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
10 lines
626 B
Plaintext
10 lines
626 B
Plaintext
==============================================================================
|
|
What a lingering Stage 1 instance sees if the drop runs before it is retired
|
|
==============================================================================
|
|
captured: 2026-09-16T19:20:58.517481426Z
|
|
|
|
Stage 1 create() after V3 dropped "email": org.springframework.jdbc.BadSqlGrammarException
|
|
message: PreparedStatementCallback; bad SQL grammar [INSERT INTO customers(name, email) VALUES (?, ?)]
|
|
root cause: org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "EMAIL" not found; SQL statement:
|
|
INSERT INTO customers(name, email) VALUES (?, ?) [42122-240]
|