<Chapter Id="release">

<Title>Release Notes</Title>

<Sect1>

<Title>Release 6.5</Title>

<!--

<docinfo>

<authorgroup>

<author>

<firstname>Bruce</firstname>

<surname>Momjian</surname>

</author>

</authorgroup>

<date>1998-06-01</date>

</docinfo>

-->

<para>

This release marks the development team's final mastery of the source

code we inherited from Berkeley. You will see we are now easily adding

major features, thanks to the increasing size and experience of our

world-wide development team: Here is a brief, incomplete summary:

<itemizedlist spacing="compact">

<listitem>

<para>

Multi-version concurrency control(MVCC): This removes our old

table-level locking, and replaces it with a locking system that is

superior to most commercial database systems. In a traditional system,

each row that is modified is locked until committed, preventing reads by

other users. MVCC uses the natural multi-version nature of PostgreSQL

to allow readers to continue reading consistent data during writer

activity. Writers continue to use the compact pg_log transaction

system. This is all preformed without having to allocate a lock for

every row like traditional database systems. So, basically, we no

longer have table-level locking, we have something better than row-level

locking.

</para>

</listitem>

<listitem>

<para>

Numeric data type: We now have a true numeric data type, with

user-specified precision.

</para>

</listitem>

<listitem>

<para>

Temporary tables: Temporary tables are guaranteed to have unique names

within a database session, and are destroyed on session exit.

</para>

</listitem>

<listitem>

<para>

New SQL features: We now have CASE, INTERSECT, and EXCEPT statement

support. We have new LIMIT/OFFSET, SET TRANSACTION ISOLATION LEVEL,

SELECT ... FOR UPDATE, and an improved LOCK command.

</para>

</listitem>

<listitem>

<para>

Speedups: We continue to speed up PostgreSQL, thanks to the variety of

talents within our team. We have sped up memory allocation,

optimization, table joins, and row transfers routines.

</para>

</listitem>

<listitem>

<para>

Other: We continue to expand our port list, this time including

Win32/NT. Most interfaces have new versions, and existing functionality

has been improved.

</para>

</listitem>

</itemizedlist>

</para>

<sect2>

<title>Migration to v6.5</title>

<para>

A dump/restore using <application>pg_dump</application>

or <application>pg_dumpall</application>

is required for those wishing to migrate data from any

previous release of <productname>Postgres</productname>.

</para>

</sect2>

<sect2>

<title>Detailed Change List</title>

<para>

<programlisting>

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 coersion 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)

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 coersion 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)

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)

</programlisting>

</Para>

</sect2>

</Sect1>

<Sect1>

<Title>Release 6.4.2</Title>