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<appendix id="release">
<title>Release Notes</title>
+ <sect1 id="release-8-3">
+ <title>Release 8.3</title>
+
+ <note>
+ <title>Release date</title>
+ <simpara>2007-??-??</simpara>
+ </note>
+
+ <sect2>
+ <title>Overview</title>
+
+ <para>
+ This release adds many functionality and performance improvements that
+ were requested by users, including:
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ ... to be filled in ...
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </para>
+
+ </sect2>
+
+ <sect2>
+ <title>Migration to version 8.3</title>
+
+ <para>
+ A dump/restore using <application>pg_dump</application> is
+ required for those wishing to migrate data from any previous
+ release.
+ </para>
+
+ <para>
+ Observe the following incompatibilities:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ ... to be filled in ...
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </sect2>
+
+ <sect2>
+ <title>Changes</title>
+
+ <para>
+ Below you will find a detailed account of the
+ changes between <productname>PostgreSQL</productname> 8.3 and
+ the previous major release.
+ </para>
+
+ <sect3>
+ <title>Performance Improvements</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Implement an optional asynchronous commit mode (Simon)
+ </para>
+
+ <para>
+ When synchronous_commit is off, we don't flush WAL before reporting
+ a transaction committed. Data consistency is still guaranteed
+ (unlike turning fsync off), but a crash may lose the effects of the
+ last few transactions. In many applications this is an acceptable
+ tradeoff for improved performance.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement "distributed" checkpoints (Itagaki Takahiro and Heikki
+ Linnakangas)
+ </para>
+
+ <para>
+ The I/O needed for a checkpoint is now spread over a fairly long
+ period of time, rather than being spat out in a burst. This happens
+ only for background checkpoints carried out by the bgwriter; other
+ cases, such as a shutdown checkpoint, are still
+ done at full speed.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Heap-Only Tuples (Pavan Deolasee, with ideas from many others)
+ </para>
+
+ <para>
+ When we update a tuple without changing any of its indexed columns,
+ and the new version can be stored on the same heap page, we no
+ longer generate extra index entries for the new version. Instead,
+ index searches follow the HOT-chain links to ensure they find the
+ correct tuple version. In addition, this patch introduces the
+ ability to "prune" dead tuples on a per-page basis, without having
+ to do a complete VACUUM pass to recover space. VACUUM is still
+ needed to clean up dead index entries, however.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Lazy XID allocation (Florian Pflug)
+ </para>
+
+ <para>
+ Formerly, every transaction obtained a transaction ID (XID). Now,
+ transactions that do not modify any database rows will typically
+ never obtain an XID at all. We already did things this way for
+ subtransactions, but this patch extends the concept to top-level
+ transactions. In applications where there are lots of short
+ read-only transactions, this should improve performance noticeably;
+ not so much from removal of the actual XID-assignments, as from
+ reduction of overhead that's driven by the rate of XID consumption.
+ We add a concept of a "virtual transaction ID" so that active
+ transactions can be uniquely identified even if they don't have a
+ regular XID. This is a much lighter-weight concept: uniqueness of
+ VXIDs is only guaranteed over the short term, and no on-disk record
+ is made about them.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Reduce contention for the ProcArrayLock (Florian Pflug, Heikki)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Just-in-time background writing strategy (Greg Smith, Itagaki
+ Takahiro)
+ </para>
+
+ <para>
+ This patch avoids re-scanning buffers that cannot possibly need to
+ be cleaned, and estimates how many buffers it should try to clean
+ based on moving averages of recent allocation requests and density
+ of reusable buffers.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support varlena fields with single-byte headers and unaligned
+ storage (Greg Stark)
+ </para>
+
+ <para>
+ This change allows a significant percentage reduction in the on-disk
+ size of short character-string fields.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Combine cmin and cmax fields of HeapTupleHeaders into a single field
+ (Heikki)
+ </para>
+
+ <para>
+ We do this by keeping private state in each backend that has
+ inserted and deleted the same tuple during its current top-level
+ transaction. This is sufficient since there is no need to be able
+ to determine the cmin/cmax from any other transaction. This gets us
+ back down to 23-byte tuple headers, removing a space penalty paid in
+ 8.0 to support subtransactions.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement "top N" sorting in ORDER BY ... LIMIT queries (Greg Stark)
+ </para>
+
+ <para>
+ We keep a heap of the current best N tuples and sift-up new tuples
+ into it as we scan the input. For M input tuples this means only
+ about M*log(N) comparisons instead of M*log(M), not to mention a lot
+ less workspace when N is small --- avoiding spill-to-disk for large
+ M is actually the most attractive thing about it.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Skip writing WAL in CLUSTER and COPY in cases where it's not needed
+ (Simon)
+ </para>
+
+ <para>
+ If WAL archiving is not enabled, it's possible to ensure
+ transactional safety by fsync'ing the destination table before
+ commit, rather than emitting WAL records for all inserted tuples.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Avoid rewriting pg_control at every WAL segment switch (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Reduce WAL output size for page splits in btree indexes (Heikki)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve hash join for cases with many input NULLs (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Avoid computing X^2 at each row in avg(bigint) and avg(numeric)
+ (Mark Kirkwood)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Suppress useless searches for unused line pointers in PageAddItem
+ (Heikki, improving on an idea from Hiroki Kataoka)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve interlocking between checkpoint start and transaction commit
+ (Heikki)
+ </para>
+
+ <para>
+ The new method both speeds up commit (less for it to do) and
+ prevents the problem of checkpoint being delayed indefinitely when
+ there's a constant flow of commits.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Put a rate limit on messages sent by backends to the stats collector
+ (Tom)
+ </para>
+
+ <para>
+ This reduces the overhead for short transactions by combining
+ reports for successive short transactions.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Avoid unnecessary disk reads during WAL recovery (Heikki)
+ </para>
+
+ <para>
+ Aside from speeding up recovery, this change eliminates a potential
+ data loss risk when restoring a WAL log that was written with
+ full_page_writes off.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve performance of mergejoin with a large sort operation as
+ inner input (Greg Stark)
+ </para>
+
+ <para>
+ This change uses a Materialize node between the mergejoin and the
+ sort to prevent the sort from having to "back up", which allows a
+ more efficient sort.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make large sequential scans and VACUUMs work in a limited-size
+ "ring" of buffers (Simon, Heikki, Tom)
+ </para>
+
+ <para>
+ Aside from avoiding cache spoliation, this fixes the problem that
+ VACUUM formerly tended to cause a WAL flush for every page it
+ modified, because we had it hacked to use only a single buffer.
