This article explains why AUTO_INCREMENT is unsupported in OceanBase Oracle tenants, introduces four practical ways to implement auto‑increment columns using sequences, DML, DDL, triggers, and the GENERATED BY DEFAULT AS IDENTITY syntax, and provides step‑by‑step SQL examples for each method.
This article describes the challenges of migrating a long‑running monolithic database to a sharded architecture, presents a two‑stage smooth migration strategy using double‑write, diff verification, and mapping‑key techniques, and details the componentized design, core implementation, and configuration of a reusable sharding framework built on MyBatis and Spring.
This article recounts how a finance team tackled a 50‑million‑row MySQL table by analyzing system bottlenecks, defining splitting goals, selecting sharding‑jdbc, addressing multi‑datasource transactions and pagination, designing data migration strategies, and executing a staged rollout to ensure stability and performance.
This article explains the reasons for splitting monolithic applications, outlines preparation steps, and provides detailed practical guidance on database vertical and horizontal splitting, global ID generation, migration, cut‑over strategies, consistency, and post‑split stability measures.
This tutorial walks through setting up Liquibase in a Spring Boot project, creating a Maven plugin to generate XML/YAML changelogs, configuring the application, and performing common database operations such as creating tables, adding columns, creating indexes, initializing data, while also addressing a common includeAll path issue.
This article introduces Flyway as a database migration solution, explains its versioned, undo and repeatable migrations, details common commands, shows Maven and YAML configuration for Spring Boot, provides sample SQL migration scripts and logs, and highlights paid‑only features.
This article explains how to add unique indexes to large MySQL tables using Online DDL, pt‑osc, and gh‑ost, compares their advantages and drawbacks, outlines common data‑loss risks, and provides practical hook scripts and best‑practice recommendations to mitigate those risks.
This article details the background, migration options, and step‑by‑step automated procedures used by a large‑scale e‑commerce platform to safely move over 400 MySQL clusters, comparing expansion‑plus‑master‑slave switching with cascading replication and explaining the chosen fast, reliable solution.
This article explains why SQL join execution plans often cause severe performance drops after moving from Oracle to domestic or open‑source databases, demonstrates each join type with PostgreSQL examples, shows how plan choices like HASH JOIN versus NESTED LOOP affect speed, and offers rewrite techniques such as NOT EXISTS or UNION to restore efficiency.
Ctrip evaluated and extended OceanBase Migration Assessment tools, built a one‑click migration workflow, implemented comprehensive monitoring and automatic fault‑diagnosis pipelines, and addressed compatibility challenges such as .NET charset issues and Druid parser errors, ultimately achieving a smooth MySQL‑to‑OceanBase transition.
This article details the background, migration plan selection, and step‑by‑step procedures—including pre‑building cascades, service pause, automated batch operations, cluster tiering, pre‑ and post‑checks, and gray‑scale validation—to achieve a fast, stable MySQL data‑center migration for a large‑scale production environment.
Teradata announced its withdrawal from China due to geopolitical uncertainty and rising competition from mature domestic data‑warehouse solutions, prompting a detailed analysis of its architecture, the main Chinese warehouse designs, global market positioning, and migration tools for replacing Teradata.
Teradata's withdrawal from China, driven by geopolitical tensions and the rise of mature domestic data‑warehouse solutions, prompts a detailed look at its MPP architecture, the three main Chinese warehouse designs, Gartner market positioning, and migration tools for alternatives like GBase 8a and GaussDB DWS.
Yanxuan migrated its monolithic trading system from a shared DDB cluster to an independent database by using Netease Data Canal for real‑time sync, a write‑stop switch with Pandora middleware, account and permission isolation, and extensive testing across three phases to ensure data consistency and minimal business impact.
The article examines why openGauss 2.0/3.0 cannot use Index‑Only Scan for covering indexes, explores the role of the visibility map and VACUUM, compares behavior with PostgreSQL 11, and shows how the USTORE storage engine can finally enable true covering indexes.
Facing rapid growth, our team evaluated ClickHouse’s hot‑cold storage and tiered‑disk policies to replace Elasticsearch, designing partitioning, TTL, and multi‑level storage strategies—including hot, cold, and archive disks, custom storage policies, and OSS integration—to achieve higher write throughput, better compression, and over 50% cost reduction.
