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David Rowley db448ce5ad Optimize alignment calculations in tuple form/deform
Here we convert CompactAttribute.attalign from a char, which is directly
derived from pg_attribute.attalign into a uint8, which stores the number
of bytes to align the column's value by in the tuple.

This allows tuple deformation and tuple size calculations to move away
from using the inefficient att_align_nominal() macro, which manually
checks each TYPALIGN_* char to translate that into the alignment bytes
for the given type.  Effectively, this commit changes those to TYPEALIGN
calls, which are branchless and only perform some simple arithmetic with
some bit-twiddling.

The removed branches were often mispredicted by CPUs, especially so in
real-world tables which often contain a mishmash of different types
with different alignment requirements.

Author: David Rowley
Reviewed-by: Andres Freund, Victor Yegorov
Discussion: https://postgr.es/m/CAApHDvrBztXP3yx=NKNmo3xwFAFhEdyPnvrDg3=M0RhDs+4vYw@mail.gmail.com
2024-12-21 09:43:26 +13:00
.github Add CODE_OF_CONDUCT.md, CONTRIBUTING.md, and SECURITY.md. 2024-07-02 13:03:58 -05:00
config Use <stdint.h> and <inttypes.h> for c.h integers. 2024-12-04 15:05:38 +13:00
contrib Optimize alignment calculations in tuple form/deform 2024-12-21 09:43:26 +13:00
doc Remove pg_attribute.attcacheoff column 2024-12-20 23:22:37 +13:00
src Optimize alignment calculations in tuple form/deform 2024-12-21 09:43:26 +13:00
.cirrus.star Remove duplicate words in docs and code comments. 2023-10-09 09:18:47 +05:30
.cirrus.tasks.yml ci: Fix cached MacPorts installation management 2024-11-27 11:51:54 -05:00
.cirrus.yml ci: Make compute resources for CI configurable 2023-08-23 15:15:28 -07:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
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.git-blame-ignore-revs Add a couple of recent commits to .git-blame-ignore-revs. 2024-11-22 12:17:35 -06:00
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.mailmap Add a Git .mailmap file 2024-11-05 13:56:02 +01:00
aclocal.m4 autoconf: Move export_dynamic determination to configure 2022-12-06 18:55:28 -08:00
configure Use <stdint.h> and <inttypes.h> for c.h integers. 2024-12-04 15:05:38 +13:00
configure.ac Use <stdint.h> and <inttypes.h> for c.h integers. 2024-12-04 15:05:38 +13:00
COPYRIGHT Update copyright for 2024 2024-01-03 20:49:05 -05:00
GNUmakefile.in Allow selecting the git revision to be packaged by "make dist". 2024-05-03 11:08:50 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Remove AIX support 2024-02-28 15:17:23 +04:00
meson_options.txt Make PG_TEST_EXTRA env var override the "meson setup" option 2024-11-04 14:09:25 +02:00
meson.build Use <stdint.h> and <inttypes.h> for c.h integers. 2024-12-04 15:05:38 +13:00
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PostgreSQL Database Management System

This directory contains the source code distribution of the PostgreSQL database management system.

PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.

Copyright and license information can be found in the file COPYRIGHT.

General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.

The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.