Each index record contains a 6-byte header. The header is used to link together consecutive records, and for row-level locking. Records in the clustered index contain fields for all user-defined columns. In addition, there is a 6-byte transaction ID field and a 7-byte roll pointer field....
Each index record contains a 6-byte header. The header is used to link together consecutive records, and for row-level locking. Records in the clustered index contain fields for all user-defined columns. In addition, there is a 6-byte transaction ID field and a 7-byte roll pointer field....
Each index record contains a five-byte header that may be preceded by a variable-length header. The header is used to link together consecutive records, and also in row-level locking. 每个索引记录包含一个五字节的头,在它之前还有一个变长的头。这个头是用来连接连续的记录,也用于行级锁。 The r...
InnoDB给 MySQL 提供了具有事务(commit)、回滚(rollback)和崩溃修复能力(crash recovery capabilities)的事务安全(transaction-safe (ACID compliant))型表。InnoDB 提供了行锁(locking on row level),提供与 Oracle 类型一致的不加锁读取(non-locking read in SELECTs)。这些特性均提高了多用户并发操作的性能表现。...
Comment: Supports transactions, row-level locking, and foreign keys Transactions: YES XA: YES Savepoints: YES *** 5. row *** Engine: CSV Support: YES Comment: CSV storage engine Transactions: NO XA: NO Savepoints: NO 5 rows in set (0.00 sec) 或者...
• Each index record contains a 6-byte header. The header is used to link together consecutive【kənˈsekjətɪv 连续的;连续不断的】 records, and for row-level locking. • Records in the clustered index contain fields for all user-defined columns. In addition, there is a 6-...
Table Row Locking Posted by:Andrew Germishuys Date: January 11, 2012 03:27PM Good day all I am currently working on a website project. This is developed in PHP, and using MySQL. Wanted to check a few points. I've read up on several possibilities, but wanted to also check other's ...
mysql-batch Updating or deleting a large amount of rows in MySQL will create locks that will paralyze other queries running in parallel. This tool will run UPDATE and DELETE queries in small batches to prevent table-level and row-level locking (with InnoDB). If a large number of rows has ...
One such place, thankfully caught in testing, is mysql.innodb_ddl_log table which tracks "a todo list of cleanup steps needed if DDL operation fails". This table *is* undo logged. Thus we do run purge for it. However, modifications to this table are done using BTR_NO_LOCKING_FLAG ...
NoteIn MySQL 5.7, when READ COMMITTED isolation level is used, or the deprecated innodb_locks_unsafe_for_binlog system variable is enabled, there is no InnoDB gap locking except for foreign-key constraint checking and duplicate-key checking. Also, record locks for nonmatching ...