clickhouse-upgrade-migration

# ClickHouse Upgrade & Migration ## Overview Safely upgrade ClickHouse server and the `@clickhouse/client` Node.js SDK, with rollback procedures and breaking change detection. ## Prerequisites - Current ClickHouse version known (`SELECT version()`) - Git for version control - Test suite for integration validation - Staging environment for pre-production testing ## Instructions ### Step 1: Check Current Versions ```bash # Check server version (via HTTP) curl 'http://localhost:8123/?query=SELECT+version()' # Check Node.js client version npm list @clickhouse/client # Check latest available npm view @clickhouse/client version ``` ```sql -- Server-side version details SELECT version() AS server_version, uptime() AS uptime_sec, currentDatabase() AS current_db; ``` ### Step 2: Review Changelog ```bash # View release notes open https://github.com/ClickHouse/clickhouse-js/releases # Server changelog open https://github.com/ClickHouse/ClickHouse/blob/master/CHANGELOG.md ``` **Key breaking changes to watch for:** - Client API signature changes (`createClient` options) - Default setting changes (compression, timeouts) - New query result format behavior - Deprecated SQL functions removed in server upgrades - MergeTree settings renamed or defaults changed ### Step 3: Upgrade the Node.js Client ```bash git checkout -b upgrade/clickhouse-client npm install @clickhouse/client@latest npm test ``` **Common migration patterns:** ```typescript ...