Re: group locking: incomplete patch, just for discussion

On Wed, Oct 29, 2014 at 2:18 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
>
> My proposal is we do a parallel index build scan... just as we
> discussed earlier, so you would be following the direction set by Dev
> Meeting, not just a proposal of mine.
>
> As I mentioned previously when you started discussing shared memory
> segments, parallel sort does NOT require shared memory. The only thing
> you need to share are files. Split the problem into N pieces, sort
> them to produce N files and then merge the files using existing code.
> That only applies to large sorts, but then those are the ones you
> cared about doing in parallel anyway.
>
> CREATE INDEX has a lock on the table. Worker tasks can be simply
> banned from acquiring new locks and doing many other tasks.