Re: Changeset Extraction v7.1

> I wonder if it wouldn't be better to get rid of the subdirectories for
> the individual slots, and just have a file pg_replslot/$SLOTNAME, or
> not.  I know there are later patches that need subdirectories for
> their own private data, but they could just create
> pg_replslot/$SLOTNAME.dir and put whatever in it they like, without
> really implicating this code that much.  The advantage of that is that
> there would be fewer intermediate states.  The slot exists if the file
> exists, and not if it doesn't.  You still need half-alive and
> half-dead until the fsync finishes, but you don't need to worry about
> tracking both the state of the directory and the state of the file.

Why do we need directories at all?  I know there might be subsidiary
files to store stuff in separate files, but maybe we can just name files
using the slot name (or a transformation thereof) as a prefix.  It
shouldn't be difficult to remove the right files whenever there's a
need, and not having to worry about a directory that might need a
separate fsync might make things easier.

On the other hand, there might still be a need to fsync the parent
directory, so maybe there is not that much gain.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
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