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PostgreSQL7.0手册-管理员手册-35. 版本信息

2019-09-08 23:33:49
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第三十五章. 版本信息
内容 
版本 7.0 
版本 6.5.3 
版本 6.5.2 
版本 6.5.1 
版本 6.5 
版本 6.4.2 
版本 6.4.1 
版本 6.4 
版本 6.3.2 
版本 6.3.1 
版本 6.3 
版本 6.2.1 
版本 6.2 
版本 6.1.1 
版本 6.1 
版本 v6.0 
版本 v1.09 
版本 v1.02 
版本 v1.01 
版本 v1.0 
Postgres95 Beta 0.03 
Postgres95 Beta 0.02 
Postgres95 Beta 0.01 
计时结果 
版本 7.0
这个版本包括许多方面的改进,表现了 PostgreSQL 的持续的进步.在 7.0 里有比以前版本更多的增强和修补.开发人员相信这是目前最好的版本;我们尽力做到只发布稳固的版本,这个也不例外. 
这个版本主要的改变: 

Foreign Keys(外键) 
  
  

Foreign keys(外键)现在已经实现了,除了 PARTIAL MATCH 外键以外.许多用户要求增加这个特性,而我们很高兴现在能提供她. 
  

重写优化器 
  
  

继续一年前开始的工作,优华器现在已经进步多了,允许更好的规划选择和更好的性能,以及更少的存储器使用. 
  

更新的 psql 
  
  

psql,我们的交互终端程序,已经更新并增加了许多新特性.参阅 psql 手册页获取细节. 
  

联合(Join)语法 
  
  

SQL92 联合(join)语法现在被支持了,尽管目前的版本只有 INNER JOIN 被支持.JOIN,NATURAL JOIN,JOIN/USING,JOIN/ON 都可用,这些是字段集合名称.

向 v7.0 移植
那些从任何以前版本的 Postgres移植的人都需要用 pg_dump 做一次倾倒/重载.对于从 6.5.*?升级,你可以使用 pg_upgrade 升级到这个版本;不过,升级最稳固的方法还是一次完整的倾倒/重载. 
这个新版本要考虑的接口和兼容性问题包括: 

日期/时间类型 datetime 和 timespan 已经被 SQL92定义类型 timestamp 和 interval 超越了.尽管我们做了一些努力令 Postgres 识别这些过时的类型名并把它们转换成新类型名以简化类型转化,但是这个机制可能不完全对你的现有应用透明. 
优化器在开销计算方面已经有了变化.有时,这样将令查询时间减少,因为优化器做出了查询规划的更好选择.不过,有一小部分情况下,通常是数据不正常(病态)分布时,你的查询时间可能增加.如果你处理大量的数据,你可能要检查你的查询以核实性能. 

JDBC 和 ODBC 接口都升级和扩展了. 

字符串函数 CHAR_LENGTH 现在是一个内部函数.以前版本是把它转换成对 LENGTH 的调用,这样做会导致与其他类型实现的 LENGTH 的混淆,比如几何类型.

详细修改列表
Bug Fixes
---------
Prevent function calls exceeding maximum number of arguments (Tom)
Improve CASE construct (Tom)
Fix SELECT coalesce(f1,0) FROM int4_tbl GROUP BY f1 (Tom)
Fix SELECT sentence.words[0] FROM sentence GROUP BY sentence.words[0] (Tom)
Fix GROUP BY scan bug (Tom)
Improvements in SQL grammar processing (Tom)
Fix for views involved in INSERT ... SELECT ... (Tom)
Fix for SELECT a/2, a/2 FROM test_missing_target GROUP BY a/2 (Tom)
Fix for subselects in INSERT ... SELECT (Tom)
Prevent INSERT ... SELECT ... ORDER BY (Tom)
Fixes for relations greater than 2GB, including vacuum
Improve propagating system table changes to other backends (Tom)
Improve propagating user table changes to other backends (Tom)
Fix handling of temp tables in complex situations (Bruce, Tom)
Allow table locking at table open, improving concurrent reliability (Tom)
Properly quote sequence names in pg_dump (Ross J. Reedstrom)
Prevent DROP DATABASE while others accessing
Prevent any rows from being returned by GROUP BY if no rows processed (Tom)
Fix SELECT COUNT(1) FROM table WHERE ...' if no rows matching WHERE (Tom)
Fix pg_upgrade so it works for MVCC (Tom)
Fix for SELECT ... WHERE x IN (SELECT ... HAVING SUM(x) > 1) (Tom)
Fix for "f1 datetime DEFAULT 'now'"  (Tom)
Fix problems with CURRENT_DATE used in DEFAULT (Tom)
Allow comment-only lines, and ;;; lines too. (Tom)
Improve recovery after failed disk writes, disk full (Hiroshi)
Fix cases where table is mentioned in FROM but not joined (Tom)
Allow HAVING clause without aggregate functions (Tom)
Fix for "--" comment and no trailing newline, as seen in perl interface
Improve pg_dump failure error reports (Bruce)
Allow sorts and hashes to exceed 2GB file sizes (Tom)
Fix for pg_dump dumping of inherited rules (Tom)
Fix for NULL handling comparisons (Tom)
Fix inconsistent state caused by failed CREATE/DROP commands (Hiroshi)
Fix for dbname with dash
Prevent DROP INDEX from interfering with other backends (Tom)
Fix file descriptor leak in verify_password()
Fix for "Unable to identify an operator =$" problem
Fix ODBC so no segfault if CommLog and Debug enabled (Dirk Niggemann)
Fix for recursive exit call (Massimo)
Fix for extra-long timezones (Jeroen van Vianen)
Make pg_dump preserve primary key information (Peter E)
Prevent databases with single quotes (Peter E)
Prevent DROP DATABASE inside  transaction (Peter E)
ecpg memory leak fixes (Stephen Birch)
Fix for SELECT null::text, SELECT int4fac(null) and SELECT 2 + (null) (Tom)
Y2K timestamp fix (Massimo)
Fix for VACUUM 'HEAP_MOVED_IN was not expected' errors (Tom)
Fix for views with tables/columns containing spaces  (Tom)
Prevent permissions on indexes (Peter E)
Fix for spinlock stuck problem when error is generated (Hiroshi)
Fix ipcclean on Linux
Fix handling of NULL constraint conditions (Tom)
Fix memory leak in odbc driver (Nick Gorham)
Fix for permission check on UNION tables (Tom)
Fix to allow SELECT 'a' LIKE 'a' (Tom)
Fix for SELECT 1 + NULL (Tom)
Fixes to CHAR
Fix log() on numeric type (Tom)
Deprecate ':' and ';' operators
Allow vacuum of temporary tables
Disallow inherited columns with the same name as new columns
Recover or force failure when disk space is exhausted(Hiroshi)
Fix INSERT INTO ... SELECT with AS columns matching result columns
Fix INSERT ... SELECT ... GROUP BY groups by target columns not source columns(Tom)
Fix CREATE TABLE test (a char(5) DEFAULT text '', b int4) with INSERT(Tom)
Fix UNION with LIMIT
Fix CREATE TABLE x AS SELECT 1 UNION SELECT 2
Fix CREATE TABLE test(col char(2) DEFAULT user)
Fix mismatched types in CREATE TABLE ... DEFAULT
Fix SELECT * FROM pg_class where oid in (0,-1)
Fix SELECT COUNT('asdf') FROM pg_class WHERE oid=12
Prevent user who can create databases can modifying pg_database table(Peter E)
Fix btree to give a useful elog when key > 1/2 (page - overhead)(Tom)
Fix INSERT of 0.0 into DECIMAL(4,4) field(Tom)

