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https://dev.mysql.com/doc/refman/8.4/en/group-replication-configuring-consistency-guarantees.html
A transaction cannot be on-hold forever, and if the time held exceeds wait_timeout it returns an ER_GR_HOLD_WAIT_TIMEOUT error. Transactions whose consistency level is not EVENTUAL hold execution until a timeout, configured by wait_timeout value is ... Although the Transaction Synchronization Points section explains that conceptually there are two synchronization points from which you can choose: on read or on write, these terms were a simplification and the terms used in Group Replication are: before and after transaction ...
https://dev.mysql.com/doc/refman/8.4/en/sys-processlist.html
time The time in seconds that the thread has been in its current state. The MySQL process list indicates the operations currently being performed by the set of threads executing within the server. By default, rows are sorted by descending process ...They provide more complete information than the SHOW PROCESSLIST statement and the INFORMATION_SCHEMA PROCESSLIST table, and are also ...
https://dev.mysql.com/doc/connectors/en/connector-j-interceptors.html
In these kinds of interceptor classes, you might log events such as rollbacks, measure the time between transaction start and end, or count events such as calls to setAutoCommit(). In these kinds of interceptor classes, you might change or augment ... An interceptor is a software design pattern that provides a transparent way to extend or modify some aspect of a program, similar to a user ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-compression-tuning.html
Whether to adjust the size of the buffer pool based on run-time performance characteristics, such as the amount of time the system spends compressing and uncompressing data. If the system performs DML operations on compressed tables, and the way the ... Most often, the internal optimizations described in InnoDB Data Storage and Compression ensure that the system runs well with compressed ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-innodb-insertbufferactivity-category.html
Delete Merges (Delta) The total number of times the InnoDB secondary index delete buffer was merged to the InnoDB datafiles. Merges (Delta) The total number of times the InnoDB secondary index insert buffer was merged to the InnoDB datafiles. Free ... Lists the InnoDB Insert Buffer Activity metrics and provides a brief description of ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-innodb-rowactivity-category.html
Table 6.15 InnoDB Row Activity Metrics NameDescriptionRow Queries Inside The number of queries executing inside InnoDB. Rows Deleted Per Sec (Delta) The number of rows deleted per second by InnoDB. Rows Inserted Per Sec (Delta) The number of rows ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-differing-tables.html
A column's default value is determined by a number of factors, including its type, whether it is defined with a DEFAULT option, whether it is declared as NULL, and the server SQL mode in effect at the time of its creation; for more information, see ... Source and target tables for replication do not have to be ...
https://dev.mysql.com/doc/internals/en/determining-authentication-method.html
Method used for authentication is tied to the user account and stored in the plugin column of mysql.user table. Client informs about the user account it wants to log into in the Handshake Response Packet. Only then server can look-up the mysql.user ...
https://dev.mysql.com/doc/extending-mysql/8.4/en/plugin-status-system-variables.html
MYSQL_THDVAR_INT(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_INT(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) An unsigned int system variable, which is typically a 4-byte unsigned word. MYSQL_THDVAR_UINT(name, opt, comment, check, update, default, min, max, blk) MYSQL_SYSVAR_UINT(name, varname, opt, comment, check, update, default, minimum, maximum, blocksize) A long system variable, which is typically either a 4- or 8-byte signed ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-memory-summary-tables.html
Allocating a single byte one million times is not the same as allocating one million bytes a single time; tracking both sizes and counts can expose the difference. Memory summary tables do not contain timing information because memory events are not ...Operation counts help to understand or tune the overall pressure the server is putting on the memory allocator, which has an impact on ...