asmhatreandClaude Sonnet 5
e478eafda3
Companion code for Zero-Downtime Database Migrations: Expand-Contract in Practice with Spring Boot: a full expand/migrate-writes/migrate-reads/contract sequence run as an actual rolling deploy across two live replicas, with a load generator sending continuous HTTP traffic through all four deploys (99.98% success, every residual error traced to a root cause rather than left unexplained). Findings include a real NOT NULL constraint trap in the expand migration, a backfill-window bug in the read switch, H2's AUTO_SERVER=TRUE single-point-of-failure behavior under a rolling restart, the drain-before-SIGTERM fix needed to close a health-check gap during graceful shutdown, and H2 silently discarding a concurrently committed INSERT during an ALTER TABLE ADD/DROP COLUMN rebuild - confirmed, by primary source, to be an H2-specific behavior rather than a property of the technique itself. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_019Fb7vW8vLyLKngBc4R3huA
93 lines
3.2 KiB
XML
93 lines
3.2 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-parent</artifactId>
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<version>4.1.1</version>
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<relativePath/>
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</parent>
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<groupId>com.ankurm</groupId>
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<artifactId>db-migrations-expand-contract</artifactId>
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<version>1.0.0</version>
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<name>db-migrations-expand-contract</name>
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<description>Companion code for Zero-Downtime Database Migrations: Expand-Contract in Practice with Spring Boot</description>
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<properties>
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<java.version>25</java.version>
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<maven.compiler.release>25</maven.compiler.release>
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</properties>
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<dependencies>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-web</artifactId>
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</dependency>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-jdbc</artifactId>
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</dependency>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-actuator</artifactId>
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</dependency>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-flyway</artifactId>
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</dependency>
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<dependency>
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<groupId>com.h2database</groupId>
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<artifactId>h2</artifactId>
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<scope>runtime</scope>
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</dependency>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-test</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-flyway-test</artifactId>
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<scope>test</scope>
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</dependency>
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</dependencies>
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<build>
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<plugins>
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<plugin>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-maven-plugin</artifactId>
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</plugin>
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<!--
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scripts/start-db-server.sh, scripts/migrate.sh and scripts/run-load-generator.sh
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all run a plain "java -cp ..." against target/classes, rather than the fat jar
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the app itself starts from - MigrationCli and LoadGenerator are deliberately NOT
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part of the Spring Boot application (see docs/03-why-migrations-run-outside-the-app.md
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and docs/11-the-load-generator.md), so they need their own classpath file. This
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writes it as a normal part of `mvn package`, so a fresh clone never needs a
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separate manual step.
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-->
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-dependency-plugin</artifactId>
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<executions>
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<execution>
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<id>write-runtime-classpath</id>
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<phase>prepare-package</phase>
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<goals>
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<goal>build-classpath</goal>
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</goals>
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<configuration>
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<outputFile>${project.basedir}/cp.txt</outputFile>
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</configuration>
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</execution>
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</executions>
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</plugin>
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</plugins>
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</build>
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</project>
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