Enhancements
------------
New CLI interface include file sqlcli.h, based on SQL3/SQL98
Remove all limits on query length, row length limit still exists (Tom)
Update jdbc protocol to 2.0 (Jens Glaser)
Add TRUNCATE command to quickly truncate relation (Mike Mascari)
Fix to give super user and createdb user proper update catalog rights (Peter E)
Allow ecpg bool variables to have NULL values (Christof)
Issue ecpg error if NULL value for variable with no NULL indicator (Christof)
Allow ^C to cancel COPY command (Massimo)
Add SET FSYNC and SHOW PG_OPTIONS commands(Massimo)
Function name overloading for dynamically-loaded C functions (Frankpitt)
Add CmdTuples() to libpq++(Vince)
New CREATE CONSTRAINT TRIGGER and SET CONSTRAINTS commands(Jan)
Allow CREATE FUNCTION/WITH clause to be used for all language types
configure --enable-debug adds -g (Peter E)
configure --disable-debug removes -g (Peter E)
Allow more complex default expressions (Tom)
First real FOREIGN KEY constraint trigger functionality (Jan)
Add FOREIGN KEY ... MATCH FULL ... ON DELETE CASCADE (Jan)
Add FOREIGN KEY ... MATCH  referential actions (Don Baccus)
Allow WHERE restriction on ctid (physical heap location) (Hiroshi)
Move pginterface from contrib to interface directory, rename to pgeasy (Bruce)
Change pgeasy connectdb() parameter ordering (Bruce)
Require SELECT DISTINCT target list to have all ORDER BY columns (Tom)
Add Oracle's COMMENT ON command (Mike Mascari)
libpq's PQsetNoticeProcessor function now returns previous hook(Peter E)
Prevent PQsetNoticeProcessor from being set to NULL (Peter E)
Make USING in COPY optional (Bruce)
Allow subselects in the target list (Tom)
Allow subselects on the left side of comparison operators (Tom)
New parallel regression test (Jan)
Change backend-side COPY to write files with permissions 644 not 666 (Tom)
Force permissions on PGDATA directory to be secure, even if it exists (Tom)
Added psql LASTOID variable to return last inserted oid (Peter E)
Allow concurrent vacuum and remove pg_vlock vacuum lock file (Tom)
Add permissions check for vacuum (Peter E)
New libpq functions to allow asynchronous connections: PQconnectStart(), 
   PQconnectPoll(), PQresetStart(), PQresetPoll(), PQsetenvStart(), 
   PQsetenvPoll(), PQsetenvAbort (Ewan Mellor)
New libpq PQsetenv() function (Ewan Mellor)
create/alter user extension (Peter E)
New postmaster.pid and postmaster.opts under $PGDATA (Tatsuo)
New scripts for create/drop user/db (Peter E)
Major psql overhaul (Peter E)
Add const to libpq interface (Peter E)
New libpq function PQoidValue (Peter E)
Show specific non-aggregate causing problem with GROUP BY (Tom)
Make changes to pg_shadow recreate pg_pwd file (Peter E)
Add aggregate(DISTINCT ...) (Tom)
Allow flag to control COPY input/output of NULLs (Peter E)
Make postgres user have a password by default (Peter E)
Add CREATE/ALTER/DROP GROUP (Peter E)
All administration scripts now support --long options (Peter E, Karel)
Vacuumdb script now supports --all option (Peter E)
ecpg new portable FETCH syntax
Add ecpg EXEC SQL IFDEF, EXEC SQL IFNDEF, EXEC SQL ELSE, EXEC SQL ELIF 
        and EXEC SQL ENDIF directives
Add pg_ctl script to control backend startup (Tatsuo)
Add postmaster.opts.default file to store startup flags (Tatsuo)
Allow --with-mb=SQL_ASCII
Increase maximum number of index keys to 16 (Bruce)
Increase maximum number of function arguments to 16 (Bruce)
Allow configuration of maximum number of index keys and arguments (Bruce)
Allow unprivileged users to change their passwords (Peter E)
Password authentication enabled; required for new users (Peter E)
Disallow dropping a user who owns a database (Peter E)
Change initdb option --with-mb to --enable-multibyte
Add option for initdb to prompts for superuser password (Peter E)
Allow complex type casts like col::numeric(9,2) and col::int2::float8 (Tom)
Updated user interfaces on initdb, initlocation, pg_dump, ipcclean (Peter E)
New pg_char_to_encoding() and pg_encoding_to_char() functions (Tatsuo)
Libpq non-blocking mode (Alfred Perlstein)
Improve conversion of types in casts that don't specify a length
New plperl internal programming language (Mark Hollomon)
Allow COPY IN to read file that do not end with a newline (Tom)
Indicate when long identifiers are truncated (Tom)
Allow aggregates to use type equivalency (Peter E)
Add Oracle's to_char(), to_date(), to_datetime(), to_timestamp(), to_number()
        conversion functions (Karel Zak )
Add SELECT DISTINCT ON (expr [, expr ...]) targetlist ... (Tom)
Check to be sure ORDER BY is compatible with the DISTINCT operation (Tom)
Add NUMERIC and int8 types to ODBC
Improve EXPLAIN results for Append, Group, Agg, Unique (Tom)
Add ALTER TABLE ... ADD FOREIGN KEY (Stephan Szabo)
Allow SELECT .. FOR UPDATE in PL/pgSQL (Hiroshi)
Enable backward sequential scan even after reaching EOF (Hiroshi)
Add btree indexing of boolean values, >= and <= (Don Baccus)
Print current line number when COPY FROM fails (Massimo)
Recognize POSIX time zone e.g. "PST+8" and "GMT-8" (Thomas)
Add DEC as synonym for DECIMAL (Thomas)
Add SESSION_USER as SQL92 keyword, same as CURRENT_USER (Thomas)
Implement SQL92 column aliases (aka correlation names) (Thomas)
Implement SQL92 join syntax (Thomas)
Make INTERVAL reserved word allowed as a column identifier (Thomas)
Implement REINDEX command (Hiroshi)
Accept ALL in aggregate function SUM(ALL col) (Tom)
Prevent GROUP BY from using column aliases (Tom)
New psql /encoding option (Tatsuo)
Allow PQrequestCancel() to terminate when in waiting-for-lock state (Hiroshi)
Allow negation of a negative number in all cases
Add ecpg descriptors (Christof, Michael)
Allow CREATE VIEW v AS SELECT f1::char(8) FROM tbl
Allow casts with length, like foo::char(8)
New libpq functions PQsetClientEncoding(), PQclientEncoding() (Tatsuo)
Add support for SJIS user defined characters (Tatsuo)
Larger views/rules supported
Make libpq's PQconndefaults() thread-safe (Tom)
Disable // as comment to be ANSI conforming, should use -- (Tom)
Allow column aliases on views CREATE VIEW name (collist)
Fixes for views with subqueries (Tom)
Allow UPDATE table SET fld = (SELECT ...) (Tom)
SET command options no longer require quotes
Update pgaccess to 0.98.5
New SET SEED command
New pg_options.sample file
New SET FSYNC command (Massimo)
Allow pg_descriptions when creating tables
Allow pg_descriptions when creating types, columns, and functions
Allow psql /copy to allow delimiters(Peter E)
Allow psql to print nulls as distinct from "" [null](Peter E)