In this interview, senior database expert Kong Zaihua explains the main performance, functional, and usability shortcomings of domestic Chinese databases compared with Oracle, and outlines practical strategies, tools, and migration techniques to evaluate compatibility, handle DDL conversion, manage online/offline data transfer, and reduce reliance on stored procedures.
This article details a low‑impact migration from MyCat to DBLE, covering required parameter adjustments, sharding function replacement, data node handling, and business‑SQL compatibility issues, while providing concrete configuration examples and practical recommendations for a smooth transition.
After a month of operating a MySQL dual‑master high‑availability cluster, the author details the numerous pitfalls encountered and explains a step‑by‑step manual process for converting the setup to a simpler master‑slave architecture, including configuration changes and Keepalived adjustments.
DataBus is a real‑time data synchronization framework designed to support Oracle de‑commissioning, micro‑service migration, and heterogeneous storage engines by providing high‑availability CDC, flexible data pipelines, and seamless full‑to‑incremental migration across multiple source and target databases.
This article shares practical experiences and lessons learned from over a hundred database migration projects, comparing storage replication, logical replication, and ASM disk‑group rebalancing, and explains how system context, vendor capabilities, and careful planning determine the most suitable approach.
This article explains how to use Oracle Data Pump's ESTIMATE and ESTIMATE_ONLY parameters to assess the size of a 1 TB production database for migration, compares BLOCKS and STATISTICS estimation methods, and details best practices for gathering accurate optimizer statistics with ANALYZE and DBMS_STATS.
This article walks you through the complete hands‑on lab for migrating a local MySQL database to Huawei Cloud RDS using the DRS service, covering environment setup, connection testing, full and incremental migration phases, and final execution tips.
This article introduces and compares three MySQL online schema‑change solutions—pt‑online‑schema‑change, gh‑ost, and native MySQL ONLINE DDL—detailing their workflows, limitations, risks, monitoring features, and practical considerations for safely altering large tables in production environments.
This article explains how DTLE supports pt-osc table schema changes by describing pt-osc's underlying mechanism, DTLE's DDL capabilities, and step‑by‑step instructions for deploying DTLE, preparing MySQL data, configuring a DTLE job, running pt‑online‑schema‑change, and verifying successful synchronization.
After months of using MongoDB for frontend monitoring logs, the data grew to billions of records causing severe query slowdown, prompting a migration to ClickHouse where columnar storage, partitioning, and OLAP capabilities dramatically improved performance and storage efficiency.
This article recounts the author's journey from using MongoDB for front‑end monitoring logs to migrating to ClickHouse, detailing the challenges with large‑scale data, optimization attempts, the fundamental differences between row‑ and column‑oriented databases, and the resulting performance and storage improvements.
This article provides a step‑by‑step guide on configuring DTLE 4.22.01.0 to perform Oracle‑to‑MySQL incremental data synchronization, covering type mapping, DML/DDL support, environment setup, job creation, data verification, and handling of compatibility limitations.
The Baidu Aifanfan lead list page evolved through six versions—from rapid MySQL‑based delivery to a metadata‑driven, ES‑backed architecture with Redis synchronization—culminating in a high‑availability, high‑performance system that slashed server latency from 25 seconds to under one second and cut frontend load times and static asset sizes dramatically.
This tutorial explains how to install, configure, and operate Phinx within a ThinkPHP project to manage database schema migrations, create and run seed data, update tables, roll back changes, and keep development environments synchronized.
This article explains why a high‑traffic platform migrated from SQL Server to Elasticsearch, covering the technical motivations, performance characteristics, indexing strategies, data synchronization methods, API design, and operational monitoring to achieve a scalable, low‑latency search solution.
This article details how a company migrated its reporting architecture to TiDB, leveraged TiFlash for HTAP workloads, upgraded to version 4.0 with new tools like DM and TiUP, achieved up to four‑fold query speedups, and shares the pitfalls and optimization tips learned along the way.
This article provides a comprehensive, step‑by‑step guide on why and how to split monolithic applications, prepare for migration, execute database vertical and horizontal sharding, handle schema changes, ensure consistency, and maintain stability during and after the split, enriched with real‑world pitfalls and solutions.
