This guide walks through a systematic approach to uncovering and fixing MySQL slow queries, covering slow‑query‑log configuration, log analysis with mysqldumpslow and pt‑query‑digest, EXPLAIN‑based execution‑plan inspection, index design principles, SQL rewrites, configuration tuning, and ongoing monitoring to prevent performance regressions.
MySQL 8.2 introduces native read/write splitting via MySQL Router, allowing automatic routing of reads to replicas and writes to the primary source; this guide shows how to set up a simple InnoDB ReplicaSet, configure Router, verify traffic flow, and leverage access mode commands for fine‑grained control.
This guide walks through MySQL’s core memory, I/O, connection, and system variable settings—explaining each parameter’s role, recommended values, and example commands—so you can systematically adjust the configuration, monitor key metrics, and achieve up to three‑fold performance gains.
This article demonstrates how MySQL Router 8.2 can automatically route read traffic to replica instances and write traffic to the primary instance in an InnoDB ReplicaSet, providing configuration steps, command examples, and observed behavior without requiring any changes to the application.
This comprehensive guide walks you through a real‑world MySQL outage, then details step‑by‑step configuration tweaks, InnoDB parameter tuning, connection and thread settings, index design, query rewrites, monitoring scripts, backup strategies, high‑availability replication, and essential tooling to keep your database fast and reliable.
Even when CPU and memory appear idle, MySQL can suffer connection timeouts, query stalls, and 100% CPU spikes during peak traffic, but by adjusting six key configuration parameters and following solid SQL‑optimization practices you can reliably support thousands of queries per second.
This article provides an in‑depth technical overview of ClickHouse, covering its OLAP‑focused architecture, key performance features, detailed configuration files, a comprehensive comparison of its many table engines, common troubleshooting tips, and real‑world deployment patterns for recommendation and advertising systems.
This article explains why OceanBase enforces minimum values for min_worker_cnt and max_worker_cnt, shows the source‑code formulas used to compute them, demonstrates how to verify and adjust these parameters, and clarifies the impact of tenant memory and Meta‑tenant reservations on the final values.
This article explains Redis's eight memory eviction policies, their ideal use cases, and provides step‑by‑step commands and configuration examples for querying and setting both the eviction strategy and maximum memory limits.
This guide walks through verifying the MariaDB server_audit plugin, installing it via configuration files or SQL, setting audit event variables, enabling logging, and restarting the MySQL service in a Kubernetes environment to achieve comprehensive query and connection auditing.
This guide covers practical MySQL performance improvements, including choosing proper data types, avoiding SELECT *, optimizing joins and UNION usage, batch inserts, query cache settings, configuration parameters like innodb_buffer_pool_size, and comprehensive index strategies to accelerate queries and reduce resource consumption.
This article provides a thorough guide to MySQL performance optimization, covering general query improvements, proper data types, index usage, configuration parameter tuning, avoiding common pitfalls, and detailed EXPLAIN analysis, with concrete SQL examples and practical recommendations for developers and DBAs.
When upgrading MySQL 8.0 to 8.4 on a host running multiple instances, some instances fail to start with a series of InnoDB errors caused by io_setup() returning EAGAIN, which can be resolved by increasing the system's aio‑max‑nr limit and adjusting InnoDB I/O thread settings.
This article walks through real‑world Oracle RAC failures caused by misconfigured VIP failover and SCAN IP load‑balancing, explains how to diagnose the symptoms, provides correct TAF and listener settings, and highlights essential configuration tips to ensure reliable high‑availability operation.
This article provides a comprehensive guide to installing and configuring OceanBase single-node (centralized) clusters, explains primary‑standby tenant architectures, details performance benchmarking against MySQL using sysbench and fio, and offers recommended resource settings and diagnostic procedures for optimal operation.
This article explains the concept of MySQL master‑slave replication, outlines its advantages and drawbacks, and provides a step‑by‑step guide—including downloading MySQL 8.0, configuring my.cnf on master and slave servers, creating replication users, setting up replication parameters, and using Laravel for read‑write splitting—complete with all necessary shell and SQL commands.
