Re: [WIP] Zipfian distribution in pgbench

On Thu, Jul 13, 2017 at 10:02 AM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> The number of leaf pages at the left hand side of the leaf level seems
> to be ~50 less than the unpatched 128 client case was the first time
> around, which seems like a significant difference. I wonder why. Maybe
> autovacuum ran at the right/wrong time this time around?

To reiterate what I say above:

The number of leaf pages with dead items is 20 with this most recent
run (128 clients, patched + unpatched). The leftmost internal page one
level up from the leaf level contains 289 items. Whereas last time it
was 353 items.

That's a difference between having 20 hot/bloated leaf pages, and
probably 84 hot/bloated pages, which I infer must have been the total
number of bloated leaf pages within "result.txt". I think that
something about all the "pgbench_index_*txt" tests are very different
to what we see within "result.txt". It's as if there was a problem
when "result.txt" ran, but that problem somehow didn't come up when
you did new tests.

--
Peter Geoghegan