Improve performance of binary COPY FROM through better buffering.
At least on Linux and macOS, fread() turns out to have far higher
per-call overhead than one could wish. Reading 64KB of data at a time
and then parceling it out with our own memcpy logic makes binary COPY
from a file significantly faster --- around 30% in simple testing for
cases with narrow text columns (on Linux ... even more on macOS).
In binary COPY from frontend, there's no per-call fread(), and this
patch introduces an extra layer of memcpy'ing, but it still manages
to eke out a small win. Apparently, the control-logic overhead in
CopyGetData() is enough to be worth avoiding for small fetches.
Bharath Rupireddy and Amit Langote, reviewed by Vignesh C,
cosmetic tweaks by me
Discussion: https://postgr.es/m/CALj2ACU5Bz06HWLwqSzNMN=Gupoj6Rcn_QVC+k070V4em9wu=A@mail.gmail.com
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/0a0727ccfc5f4e2926623abe877bdc0b5bfd682e
Modified Files
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src/backend/commands/copy.c | 118 +++++++++++++++++++++++++++++++-------------
1 file changed, 83 insertions(+), 35 deletions(-)