This article explains how to set up read/write database separation in Laravel by configuring multiple database connections in the config/database.php file, covering both identical and distinct credentials for read and write servers, and describing the purpose of the sticky option to ensure data consistency during a request.
This article summarizes the major changes introduced in MySQL 8.4, including updated InnoDB parameters, revised default values, new cloning plugin rules, Windows SASL‑based LDAP authentication, and adjustments to replication settings, helping developers and DBAs optimize their database configurations.
An extensive benchmark compares MySQL 8.2 Community and Enterprise editions using sysbench and TPC‑C on identical EC2 instances, revealing that, under default configurations, the Enterprise edition offers no consistent performance advantage over the Community edition, with only occasional gains from optional plugins.
This guide walks through setting up a Dameng data‑guard service using a primary, standby, and monitor server, covering data preparation, configuration of dm.ini, dmmal.ini, dmarch.ini, dmwatcher.ini, starting services, OGUID setup, mode switching, and monitoring to achieve high‑availability replication.
This article investigates why Sharding-JDBC takes over half of the application startup time to load metadata, explains the role of the max.connections.size.per.query setting, demonstrates how adjusting it speeds up startup, and discusses the trade‑offs and potential dead‑lock risks of increasing the value.
This article presents a detailed reference of MySQL server configuration options (my.cnf), explaining each setting such as storage engine, networking, replication, logging, cache sizes, and performance‑related parameters to help administrators fine‑tune their databases.
This article explains the MySQL sql_mode setting, details each of its ten modes—including STRICT_TRANS_TABLES, STRICT_ALL_TABLES, and ONLY_FULL_GROUP_BY—provides a command to view the current mode, and also includes a brief promotion for a PHP training class.
This article demonstrates how to deploy OceanBase 4.X in a minimal single‑node configuration, explains the key resource parameters, provides the necessary YAML configuration and command‑line steps to start the server, create a MySQL‑compatible tenant, and verify resource usage and basic database operations.
The article investigates why two MySQL 5.7.32 installations on RedHat 7 show different client character sets—utf8 in the first batch and latin1 in the second—by reviewing MySQL charset settings, OS locale configuration, and providing corrective commands.
This article investigates a MySQL 5.7.30 replica crash caused by an InnoDB assertion in btr0btr.cc when handling temporary tables, reproduces the issue using the MySQL Test Run framework, analyzes logs and parameters, and proposes configuration and SQL‑optimisation fixes.
This article explains MySQL's character encoding workflow, illustrates why queries containing Chinese characters fail without proper settings, and shows how to configure JDBC URLs, server variables, and Docker‑based MySQL instances to ensure lossless UTF‑8 handling.
This guide explains how to identify MySQL max‑connection errors, check the current limit, and increase it using configuration files, global variables, source‑code changes, or mysqld_safe adjustments, with detailed commands and code examples for various MySQL versions.
This article examines how slave crashes in MySQL replication can cause inconsistencies between master info and relay log positions, leading to duplicate events and errors such as 1062 and 1032, analyzes underlying mechanisms, presents case studies, and proposes configuration settings to achieve server‑crash‑safe replication.
This article explains how to troubleshoot and fix the MySQL 5.7 ONLY_FULL_GROUP_BY error in a Laravel application by inspecting sql_mode, understanding Laravel's strict mode behavior, and customizing the framework's mode configuration to remove the problematic setting without changing global MySQL settings.
This article explains the cause of InfluxDB’s max‑value‑per‑tag error when Prometheus remote‑writes high‑cardinality tags, analyzes why the built‑in memory index triggers OOM protection, and presents three practical solutions—including moving indexes to disk, storing high‑cardinality tags as fields, and filtering them before write—to ensure stable monitoring data persistence.
This guide explains MongoDB replica set fundamentals, walks through local deployment of a primary‑secondary‑secondary cluster, demonstrates automatic failover, and details write concern and read preference options—including member attributes, connection string parameters, and shell commands—for reliable high‑availability data handling.
