Re: pg_dump, pg_dumpall and data durability

Michael Paquier wrote:
> A typo s/pre_fsync_fname/pre_sync_fname, and a mistake from me because
> I did not compile with -DPG_FLUSH_DATA_WORKS to check this code.
> 
> v2 is attached, fixing those issues.

The patch applies and compiles fine.

I have tested it on Linux and MinGW and could see the fsync(2) and
FlushFileBuffers calls I expected.
This adds crash safety for a reasonable price, and I think we should have that.

The documentation additions are sufficient.

Looking through the patch, I had two questions that are more about
style and consistency than anything else:

- In pg_dumpall.c, the result of fsync_fname() is cast to "void" to show that
  the return code is ignored, but not anywhere else.  Is that by design?

- For pg_dumpall, a short option "-N" is added for "--no-sync", but not for
  pg_dump (because -N is already taken there).
  I'd opt for either using the same short option for both or (IMO better)
  only offering a long option for both.
  This would avoid confusion, and we expect that few people will want to use
  this option anyway, right?

Yours,
Laurenz Albe