip_errorsenabled. In cases when opening and locking a table failed or when field conversions failed on a server running row-based replication, the error is considered critical and the state ofslave_skip...
table_open_cache = 2048 # Enable external file level locking. Enabled file locking will have a # negative impact on performance, so only use it in case you have # multiple database instances running on the same files (note some # restrictions still apply!) or if you use other software ...
Galera cluster has known limitations, one of them is that it uses cluster-wide optimistic locking. This may cause some transactions to rollback. With an increasing number of writeable masters, the transaction rollback rate may increase, especially if there is write contention on the same dataset...
So if you do this often, it is very important to perform an OPTIMIZE TABLE sometimes. See Section 4.5.1. Speed of DELETE Queries If you want to delete all rows in the table, you should use TRUNCATE TABLE table_name. See Section 6.4.7. The time to delete a record is exactly ...