+ Those flushes will now occur only once per ring-ful.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Synchronize sequential scans (Jeff Davis)
+ </para>
+
+ <para>
+ Large sequential scans now synchronize with each other, so that when
+ multiple backends are scanning the same relation concurrently, each
+ page is (ideally) read only once. Note that a backend joining such
+ a scan starts in the middle of the relation and "wraps around" to
+ cover all blocks; this may affect the order in which rows are
+ returned.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Create a dedicated "wal writer" process to offload WAL-writing work
+ from backends (Simon)
+ </para>
+
+ <para>
+ This process is also responsible for guaranteeing a maximum delay
+ before asynchronously-committed transactions will be flushed to
+ disk.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Server Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Autovacuum is now enabled by default (Alvaro)
+ </para>
+
+ <para>
+ Considerable work was done to make autovacuum less intrusive,
+ allowing this to become a reasonable default.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support multiple concurrent autovacuum processes (Alvaro, Itagaki
+ Takahiro)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Set the default autovacuum vacuum_cost_delay value to 20ms, and
+ reduce the default autovacuum vacuum and analyze threshold values to
+ 50 tuples (Alvaro)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make autovacuum report the start time of its current activity in
+ pg_stat_activity (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Provide for logfiles in machine readable CSV format (Arul Shaji,
+ Greg Smith, Andrew Dunstan)
+ </para>
+
+ <para>
+ In consequence, rename redirect_stderr to logging_collector.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add log_autovacuum_min_duration parameter to support configurable
+ logging of autovacuum actions (Simon, Alvaro)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add log_lock_waits parameter to log long wait times (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add log_temp_files parameter to log usage of temporary files (Bill
+ Moran)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add log_checkpoints parameter to improve logging of checkpoints
+ (Greg Smith, Heikki)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Use our own timezone support for formatting timestamps displayed in
+ the server log (Tom)
+ </para>
+
+ <para>
+ This avoids Windows-specific problems with localized time zone names
+ that are in the wrong encoding. There is a new log_timezone
+ parameter that controls the timezone used in log messages,
+ separately from the client-visible timezone parameter.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ %s and %c escapes in log_line_prefix can now be used in all
+ processes (Andrew)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support a global SSL configuration file (Victor Wagner)
+ </para>
+
+ <para>
+ Add ssl_ciphers parameter to control allowed ciphers (Victor Wagner)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Invalidate and rebuild cached plans whenever there is a schema
+ change or statistics update to referenced relations (Tom)
+ </para>
+
+ <para>
+ Aside from improving performance (for example, by being able to make
+ use of newly-added indexes), this finally fixes the ancient gotcha
+ that you can't drop and recreate a temp table that's used by a
+ PL/PgSQL function, unless you use EXECUTE for all references to it.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Split the archive_command parameter into separate archive_mode and
+ archive_command parameters (Simon)
+ </para>
+
+ <para>
+ This avoids some problems that occur if the user wishes to stop
+ archiving temporarily.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add a %r option in recovery.conf to provide last restartpoint to
+ recovery_command (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add log_restartpoints recovery option to emit LOG message at each
+ restartpoint (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Last transaction end time is now logged at end of recovery and at
+ each logged restartpoint (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ New system view pg_stat_bgwriter displays statistics about the
+ background writer process's performance (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add new columns for database-wide tuple statistics to
+ pg_stat_database (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add an xact_start column to pg_stat_activity (Neil)
+ </para>
+
+ <para>
+ This makes it easier to identify long-running transactions.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add n_live_tuples and n_dead_tuples columns to pg_stat_all_tables
+ and related views (Glen Parker)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add new encoding EUC_JIS_2004 and SHIFT_JIS_2004, along with new
+ conversions among EUC_JIS_2004, SHIFT_JIS_2004 and UTF-8 (Tatsuo)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make JOHAB encoding client-only (Tatsuo)
+ </para>
+
+ <para>
+ It was found that JOHAB does not meet the assumptions needed to be
+ used safely as a server-side encoding.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make configuration parameters fall back to their default values when
+ they are removed from the configuration file (Joachim Wieland)
+ </para>
+
+ <para>
+ This fixes an ancient gotcha that returning a configuration file
+ line to its original commented-out state did not undo the change.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Change the timestamps recorded in transaction commit/abort xlog
