mirror of
https://github.com/postgres/postgres.git
synced 2025-07-27 12:41:57 +03:00
870a980aaf
Up to now, PG has assumed that any given timezone abbreviation (such as
"EDT") represents a constant GMT offset in the usage of any particular
region; we had a way to configure what that offset was, but not for it
to be changeable over time. But, as with most things horological, this
view of the world is too simplistic: there are numerous regions that have
at one time or another switched to a different GMT offset but kept using
the same timezone abbreviation. Almost the entire Russian Federation did
that a few years ago, and later this month they're going to do it again.
And there are similar examples all over the world.
To cope with this, invent the notion of a "dynamic timezone abbreviation",
which is one that is referenced to a particular underlying timezone
(as defined in the IANA timezone database) and means whatever it currently
means in that zone. For zones that use or have used daylight-savings time,
the standard and DST abbreviations continue to have the property that you
can specify standard or DST time and get that time offset whether or not
DST was theoretically in effect at the time. However, the abbreviations
mean what they meant at the time in question (or most recently before that
time) rather than being absolutely fixed.
The standard abbreviation-list files have been changed to use this behavior
for abbreviations that have actually varied in meaning since 1970. The
old simple-numeric definitions are kept for abbreviations that have not
changed, since they are a bit faster to resolve.
While this is clearly a new feature, it seems necessary to back-patch it
into all active branches, because otherwise use of Russian zone
abbreviations is going to become even more problematic than it already was.
This change supersedes the changes in commit 513d06ded et al to modify the
fixed meanings of the Russian abbreviations; since we've not shipped that
yet, this will avoid an undesirably incompatible (not to mention incorrect)
change in behavior for timestamps between 2011 and 2014.
This patch makes some cosmetic changes in ecpglib to keep its usage of
datetime lookup tables as similar as possible to the backend code, but
doesn't do anything about the increasingly obsolete set of timezone
abbreviation definitions that are hard-wired into ecpglib. Whatever we
do about that will likely not be appropriate material for back-patching.
Also, a potential free() of a garbage pointer after an out-of-memory
failure in ecpglib has been fixed.
This patch also fixes pre-existing bugs in DetermineTimeZoneOffset() that
caused it to produce unexpected results near a timezone transition, if
both the "before" and "after" states are marked as standard time. We'd
only ever thought about or tested transitions between standard and DST
time, but that's not what's happening when a zone simply redefines their
base GMT offset.
In passing, update the SGML documentation to refer to the Olson/zoneinfo/
zic timezone database as the "IANA" database, since it's now being
maintained under the auspices of IANA.
The PostgreSQL contrib tree
---------------------------
This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly because
they address a limited audience or are too experimental to be part of
the main source tree. This does not preclude their usefulness.
User documentation for each module appears in the main SGML documentation.
Most items can be built with `gmake all' and installed with
`gmake install' in the usual fashion, after you have run the `configure'
script in the top-level directory. Some directories supply new
user-defined functions, operators, or types. In these cases, after you have
installed the files you need to register the new entities in the database
system by running the commands in the supplied .sql file. For example,
$ psql -d dbname -f module.sql
See the PostgreSQL documentation for more information about this
procedure.
