Request: Option to specify function to use for importing foreign schema

[einhverfr]

In general there may be different ways we need to be able to import a foreign schema. Someone might assume that all files are to be imported, but others might need to be able to rotate files atomically according to some logic. Having some interface for specifying this function would be really helpful.

[Seth-PM]

needed for AB 2.0, will be done after 15.https://github.com/adjust/parquet_fdw/issues/15

[Seth-PM]

to be done by @zilder

[zilder]

Hi @einhverfr,

I'm working on a solution. I decided to add a separate function import_parquet() for this tasks (it think IMPORT FOREIGN SCHEMA is not well suited for it). You can find its description in README.md in the import branch. It's still in early stage of development and wasn't tested. I'll add a way to specify extra foreign table options and also to provide a list of table attributes (columns) to import in case end-user would want customize their foreign table.

[zilder]

The feature is ready for testing. The description is in README.md (the import section). The code is in import branch.

[alexeyklyukin]

@zilder Would you like to make a PR from this at this point (and also, perhaps, merge the current master in)?

Not a proper review, but there were some compiler warnings about unused variables in the parquet_impl.cpp

On thing I had to add here on MacOS is

#ifndef _GNU_SOURCE
#include <libgen.h>
#endif

that contains basename. Also, basename won't work on Windows.

[zilder]

@alexeyklyukin I'm going to do some refactoring regarding the use of postgres and c++ exceptions together. Things are not good right now. I'll create a PR after I finish this.

[zilder]

Merged into master