Author: MariaDB Knowledge Database

Feed: MariaDB Knowledge Base Article Feed. Author: . This guide will cover: The load balancing and high availability concepts in Mariadb Connector/J for version before 3.0 The different options. Failover and high availability were introduced in 1.2.0. Failover occurs when a connection to a primary database server fails and the connector opens up a connection to another database server.For example, server A has the current connection. After a failure (server crash, network down …) the connection will switch to another server (B). Load balancing allows load (read and write) to be distributed over multiple servers. In MariaDB (and MySQL) replication, ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . MariaDB has an event scheduler that can be used to automate tasks, making them run at regular intervals of time. This page is about using events for automation. For more information about events themselves, and how to work with them, see event scheduler. Pro's and Con's of Using Events for Automation Events can be compared to Unix cron jobs or Windows scheduled tasks. MariaDB events have at least the following benefits compared to those tools: Events are system-independent. Events are written in procedural SQL. There is no need for other languages. Events ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . The MariaDB Foundation maintains a Downloads REST API. See the Downloads API documentation to find out all the tasks that you can accomplish with this API. Generally speaking, we can say that it provides information about MariaDB products and available versions. This allows to easily automate upgrades for MariaDB and related products. The Downloads API exposes HTTPS endpoints that return information in JSON format. HTTP and JSON are extremely common standards that can be easily used with any programming language. How to Use the API with a Unix Shell Linux shells are ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . MariaDB starting with 10.8Introduced in MariaDB 10.8.0 to compute a cyclic redundancy check (CRC) value using the Castagnoli polynomia. Syntax CRC32C(expr[,par]) Description MariaDB has always included a native unary function CRC32() that computes the CRC-32 of a string using the ISO 3309 polynomial that used by zlib and many others. InnoDB and MyRocks use a different polynomial, which was implemented in SSE4.2 instructions that were introduced in the Intel Nehalem microarchitecture. This is commonly called CRC-32C (Castagnoli). The CRC32C function uses the Castagnoli polynomia. This allows SELECT...INTO DUMPFILE to be used for ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This filter was introduced in MariaDB MaxScale 2.1. Overview From MaxScale version 2.2.11 onwards, the cache filter is no longer considered experimental. The following changes to the default behaviour have also been made: The default value of cached_data is now thread_specific (used to be shared). The default value of selects is now assume_cacheable (used to be verify_cacheable). The cache filter is a simple cache that is capable of caching the result of SELECTs, so that subsequent identical SELECTs are served directly by MaxScale, without the queries being routed to any server. By ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . The Transaction Performance Monitoring (TPM) filter is a filter module for MaxScale that monitors every SQL statement that passes through the filter. The filter groups a series of SQL statements into a transaction by detecting 'commit' or 'rollback' statements. It logs all committed transactions with necessary information, such as timestamp, client, SQL statements, latency, etc., which can be used later for transaction performance analysis.The configuration block for the TPM filter requires the minimal filter options in it's section within the maxscale.cnf file, stored in /etc/maxscale.cnf.The TPM filter does not support any filter ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This filter was added in MariaDB MaxScale 2.3 Overview The throttle filter replaces and extends on the limit_queries functionality of the Database Firewall filter. The throttle filter is used to limit the maximum query frequency (QPS - queries per second) of a database session to a configurable value. The main use cases are to prevent a rogue session (client side error) and a DoS attack from overloading the system. The throttling is dynamic. The query frequency is not limited to an absolute value. Depending on the configuration the throttle will allow some ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This filter was introduced in MariaDB MaxScale 2.1. Overview The Maxrows filter is capable of restricting the amount of rows that a SELECT, a prepared statement or stored procedure could return to the client application. If a resultset from a backend server has more rows than the configured limit or the resultset size exceeds the configured size, an empty result will be sent to the client. Configuration The Maxrows filter is easy to configure and to add to any existing service. [MaxRows] type=filter module=maxrows [MaxRows-Routing-Service] type=service ... filters=MaxRows Filter Parameters The Maxrows ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . This filter was introduced in MariaDB MaxScale 2.1. Overview With the masking filter it is possible to obfuscate the returned value of a particular column. For instance, suppose there is a table person that, among other columns, contains the column ssn where the social security number of a person is stored. With the masking filter it is possible to specify that when the ssn field is queried, a masked value is returned unless the user making the query is a specific one. That is, when making the query > SELECT name, ssn ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . The luafilter is a filter that calls a set of functions in a Lua script. Read the Lua language documentation for information on how to write Lua scripts. Note: This module is a part of the experimental module package, maxscale-experimental. Filter Parameters The luafilter has two parameters. They control which scripts will be called by the filter. Both parameters are optional but at least one should be defined. If both global_script and session_script are defined, the entry points in both scripts will be called. global_script The global Lua script. The parameter value ... Read More