Index:
------
adminpack -
File and log manipulation routines, used by pgAdmin
by Dave Page <dpage@vale-housing.co.uk>
auto_explain -
Log EXPLAIN output for long-running queries
by Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>
btree_gin -
Support for emulating BTREE indexing in GIN
by Oleg Bartunov <oleg@sai.msu.su> and Teodor Sigaev <teodor@sigaev.ru>
btree_gist -
Support for emulating BTREE indexing in GiST
by Oleg Bartunov <oleg@sai.msu.su> and Teodor Sigaev <teodor@sigaev.ru>
chkpass -
An auto-encrypted password datatype
by D'Arcy J.M. Cain <darcy@druid.net>
citext -
A case-insensitive character string datatype
by David E. Wheeler <david@kineticode.com>
cube -
Multidimensional-cube datatype (GiST indexing example)
by Gene Selkov, Jr. <selkovjr@mcs.anl.gov>
dblink -
Allows remote query execution
by Joe Conway <mail@joeconway.com>
dict_int -
Text search dictionary template for integers
by Sergey Karpov <karpov@sao.ru>
dict_xsyn -
Text search dictionary template for extended synonym processing
by Sergey Karpov <karpov@sao.ru>
earthdistance -
Functions for computing distances between two points on Earth
by Bruno Wolff III <bruno@wolff.to> and Hal Snyder <hal@vailsys.com>
fuzzystrmatch -
Levenshtein, metaphone, and soundex fuzzy string matching
by Joe Conway <mail@joeconway.com> and Joel Burton <jburton@scw.org>
hstore -
Module for storing (key, value) pairs
by Oleg Bartunov <oleg@sai.msu.su> and Teodor Sigaev <teodor@sigaev.ru>
intagg -
Integer aggregator
by mlw <markw@mohawksoft.com>
intarray -
Index support for arrays of int4, using GiST
by Teodor Sigaev <teodor@sigaev.ru> and Oleg Bartunov <oleg@sai.msu.su>
isn -
PostgreSQL type extensions for ISBN, ISSN, ISMN, EAN13 product numbers
by Germ<72>n M<>ndez Bravo (Kronuz) <kronuz@hotmail.com>
lo -
Large Object maintenance
by Peter Mount <peter@retep.org.uk>
ltree -
Tree-like data structures
by Teodor Sigaev <teodor@sigaev.ru> and Oleg Bartunov <oleg@sai.msu.su>
oid2name -
Maps numeric files to table names
by B Palmer <bpalmer@crimelabs.net>
pageinspect -
Allows inspection of database pages
Heikki Linnakangas <heikki@enterprisedb.com>
passwordcheck -
Simple password strength checker
Laurenz Albe <laurenz.albe@wien.gv.at>
pg_buffercache -
Real time queries on the shared buffer cache
by Mark Kirkwood <markir@paradise.net.nz>
pg_freespacemap -
Displays the contents of the free space map (FSM)
by Mark Kirkwood <markir@paradise.net.nz>
pg_standby -
Sample archive_command for warm standby operation
by Simon Riggs <simon@2ndquadrant.com>
pg_stat_statements -
Track statement execution times across a whole database cluster
by Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp>
pg_trgm -
Functions for determining the similarity of text based on trigram
matching.
by Oleg Bartunov <oleg@sai.msu.su> and Teodor Sigaev <teodor@sigaev.ru>
pg_upgrade -
Support for in-place upgrade between major releases of PostgreSQL
Bruce Momjian <bruce@momjian.us> and others
pgbench -
TPC-B like benchmarking tool
by Tatsuo Ishii <ishii@sraoss.co.jp>
pgcrypto -
Cryptographic functions
by Marko Kreen <marko@l-t.ee>
pgrowlocks -
A function to return row locking information
by Tatsuo Ishii <ishii@sraoss.co.jp>
pgstattuple -
Functions to return statistics about "dead" tuples and free
space within a table
by Tatsuo Ishii <ishii@sraoss.co.jp>
seg -
Confidence-interval datatype (GiST indexing example)
by Gene Selkov, Jr. <selkovjr@mcs.anl.gov>
spi -
Various trigger functions, examples for using SPI.
sslinfo -
Functions to get information about SSL certificates
by Victor Wagner <vitus@cryptocom.ru>
start-scripts -
Scripts for starting the server at boot time on various platforms.
tablefunc -
Examples of functions returning tables
by Joe Conway <mail@joeconway.com>
test_parser -
Sample text search parser
by Sergey Karpov <karpov@sao.ru>
tsearch2 -
Compatibility package for the pre-8.3 implementation of text search.
Pavel Stehule <pavel.stehule@gmail.com>, based on code originally by
Teodor Sigaev <teodor@sigaev.ru> and Oleg Bartunov <oleg@sai.msu.su>.
unaccent -
Unaccent dictionary for text search
Teodor Sigaev <teodor@sigaev.ru> and Oleg Bartunov <oleg@sai.msu.su>.
uuid-ossp -
UUID generation functions
by Peter Eisentraut <peter_e@gmx.net>
vacuumlo -
Remove orphaned large objects
by Peter T Mount <peter@retep.org.uk>
xml2 -
Storing XML in PostgreSQL
by John Gray <jgray@azuli.co.uk>