Re: Serializable Isolation without blocking

Robert Haas <robertmhaas@gmail.com> wrote:

> Nope, you're on target.  Although - if I were you - I would post
> the ACCESS EXCLUSIVE lock version of the patch for feedback.  I
> can't speak for anyone else, but I'll read it.

Here you go!  :-)

This is the milestone of having full serializable behavior, albeit
with horrible performance, using the simplest implementation
possible.  I didn't use ACCESS EXCLUSIVE locks, because on review it
seemed to me that a SHARE lock would be strong enough.  It compiles
and passes the regression tests, and I've been testing some of the
scenarios previously used to show the snapshot anomalies; I now get
correct behavior through blocking.

I identified the points to insert predicate locking by looking for
places where ExecStoreTuple was called with a valid heap buffer; if
there is anywhere that obtains tuples from the heap without going
through that method, I have more work to do.  If anyone knows of
such locations, I'd be grateful for a "heads up".

If I've done anything horribly wrong in organizing the code, that'd
be nice to hear about before I go too much farther, too.

I'm definitely not looking for this to be committed, but should I
add it to the CF page just for a "feedback" review?  (I'm OK with
keeping it more ad hoc, especially if it's going to hold up the
beta at all.)

-Kevin