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Dean Rasheed d1b307eef2 Optimise numeric division for one and two base-NBASE digit divisors.
Formerly div_var() had "fast path" short division code that was
significantly faster when the divisor was just one base-NBASE digit,
but otherwise used long division.

This commit adds a new function div_var_int() that divides by an
arbitrary 32-bit integer, using the fast short division algorithm, and
updates both div_var() and div_var_fast() to use it for one and two
digit divisors. In the case of div_var(), this is slightly faster in
the one-digit case, because it avoids some digit array copying, and is
much faster in the two-digit case where it replaces long division. For
div_var_fast(), it is much faster in both cases because the main
div_var_fast() algorithm is optimised for larger inputs.

Additionally, optimise exp() and ln() by using div_var_int(), allowing
a NumericVar to be replaced by an int in a couple of places, most
notably in the Taylor series code. This produces a significant speedup
of exp(), ln() and the numeric_big regression test.

Dean Rasheed, reviewed by Tom Lane.

Discussion: https://postgr.es/m/CAEZATCVwsBi-ND-t82Cuuh1=8ee6jdOpzsmGN+CUZB6yjLg9jw@mail.gmail.com
2022-02-27 11:12:30 +00:00
config Ensure the right perl is used for TAP tests on msys 2022-02-20 11:51:44 -05:00
contrib Simplify more checks related to set-returning functions 2022-02-24 16:54:59 +09:00
doc postgres_fdw: Add support for parallel commit. 2022-02-24 14:30:00 +09:00
src Optimise numeric division for one and two base-NBASE digit divisors. 2022-02-27 11:12:30 +00:00
.cirrus.yml ci: fix copy-paste mistake in 16eb8231d1. 2022-02-12 19:38:06 -08:00
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.git-blame-ignore-revs Add another old commit to git-blame-ignore-revs. 2021-11-03 17:34:19 -07:00
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aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Ensure the right perl is used for TAP tests on msys 2022-02-20 11:51:44 -05:00
configure.ac Ensure the right perl is used for TAP tests on msys 2022-02-20 11:51:44 -05:00
COPYRIGHT Update copyright for 2022 2022-01-07 19:04:57 -05:00
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Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README
README.git

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
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PostgreSQL is an advanced object-relational database management system
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PostgreSQL has many language interfaces, many of which are listed here:

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