Changelog files + databasechangelog table: Does Liquibase treat id/author/file path as unique?

Answer

Yes. Liquibase treats a changeset as unique by the composite key id + author + filepath. The filepath is stored in DATABASECHANGELOG.FILENAME and is part of the lookup that decides whether a changeset has already run.

Two changesets with the same id and author but different filepaths are distinct. Both will be executed and both will be recorded as separate rows with the same ID and AUTHOR but different FILENAME.

There is no configuration option to make uniqueness (id, author) only. Filepath has been part of the key since early Liquibase releases and remains so in 4.x.

Confirmed facts

• DATABASECHANGELOG contains ID, AUTHOR and FILENAME columns. The history service queries by all three when checking if a changeset has run.
• ChangeSet equality and hashing in Liquibase uses id, author and filepath. That is why the same logical changeset in two different files is treated as two different changesets.
• Renaming or moving a changelog file changes the filepath key. Liquibase will treat it as a new changeset and will attempt to re-run it unless the FILENAME values in DATABASECHANGELOG are also updated.
• Duplicate-changeset warnings about the same id/author appearing in multiple included files are emitted during parsing. The warning is informational. It does not skip execution.

Likely explanation for the warning behavior you saw

The warning "Duplicate changeset id/author found in multiple files" is parse-time information. Execution is still allowed because the filepath differs, so the composite key differs.

Liquibase 4.20+ adds duplicateChangesetMode with values WARN, ERROR, IGNORE. This controls what happens when the exact same changeset, same id, author AND filepath, is encountered multiple times in a single run, for example via multiple include paths. It does not change cross-file id/author uniqueness.

What to check for your CI/CD idempotency

1. Confirm Liquibase version and how changelogs are included. The exact include path string matters because filepath matching is literal.
2. Run an update against a test database with two files containing the same id/author but different paths, then inspect DATABASECHANGELOG for two rows with same ID/AUTHOR and different FILENAME.
3. If you want to avoid the duplicate id/author warning noise, use unique id prefixes per file, e.g., users-create-table vs orders-create-table. This does not change execution semantics.

One diagnostic detail that changes the recommendation: which Liquibase version and which duplicateChangesetMode value, if any, is set in your liquibase.properties or CLI. That determines whether duplicate same-filepath encounters are warned, errored or ignored.