+ records from time_t to TimestampTz representation (Tom)
+ </para>
+
+ <para>
+ This provides full gettimeofday() resolution for the timestamps,
+ which might be useful when attempting to do point-in-time recovery
+ --- previously it was not possible to specify the stop point with
+ sub-second resolution.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Limit the amount of information reported when a user is dropped
+ (Alvaro)
+ </para>
+
+ <para>
+ Previously, dropping (or attempting to drop) a user who owned many
+ objects could result in extremely large NOTICE or ERROR messages
+ listing all these objects; this caused problems for some client
+ applications. The length of the list is now limited, although a
+ full list is still sent to the server log.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Create a temp_tablespaces parameter to allow selection of the
+ tablespace(s) in which to store temp tables and temporary files
+ (Jaime Casanova, Albert Cervera, Bernd Helmle)
+ </para>
+
+ <para>
+ This is a list to allow spreading the load across multiple
+ tablespaces; a random list element is chosen each time a temp object
+ is to be created. Temp files are not stored in per-database
+ pgsql_tmp/ directories anymore, but per-tablespace directories.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Arrange to put TOAST tables belonging to temporary tables into
+ special schemas named pg_toast_temp_nnn (Tom)
+ </para>
+
+ <para>
+ This allows low-level code such as the relcache to recognize that
+ these tables are indeed temporary, which enables various
+ optimizations such as not WAL-logging changes and using local rather
+ than shared buffers for access. Aside from obvious performance
+ benefits, this provides a solution to bug #3483, in which other
+ backends unexpectedly held open file references to temporary tables.
+ The scheme preserves the property that TOAST tables are not in any
+ schema that's normally in the search path, so they don't conflict
+ with user table names.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add support for GSSAPI authentication (Henry Hotz, Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support SSPI authentication on Windows (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix problem that a constant flow of new connection requests could
+ indefinitely delay the postmaster from completing a shutdown or
+ crash restart (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow CREATE INDEX CONCURRENTLY to disregard transactions in other
+ databases (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove stats_start_collector parameter (Tom)
+ </para>
+
+ <para>
+ We now always start the collector process, unless prevented by a
+ problem with setting up the stats UDP socket.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove stats_reset_on_server_start parameter (Tom)
+ </para>
+
+ <para>
+ This seemed useless in view of the availability of pg_stat_reset().
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Merge stats_block_level and stats_row_level parameters into a single
+ parameter track_counts, which controls all reports sent to the
+ collector process (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Rename stats_command_string parameter to track_activities (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Query Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Text search capability is now in core Postgres (Teodor, Oleg)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support ORDER BY ... NULLS FIRST/LAST, and add ASC/DESC/NULLS
+ FIRST/NULLS LAST per-column options for btree indexes (Tom, Teodor)
+ </para>
+
+ <para>
+ Note incompatible change from prior behavior: ORDER BY ... USING
+ will now be rejected if the operator is not a less-than or
+ greater-than member of some btree opclass. This prevents
+ less-than-sane behavior if an operator that doesn't actually define
+ a proper sort ordering is selected.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support UPDATE/DELETE WHERE CURRENT OF cursor_name (Arul Shaji, Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow FOR UPDATE in cursors (Arul Shaji, Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add support for cross-type hashing (Tom)
+ </para>
+
+ <para>
+ This allows hash joins, hash indexes, hashed subplans, and hash
+ aggregation to be used in situations involving cross-data-type
+ comparisons, if the data types have compatible hash functions. That
+ is currently the case for smallint/integer/bigint, and also for
+ float4/float8.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make 'col IS NULL' clauses be btree-indexable conditions (Teodor)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Downgrade implicit casts to text to be assignment-only, except for
+ the ones from the other string-category types (Peter, Tom)
+ </para>
+
+ <para>
+ This change eliminates a lot of surprising interpretations that the
+ parser could formerly make in cases when there was no directly
+ applicable operator.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Create a general mechanism that supports casts to and from the
+ standard string types (text,varchar,bpchar) for *every* datatype, by
+ invoking the datatype's I/O functions (Tom)
+ </para>
+
+ <para>
+ These new casts are assignment-only in the to-string direction,
+ explicit-only in the other, and therefore should create no
+ surprising behavior. Remove a bunch of thereby-obsoleted
+ datatype-specific casting functions.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make ARRAY(SELECT ...) return an empty array, rather than a NULL,
