Re: shared-memory based stats collector

At Thu, 04 Jul 2019 19:27:54 +0900 (Tokyo Standard Time), Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com> wrote in <20190704(dot)192754(dot)27063464(dot)horikyota(dot)ntt(at)gmail(dot)com>
> #db #tbl #clients #iter #xactlen #referers
> A1: 1 1 1 20000 10 0
> A2: 1 1 1 20000 10 1
> B1: 1 1 90 2000 10 0
> B2: 1 1 90 2000 10 1
> C1: 1 50 90 2000 10 0
> C2: 1 50 90 2000 10 1
> D1: 50 1 90 2000 10 0
> D2: 50 1 90 2000 10 1
> E1: 50 1 90 2000 10 10
> F1: 50 1 10 2000 10 90
>
>
>
> master patched
> updator referrer updator referrer
> time / stdev count / stdev time / stdev count / stdev
> A1: 1769.13 / 71.87 1729.97 / 61.58
> A2: 1903.94 / 75.65 2906.67 / 78.28 1849.41 / 43.00 2855.33 / 62.95
> B1: 2967.84 / 9.88 2984.20 / 6.10
> B2: 3005.38 / 5.32 253.00 / 33.09 3007.26 / 5.70 253.33 / 60.63
> C1: 3066.14 / 13.80 3069.34 / 11.65
> C2: 3353.66 / 8.14 282.92 / 20.65 3341.36 / 12.44 251.65 / 21.13
> D1: 2977.12 / 5.12 2991.60 / 6.68
> D2: 3005.80 / 6.44 252.50 / 38.34 3010.58 / 7.34 282.33 / 57.07
> E1: 3255.47 / 8.91 244.02 / 17.03 3293.88 / 18.05 249.13 / 14.58
> F1: 2620.85 / 9.17 202.46 / 3.35 2668.60 / 41.04 208.19 / 6.79
>
>
> ratio (100: same, smaller value means patched version is faster)
>
> updator referrer
> patched/master(%) master/patched (%)
> A1: 97.79 -
> A2: 97.14 101.80
> B1: 100.55
> B2: 100.06 99.87
> C1: 100.10
> C2: 99.63 112.43
> D1: 100.49
> D2: 100.16 89.43
> E1: 101.18 97.95
> F1: 101.82 97.25
>
>
> Mmm... I don't see distinctive tendency.. Referrer side shows
> larger fluctuation but I'm not sure that suggests something
> meaningful.
>
> I'll rerun the bencmarks with loger period (many itererations).

I put more puressure to the system.

G1: 1 db, 400 clients, 1000 tables, 20000 loops/client, 1000 query/tr, 0 reader
G2: 1 db, 400 clients, 1000 tables, 20000 loops/client, 1000 query/tr, 1 reader

Result:
master patched
updator referrer updator referrer
time / stdev count / stdev time / stdev count / stdev
G1: 125946.22 / 796.83 125227.24 / 89.82
G2: 126463.47 / 81.87 1985.70 / 33.96 125427.95 / 82.35 1985.60 / 55.24

Ratio: (100: same, smaller value means patched version is faster)

updator referrer
patched/master(%) master/patched (%)
G1: 99.40 -
G2: 99.18 100.0

Slightly faster, or maybe significantly enough considering the
stdev. More crucial difference is shown outside the
numbers. Non-patched version complained that (incorrectly) "stats
collector not respond, used stale stats" many times, which is not
seen on patched version. That means that the reader reads older
numbers as far as 1 second ago. (It might be good that writer
should complain about update holdoff for more than, say 0.75s.)

CF-bot warned that it doesn't work on Windows. I'm experiencing
an very painful time to wait for tortoise git is walking slowly
as its name suggests. It would be fixed in the next version.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center