Re: Serializable Isolation without blocking

On Thu, Jan 7, 2010 at 2:40 PM, Greg Stark <gsstark@mit.edu> wrote:
> On Thu, Jan 7, 2010 at 11:08 AM, Markus Wanner <markus@bluegap.ch> wrote:
>> Row level locks are very fine grained, but those are spilled to disk in
>> its current implementation. So those are an even worse fit for the needs
>> of SIREAD.
>
> I think we're still talking past the issue. Predicate locks are not
> row level, nor page level, nor table level.

They're not?  They're just floating out in space somewhere?  There are
several possible ways to implement predicate locks, but every possible
method I can think of involves attaching them at one of those places.

> And how do you do that without tying the implementation to specific
> details of how our planner, table scans, and index access methods
> work?

You don't.  You add additional methods to the index AMs to support
predicate locks, just lilke we do when we want them to support
anything else (bitmap index scans, index-only scans, etc.).

...Robert