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Previously, server status changes from MaxAdmin would be set immediately as long as the server lock could be acquired. This meant that it might take several seconds until the next monitor pass is executed. Usually, this was fine but in some situations we would want the monitor to run immediately after the change (MXS-740 and Galera). This patch changes the logic of setting and clearing status bits to a delayed mode: changes are first applied to a "status_pending"-variable, and only once the monitor runs will the setting be applied. To reduce the delay, the monitor now has a flag which is checked during sleep (between short 0.1s naps). If set, the sleep is cut short. If a server is not monitored, the status bits are set directly. There is a small possibility of a race condition: If a monitor is stopped or destroyed before the pending change is applied, the change is forgotten.
MaxScale by MariaDB Corporation
The MariaDB Corporation MaxScale is an intelligent proxy that allows forwarding of database statements to one or more database servers using complex rules, a semantic understanding of the database statements and the roles of the various servers within the backend cluster of databases.
MaxScale is designed to provide load balancing and high availability functionality transparently to the applications. In addition it provides a highly scalable and flexible architecture, with plugin components to support different protocols and routing decisions.
MaxScale is implemented in C and makes extensive use of the asynchronous I/O capabilities of the Linux operating system. The epoll system is used to provide the event driven framework for the input and output via sockets.
The protocols are implemented as external shared object modules which can be loaded at runtime. These modules support a fixed interface, communicating the entries points via a structure consisting of a set of function pointers. This structure is called the "module object".
The code that routes the queries to the database servers is also loaded as external shared objects and are referred to as routing modules.
An Google Group exists for MaxScale that can be used to discuss ideas, issues and communicate with the MaxScale community.
Please report all feature requests, improvements and bugs in the MariaDB Jira.
Documentation
For information about installing and using MaxScale, please refer to the documentation. The official documentation can be found on the MariaDB Knowledge Base.
The module and configuration documentation can be found in the Documentation directory of the source tree.
Contributing Code
Read the Contributing page on the wiki for more information on how to do pull request and where to do them.