Learn step-by-step how to set up and test multiple data sources in a Spring Boot application using MyBatis, covering property configuration, DataSource beans, mapper scanning, entity definitions, and verification through unit tests with complete code examples and key configuration notes.
This article explains how MySQL variables are stored in memory and configuration files, the challenges of modifying them before MySQL 8, and how the new SET PERSIST and SET PERSIST_ONLY statements simplify persistent variable management with proper permissions and examples.
An investigation of a DBLE performance issue revealed that identical sharding keys with the same stringhash rule failed to improve query speed because differing hashSlice configurations prevented proper partitioning, and after correcting the rule.xml function settings, the SQL executed efficiently with sub‑second response times.
This tutorial demonstrates how to configure and use DBLE's global sequence feature, covering the timestamp‑based Snowflake algorithm and the offset‑setup type, including server.xml settings, table definitions, insertion behavior, and handling of restarts to ensure unique identifiers.
This guide explains the complete process of configuring MySQL master‑slave replication on two CentOS machines, covering prerequisite setup, enabling binary logging, creating a replication user, capturing binlog coordinates, configuring the slave, and verifying successful synchronization.
This step‑by‑step guide shows how to edit MySQL’s my.cnf on Ubuntu 14.04, change the bind‑address, restart the service, grant remote privileges, and verify the connection using Navicat, enabling secure remote database access.
This guide explains why MySQL tables default to latin1, demonstrates how to check and change table, session, and global character set settings, and shows the necessary my.cnf configuration changes to permanently enable UTF‑8 support for storing Chinese characters.
This guide explains how to boost MySQL performance by tuning hardware factors such as disk I/O, CPU and memory, and by adjusting key my.cnf parameters—including skip-name-resolve, back_log, key_buffer_size, query cache, and connection limits—to match server resources and workload.
This article explains why Greenplum can encounter out‑of‑memory (OOM) errors, lists the typical causes, and provides detailed recommendations for memory‑related OS and database parameters, statement_mem settings, and the proper use of Greenplum resource queues to achieve stable and efficient cluster operation.
This article explains how to secure MySQL data by configuring single‑node safeguards, implementing cluster replication (including semi‑sync), and applying proper backup methods, guiding readers through practical settings and best practices for reliable data persistence.
This article explains the structure and components of MySQL 5.7 InnoDB tablespaces—including system, undo, temporary, and general tablespaces—covers double‑write buffering, redo logs, encryption with keyring, and provides practical configuration examples and command‑line demonstrations.
This guide explains how to use the Chef PostgreSQL cookbook to install and configure PostgreSQL as a client or server across multiple Linux platforms, detailing attribute-driven generation of postgresql.conf and pg_hba.conf, performance tuning options, contrib module installation, and repository setup for apt and yum.
This article explains the new shared temporary tablespace introduced in MySQL 5.7, how to configure its size and location with innodb_temp_data_file_path, compares it with tmpdir, demonstrates the impact on compressed and uncompressed InnoDB temporary tables, and highlights related parameters and potential pitfalls.
This guide explains essential MySQL InnoDB parameters—such as buffer pool size, instances, connection limits, log buffer, statistics collection, lock timeout, thread concurrency, and I/O threads—and provides practical CPU‑based settings to help you optimize database performance.
This guide explains why Chinese characters appear as question marks in Sqlplus on Linux, how to identify the server character set, and provides step‑by‑step instructions to set the NLS_LANG environment variable and apply it instantly using the source command.
The article explains how MySQL replication parameters such as expire_logs_days, relay-log-recovery, and relay-log-info-repository affect binlog cleanup, SQL and I/O thread consistency, and why crashes can produce duplicate‑key errors, then offers configuration fixes including the critical relay‑log cleaning option and the super_read_only setting.
This step‑by‑step guide shows how to completely remove any existing MySQL installation on Linux, reinstall it, and correctly configure the server and client character sets to UTF‑8, including version‑specific settings and verification.
This guide walks through identifying MySQL CPU overload caused by excessive temporary tables and thread creation, then details configuration tweaks and SQL optimizations—including adjusting tmp_table_size, thread_cache_size, and join/sort buffers—to restore normal performance.