Types
-----
Many array fixes (Tom)
Allow bare column names to be subscripted as arrays (Tom)
Improve type casting of int and float constants (Tom)
Cleanups for int8 inputs, range checking, and type conversion (Tom)
Fix for SELECT timespan('21:11:26'::time) (Tom)
netmask('x.x.x.x/0') is 255.255.255.255 instead of 0.0.0.0 (Oleg Sharoiko)
Add btree index on NUMERIC (Jan)
Perl fix for large objects containing NUL characters (Douglas Thomson) 
ODBC fix for for large objects (free)
Fix indexing of cidr data type
Fix for Ethernet MAC addresses (macaddr type) comparisons
Fix for date/time types when overflows happened in computations (Tom)
Allow array on int8 (Peter E)
Fix for rounding/overflow of NUMERIC type, like NUMERIC(4,4) (Tom)
Allow NUMERIC arrays
Fix bugs in NUMERIC ceil() and floor() functions (Tom)
Make char_length()/octet_length including trailing blanks (Tom)
Made abstime/reltime use int4 instead of time_t (Peter E)
New lztext data type for compressed text fields
Revise code to handle coercion of int and float constants (Tom)
Start at new code to implement a BIT and BIT VARYING type (Adriaan Joubert)
NUMERIC now accepts scientific notation (Tom)
NUMERIC to int4 rounds (Tom)
Convert float4/8 to NUMERIC properly (Tom)
Allow type conversion with NUMERIC (Thomas)
Make ISO date style (2000-02-16 09:33) the default (Thomas)
Add NATIONAL CHAR [ VARYING ] (Thomas)
Allow NUMERIC round and trunc to accept negative scales (Tom)
New TIME WITH TIME ZONE type (Thomas)
Add MAX()/MIN() on time type (Thomas)
Add abs(), mod(), fac() for int8 (Thomas)
Rename functions to round(), sqrt(), cbrt(), pow() for float8 (Thomas)
Add transcendental math functions (e.g. sin(), acos()) for float8 (Thomas)
Add exp() and ln() for NUMERIC type
Rename NUMERIC power() to pow() (Thomas)
Improved TRANSLATE() function (Edwin Ramirez, Tom)
Allow X=-Y operators  (Tom)
Allow SELECT float8(COUNT(*))/(SELECT COUNT(*) FROM t) FROM t GROUP BY f1; (Tom)
Allow LOCALE to use indexes in regular expression searches (Tom)
Allow creation of functional indexes to use default types

Performance
-----------
Prevent exponential space consumption with many AND's and OR's (Tom)
Collect attribute selectivity values for system columns (Tom)
Reduce memory usage of aggregates (Tom)
Fix for LIKE optimization to use indexes with multi-byte encodings (Tom)
Fix r-tree index optimizer selectivity (Thomas)
Improve optimizer selectivity computations and functions (Tom)
Optimize btree searching for cases where many equal keys exist (Tom)
Enable fast LIKE index processing only if index present (Tom)
Re-use free space on index pages with duplicates (Tom)
Improve hash join processing (Tom)
Prevent descending sort if result is already sorted(Hiroshi)
Allow commuting of index scan query qualifications (Tom)
Prefer index scans in cases where ORDER BY/GROUP BY is required (Tom)
Allocate large memory requests in fix-sized chunks for performance (Tom)
Fix vacuum's performance by reducing memory allocation requests (Tom)
Implement constant-expression simplification (Bernard Frankpitt, Tom)
Use secondary columns to be used to determine start of index scan (Hiroshi)
Prevent quadruple use of disk space when doing internal sorting (Tom)
Faster sorting by calling fewer functions (Tom)
Create system indexes to match all system caches (Bruce, Hiroshi)
Make system caches use system indexes (Bruce)
Make all system indexes unique (Bruce)
Improve pg_statistics management for VACUUM speed improvement (Tom)
Flush backend cache less frequently (Tom, Hiroshi)
COPY now reuses previous memory allocation, improving performance (Tom)
Improve optimization cost estimation (Tom)
Improve optimizer estimate of range queries x > lowbound AND x < highbound (Tom)
Use DNF instead of CNF where appropriate (Tom, Taral)
Further cleanup for OR-of-AND WHERE-clauses (Tom)
Make use of index in OR clauses (x = 1 AND y = 2) OR (x = 2 AND y = 4) (Tom)
Smarter optimizer computations for random index page access (Tom)
New SET variable to control optimizer costs (Tom)
Optimizer queries based on LIMIT, OFFSET, and EXISTS qualifications (Tom)
Reduce optimizer internal housekeeping of join paths for speedup (Tom)
Major subquery speedup (Tom)
Fewer fsync writes when fsync is not disabled (Tom)
Improved LIKE optimizer estimates (Tom)
Prevent fsync in SELECT-only queries (Vadim)
Make index creation use psort code, because it is now faster (Tom)
Allow creation of sort temp tables > 1 Gig

Source Tree Changes
-------------------
Fix for linux PPC compile
New generic expression-tree-walker subroutine (Tom)
Change form() to varargform() to prevent portability problems
Improved range checking for large integers on Alphas
Clean up #include in /include directory (Bruce)
Add scripts for checking includes (Bruce)
Remove un-needed #include's from *.c files (Bruce)
Change #include's to use <> and "" as appropriate (Bruce)
Enable WIN32 compilation of libpq
Alpha spinlock fix from Uncle George
Overhaul of optimizer data structures (Tom)
Fix to cygipc library (Yutaka Tanida)
Allow pgsql to work on newer Cygwin snapshots (Dan)
New catalog version number (Tom)
Add Linux ARM
Rename heap_replace to heap_update
Update for QNX (Dr. Andreas Kardos)
New platform-specific regression handling (Tom)
Rename oid8 -> oidvector and int28 -> int2vector (Bruce)
Included all yacc and lex files into the distribution (Peter E.)
Remove lextest, no longer needed (Peter E)
Fix for libpq and psql on Win32 (Magnus)
Internally change datetime and timespan into timestamp and interval (Thomas)
Fix for plpgsql on BSDI
Add SQL_ASCII test case to the regression test (Tatsuo)
configure --with-mb now deprecated (Tatsuo)
NT fixes
NetBSD fixes Johnny C. Lam
Fixes for Alpha compiles
New multibyte encodings

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版本 6.5.3
这主要是 6.5.2 的净化版。我们增加了 6.5.2 里漏了的新的 pgaccess,并且安装了一个 NT 相关的补丁。 
向 v6.5.3 移植
那些运行 6.5.* 的人不需要输出/恢复工作。 
详细修改列表
Updated version of pgaccess 0.98
NT-specific patch
Fix dumping rules on inherited tables

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版本 6.5.2
这主要是 6.5.1 的净化版。我们修补了一些 6.5.1 的用户报告的一系列错误。 
向 v6.5.2 迁移
那些运行 6.5.* 的人不需要输出/恢复工作。 
详细修改列表
subselect+CASE fixes(Tom)
Add SHLIB_LINK setting for solaris_i386 and solaris_sparc ports(Daren Sefcik)
Fixes for CASE in WHERE join clauses(Tom)
Fix BTScan abort(Tom)
Repair the check for redundant UNIQUE and PRIMARY KEY indices(Thomas)
Improve it so that it checks for multi-column constraints(Thomas)
Fix for Win32 making problem with MB enabled(Hiroki Kataoka)
Allow BSD yacc and bison to compile pl code(Bruce)
Fix SET NAMES working
int8 fixes(Thomas)
Fix vacuum's memory consumption(Hiroshi,Tatsuo)
Reduce the total memory consumption of vacuum(Tom)
Fix for timestamp(datetime)
Rule deparsing bugfixes(Tom)
Fix quoting problems in mkMakefile.tcldefs.sh.in and mkMakefile.tkdefs.sh.in(Tom)
This is to re-use space on index pages freed by vacuum(Vadim)
document -x for pg_dump(Bruce)
Fix for unary operators in rule deparser(Tom)
Comment out FileUnlink of excess segments during mdtruncate()(Tom)
Irix linking fix from Yu Cao >yucao@falcon.kla-tencor.com<
Repair logic error in LIKE: should not return LIKE_ABORT
   when reach end of pattern before end of text(Tom)
Repair incorrect cleanup of heap memory allocation during transaction abort(Tom)
Updated version of pgaccess 0.98

