From: | Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> |
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To: | robertmhaas(at)gmail(dot)com |
Cc: | tgl(at)sss(dot)pgh(dot)pa(dot)us, ah(at)cybertec(dot)at, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: [HACKERS] asynchronous execution |
Date: | 2017-12-11 11:07:53 |
Message-ID: | 20171211.200753.191768178.horiguchi.kyotaro@lab.ntt.co.jp |
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Lists: | pgsql-hackers |
Hello,
At Fri, 20 Oct 2017 17:37:07 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote in <20171020(dot)173707(dot)12913619(dot)horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
> The attached PoC patch theoretically has no impact on the normal
> code paths and just brings gain in async cases.
The parallel append just committed hit this and the attached are
the rebased version to the current HEAD. The result of a concise
performance test follows.
patched(ms) unpatched(ms) gain(%)
A: simple table scan : 3562.32 3444.81 -3.4
B: local partitioning : 1451.25 1604.38 9.5
C: single remote table : 8818.92 9297.76 5.1
D: sharding (single con) : 5966.14 6646.73 10.2
E: sharding (multi con) : 1802.25 6515.49 72.3
> A and B are degradation checks, which are expected to show no
> degradation. C is the gain only by postgres_fdw's command
> presending on a remote table. D is the gain of sharding on a
> connection. The number of partitions/shards is 4. E is the gain
> using dedicate connection per shard.
Test A is accelerated by parallel sequential scan. Introducing
parallel append accelerates test B. Comparing A and B, I doubt
that degradation is stably measurable at least my environment but
I believe that there's no degradation theoreticaly. The test C to
E still shows apparent gain.
regards,
--
Kyotaro Horiguchi
NTT Open Source Software Center
Attachment | Content-Type | Size |
---|---|---|
0001-Allow-wait-event-set-to-be-registered-to-resource-ow.patch | text/x-patch | 9.4 KB |
0002-core-side-modification.patch | text/x-patch | 29.1 KB |
0003-async-postgres_fdw.patch | text/x-patch | 48.0 KB |
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