This pgloader command allows to migrate tables while changing the schema
they are found into in between their MySQL source database and their
PostgreSQL target database.
This changes the default behavior of pgloader with MySQL from always
targetting the 'public' schema to targetting by default a schema named
the same as the MySQL database. You can revert to the old behavior by
adding a rule:
ALTER SCHEMA 'dbname' RENAME TO 'public
We might want to add a patch to re-install the default behavior later.
Also see #489 where it used not to be possible to rename the schema at
migration time, causing strange errors (you need to spot NIL as the
schema name in the "failed to find target table" messages.
When loading data into an existing PostgreSQL catalog, we DROP the
indexes for better performance of the data loading. Some of the indexes
are UNIQUE or even PRIMARY KEYS, and some FOREIGN KEYS might depend on
them in the PostgreSQL dependency tracking of the catalog.
We used to use the CASCADE option when dropping the indexes, which hides
a bug: if we exclude from the load tables with foreign keys pointing to
tables we target, then we would DROP those foreign keys because of the
CASCADE option, but fail to install them again at the end of the load.
To prevent that from happening, pgloader now query the PostgreSQL
pg_depend system catalog to list the “missing” foreign keys and add them
to our internal catalog representation, from which we know to DROP then
CREATE the SQL object at the proper times.
See #400 as this was an oversight in fixing this issue.
