Author: MariaDB Knowledge Database

Feed: MariaDB Knowledge Base Article Feed. Author: . The command line interface as used by maxadmin. The CLI router requires the use of the maxscaled protocol. Configuration Two components are required to run the command line interface for maxadmin; a service and a listener. The listener may either use a Unix domain socket or an internet socket. The default entries required are shown below. [CLI] type=service router=cli # Unix Domain Socket [CLI-Unix-Listener] type=listener service=CLI protocol=maxscaled socket=default # Internet Socket [CLI-Inet-Listener] type=listener service=CLI protocol=maxscaled address=localhost port=6603 In the example above, two listeners have been specified; one that listens on the default ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Since version 2.4, MaxScale has built-in support for Clustrix. This tutorial explains how to setup MaxScale in front of a Clustrix cluster. There is no Clustrix specific router, but both the readconnroute and the readwritesplit routers can be used. Clustrix and Readconnroute With readconnroute you get simple connection based routing, where each new connection is created (by default) to the Clustrix node with the least amount of existing connections. That is, with readconnroute the behaviour will be very similar to the behaviour when HAProxy is used as the Clustrix load balancer. Bootstrap ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This document describes how to configure the Clustrix monitor for use with a Clustrix cluster. Configuring the Monitor Contrary to the other monitors of MaxScale, the Clustrix monitor will autonomously figure out the cluster configuration and for each Clustrix node create the corresponding MaxScale server object. In order to do that, a sufficient number of "bootstrap" server instances must be specified in the MaxScale configuration file for the Clustrix monitor to start with. One server instance is in principle sufficient, but if the corresponding node happens to be down when MaxScale starts, ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Overview The Clustrix Monitor is a monitor that monitors a Clustrix cluster. It is capable of detecting the cluster setup and creating corresponding server instances within MaxScale. Configuration A minimal configuration for a monitor requires one server in the Clustrix cluster, and a username and a password to connect to the server. Note that by default the Clustrix monitor will only use that server in order to dynamically find out the configuration of the cluster; after startup it will completely rely upon information obtained at runtime. To change the default behaviour, please ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Overview SmartRouter is the query router of the SmartQuery framework. Based on the type of the query, each query is routed to the server or cluster that can best handle it. For workloads where both transactional and analytical queries are needed, SmartRouter unites the Transactional (OLTP) and Analytical (OLAP) workloads into a single entry point in MaxScale. This allows a MaxScale client to freely mix transactional and analytical queries using the same connection. This is known as Hybrid Transactional and Analytical Processing, HTAP. Configuration SmartRouter is configured as a service that either ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Overview The namedserverfilter is a MariaDB MaxScale filter module able to route queries to servers based on regular expression (regex) matches. Since it is a filter instead of a router, the NamedServerFilter only sets routing suggestions. It requires a compatible router to be effective. Currently, both readwritesplit and hintrouter take advantage of routing hints in the data packets. This filter uses the PCRE2 library for regular expression matching. Configuration The filter accepts settings in two modes: legacy and indexed. Only one of the modes may be used for a given filter instance ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Introduced in MaxScale 2.1, the module commands are special, module-specific commands. They allow the modules to expand beyond the capabilities of the module API. Currently, only MaxAdmin implements an interface to the module commands. All registered module commands can be shown with maxadmin list commands and they can be executed with maxadmin call command ARGS... where is the name of the module and is the name of the command. ARGS is a command specific list of arguments. Developer reference The module command API is defined in the modulecmd.h header. It consists of ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This document describes how to configure a MariaDB master-slave cluster monitor to be used with MaxScale. Configuring the Monitor Define the monitor that monitors the servers. [Replication-Monitor] type=monitor module=mariadbmon servers=dbserv1, dbserv2, dbserv3 user=monitor_user password=my_password monitor_interval=2000ms The mandatory parameters are the object type, the monitor module to use, the list of servers to monitor and the username and password to use when connecting to the servers. The monitor_interval parameter controls for how long the monitor waits between each monitoring loop. Monitor User The monitor user requires the REPLICATION CLIENT privileges to do basic ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . 有以下的几种数据类型： 如果需要获得详细的信息，可以查看每种数据类型对应的文档。 SIGNED，UNSIGNED和ZEROFILL属性 多数的数值类型都可以被定义为SIGNED，UNSIGNED或者ZEROFILL，例子如下: TINYINT[(M)] [SIGNED | UNSIGNED | ZEROFILL] 如果被定义为SIGNED，不指定属性(默认)，那么存储这类数据时就会用一个比特作为符号位(来表示正负)。 例如，TINYINT SIGNED可以表示-128到127的数。 如果定义了UNSIGNED的属性，那么存储这类数据时不会专门表示符号位，所以可以表示更大的范围。距离来说一个TINYINT UNSIGNED数据可以表示的范围是从0到255。此外，浮点小数和定点小数也可以是UNSIGNED的，在这种情况下，它们只能防止存储负数，但不能够增加表示范围。 如果指定了ZEROFILL属性, 那么这一列就会被设定为无符号的UNSIGNED，并且默认情况下用于填充字段的空格将替换为零。在表达式中或者在[[union|UNION]的一部分中，ZEROFILL会被忽略。这里要指出，ZEROFILL是一个非标准的MySQL和MariaDB的增加属性。 要注意的是，虽然在语法上，属性是具有排他性的，实际上可以指定超过一个的属性。 截止到MariaDB 10.2.7 (MDEV-8659)，属性的组合可以重复出现，并且顺序可以是任意的。在这种情况下： 只要出现ZEROFILL就让这一列变为UNSIGNED ZEROFILL。 只要出现UNSIGNED就会让这一列变为UNSIGNED。 到了MariaDB 10.2.8, 只能够支持以下的组合 SIGNED UNSIGNED ZEROFILL UNSIGNED ZEROFILL ZEROFILL UNSIGNED 最后的两个可以被简单地替换为ZEROFILL，但是写成最后两个再语法上仍然可以被识别。 举例 CREATE TABLE zf ( i1 TINYINT SIGNED, i2 TINYINT UNSIGNED, i3 TINYINT ZEROFILL ); INSERT INTO zf VALUES (2,2,2); SELECT * FROM zf; +------+------+------+ | i1 | i2 | i3 | +------+------+------+ | 2 | 2 | 002 | +------+------+------+ Range范围 如果新增加的一个值超出了这个数据类型能够表示的范围，MariaDB的反应取决于对strict SQL_MODE的设置。 如果strict_mode已经被设置(从MariaDB 10.2.4开始的默认值)，MariaDB会返回一个错误。 如果strict_mode没有被设置(直到MariaDB 10.2.3的默认值)，MariaDB会调整这个值，让它属于该数据类型能表示的范围，并且返回一个警告。 举例 当设定了strict_mode时： SHOW VARIABLES LIKE 'sql_mode'; +---------------+-------------------------------------------------------------------------------------------+ | Variable_name ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Changes in 1.2.1 and later libjemalloc dependency ColumnStore 1.2.3 onward requires libjemalloc to be installed. For Ubuntu & Debian based distributions this is installed using the package "libjemalloc1" in the standard repositories. For CentOS the package is in RedHat's EPEL repository: sudo yum -y install epel-release sudo yum install jemalloc Non-distributed is the default distribution mode in postConfigure The default distribution mode has changed from 'distributed' to 'non-distributed'. During an upgrade, however, the default is to use the distribution mode used in the original installation. The options '-d' and '-n' can always ... Read More