Hello Tom,

FWIW, I vote with Tatsuo-san.  Such a change will break comparability of
results

I would not classify a performance measure as a "result compatibility" issue. What matters is the *correction* of the results.

When a bug is fixed anywhere in pg it may change performance significantly for some tests, and I have never seen this as a relevant consideration not to fix a problem...

with all previous versions, which means it's not something to do
in minor releases, even if we now believe the previous results were
somewhat bogus.  Arguing that it's "not a behavioral change" seems
quite loony to me: for most people, the TPS numbers are the only
interesting output of pgbench.

I think that if people are interested in tps without reconnecting on each transaction they would not run with "-C" to trigger reconnections and then look at the "tps without connections" for the figure they want... so I do not think that keeping this error is worth anything.

On the other hand, and on the principle, keeping the bug looks wrong. I cannot agree with the logic behind shipping something which is known bad, especially to display *optimistic* performances... It looks too much like the VW way:-)

I think we should fix it in 9.5 and document it as an incompatible change.

Hmm.

(Note: I've not read the patch, so this is not an opinion about its
correctness.)

That is another question:-)

--
Fabien.


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