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版本 6.5.1
这主要是 6.5 的净化版。我们修补了一些 6.5 的用户报告的一系列错误。 
向 v6.5.1 迁移
那些运行 6.5 的人不需要输出/恢复工作。 
详细修改列表
Add NT README file
Portability fixes for linux_ppc, Irix, linux_alpha, OpenBSD, alpha
Remove QUERY_LIMIT, use SELECT...LIMIT
Fix for EXPLAIN on inheritance(Tom)
Patch to allow vacuum on multi-segment tables(Hiroshi)
R-Tree optimizer selectivity fix(Tom)
ACL file descriptor leak fix(Atsushi Ogawa)
New expresssion subtree code(Tom)
Avoid disk writes for read-only transactions(Vadim)
Fix for removal of temp tables if last transaction was aborted(Bruce)
Fix to prevent too large tuple from being created(Bruce)
plpgsql fixes
Allow port numbers 32k - 64k(Bruce)
Add ^ precidence(Bruce)
Rename sort files called pg_temp to pg_sorttemp(Bruce)
Fix for microseconds in time values(Tom)
Tutorial source cleanup
New linux_m68k port
Fix for sorting of NULL's in some cases(Tom)
Shared library dependencies fixed (Tom)
Fixed glitches affecting GROUP BY in subselects(Tom)
Fix some compiler warnings (Tomoaki Nishiyama)
Add Win1250 (Czech) support (Pavel Behal)

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版本 6.5
这个版本标志着开发队伍对从伯克利继承过来的代码的掌握的一个主要的里程碑。你将看到现在我们更容易增加新的特性,感谢我们全世界开发队伍的不断壮大和经验的不断丰富。 
下面是一些最引人注意的改变的简介: 

多版本并行控制(MVCC) 
这个东西废止了我们老式的表级别的锁,取而代之的是一个比大多数商用数据库系统都先进的锁定系统。在传统的系统里,每行的修改是先锁住,直到提交,以此避免被其他用户读取。MVCC 利用 PostgreSQL 天生的多版本特性允许读者在写活动中读取连贯的数据。写入者继续使用紧凑的 pg_log 事务系统。所有这些都是在不用为每行分配一个锁(象传统的数据库系统那样)的情况下进行的。因此,原则上我们不再受制与简单的表级别锁定;我们有比行级别锁定更好的技术。 
pg_dump 的热备份 
pg_dump 利用了新的 MVCC 特性,可以在数据库保持在线和可以执行查询的情况下进行一次持续的数据输出/备份。 
数字(Numeric)数据类型 
我们现在有了真正的数字数据类型,可以由用户定义精度。 
临时表 
我们保证临时表在一次数据库会话过程中唯一,并且在会话结束时删除。 
新的 SQL 特性 
我们现在有了 CASE,INTERSECT 和 EXCEPT 语句。我们有了新的 LIMIT/OFFSET,SET TRANSACTION ISOLATION LEVEL,SELECT ... FOR UPDATE 和一个改进了的 LOCK TABLE 命令。 
提速 
我们继续给 PostgreSQL 提速,感谢我们队伍里各种才智。我们加速了存储器分配,优化,表联合以及行传输过程。 
移植 
我们继续扩展我们的移植列表,这回包括了 WinNT/ix86 和 NetBSD/arm32。 
接口 
大多数借口有了新的版本,现有的功能也被改进了。 
文档 
在这个文档里所有地方都有新的和更新了的内容。新的FAQ 已经包含了 SGI 和 AIX 平台的内容。教程 里包含了来自 Stefan Simkovics 的关于SQL 的介绍性信息。对于用户手册,我们包括了关于 postmaster 和更多工具程序的参考内容,和一个描述日期时间详细特性的附件。管理员手册包含了一个 Tom Lane 写的新的关于错误分析的章节。程序员手册包括了也是 Stefan 写的查询处理的描述,以及通过匿名 CVS 和 CVSup 获取 Postgres 源码树的详细内容。
向 v6.5 迁移
要想从以前的 Postgres 版本迁移到新的版本,我们需要进行一个用 pg_dump 或 pg_dumpall进行一个倾倒/重载的动作.pg_upgrade不能用于升级到这个版本,因为和以前版本相比,表在磁盘上的(存储)结构已经被修改了。 
新的多版本并行控制(MVCC)特性在多用户环境里可能有一些不同的表现。阅读并理解下面段落,确保你现有的应用将表现出你所希望的特性。 

多版本并行控制
因为 6.5 里的读动作不锁定数据,不管事务的隔离级别是什么,一个事务读的数据可能被其他事务覆盖。换句话说,如果 SELECT 返回了一行并不意味着该行在被返回的时候(也就是说在语句或者事务开始后的某个时间)真正存在,也不意味着在当前事务做提交或者回卷之前该行被保护免于被并行事务删除或者修改。 
要保证一行的确实存在或者保护它免于被并行更新,我们必须使用 SELECT FOR UPDATE 或一个合适的 LOCK TABLE 语句。我们在从以前的 Postgres 和其他环境移植应用时必须考虑这一点。 

如果你正用 contrib/refint.* 触发器保证参考完整性,你就必须记住上面几条。现在还需要额外的技巧。一个方法是:如果一个事务准备更新/删除一个主键时,使用 LOCK parent_table IN SHARE ROW EXCLUSIVE MODE 命令,如果一个事务准备更新/插入一个外键时使用 LOCK parent_table IN SHARE MODE 命令。 

注意:要注意如果你运行一个处于 SERIALIZABLE 模式下的事务,在该事务里,你必须在执行任何 DML(SELECT/INSERT/DELETE/UPDATE/FETCH/COPY_TO)语句之前执行上面提到的 LOCK 命令。
这些不便将在今后我们实现了读污染(未提交)数据的能力(不管什么隔离级别)和真正的参考完整性后消失。
详细修改列表
Bug Fixes
---------
Fix text<->float8 and text<->float4 conversion functions(Thomas)
Fix for creating tables with mixed-case constraints(Billy)
Change exp()/pow() behavior to generate error on underflow/overflow(Jan)
Fix bug in pg_dump -z
Memory overrun cleanups(Tatsuo)
Fix for lo_import crash(Tatsuo)
Adjust handling of data type names to suppress double quotes(Thomas)
Use type coercion for matching columns and DEFAULT(Thomas)
Fix deadlock so it only checks once after one second of sleep(Bruce)
Fixes for aggregates and PL/pgsql(Hiroshi)
Fix for subquery crash(Vadim)
Fix for libpq function PQfnumber and case-insensitive names(Bahman Rafatjoo)
Fix for large object write-in-middle, no extra block, memory consumption(Tatsuo)
Fix for pg_dump -d or -D and  quote special characters in INSERT
Repair serious problems with dynahash(Tom)
Fix INET/CIDR portability problems
Fix problem with selectivity error in ALTER TABLE ADD COLUMN(Bruce)
Fix executor so mergejoin of different column types works(Tom)
Fix for Alpha OR selectivity bug
Fix OR index selectivity problem(Bruce)
Fix so /d shows proper length for char()/varchar()(Ryan)
Fix tutorial code(Clark)
Improve destroyuser checking(Oliver)
Fix for Kerberos(Rodney McDuff)
Fix for dropping database while dirty buffers(Bruce)
Fix so sequence nextval() can be case-sensitive(Bruce)
Fix !!= operator
Drop buffers before destroying database files(Bruce)
Fix case where executor evaluates functions twice(Tatsuo)
Allow sequence nextval actions to be case-sensitive(Bruce)
Fix optimizer indexing not working for negative numbers(Bruce)
Fix for memory leak in executor with fjIsNull
Fix for aggregate memory leaks(Erik Riedel)
Allow username containing a dash GRANT permissions
Cleanup of NULL in inet types
Clean up system table bugs(Tom)
Fix problems of PAGER and /? command(Masaaki Sakaida)
Reduce default multi-segment file size limit to 1GB(Peter)
Fix for dumping of CREATE OPERATOR(Tom)
Fix for backward scanning of cursors(Hiroshi Inoue)
Fix for COPY FROM STDIN when using /i(Tom)
Fix for subselect is compared inside an expression(Jan)
Fix handling of error reporting while returning rows(Tom)
Fix problems with reference to array types(Tom,Jan)
Prevent UPDATE SET oid(Jan)
Fix pg_dump so -t option can handle case-sensitive tablenames
Fixes for GROUP BY in special cases(Tom, Jan)
Fix for memory leak in failed queries(Tom)
DEFAULT now supports mixed-case identifiers(Tom)
Fix for multi-segment uses of DROP/RENAME table, indexes(Ole Gjerde)
Disable use of pg_dump with both -o and -d options(Bruce)
Allow pg_dump to properly dump GROUP permissions(Bruce)
Fix GROUP BY in INSERT INTO table SELECT * FROM table2(Jan)
Fix for computations in views(Jan)
Fix for aggregates on array indexes(Tom)
Fix for DEFAULT handles single quotes in value requiring too many quotes
Fix security problem with non-super users importing/exporting large objects(Tom)
Rollback of transaction that creates table cleaned up properly(Tom)
Fix to allow long table and column names to generate proper serial names(Tom)