A former Oracle MySQL lead engineer explains why, after five years of work, he finds PostgreSQL a superior open‑source RDBMS, criticizing MySQL’s design flaws, comparing MariaDB, and highlighting real‑world migration experiences and industry perspectives.
This article walks through the complete process of moving an Oracle database to PostgreSQL, covering the rationale for open‑source and cloud solutions, the three core migration phases, hands‑on demos of AWS SCT, Ora2PG, and a Python‑based data‑replication example, plus performance results.
This article examines MySQL 5.7 replication issues caused by GTID settings during database migration, detailing environment setup, problem description, reproduction steps, analysis, conclusions on --set-gtid-purged usage, and practical solutions to ensure consistent in master‑slave synchronization.
This article explains the reasons for splitting monolithic applications, outlines multi‑dimensional preparation, defines service boundaries, details DB vertical and horizontal splitting, global ID generation, migration steps, cut‑over strategies, consistency guarantees, and stability measures to ensure a successful transformation.
This article documents a reproducible test that shows gh-ost can lose rows when used on a MySQL 5.7 AFTER_SYNC semi‑synchronous replica, explains the underlying cause, and presents a source‑code modification that prevents the loss.
This article outlines the principles, recommended practices, and detailed steps for upgrading MySQL from 5.7 to 8.0, covering version compatibility, major 8.0 feature changes, pre‑upgrade checks, in‑place and logical migration procedures, and essential configuration adjustments with example commands.
This article explains how the MySQL system variable explicit_defaults_for_timestamp controls the default and NULL handling of TIMESTAMP columns, demonstrates the differences between OFF and ON settings with practical tests, and discusses why the parameter is being deprecated for stricter time‑data management.
This article provides a detailed, online, in‑place upgrade procedure for MySQL InnoDB Cluster (MGR) from version 5.7.25 single‑primary mode to version 8.0.26, covering preparation, backup, node‑by‑node upgrade, configuration changes, and communication‑protocol updates.
Facebook’s engineering team detailed the multi‑year effort to upgrade a heavily customized MySQL 5.6 deployment to MySQL 8.0, describing the migration strategy, code‑patch classification, row‑based replication adoption, extensive automation testing, and the performance and compatibility issues they resolved along the way.
Facebook detailed its multi‑year journey from MySQL 5.6 to 8.0, explaining why it stayed on 5.6 for MyRocks development, the massive patch‑porting effort, replica‑set migration steps, adoption of row‑based replication, extensive automation testing, and the performance and compatibility issues uncovered along the way.
This article details the practical challenges encountered when migrating a MariaDB 10.3 database to MySQL 5.7.25, explains why certain defaults and engine-specific options cause import errors, and provides step‑by‑step fixes such as adjusting default expressions, removing Aria‑specific parameters, and configuring sql_mode.
Flyway is an open‑source database migration tool that version‑controls SQL scripts, supports many databases, and integrates with Maven and Spring to automate schema changes across environments, offering commands such as migrate, clean, info, validate, baseline, undo and repair, with detailed configuration examples.
Facebook’s engineering team detailed a multi‑year, complex migration from MySQL 5.6 to 8.0, highlighting custom‑feature porting, replication compatibility, query changes, performance regressions, and documentation gaps, and explaining how they finally achieved a successful upgrade.
This guide walks you through installing Django, creating an app, defining a custom user model with a manager, configuring AUTH_USER_MODEL, and migrating the database, enabling email‑based authentication and flexible user fields.
This article outlines a comprehensive, step‑by‑step approach for migrating massive tables—up to billions of rows—through sharding, dual‑write, data synchronization, validation, testing, and controlled switch‑over to ensure minimal impact on production services.
This article explores the RedisSyncer toolkit for achieving reliable bidirectional Redis synchronization, explains the necessity of cache sync, details the data offset solution and double‑read approach, and provides step‑by‑step deployment instructions with code examples and practical considerations.
This article explains the background of migrating from MySQL to TiDB, introduces the Snowflake algorithm’s 64‑bit ID structure, discusses its advantages and disadvantages, provides a Python implementation, and highlights its impact on achieving globally unique, time‑ordered identifiers in distributed systems.
