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David Rowley 1b0d9aa4f7 Improve the generation memory allocator
Here we make a series of improvements to the generation memory
allocator, namely:

1. Allow generation contexts to have a minimum, initial and maximum block
sizes. The standard allocator allows this already but when the generation
context was added, it only allowed fixed-sized blocks.  The problem with
fixed-sized blocks is that it's difficult to choose how large to make the
blocks.  If the chosen size is too small then we'd end up with a large
number of blocks and a large number of malloc calls. If the block size is
made too large, then memory is wasted.

2. Add support for "keeper" blocks.  This is a special block that is
allocated along with the context itself but is never freed.  Instead,
when the last chunk in the keeper block is freed, we simply mark the block
as empty to allow new allocations to make use of it.

3. Add facility to "recycle" newly empty blocks instead of freeing them
and having to later malloc an entire new block again.  We do this by
recording a single GenerationBlock which has become empty of any chunks.
When we run out of space in the current block, we check to see if there is
a "freeblock" and use that if it contains enough space for the allocation.

Author: David Rowley, Tomas Vondra
Reviewed-by: Andy Fan
Discussion: https://postgr.es/m/d987fd54-01f8-0f73-af6c-519f799a0ab8@enterprisedb.com
2022-04-04 20:53:13 +12:00
config Refactor DLSUFFIX handling 2022-03-25 08:56:02 +01:00
contrib Use has_privs_for_roles for predefined role checks: round 2 2022-04-02 13:24:38 -04:00
doc Set relfrozenxid to oldest extant XID seen by VACUUM. 2022-04-03 09:57:21 -07:00
src Improve the generation memory allocator 2022-04-04 20:53:13 +12:00
.cirrus.yml Make upgradecheck a no-op in MSVC's vcregress.pl 2022-04-02 12:06:11 +09:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Add a few recent and not so recent revs to git-blame-ignore-revs. 2022-03-19 12:37:28 -07:00
.gitattributes gitattributes: Add new entry to silence whitespace error 2021-06-05 07:57:31 +02:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2022 2022-01-07 19:04:57 -05:00
GNUmakefile.in add missing tag from commit b8c4261e5e 2021-07-01 15:47:46 -04:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Set minimum required version of zstd as 1.4.0. 2022-04-01 11:05:52 -04:00
configure.ac Set minimum required version of zstd as 1.4.0. 2022-04-01 11:05:52 -04:00

README

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.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

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