Enhancements
------------
Add "vacuumdb" utility
Speed up libpq by allocating memory better(Tom)
EXPLAIN all indices used(Tom)
Implement CASE, COALESCE, NULLIF  expression(Thomas)
New pg_dump table output format(Constantin)
Add string min()/max() functions(Thomas)
Extend new type coercion techniques to aggregates(Thomas)
New moddatetime contrib(Terry)
Update to pgaccess 0.96(Constantin)
Add routines for single-byte "char" type(Thomas)
Improved substr() function(Thomas)
Improved multi-byte handling(Tatsuo)
Multi-version concurrency control/MVCC(Vadim)
New Serialized mode(Vadim)
Fix for tables over 2gigs(Peter)
New SET TRANSACTION ISOLATION LEVEL(Vadim)
New LOCK TABLE IN ... MODE(Vadim)
Update ODBC driver(Byron)
New NUMERIC data type(Jan)
New SELECT FOR UPDATE(Vadim)
Handle "NaN" and "Infinity" for input values(Jan)
Improved date/year handling(Thomas)
Improved handling of backend connections(Magnus)
New options ELOG_TIMESTAMPS and USE_SYSLOG options for log files(Massimo)
New TCL_ARRAYS option(Massimo)
New INTERSECT and EXCEPT(Stefan)
New pg_index.indisprimary for primary key tracking(D'Arcy)
New pg_dump option to allow dropping of tables before creation(Brook)
Speedup of row output routines(Tom)
New READ COMMITTED isolation level(Vadim)
New TEMP tables/indexes(Bruce)
Prevent sorting if result is already sorted(Jan)
New memory allocation optimization(Jan)
Allow psql to do /p/g(Bruce)
Allow multiple rule actions(Jan)
Added LIMIT/OFFSET functionality(Jan)
Improve optimizer when joining a large number of tables(Bruce)
New intro to SQL from S. Simkovics' Master's Thesis (Stefan, Thomas)
New intro to backend processing from S. Simkovics' Master's Thesis (Stefan)
Improved int8 support(Ryan Bradetich, Thomas, Tom)
New routines to convert between int8 and text/varchar types(Thomas)
New bushy plans, where meta-tables are joined(Bruce)
Enable right-hand queries by default(Bruce)
Allow reliable maximum number of backends to be set at configure time
      (--with-maxbackends and postmaster switch (-N backends))(Tom)
GEQO default now 10 tables because of optimizer speedups(Tom)
Allow NULL=Var for MS-SQL portability(Michael, Bruce)
Modify contrib check_primary_key() so either "automatic" or "dependent"(Anand)
Allow psql /d on a view show query(Ryan)
Speedup for LIKE(Bruce)
Ecpg fixes/features, see src/interfaces/ecpg/ChangeLog file(Michael)
JDBC fixes/features, see src/interfaces/jdbc/CHANGELOG(Peter)
Make % operator have precedence like /(Bruce)
Add new postgres -O option to allow system table structure changes(Bruce)
Update contrib/pginterface/findoidjoins script(Tom)
Major speedup in vacuum of deleted rows with indexes(Vadim) 
Allow non-SQL functions to run different versions based on arguments(Tom)
Add -E option that shows actual queries sent by /dt and friends(Masaaki Sakaida)
Add version number in startup banners for psql(Masaaki Sakaida)
New contrib/vacuumlo removes large objects not referenced(Peter)
New initialization for table sizes so non-vacuumed tables perform better(Tom)
Improve error messages when a connection is rejected(Tom)
Support for arrays of char() and varchar() fields(Massimo)
Overhaul of hash code to increase reliability and performance(Tom)
Update to PyGreSQL 2.4(D'Arcy)
Changed debug options so -d4 and -d5 produce different node displays(Jan)
New pg_options: pretty_plan, pretty_parse, pretty_rewritten(Jan)
Better optimization statistics for system table access(Tom)
Better handling of non-default block sizes(Massimo)
Improve GEQO optimizer memory consumption(Tom)
UNION now suppports ORDER BY of columns not in target list(Jan)
Major libpq++ improvements(Vince Vielhaber)
pg_dump now uses -z(ACL's) as default(Bruce)
backend cache, memory speedups(Tom)
have pg_dump do everything in one snapshot transaction(Vadim)
fix for large object memory leakage, fix for pg_dumping(Tom)
INET type now respects netmask for comparisons
Make VACUUM ANALYZE only use a readlock(Vadim)
Allow VIEWs on UNIONS(Jan)
pg_dump now can generate consistent snapshots on active databases(Vadim)

Source Tree Changes
-------------------
Improve port matching(Tom)
Portability fixes for SunOS
Add NT/Win32 backend port and enable dynamic loading(Magnus and Daniel Horak)
New port to Cobalt Qube(Mips) running Linux(Tatsuo)
Port to NetBSD/m68k(Mr. Mutsuki Nakajima)
Port to NetBSD/sun3(Mr. Mutsuki Nakajima)
Port to NetBSD/macppc(Toshimi Aoki)
Fix for tcl/tk configuration(Vince)
Removed CURRENT keyword for rule queries(Jan)
NT dynamic loading now works(Daniel Horak)
Add ARM32 support(Andrew McMurry)
Better support for HPUX 11 and Unixware
Improve file handling to be more uniform, prevent file descriptor leak(Tom)
New install commands for plpgsql(Jan)

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版本 6.4.2
版本 6.4.1 的包打得不好。这个版本也有一些错误修补。 
向 v6.4.2 迁移
那些运行 6.4.* 的人不需要倾倒/重载工作。 
详细修改列表
修补了一些平台上的日期/时间常量问题(Thomas)
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版本 6.4.1
这主要是 6.4 的净化版。我们修补了一些 6.4 的用户报告的一系列错误。 
向 v6.4.1 迁移
那些运行 6.4 的人不需要倾倒/重载工作。 
详细修改列表
Add pg_dump -N flag to force double quotes around identifiers.  This is
        the default(Thomas)
Fix for NOT in where clause causing crash(Bruce)
EXPLAIN VERBOSE coredump fix(Vadim)
Fix shared-library problems on Linux
Fix test for table existance to allow mixed-case and whitespace in
        the table name(Thomas)
Fix a couple of pg_dump bugs
Configure matches template/.similar entries better(Tom)
Change builtin function names from SPI_* to spi_*
OR WHERE clause fix(Vadim)
Fixes for mixed-case table names(Billy)
contrib/linux/postgres.init.csh/sh fix(Thomas)
libpq memory overrun fix
SunOS fixes(Tom)
Change exp() behavior to generate error on underflow(Thomas)
pg_dump fixes for memory leak, inheritance constraints, layout change
update pgaccess to 0.93
Fix prototype for 64-bit platforms
Multi-byte fixes(Tatsuo)
New ecpg man page
Fix memory overruns(Tatsuo)
Fix for lo_import() crash(Bruce)
Better search for install program(Tom)
Timezone fixes(Tom)
HPUX fixes(Tom)
Use implicit type coercion for matching DEFAULT values(Thomas)
Add routines to help with single-byte (internal) character type(Thomas)
Compilation of libpq for Win32 fixes(Magnus)
Upgrade to PyGreSQL 2.2(D'Arcy)

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版本 6.4
这个版本有 许多 新特性和改进.感谢开发者和维护者,与前一个版本相比,几乎系统的每个方面都得到了重视.下面是一个简短的不完全的概要: 
感谢 Jan Wieck 为重写规则系统添加的新的代码,视图和规则现在可以工作了.他就此还为 程序员手册 写了一章. 
与他在上一版本提供的最初的 PL/pgTCL 过程语言一起,Jan 还提供了第二种过程语言,PL/pgSQL. 