This article details the billing group's challenges with single‑node MySQL, the evaluation of alternative databases such as TiDB and CockroachDB, performance testing, migration strategies, operational best practices, and the final decision to adopt TiDB for scalable, high‑availability data services.
A large‑scale IoT service migrated 40 billion rows from MySQL to MongoDB, solving capacity, cost, and data‑skew issues while achieving higher performance, lower storage consumption, and a flexible, highly available architecture, with detailed resource evaluation, migration steps, optimization tactics, and cost‑benefit analysis.
This article explains MySQL's Unicode character set support, compares the deprecated utf8mb3 with the modern utf8mb4, and provides step‑by‑step SQL commands for safely converting existing databases to the newer charset.
This article demonstrates how to recover MySQL data from a crashed Linux virtual machine by mounting its disk on a new VM, activating LVM logical volumes, copying configuration and data files, and restarting MySQL, illustrating a practical data rescue workflow.
This article explains the concept of gray (canary) release, outlines a simple system architecture with essential components, details common traffic‑splitting strategies, and demonstrates both basic and complex implementation scenarios using Nginx, gateway services, and database migration techniques.
This comprehensive guide explains how to migrate Oracle databases to MySQL by detailing type differences, migration steps, performance tuning, and validation techniques, while highlighting common pitfalls such as data‑type mismatches, character‑set issues, LOB handling, and transaction isolation nuances.
The 2020‑2021 Cloud‑Native Technology Landing Survey, conducted by CNBPA, Lingqu Cloud and the Cloud‑Native Community, collected 783 responses from finance, manufacturing, energy, pharma, telecom and government sectors, revealing that cloud‑native adoption—including containers, DevOps, micro‑services, Kubernetes, Service Mesh and cloud‑native databases—has roughly doubled in production environments and is now the primary driver of digital transformation in traditional enterprises.
This article summarizes a real‑world MySQL database migration project, detailing pre‑migration preparation, backup and import commands, replication setup—including multi‑source replication for merging databases—and post‑migration verification steps, while sharing practical tips and pitfalls.
To support Gaode Taxi’s soaring order volume, the team expanded from four to eight ECS instances, re‑sharded 256 tables into 4,096, built a custom binlog‑to‑Kafka sync middleware for full‑load and incremental migration, implemented rigorous validation and repair processes, and employed a gray‑rollout with ABC verification, completing the migration without code changes or incidents.
This article describes how Coffee Meets Bagel upgraded a five‑node PostgreSQL 9.6 cluster to version 12.4 on AWS using pglogical logical replication, achieving less than 30 minutes of total downtime while sharing the architecture, migration steps, and lessons learned.
This step‑by‑step tutorial shows how to create a Django website with user authentication features—including login, registration, logout, password change, password‑less login and reset—by configuring the project, defining models, forms, views, URLs, performing migrations, and running the server.
This tutorial walks you through using Flyway in a Spring Boot application to manage MySQL schema versions, from initial table creation and CRUD implementation to incremental migrations like adding new columns, complete with Maven dependencies, SQL scripts, Java code, and automated tests.
This article shares the Ctrip flight big‑data platform’s journey of evaluating and migrating data storage from Hive, MySQL and Redis to CrateDB, covering performance requirements, query patterns, maintenance challenges, containerization, and production results that reduced interface latency and resource consumption.
This guide explains how Flyway automates database schema migrations using version‑controlled SQL scripts, covering its core concepts, naming conventions, command‑line usage, Maven integration, and seamless Spring Boot configuration to keep databases in sync with application releases.
This article details Zhihu's Moneta service handling over a trillion rows, the scalability challenges it faced, the evaluation of MySQL sharding and MHA, and how adopting the open‑source HTAP database TiDB enabled millisecond‑level query latency, high availability, and easy horizontal expansion.
This article presents a comprehensive, step‑by‑step guide on why and how to split monolithic applications and databases, covering business complexity analysis, service boundary definition, migration planning, global ID generation, data sync, query refactoring, switch‑over strategies, consistency guarantees, and post‑split stability measures.