+ when the sub-select returns zero rows (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix some issues with user tables and views that are named similarly
+ to system catalogs (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove the undocumented "not in" operator (!!=) (Tom)
+ </para>
+
+ <para>
+ This operator was obsoleted long ago by IN (sub-SELECT) queries.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Planner Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Improve handling of "equivalence classes" of variables that are
+ constrained to be equal within a query's WHERE clause (Tom)
+ </para>
+
+ <para>
+ Among other things, this change allows mergejoins to work with
+ descending sort orders, and improves recognition of redundant sort
+ columns.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix problems with selectivity estimation for partial indexes (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve performance for planning large inheritance trees that are
+ mostly excluded by constraints (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix cost estimates for EXISTS subqueries that are evaluated as
+ initPlans (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Object Manipulation Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Support arrays of composite types, including the rowtypes of regular
+ tables and views (but not system catalogs, nor sequences or toast
+ tables) (David Fetter, Andrew, Tom)
+ </para>
+
+ <para>
+ This change also removes the hardwired convention that a type's
+ array type is named exactly "_type", instead using a new column
+ pg_type.typarray to provide the linkage. (It still will be named
+ "_type", though, except in odd corner cases such as maximum-length
+ type names or collisions with a pre-existing type named with a
+ leading underscore.)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support per-function GUC parameter settings (Tom)
+ </para>
+
+ <para>
+ This provides a simple solution for functions that need local
+ settings for parameters; in particular, security definer functions
+ that must set search_path to avoid security loopholes.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add COST and ROWS options to CREATE/ALTER FUNCTION (Tom)
+ </para>
+
+ <para>
+ This change allows simple user adjustment of the estimated cost of a
+ function call, as well as control of the estimated number of rows
+ returned by a set-returning function. We might eventually wish to
+ extend this to allow function-specific estimation routines, but
+ there seems to be consensus that we should try a simple constant
+ estimate first.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow triggers and rules to be defined with different, per session
+ controllable, behaviors for replication purposes (Jan)
+ </para>
+
+ <para>
+ This will allow replication systems to control the firing mechanism
+ of triggers and rewrite rules without modifying the system catalogs
+ directly. The behavior is controlled by a new superuser-only
+ parameter session_replication_role.
+
+ psql's \d command as well as pg_dump are extended in a backward
+ compatible fashion.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Invent "operator families" to allow improved handling of
+ cross-data-type operators (Tom)
+ </para>
+
+ <para>
+ This change allows significantly better planning of queries
+ involving cross-data-type comparisons.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support type modifiers for user-defined types (Teodor, Tom)
+ </para>
+
+ <para>
+ User-defined types can now use parameters, similar to the maximum
+ length and precision parameters used by some built-in types. Any
+ simple constant (numeric or string) or identifier can be used as a
+ parameter value. A type-specific function must be provided to
+ validate this information and pack it into a 32-bit "typmod" value
+ for storage.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Clean up semantic assumptions for foreign keys (Tom)
+ </para>
+
+ <para>
+ There is now a sound semantic basis for the equality checks applied
+ by foreign-key constraints; formerly the system tended to assume
+ that any operator named "=" was the right thing. The equality
+ operators will now be selected from the opfamily of the unique index
+ that the FK constraint depends on to enforce uniqueness of the
+ referenced columns; therefore they are certain to be consistent with
+ that index's notion of equality. Among other things this should fix
+ the problem noted awhile back that pg_dump may fail for foreign-key
+ constraints on user-defined types when the required operators aren't
+ in the search path. This also means that the former warning
+ condition about "foreign key constraint will require costly
+ sequential scans" is gone: if the comparison condition isn't
+ indexable then we'll reject the constraint entirely.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Utility Command Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Support SET FROM CURRENT in CREATE/ALTER FUNCTION, ALTER DATABASE,
+ ALTER ROLE (Tom)
+ </para>
+
+ <para>
+ This provides a convenient way of applying a session's current
+ parameter setting as the default for future sessions or function
+ calls.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Arrange for SET LOCAL's effects to persist until the end of the
+ current top transaction, unless rolled back or overridden by a SET
+ clause for the same variable attached to a surrounding function call
+ (Tom)
+ </para>
+
+ <para>
+ This is an INCOMPATIBLE CHANGE: in 8.0 through 8.2, SET LOCAL's
+ effects disappeared at subtransaction commit (leading to behavior
+ that made little sense at the SQL level).
