Re: please update ps display for recovery checkpoint

Hi,

I like the idea behind this patch.  I wrote a new version with a
couple of changes:

    1. Instead of using StringInfoData, just use a small buffer along
       with snprintf().  This is similar to what the WAL receiver
       process does.
    2. If the process is the checkpointer, reset the display to "idle"
       once the checkpoint or restartpoint is finished.  It's easy
       enough to discover the backend type, and I think adding a bit
       more clarity to the checkpointer display is a nice touch.
    3. Instead of "running," use "creating."  IMO that's a bit more
       accurate.

I considered also checking that update_process_title was enabled, but
I figured that these ps display updates should happen sparsely enough
that it wouldn't make much of an impact.

What do you think?

Nathan