In May 2020 GitLab partnered with OnGres to upgrade a 12‑node PostgreSQL 9.6 cluster to version 11, using a carefully planned pg_upgrade process, automated Ansible playbooks, Patroni HA, and a detailed rollback strategy to keep a 6 TB dataset consistent while serving 300 k transactions per second.
This article explains how using MySQL's INSERT INTO … SELECT without proper indexing can cause full‑table scans and locks, illustrates the problem with a real‑world order‑migration incident, and provides a concrete solution by adding an index to the source column.
This article explains the reasons for breaking monolithic applications, outlines the preparatory steps for understanding business complexity and defining service boundaries, and provides detailed, step‑by‑step practices for vertical and horizontal database splitting, global ID generation, migration, cut‑over strategies, consistency handling, and post‑split stability measures.
This article outlines why and how to split monolithic applications and databases, covering preparation, boundary definition, migration steps, DB sharding strategies, consistency guarantees, and operational safeguards to ensure a smooth transition to a more modular, scalable architecture.
This article details Suning's journey of replacing commercial databases with PostgreSQL and Citus, covering background, feature and performance comparisons, reliability tests, deployment architecture, real‑world use cases, operational tips, and a comprehensive Q&A on migration and maintenance.
This guide explains how to install and use the topthink/think-migration package with ThinkPHP to create, run, and roll back database migration scripts, covering version compatibility, command‑line operations, migration class creation, and practical examples for creating, updating, and deleting tables and columns.
This article explains why monolithic systems need to be split, outlines multi‑dimensional preparation steps, details database vertical and horizontal partitioning, global ID generation, cut‑over strategies, consistency handling, and operational safeguards to ensure a smooth migration.
Lufax completed a two‑year, zero‑downtime, 100% Oracle‑to‑MySQL migration across its entire financial platform, detailing the dual‑write strategy, fine‑grained batch switching, tool‑driven automation, and the resulting cost and operational benefits for over 45 million users and supporting critical transaction services.
This article explains Google DevOps’s four capability categories, dives into DORA‑backed best practices for database change management—including communication, migration scripts, tooling, zero‑downtime strategies, common pitfalls, and key metrics—to help teams deliver changes safely and quickly.
This article introduces ClickHouse as an OLAP columnar database, explains the differences between row‑ and column‑oriented storage, details a real‑world migration from MySQL using a CREATE TABLE AS SELECT approach, presents performance comparisons, discusses synchronization methods, and shares common pitfalls and solutions.
Facing growing log volumes and high Elasticsearch costs, Ctrip migrated its 200 TB daily logs to ClickHouse, achieving up to 38× faster queries, 60 % lower server resources, and simplified operations through columnar storage, sharding, and custom dashboards, while detailing deployment, tuning, and common pitfalls.
This article evaluates whether openGauss can serve as an Oracle replacement in OLTP scenarios by systematically testing compatibility of Oracle's character, numeric, date/time, large object, ROWID, and RAW data types, presenting command‑line results and practical substitution recommendations.
This article provides a comprehensive guide to the pt-online-schema-change (pt-osc) tool for MySQL online DDL, covering its underlying mechanism, limitations, installation steps, command‑line syntax, practical examples, and a comparative analysis with native Online DDL and gh‑ost to help users choose the appropriate solution.
This article analyzes a real‑world incident where using INSERT INTO SELECT to migrate large order data caused full‑table scans and locking in MySQL, explains the underlying lock behavior, and presents a solution that adds an index and forces its use to avoid the problem.
Facing high licensing costs and poor scalability, Lujinso embarked on an 18‑month, self‑driven project to replace 90% of its Oracle databases—spanning billions of rows across financial services—with MySQL, supplemented by Elasticsearch, Redis, TiDB and HBase, using an automated migration platform.
The article presents a series of interviews from Qunar's Technology Carnival, featuring experts Liang Zhangping, Wang Zhufeng, and Zheng Jimin who discuss hotel booking flow improvements, database architecture comparisons and migration to PXC, and comprehensive system stability governance practices.
A telecom client migrated from IBM AIX/Oracle 11g to a domestic X86 appliance with Oracle 19c, encountering slow TimesTen Cache Group rebuilds, and the article details the root‑cause analysis and step‑by‑step optimization that cut rebuild time to one‑third.