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add ALTER VIEW ... RENAME TO and ALTER SEQUENCE ... RENAME TO (David
+ Fetter, Neil)
+ </para>
+
+ <para>
+ While it's (still) possible to perform these operations using ALTER
+ TABLE, users were often surprised that they couldn't say ALTER VIEW
+ or ALTER SEQUENCE as appropriate.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement CREATE TABLE LIKE ... INCLUDING INDEXES (Trevor
+ Hardcastle, Nikhil S, Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix EXPLAIN so it can always print the correct referent of an upper
+ plan level expression (Tom)
+ </para>
+
+ <para>
+ This fix banishes the old hack of showing "?columnN?" when things
+ got too complicated.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make EXPLAIN ANALYZE show which sort method was used by a Sort node
+ (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make PreventTransactionChain reject commands submitted as part of a
+ multi-statement simple-Query message (Tom)
+ </para>
+
+ <para>
+ For example, "BEGIN; DROP DATABASE; COMMIT" will now be rejected
+ even if submitted as a single Query message. This is a potential
+ incompatibility since some clients expected such strings to work;
+ but it was always unsafe.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow non-superuser database owners to create procedural languages
+ (Jeremy Drake)
+ </para>
+
+ <para>
+ A database owner is now allowed to create a language in his database
+ if it's marked "tmpldbacreate" in pg_pltemplate. The factory
+ default is that this is set for all standard trusted languages, but
+ of course a superuser may adjust the settings. In service of this,
+ add the long-foreseen owner column to pg_language; renaming,
+ dropping, and altering owner of a PL now follow normal ownership
+ rules instead of being superuser-only.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make NOTIFY/LISTEN/UNLISTEN only accept simple relation names
+ (Bruce)
+ </para>
+
+ <para>
+ Formerly, these commands accepted "schema.relation" but then ignored
+ the schema part, leading to confusion.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support syntax "CLUSTER table USING index", which is more logical
+ than the old CLUSTER syntax (Holger Schurig)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make CLUSTER MVCC-safe (Heikki Linnakangas)
+ </para>
+
+ <para>
+ Formerly, a CLUSTER command would discard all tuples that were
+ committed dead, even if there were still transactions that should be
+ able to see them under the MVCC snapshot rules.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement new commands DISCARD ALL, DISCARD PLANS, DISCARD TEMP,
+ CLOSE ALL, and DEALLOCATE ALL (Marko Kreen, Neil)
+ </para>
+
+ <para>
+ These commands simplify resetting a database session to initial
+ state, and are particularly handy for connection-pooling software.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make CLUSTER freeze tuples where possible (Heikki, Alvaro)
+ </para>
+
+ <para>
+ This is nearly free and may avoid the need for a subsequent VACUUM
+ of the table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make CLUSTER and TRUNCATE advance the table's relfrozenxid to
+ RecentXmin (Alvaro)
+ </para>
+
+ <para>
+ This may avoid the need for a subsequent VACUUM of the table. The
+ table-rewriting variants of ALTER TABLE do it too.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make CREATE/DROP/RENAME DATABASE wait a little bit to see if other
+ backends will exit before failing because of conflicting DB usage
+ (Tom)
+ </para>
+
+ <para>
+ This helps mask the fact that backend exit takes nonzero time.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Data Type and Function Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ SQL/XML support (Nikolay Samokhvalov, Peter)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support enum data types (Tom Dunstan)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add a "uuid" data type similar to that defined in RFC 4122 (Gevik
+ Babakhani)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Widen the money data type to 64 bits (D'Arcy Cain)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add "isodow" option to EXTRACT() and date_part() (Bruce)
+ </para>
+
+ <para>
+ This is day of the week, with Sunday = 7.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check for overflow when converting far-future date values to
+ timestamp (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make to_timestamp() and to_date() assume "TM" for potentially
+ variable-width fields (Bruce)
+ </para>
+
+ <para>
+ This matches Oracle behavior.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix off-by-one conversion in to_date()/to_timestamp() 'D' fields
+ (Bruce)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add ID (ISO day of week) and IDDD (ISO day of year) format types for
+ to_char(), to_date() and to_timestamp() (Brendan Jurd)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add lo_truncate() function for large object truncation (Kris Jurka)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix float4/float8 to handle Infinity and Nan consistently (Bruce)
+ </para>
+
+ <para>
+ The code formerly was not consistent about distinguishing Infinity
+ symbols from overflow conditions.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement width_bucket() for the float8 data type (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make setseed() return void, rather than a useless integer value
+ (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add a function pg_stat_clear_snapshot() that discards any statistics
+ snapshot already collected in the current transaction (Tom)
+ </para>
+
+ <para>
+ This allows plpgsql functions to watch for stats updates even though
+ they are confined to a single transaction.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add new regexp functions regexp_matches(), regexp_split_to_array(),
+ and regexp_split_to_table() (Jeremy Drake, Neil)
+ </para>
+
+ <para>
+ These functions provide access to the capture groups resulting from
+ a POSIX regular expression match, and provide the ability to split a
+ string on a POSIX regular expression.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add a hash function for "numeric" (Neil)
+ </para>
+
+ <para>
+ This enables use of hash indexes and hash-based plans with
+ the numeric datatype.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve efficiency of LIKE/ILIKE code, especially for multi-byte
+ charsets, and most especially for UTF8 (Andrew, Itagaki Takahiro)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow leading and trailing
+ whitespace in the input to the boolean type (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add explicit casts between boolean and text/varchar (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add additional checks for invalidly-encoded data (Andrew)
+ </para>
+
+ <para>
+ This change plugs some holes that formerly existed in SQL literal
+ backslash escape processing and COPY escape processing: the
+ de-escaped string is rechecked if it might have resulted in creating
+ invalid multi-byte characters.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Ensure that chr() cannot create invalidly encoded text (Andrew)
+ </para>
+
+ <para>
+ In UTF8-encoded databases the argument is treated as a Unicode code
+ point. In other multi-byte encodings the argument must designate a
+ 7-bit ASCII character, or an error is raised, as is also the case if
+ the argument is 0.
+
+ ascii() is adjusted so that it remains the inverse of chr().
