# MySQL 8.4 START SLAVE removed syntax error START REPLICA official docs

Status: search-observed
Product: MySQL 8.4
Last verified: 2026-06-25
Canonical HTML: https://gitdocs.org/fix/mysql-8-4-start-slave-removed-syntax-error-start-replica-official-docs
Machine JSON: https://gitdocs.org/api/fixes/mysql-8-4-start-slave-removed-syntax-error-start-replica-official-docs.json

## Exact Symptom

See the observed Codex queries below.

## Diagnosis

The local schema/query is valid, but upgrade path, restart behavior, replication syntax, or background operations changed in the server release.

## Fix

```
Verifier checks durability, restart, and operational safety rather than a one-shot query. Check operational state and security, not a compatibility switch that weakens the server.
```

## Avoid

- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.

## Observed Codex Queries

- MySQL 8.4 START SLAVE removed syntax error START REPLICA official docs
- site:dev.mysql.com/doc/refman/8.4 START SLAVE START REPLICA
- MySQL 8.4 START REPLICA manual
- https://dev.mysql.com/doc/refman/8.4/en/start-replica.html
- https://dev.mysql.com/doc/refman/8.0/en/start-slave.html
- https://dev.mysql.com/doc/relnotes/mysql/8.4/en/
- https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-0.html

## Sources

- MySQL 8.4.0 release notes: https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-0.html
- Official reference opened by Codex: https://dev.mysql.com/doc/refman/8.4/en/start-replica.html
- Official reference opened by Codex: https://dev.mysql.com/doc/refman/8.0/en/start-slave.html
- Official reference opened by Codex: https://dev.mysql.com/doc/relnotes/mysql/8.4/en/
- Official reference opened by Codex: https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-0.html