我们有了可选的多字节字符集支持,是 Tatsuo Iishi 提供的,用以完善我们现存的本地支持. 

感谢 Tom Lane 清理了 Client/server(客户/服务器)通讯部分,对异步消息和中断有了更好的支持. 

分析器现在会进行自动的类型转换,以与现有的操作符和函数的参数相匹配,以及与目标字段的字段(类型)和表达式匹配.这是通过通用的机制实现的,该机制支持 Postgres 的类型扩展特性.在用户手册中有一章介绍这个主题. 

新增了三种数据类型.其中两种类型 inet 和 cidr,支持各种各样的IP网络,子网和机器寻址形式.而且现在在某些平台上有8-字节整数支持了.请参阅用户手册中的数据类型章节获取详细信息.第四种类型,serial,现在被分析器当作 int4 类型,序列号,和唯一索引的混合物来支持. 

增加了更多 SQL92-兼容的语法特性,包括 INSERT DEFAULT VALUES 

自动配置和安装系统受到了一定的重视,现在应该在大多数平台上比以前更坚固,稳定了.

向 v6.4 迁移
要想从以前的 Postgres 版本迁移到新的版本,我们需要进行一个用 pg_dump 或 pg_dumpall 进行一个倾倒/重载的动作.
详细的修改列表
Bug Fixes
---------
Fix for a tiny memory leak in PQsetdb/PQfinish(Bryan)
Remove char2-16 data types, use char/varchar(Darren)
Pqfn not handles a NOTICE message(Anders)
Reduced busywaiting overhead for spinlocks with many backends (dg)
Stuck spinlock detection (dg)
Fix up "ISO-style" timespan decoding and encoding(Thomas)
Fix problem with table drop after rollback of transaction(Vadim)
Change error message and remove non-functional update message(Vadim)
Fix for COPY array checking
Fix for SELECT 1 UNION SELECT NULL
Fix for buffer leaks in large object calls(Pascal)
Change owner from oid to int4 type(Bruce)
Fix a bug in the oracle compatibility functions btrim() ltrim() and rtrim()
Fix for shared invalidation cache overflow(Massimo)
Prevent file descriptor leaks in failed COPY's(Bruce)
Fix memory leak in libpgtcl's pg_select(Constantin)
Fix problems with username/passwords over 8 characters(Tom)
Fix problems with handling of asynchronous NOTIFY in backend(Tom)
Fix of many bad system table entries(Tom)

Enhancements
------------
Upgrade ecpg and ecpglib,see src/interfaces/ecpc/ChangeLog(Michael)
Show the index used in an EXPLAIN(Zeugswetter)
EXPLAIN  invokes  rule system and shows plan(s) for rewritten queries(Jan)
Multi-byte awareness of many data types and functions, via configure(Tatsuo)
New configure --with-mb option(Tatsuo)
New initdb --pgencoding option(Tatsuo)
New createdb -E multibyte option(Tatsuo)
Select version(); now returns PostgreSQL version(Jeroen)
Libpq now allows asynchronous clients(Tom)
Allow cancel from client of backend query(Tom)
Psql now cancels query with Control-C(Tom)
Libpq users need not issue dummy queries to get NOTIFY messages(Tom)
NOTIFY now sends sender's PID, so you can tell whether it was your own(Tom)
PGresult struct now includes associated error message, if any(Tom)
Define "tz_hour" and "tz_minute" arguments to date_part()(Thomas)
Add routines to convert between varchar and bpchar(Thomas)
Add routines to allow sizing of varchar and bpchar into target columns(Thomas)
Add bit flags to support timezonehour and minute in data retrieval(Thomas)
Allow more variations on valid floating point numbers (e.g. ".1", "1e6")(Thomas)
Fixes for unary minus parsing with leading spaces(Thomas)
Implement TIMEZONE_HOUR, TIMEZONE_MINUTE per SQL92 specs(Thomas)
Check for and properly ignore FOREIGN KEY column constraints(Thomas)
Define USER as synonym for CURRENT_USER per SQL92 specs(Thomas)
Enable HAVING clause but no fixes elsewhere yet.
Make "char" type a synonym for "char(1)" (actually implemented as bpchar)(Thomas)
Save string type if specified for DEFAULT clause handling(Thomas)
Coerce operations involving different data types(Thomas)
Allow some index use for columns of different types(Thomas)
Add capabilities for automatic type conversion(Thomas)
Cleanups for large objects, so file is truncated on open(Peter)
Readline cleanups(Tom)
Allow psql  /f / to make spaces as delimiter(Bruce)
Pass pg_attribute.atttypmod to the frontend for column field lengths(Tom,Bruce)
Msql compatibility library in /contrib(Aldrin)
Remove the requirement that ORDER/GROUP BY clause identifiers be 
included in the target list(David)
Convert columns to match columns in UNION clauses(Thomas)
Remove fork()/exec() and only do fork()(Bruce)
Jdbc cleanups(Peter)
Show backend status on ps command line(only works on some platforms)(Bruce)
Pg_hba.conf now has a sameuser option in the database field
Make lo_unlink take oid param, not int4
New DISABLE_COMPLEX_MACRO for compilers that can't handle our macros(Bruce)
Libpgtcl now handles NOTIFY as a Tcl event, need not send dummy queries(Tom)
libpgtcl cleanups(Tom)
Add -error option to libpgtcl's pg_result command(Tom)
New locale patch, see docs/README/locale(Oleg)
Fix for pg_dump so CONSTRAINT and CHECK syntax is correct(ccb)
New contrib/lo code for large object orphan removal(Peter)
New psql command "SET CLIENT_ENCODING TO 'encoding'" for multi-bytes
feature, see /doc/README.mb(Tatsuo)
/contrib/noupdate code to revoke update permission on a column
Libpq can now be compiled on win32(Magnus)
Add PQsetdbLogin() in libpq
New 8-byte integer type, checked by configure for OS support(Thomas)
Better support for quoted table/column names(Thomas)
Surround table and column names with double-quotes in pg_dump(Thomas)
PQreset() now works with passwords(Tom)
Handle case of GROUP BY target list column number out of range(David)
Allow UNION in subselects
Add auto-size to screen to /d? commands(Bruce)
Use UNION to show all /d? results in one query(Bruce)
Add /d? field search feature(Bruce)
Pg_dump issues fewer /connect requests(Tom)
Make pg_dump -z flag work better, document it in manual page(Tom)
Add HAVING clause with full support for subselects and unions(Stephan)
Full text indexing routines in contrib/fulltextindex(Maarten)
Transaction ids now stored in shared memory(Vadim)
New PGCLIENTENCODING when issuing COPY command(Tatsuo)
Support for SQL92 syntax "SET NAMES"(Tatsuo)
Support for LATIN2-5(Tatsuo)
Add UNICODE regression test case(Tatsuo)
Lock manager cleanup, new locking modes for LLL(Vadim)
Allow index use with OR clauses(Bruce)
Allows "SELECT NULL ORDER BY 1;"
Explain VERBOSE prints the plan, and now pretty-prints the plan to
the postmaster log file(Bruce)
Add Indices display to /d command(Bruce)
Allow GROUP BY on functions(David)
New pg_class.relkind for large objects(Bruce)
New way to send libpq NOTICE messages to a different location(Tom)
New /w write command to psql(Bruce)
New /contrib/findoidjoins scans oid columns to find join relationships(Bruce)
Allow binary-compatible indices to be considered when checking for valid
indices for restriction clauses containing a constant(Thomas)
New ISBN/ISSN code in /contrib/isbn_issn
Allow NOT LIKE, IN, NOT IN, BETWEEN, and NOT BETWEEN constraint(Thomas)
New rewrite system fixes many problems with rules and views(Jan)
        * Rules on relations work
        * Event qualifications on insert/update/delete work
        * New OLD variable to reference CURRENT, CURRENT will be remove in future
        * Update rules can reference NEW and OLD in rule qualifications/actions
        * Insert/update/delete rules on views work
        * Multiple rule actions are now supported, surrounded by parentheses
        * Regular users can create views/rules on tables they have RULE permits
        * Rules and views inherit the permissions on the creator
        * No rules at the column level
        * No UPDATE NEW/OLD rules
        * New pg_tables, pg_indexes, pg_rules and pg_views system views
        * Only a single action on SELECT rules
        * Total rewrite overhaul, perhaps for 6.5
        * handle subselects
        * handle aggregates on views
        * handle insert into select from view works
System indexes are now multi-key(Bruce)
Oidint2, oidint4, and oidname types are removed(Bruce)
Use system cache for more system table lookups(Bruce)
New backend programming language PL/pgSQL in backend/pl(Jan)
New SERIAL data type, auto-creates sequence/index(Thomas)
Enable assert checking without a recompile(Massimo)
User lock enhancements(Massimo)
New setval() command to set sequence value(Massimo)
Auto-remove unix socket file on startup if no postmaster running(Massimo)
Conditional trace package(Massimo)
New UNLISTEN command(Massimo)
Psql and libpq now compile under win32 using win32.mak(Magnus)
Lo_read no longer stores trailing NULL(Bruce)
Identifiers are now truncated to 31 characters internally(Bruce)
Createuser options now availble on the command line
Code for 64-bit integer supported added, configure tested, int8 type(Thomas)
Prevent file descriptor leaf from failed COPY(Bruce)
New pg_upgrade command(Bruce)
Updated /contrib directories(Massimo)
New CREATE TABLE DEFAULT VALUES statement available(Thomas)
New INSERT INTO TABLE DEFAULT VALUES statement available(Thomas)
New DECLARE and FETCH feature(Thomas)
libpq's internal structures now not exported(Tom)
Allow up to 8 key indexes(Bruce)
Remove ARCHIVE keyword, that is no longer used(Thomas)
pg_dump -n flag to supress quotes around indentifiers
disable system columns for views(Jan)
new INET and CIDR types for network addresses(TomH, Paul)
no more double quotes in psql output
pg_dump now dumps views(Terry)
new SET QUERY_LIMIT(Tatsuo,Jan)