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Adjust convert() behavior to ensure encoding validity (Andrew)
+ </para>
+
+ <para>
+ The two argument form of convert() is gone, and the three argument
+ form now takes a bytea first argument and returns a bytea. To cover
+ this loss three new functions are introduced: . convert_from(bytea,
+ name) returns text - converts the first argument from the named
+ encoding to the database encoding . convert_to(text, name) returns
+ bytea - converts the first argument from the database encoding to
+ the named encoding . length(bytea, name) returns int - gives the
+ length of the first argument in characters in the named encoding.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove CONVERT(argument USING conversion_name) (Andrew)
+ </para>
+
+ <para>
+ Although this syntax is required by the SQL standard, it's not clear
+ what the standard expects it to do, except that it's most likely not
+ what we were doing. The former behavior was an encoding security
+ hole, too.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Put some security restrictions on the dbsize functions (Tom)
+ </para>
+
+ <para>
+ Restrict pg_database_size() to users who can connect to the target
+ database (note that CONNECT privilege is granted by default, so this
+ does not change the default behavior). Restrict
+ pg_tablespace_size() to users who have CREATE privilege on the
+ tablespace (which is *not* granted by default), except when the
+ tablespace is the default tablespace for the current database (since
+ we treat that as implicitly allowing use of the tablespace).
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Make currtid() functions require SELECT privileges on the target
+ table (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>PL/PgSQL Server-Side Language Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Support scrollable cursors (ie, add a "direction" clause in FETCH)
+ in plpgsql (Pavel Stehule)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add support for IN as alternative to FROM in PL/PgSQL's FETCH
+ statement, for consistency with the backend's FETCH command (Pavel
+ Stehule)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support MOVE in PL/PgSQL (Magnus, Pavel Stehule, Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Implement RETURN QUERY for PL/PgSQL (Pavel Stehule, Tom)
+ </para>
+
+ <para>
+ This provides some convenient syntax sugar for PL/PgSQL
+ set-returning functions that want to return the result of evaluating
+ a query; it should also be more efficient than repeated RETURN NEXT
+ statements.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow plpgsql function parameter names to be qualified with the
+ function's name (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Reject zero or negative BY step in plpgsql integer FOR-loops, and
+ behave sanely if the loop value overflows int32 on the way to the
+ end value (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve accuracy of error locations in PL/PgSQL syntax errors (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>PL/Perl Server-Side Language Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Allow type-name arguments to spi_prepare() to be standard type
+ aliases as well as the names given in pg_type (Andrew)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>PL/Python Server-Side Language Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Enable PL/PythonU to compile on Python 2.5 (Marko Kreen)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow type-name arguments to plpy.prepare() to be standard type
+ aliases as well as the names given in pg_type (Andrew)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support true boolean type in Python versions that have it, i.e.,
+ version 2.3 and later (Marko Kreen)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>PL/Tcl Server-Side Language Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Allow type-name arguments to spi_prepare to be standard type aliases
+ as well as the names given in pg_type (Andrew)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix problems with thread-enabled libtcl spawning multiple threads
+ within the backend (Steve Marshall, Paul Bayer, Doug Knight)
+ </para>
+
+ <para>
+ This caused all sorts of unpleasantness.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title><link linkend="APP-PSQL"><application>psql</></link> Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ List disabled triggers separately in "\d" output
+ (Brendan Jurd)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Identify schema of inherited table in "\d" output (Bernd Helmle)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Show aggregate return types in "\da" output (Greg Sabino Mullane)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add the function's volatility to the output of \df+ (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ In \d patterns, always match $ literally, whether quoted or not
+ (Tom)
+ </para>
+
+ <para>
+ Since we allow $ as a character within identifiers, this behavior is
+ useful, whereas the previous behavior of treating it as the regexp
+ ending anchor was nearly useless given that the pattern is
+ automatically anchored anyway.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add \prompt command (Chad Wagner)
+ </para>
+
+ <para>
+ This lets a psql script prompt the user for input.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow \pset and \x, \t to use boolean constants on/off, rather than
+ always toggling (Chad Wagner)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add \sleep command to allow delays in psql scripts (Jan)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Enable \timing output for \copy commands (Andrew)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow \timing to have better resolution than ~15ms on Windows
+ (Itagaki Takahiro)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Flush the \o file, if any, after each backslash command (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title><link linkend="APP-PGDUMP"><application>pg_dump</></link> Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Add output-file option for pg_dumpall (Dave Page)
+ </para>
+
+ <para>
+ This is primarily useful on Windows, where output redirection of
+ child pg_dump processes doesn't work.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow pg_dumpall to accept an initial-connection database name
+ rather than the default "template1" (Dave Page)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add --tablespaces-only and --roles-only options to pg_dumpall (Dave
+ Page)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ In -n and -t switches, always match $ literally, whether quoted or
+ not (Tom)
+ </para>
+
+ <para>
+ Since we allow $ as a character within identifiers, this behavior is
+ useful, whereas the previous behavior of treating it as the regexp
+ ending anchor was nearly useless given that the pattern is
+ automatically anchored anyway.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Replace linear searches with binary searches in pg_dump's code to
+ lookup objects by OID (Tom)
+ </para>
+
+ <para>
+ This can improve speed materially in databases with thousands of
+ objects of the same kind (for instances, thousands of functions).