This article details a real‑world migration from Oracle 11g on IBM AIX to Oracle 19c, focusing on exporting a 2 TB LOB‑heavy table by adjusting undo retention, then using ROWID‑based modulo queries with Data Pump to achieve balanced, error‑free parallel exports.
This article explains the background of Oracle 19c hot clone, lists the prerequisites, details the three‑phase cloning process, provides exhaustive local, remote, subset and refreshable PDB scenarios with exact SQL commands, highlights common errors and their solutions, and concludes with best‑practice recommendations.
This article explains how to upgrade the think-mongo module for ThinkJS to work with MongoDB 4.x, detailing API changes, new CRUD method mappings, transaction support, and provides code examples for adapting existing projects to the latest MongoDB features.
This guide explains why Tencent Cloud’s Basic Network must be replaced by VPC for security isolation and details migration methods—including interconnection, CVM conversion, IP changes, image rebuilding, database VPC conversion, DTS, and load‑balancer adjustments—illustrated by a case study moving 600+ CVMs across 80 projects.
This case study details the migration of Weimeng's MySQL databases to Tencent Cloud CDB, describing the testing methodology, performance bottlenecks discovered (NUMA, network parameters, low‑concurrency issues, and version bugs), the step‑by‑step optimizations applied, and the resulting QPS improvements across various workloads.
An engineer’s mishap with a massive ‘INSERT INTO … SELECT’ migration exposed how full‑table scans lock MySQL tables, causing payment failures, and shows that adding an index on the filter column prevents the lock and ensures safe, efficient data transfer.
This report details the background, testing methodology, encountered issues, optimization steps, migration process, and final performance outcomes of moving Weimeng's MySQL databases to Tencent Cloud CDB, providing a comprehensive case study for database engineers and cloud architects.
This Laravel Schema cheat sheet provides concise, English-translated code examples for creating, modifying, and managing database tables, columns, indexes, and foreign keys, covering table creation, column types, indexing options, and common schema operations with clear syntax.
This article details the DRS team's step‑by‑step investigation and optimization of a massive MySQL migration involving 860,000 tables, addressing timeout, OOM, and performance bottlenecks to reduce total migration time from over 19 hours to under 10 hours.
An engineer’s attempt to migrate millions of orders using INSERT INTO SELECT caused massive table locking, payment failures, and system alerts, but by analyzing the locking behavior and adding an index on the timestamp column, the migration succeeded efficiently, illustrating the importance of proper indexing for large‑scale data moves.
This article walks through the entire Oracle‑to‑GaussDB migration process with Huawei DataSync, covering environment setup, tool constraints, NFS mounting, JDBC driver preparation, configuration file editing, password encryption, export and import execution, and post‑migration validation.
This article introduces Flyway as a database migration tool, explains its working principle, directory and naming conventions, supported databases, and provides detailed step‑by‑step instructions, best‑practice guidelines, and troubleshooting tips for safely managing MySQL schema changes in production environments.
This article explains how to identify and remove various kinds of duplicate data in MySQL—including fully duplicated rows, records with duplicate non‑key columns, and unwanted whitespace inside fields—by using SQL statements, table cloning, OS utilities, and regular‑expression updates, with performance measurements for each method.
This article details Ctrip's migration of large‑scale log processing from Elasticsearch to ClickHouse, explaining why ClickHouse was chosen, the high‑availability deployment architecture, data ingestion strategies, dashboard integration, performance gains, operational practices, and overall cost and reliability improvements.
The article recounts Olery’s five‑year evolution from a Ruby‑centric stack using MongoDB and MySQL to a PostgreSQL‑based architecture, detailing schema‑less pitfalls, database requirements, migration strategies, code adaptations, and the measurable performance gains achieved after the transition.
The article explains various database migration approaches—including code‑first, data‑first, big‑bang releases, expand‑contract migrations, and double‑writing with dark reads—highlighting how feature toggles influence compatibility and safety during production system changes.
Meitu migrated its high‑traffic push‑service storage from fragmented Redis nodes to the TiKV‑based Titan system, using a dual‑write rollout, batch‑operation tuning, and TiKV configuration tweaks, achieving required QPS, cutting costs by about 60%, and delivering stable, maintainable service after six months.