Source Tree Changes
-------------------
/contrib cleanup(Jun)
Inline some small functions called for every row(Bruce)
Alpha/linux fixes
Hp/UX cleanups(Tom)
Multi-byte regression tests(Soonmyung.)
Remove --disabled options from configure
Define PGDOC to use POSTGRESDIR by default
Make regression optional
Remove extra braces code to pgindent(Bruce)
Add bsdi shared library support(Bruce)
New --without-CXX support configure option(Brook)
New FAQ_CVS
Update backend flowchart in tools/backend(Bruce)
Change atttypmod from int16 to int32(Bruce, Tom)
Getrusage() fix for platforms that do not have it(Tom)
Add PQconnectdb, PGUSER, PGPASSWORD to libpq man page
NS32K platform fixes(Phil Nelson, John Buller)
Sco 7/UnixWare 2.x fixes(Billy,others)
Sparc/Solaris 2.5 fixes(Ryan)
Pgbuiltin.3 is obsolete, move to doc files(Thomas)
Even more documention(Thomas)
Nextstep support(Jacek)
Aix support(David)
pginterface manual page(Bruce)
shared libraries all have version numbers
merged all OS-specific shared library defines into one file
smarter TCL/TK configuration checking(Billy)
smarter perl configuration(Brook)
configure uses supplied install-sh if no install script found(Tom)
new Makefile.shlib for shared library configuration(Tom)

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版本 6.4.1 开头 版本 6.3.2 
  PostgreSQL 
上一页 第三十五章. 版本信息 下一页 

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版本 6.3.2
这是一个 6.3.x 的除错版本.请参阅 v6.3 的版本信息获取新特性的更完整的概述信息. 
概要: 

修复了对一些平台(包括 Linux)的自动配置的支持,在v6.3.1中由于一些小错误带进来了这些破损. 
正确地处理在 BETWEEN 和 LIKE 子句左边的函数调用.

对运行在6.3或6.3.1上的数据库不需要进行倾倒/重载(dump/restore)工作.所要做的所有工作是简单的 'make distclean','make',和 'make install'.最后一步应该在 postmaster 停止运行后进行.你应该用 Postgres 库对所有用户应用进行重新链接. 
对于从v6.3以前的版本升级,请参考v6.3的安装和移植指导. 

详细修改列表
Changes
-------
Configure detection improvements for tcl/tk(Brook Milligan, Alvin)
Manual page improvements(Bruce)
BETWEEN and LIKE fix(Thomas)
fix for psql /connect used by pg_dump(Oliver Elphick)
New odbc driver
pgaccess, version 0.86
qsort removed, now uses libc version, cleanups(Jeroen)
fix for buffer over-runs detected(Maurice Gittens)
fix for buffer overrun in libpgtcl(Randy Kunkee)
fix for UNION with DISTINCT or ORDER BY(Bruce)
gettimeofday configure check(Doug Winterburn)
Fix "indexes not used" bug(Vadim)
docs additions(Thomas)
Fix for backend memory leak(Bruce)
libreadline cleanup(Erwan MAS)
Remove DISTDIR(Bruce)
Makefile dependency cleanup(Jeroen van Vianen)
ASSERT fixes(Bruce)

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版本 6.4 开头 版本 6.3.1 
  PostgreSQL 
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版本 6.3.1
概要: 
对多字节字符集的附加支持. 
对多字节字符集的附加支持. 

对允许的 SQL 语法进行了小的升级. 

改善了安装过程的配置自动侦测功能.

对那些运行着6.3版本的应用不需要进行倾倒/重载操作.升级工作只需要简单的 'make distclean','make',和 'make install'.最后一步应该在 postmaster 没有运行时进行.升级后你应该对所有使用 Postgres 库的用户应用重新进行连接. 
  
对于从v6.3以前的版本升级,请参考v6.3的安装和移植指导. 
详细修改列表
Changes
-------
ecpg cleanup/fixes, now version 1.1(Michael Meskes)
pg_user cleanup(Bruce)
large object fix for pg_dump and tclsh (alvin)
LIKE fix for multiple adjacent underscores
fix for redefining builtin functions(Thomas)
ultrix4 cleanup
upgrade to pg_access 0.83
updated CLUSTER manual page
multi-byte character set support, see doc/README.mb(Tatsuo)
configure --with-pgport fix
pg_ident fix
big-endian fix for backend communications(Kataoka)
SUBSTR() and substring() fix(Jan)
several jdbc fixes(Peter)
libpgtcl improvements, see libptcl/README(Randy Kunkee)
Fix for "Datasize = 0" error(Vadim)
Prevent /do from wrapping(Bruce)
Remove duplicate Russian character set entries
Sunos4 cleanup
Allow optional TABLE keyword in LOCK and SELECT INTO(Thomas)
CREATE SEQUENCE options to allow a negative integer(Thomas)
Add "PASSWORD" as an allowed column identifier(Thomas)
Add checks for UNION target fields(Bruce)
Fix Alpha port(Dwayne Bailey)
Fix for text arrays containing quotes(Doug Gibson)
Solaris compile fix(Albert Chin-A-Young)
Better identify tcl and tk libs and includes(Bruce)

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版本 6.3.2 开头 版本 6.3 
   
  PostgreSQL 
上一页 第三十五章. 版本信息 下一页 

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版本 6.3
在这个版本中有 许多 新的特性和改进.下面是一个简短的不完整的概要: 
增加了许多新的 SQL 特性,包括完整的 SQL92 子查询功能(除目标列子查询外所有的东西都实现了). 
支持客户端环境变量声明时区和日期风格. 