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Other Client Application Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Allow a nondefault pg_xlog directory location to be specified to
+ initdb (Euler Taveira de Oliveira)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Call setrlimit if possible in pg_regress to allow core file
+ generation, and provide a switch for similar behavior in pg_ctl
+ (Andrew)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add cancel handlers so it's possible to Ctrl-C clusterdb, reindexdb
+ and vacuumdb (Itagaki Takahiro, Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove gratuitous response messages from utility programs (Peter)
+ </para>
+
+ <para>
+ The --quiet option is now obsolete and without effect in createdb,
+ createuser, dropdb, dropuser; kept for compatibility but marked for
+ removal in 8.4.
+
+ Progress messages when acting on all databases now go to stdout
+ instead of stderr, since they are not in fact errors.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title><link linkend="libpq"><application>libpq</></link> Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Support a global SSL configuration file (Victor Wagner)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add libpq environment variable PGSSLKEY to control SSL hardware keys
+ (Victor Wagner)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Interpret the dbName parameter of PQsetdbLogin as a conninfo string
+ if it contains an = sign (Andrew)
+ </para>
+
+ <para>
+ This allows use of all the options of conninfo strings through
+ client programs that still use PQsetdbLogin.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add lo_truncate() function for large object truncation (Kris Jurka)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Provide PQconnectionUsedPassword() function that returns true if the
+ server demanded a password during authentication (Joe Conway)
+ </para>
+
+ <para>
+ If this is true after a failed connection, and the user did not give
+ a password, clients may choose to prompt for a password and retry.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Get rid of client-code dependencies on the exact text of the
+ no-password error message, by using PQconnectionUsedPassword()
+ instead (Tom)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title><link linkend="ecpg"><application>ecpg</></link> Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Major rewrite to use V3 frontend/backend protocol (Michael)
+ </para>
+
+ <para>
+ Among other things, prepared statements can now be prepared on the
+ server side.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Use native threads, instead of pthreads, on Windows (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Improve thread-safety of ecpglib (Itagaki Takahiro)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title><application>Windows</> Port</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Support building the entire Postgres system with Visual C++ (Magnus
+ and others)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove old-style client-only Visual C++ build infrastructure for
+ everything except libpq (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow regression tests to be started by an admin user (Magnus)
+ </para>
+
+ <para>
+ This uses the same privilege-dropping method that's used by pg_ctl
+ and initdb.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Native shared memory implementation for Windows (Magnus)
+ </para>
+
+ <para>
+ Same underlying tech as before, but removes the useless SysV
+ emulation layer.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Source Code Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Improve smgr/md API (Tom)
+ </para>
+
+ <para>
+ This improves error detection and reporting, both for external
+ problems and for coding errors inside the backend. Notably,
+ disallow mdread() beyond EOF, and enforce that mdwrite() is to be
+ used for rewriting existing blocks while mdextend() is to be used
+ for extending the relation EOF.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Support "gmake draft" in doc/src/sgml/Makefile (Bruce)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Allow GIN's extractQuery method to signal that nothing can satisfy
+ the query (Teodor)
+ </para>
+
+ <para>
+ This changes prototype of extractQuery method to use int32* instead
+ of uint32* for nentries argument. A -1 result means that no search
+ is needed.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Rename MaxTupleSize to MaxHeapTupleSize to clarify that it's not
+ meant to describe the maximum size of index tuples (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove the xlog-centric "database system is ready" message and
+ replace it with "database system is ready to accept connections"
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Provide strlcpy() and strlcat() on all platforms, and replace
+ error-prone uses of strncpy(), strncat(), etc (Peter)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Move NAMEDATALEN definition from postgres_ext.h to
+ pg_config_manual.h (Peter)
+ </para>
+
+ <para>
+ It used to be part of libpq's exported interface many releases ago,
+ but now it's no longer necessary to make it accessible to clients.
+ We may eventually make it configurable via a configure switch, but
+ we should first flush out any client-side code that thinks it needs
+ to know the value.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Restructure planner-to-executor API (Tom)
+ </para>
+
+ <para>
+ Notably, the executor no longer sees the Query structure at all, but
+ gets a new node type called PlannedStmt that is more suitable as
+ executor input. This allows us to stop storing mostly-redundant
+ Query trees in prepared statements, portals, etc. Also, the
+ rangetable used by the executor is now a flat list with no
+ unnecessary substructure --- this simplifies many things.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add configure --enable-profiling switch to enable code profiling
+ (works with gcc only, for now) (Korry Douglas and Nikhil S)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Replace direct assignments to VARATT_SIZEP(x) with SET_VARSIZE(x,
+ len) (Greg Stark, Tom)
+ </para>
+
+ <para>
+ Third-party code that manipulates varlena datums *must* convert to
+ this convention, since the varvarlena patch changes the
+ representation of length words on some architectures.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Preserve typmod information in Const, Param, ArrayRef, ArrayExpr,
+ and EXPR and ARRAY SubLink nodes (Tom)
+ </para>
+
+ <para>
+ This seems like a good idea in view of the expected increase in
+ typmod usage from Teodor's work to allow user-defined types to have
+ typmods.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove advertising clause from Berkeley BSD-licensed files, per
+ instructions from Berkeley (Bruce)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Replace 4-clause licensed blf.[ch] in contrib/pgcrypto with blowfish
+ implementation from PuTTY which is under minimal BSD/MIT license
+ (Marko Kreen)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Decouple the values of TOAST_TUPLE_THRESHOLD and
+ TOAST_MAX_CHUNK_SIZE, and adjust them to avoid wasting two bytes per
+ toast chunk (Tom)
+ </para>
+
+ <para>
+ This forces initdb because the value of TOAST_MAX_CHUNK_SIZE
+ determines the content of toast tables. Add TOAST_MAX_CHUNK_SIZE to
+ the values checked in pg_control, since it can't be changed without
+ invalidating toast table content.
+
+ Note: while TOAST_TUPLE_THRESHOLD can now be changed without
+ initdb, some thought still needs to be given to needs_toast_table()
+ in toasting.c before unleashing random changes.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Remove the prohibition on executing cursor commands through
+ SPI_execute (Tom)
+ </para>
+
+ <para>
+ The macro definition of SPI_ERROR_CURSOR still exists, so as not to
+ needlessly break any SPI callers that are checking for it, but that
+ code will never actually be returned anymore.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Clean up SPI's API a little bit by declaring SPI plan pointers as
+ "SPIPlanPtr" instead of "void *" (Tom)
+ </para>
+
+ <para>
+ This does not break any existing code, but switching is recommended
+ to help catch simple programming mistakes.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Expose more cursor-related functionality in SPI (Pavel Stehule)
+ </para>
+
+ <para>
+ Allow access to the planner's cursor-related planning options, and
+ provide new FETCH/MOVE routines that allow access to the full power
+ of those commands.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add tas() support for Renesas' M32R processor (Kazuhiro Inaoka)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add a flag bit to WAL records that shows whether it is safe to
+ remove full-page images (Koichi Suzuki)
+ </para>
+
+ <para>
+ This supports implementation of external WAL-compression filters
+ that remove such images.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix pgstats counting of live and dead tuples to recognize that
+ committed and aborted transactions have different effects (Tom)
+ </para>
+
+ <para>
+ This should result in noticeably more accurate tracking of
+ n_live_tuples and n_dead_tuples.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Create hooks to let a loadable plugin monitor (or even replace) the
+ planner and/or create plans for hypothetical situations (Gurjeet
+ Singh, Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Create a function variable "join_search_hook" to let plugins
+ override the join search order portion of the planner (Julius
+ Stroffek)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Downgrade some low-level startup messages to DEBUG1 (Peter)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix several hash functions that were taking chintzy shortcuts
+ instead of delivering a well-randomized hash value (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Redefine IsTransactionState() to only return true for
+ TRANS_INPROGRESS state (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Arrange for quote_identifier() and pg_dump to not quote keywords
+ that are unreserved according to the grammar (Tom)
+ </para>
+
+ <para>
+ Should this be flagged as a potential incompatibility?
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Fix PGXS conventions so that extensions can be built against
+ Postgres installations whose pg_config program does not appear first
+ in the PATH (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Rename DLLIMPORT macro to PGDLLIMPORT to avoid conflict with third
+ party includes (like tcl) that define DLLIMPORT (Magnus)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Adjust the output of MemoryContextStats() so that the line for a
+ child memory context is indented two spaces to the right of its
+ parent context (Neil)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add configure option --with-system-tzdata to use operating system
+ time zone database (Peter)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Change on-disk representation of NUMERIC datatype so that the
+ sign_dscale word comes before the weight instead of after (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Use SYSV semaphores rather than POSIX on Darwin >= 6.0, i.e., OS X
+ 10.2 and up (Chris Marcellino)
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ <sect3>
+ <title>Contrib Changes</title>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Add /contrib/pageinspect module for low-level page inspection
+ (Simon, Heikki)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add /contrib/pg_standby module for warm standby operation (Simon)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add /contrib/uuid-ossp module for generating UUID values using the OSSP
+ UUID library (Peter)
+ </para>
+
+ <para>
+ Use configure option --with-ossp-uuid to activate.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add pgbench option to set fillfactor (Pavan Deolasee)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Enhance pgbench -l option to add timestamp (Greg Smith)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add usage count statistics to the information available from
+ contrib/pgbuffercache (Greg Smith)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add GIN support for hstore (Guillaume Smet, Teodor)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Add GIN support for pg_trgm (Guillaume Smet, Teodor0
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Update /contrib/start-scripts OS/X startup files, and move to a
+ separate OS/X directory (Mark Cotner, David Fetter)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Restrict pgrowlocks() and dblink_get_pkey() to users who have SELECT
+ privilege on the target table (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Restrict contrib/pgstattuple functions to superusers (Tom)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ contrib/xml2 is deprecated and planned for removal in 8.4 (Peter)
+ </para>
+
+ <para>
+ The new XML support in core Postgres supersedes this module.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect3>
+
+ </sect2>
+ </sect1>
+
<sect1 id="release-8-2-5">
<title>Release 8.2.5</title>
projects / postgresql / commitdiff