用于 客户端/服务器 联接的套接字(Socket)接口.现在这个是缺省的值,所以你可能需要带 “-i” 参数运行 postmaster. 

更完善的口令认证机制.修改了缺省的表权限. 

删除了老式的 “时间跟踪” 特性.改善了性能.

注意:Bruce Momjian 写下了下面的介绍新版本的文字.
我在这里想提一些关于 6.3 的事情.这些都是一些无法在一句话中描述的比较大的课题.所以仍需要你回过头去看看修改的详细列表. 
首先,我们现在有了子查询.既然我们已经拥有子查询了,我要很客观的说,如果没有子查询,SQL 就是一种作用非常有限的语言.子查询是一种很重要的特性,你应该复查一下你的代码,以便找出子查询能给你提供更好解决方法的地方.我相信你会发现子查询可以应用在比你想象得到多得多的地方.Vadim 把我们放在了一个拥有完整功能的带子查询功能的巨大的 SQL 图上面.你不能应用子查询的唯一方面是目标列. 

第二,6.3 使用 unix 域套接字作为缺省而不是 TCP/IP.要允许从其他机器来的联接,你必须使用新的 postmaster 的 -i 选项,当然你还要编辑 pg_hba.conf.同样,pg_hba.conf 的格式也因此而改变了. 

第三,现在使用char() 字段将比使用 varchar() 或 text 时访问的更快.具体地说,在对第一个 text 和 varchar() 类型的字段进行访问之后再对同类型字段访问将有一些访问延迟.char() 型原先也有这种访问延迟,但现在已经没有了.这或许意味着你重新设计你的一些表,尤其是那些你已经定义为 varchar() 或 text 的短的字符型字段.这个和其他的一些修改使 6.3 比早期的版本有更快的速度. 

我们现在有了独立于任何 Unix 文件的可定义的口令.现在有了新的 SQL USER 命令.参阅 pg_hba.conf 的手册页获取更多信息.同时我们还有了一个新的表,pg_shadow,用来存放用户信息和用户口令,并且缺省时只有 postgres 超级用户对其有(SELECT)查询权限.pg_user 现在是 pg_shadow 的一个视图,并且可以被公众(PUBLIC)读取(SELECT).你可以在你的应用里继续使用 pg_user 而不需做任何更改. 

用户创建的表缺省时不再被公众(PUBLIC)拥有读取(SELECT)权限.这么做是因为 ANSI 标准要求这样做.你当然可以在创建表后用 GRANT 赋予他人任何你希望的权限.系统表仍然可以被公众(PUBLIC)读取(SELECT). 

我们仍然有实时的死锁侦测代码.超时时间不超过60秒.并且新的锁定代码实现了更好的FIFO(先入先出),所以在重负荷时对资源的需求会轻一些. 

在以前的版本中我们听到了许多关于缺乏文档的抱怨.Thomas 在这个版本中努力增加了许多新的手册.请查阅 doc/ 目录. 

出于性能考虑,时间跟踪特性取消了,但是可以使用触发器实现(参阅 pgsql/contrib/spi/README).请使用新的/d命令查询关于类型,操作符等的信息.同时,视图拥有了他们自己的权限,而不是以它们依赖的表为基础.所以它们的权限应该独立的设置.请检查 /pgsql/interfaces 文件获取更多与 Postgres 对话的方法. 

这是第一个需要向已有的用户进行说明的版本.不管从哪个角度来说,我们都需要做这样的说明,因为新版本取消了许多限制,因而许多原先人们需要做的许多防范性工作都不再需要了. 

向 v6.3 迁移
任何希望从以前的 Postgres 版本移植到新版本的数据库都需要用 pg_dump 或 pg_dumpall 进行一次倾倒/重载工作.
详细修改列表
Bug Fixes
---------
Fix binary cursors broken by MOVE implementation(Vadim)
Fix for tcl library crash(Jan)
Fix for array handling, from Gerhard Hintermayer
Fix acl error, and remove duplicate pqtrace(Bruce)
Fix psql /e for empty file(Bruce)
Fix for textcat on varchar() fields(Bruce)
Fix for DBT Sendproc (Zeugswetter Andres)
Fix vacuum analyze syntax problem(Bruce)
Fix for international identifiers(Tatsuo)
Fix aggregates on inherited tables(Bruce)
Fix substr() for out-of-bounds data
Fix for select 1=1 or 2=2, select 1=1 and 2=2, and select sum(2+2)(Bruce)
Fix notty output to show status result.  -q option still turns it off(Bruce)
Fix for count(*), aggs with views and multiple tables and sum(3)(Bruce)
Fix cluster(Bruce)
Fix for PQtrace start/stop several times(Bruce)
Fix a variety of locking problems like newer lock waiters getting
        lock before older waiters, and having readlock people not share
        locks if a writer is waiting for a lock, and waiting writers not
        getting priority over waiting readers(Bruce)
Fix crashes in psql when executing queries from external files(James)
Fix problem with multiple order by columns, with the first one having
        NULL values(Jeroen)
Use correct hash table support functions for float8 and int4(Thomas)
Re-enable JOIN= option in CREATE OPERATOR statement (Thomas)
Change precedence for boolean operators to match expected behavior(Thomas)
Generate elog(ERROR) on over-large integer(Bruce)
Allow multiple-argument functions in constraint clauses(Thomas)
Check boolean input literals for 'true','false','yes','no','1','0'
        and throw elog(ERROR) if unrecognized(Thomas)
Major large objects fix
Fix for GROUP BY showing duplicates(Vadim)
Fix for index scans in MergeJion(Vadim)

Enhancements
------------
Subselects with EXISTS, IN, ALL, ANY keywords (Vadim, Bruce, Thomas)
New User Manual(Thomas, others)
Speedup by inlining some frequently-called functions
Real deadlock detection, no more timeouts(Bruce)
Add SQL92 "constants" CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, 
        CURRENT_USER(Thomas)
Modify constraint syntax to be SQL92-compliant(Thomas)
Implement SQL92 PRIMARY KEY and UNIQUE clauses using indices(Thomas)
Recognize SQL92 syntax for FOREIGN KEY. Throw elog notice(Thomas)
Allow NOT NULL UNIQUE constraint clause (each allowed separately before)(Thomas)
Allow Postgres-style casting ("::") of non-constants(Thomas)
Add support for SQL3 TRUE and FALSE boolean constants(Thomas)
Support SQL92 syntax for IS TRUE/IS FALSE/IS NOT TRUE/IS NOT FALSE(Thomas)
Allow shorter strings for boolean literals (e.g. "t", "tr", "tru")(Thomas)
Allow SQL92 delimited identifiers(Thomas)
Implement SQL92 binary and hexadecimal string decoding (b'10' and x'1F')(Thomas)
Support SQL92 syntax for type coercion of literal strings
        (e.g. "DATETIME 'now'")(Thomas)
Add conversions for int2, int4, and OID types to and from text(Thomas)
Use shared lock when building indices(Vadim)
Free memory allocated for an user query inside transaction block after
        this query is done, was turned off in <= 6.2.1(Vadim)
New SQL statement CREATE PROCEDURAL LANGUAGE(Jan)
New Postgres Procedural Language (PL) backend interface(Jan)
Rename pg_dump -H option to -h(Bruce)
Add Java support for passwords, European dates(Peter)
Use indices for LIKE and ~, !~ operations(Bruce)
Add hash functions for datetime and timespan(Thomas)
Time Travel removed(Vadim, Bruce)
Add paging for /d and /z, and fix /i(Bruce)
Add Unix domain socket support to backend and to f
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