Release Notes
Release 7.4
- _________________________________________________________________
-
+
Overview
Major changes in this release:
+ Performance
+ IN/NOT IN subqueries are now much more efficient
+
+ Improved GROUP BY processing by using hash buckets
+
+ New multi-key hash join capability
+
+ ANSI joins are now better optimized
+
+ Faster and more powerful regular expression code
+
+ Function-inlining for simple SQL functions
+
IPv6
Full support for IPv6 connections and IPv6 address data types
and other free space management improvements.
Standards Compliance
- Implement information schema Support for read-only transactions
+ Implement information schema
+
+ Support for read-only transactions
Make cursors comply more closely with the SQL standard
error codes, status information, a binary protocol, error
reporting verbosity, and cleaner startup packets.
- Performance
- IN/NOT IN subqueries now perform as efficiently as joins
-
- Improved GROUP BY processing by using hash buckets
-
- New multi-key hash join capability
-
- ANSI joins are now better optimized
-
- Faster and more powerful regular expression code
-
- Function-inlining for simple SQL functions
-
Holdable Cursors
Allow cursors to exist outside transactions
in client applications and languages.
* Error message wording has changed substantially in this release,
and error codes have been added.
- * ANSI joins may behave differently because they are now better
- optimized
+ * ANSI inner joins may behave differently because they are now
+ better optimized
* A number of server variables have been renamed for clarity
* MOVE/FETCH 0 now does nothing; return value of MOVE/FETCH 1/0
varies based on the current offset in the cursor
* Assume WHERE a.x = b.y and b.y = 42 also means a.x = 42 (Tom)
* Allow hash/merge joins on complex joins (Tom)
* Allow hash joins for more data types (Tom)
- * Allow join optimization of ANSI joins, disable with
+ * Allow join optimization of ANSI inner joins, disable with
join_collapse_limit (Tom)
* Add from_collapse_limit to control conversion of subqueries to
joins (Tom)
- * Use faster regular expression code from TCL (Henry Spencer, Tom)
+ * Use faster and more powerful regular expression code from TCL
+ (Henry Spencer, Tom)
* Use bit-mapped relation sets in the optimizer (Tom)
* Improve backend startup time (Tom)
* Improve trigger/constraint performance (Stephan)
* Improve hash index concurrency and speed (Tom)
* Align shared buffers on 32-byte boundary for copy speed
improvement (Manfred Spraul)
+ * The NUMERIC datatype has been reimplemented for better performance
+ (Tom)
_________________________________________________________________
Server Configuration
* New is_superuser read-only variable (Tom)
* New server-side parameter log_error_verbosity to control error
detail (Tom)
- * postgres --help-config now dumps server config variables (Aizaz
- Ahmed)
+ * postgres --describe-config now dumps server config variables
+ (Aizaz Ahmed, Peter)
* Make default shared_buffers 1000 and max_connections 100, if
possible (Tom)
- * Add new columns in pg_settings: context, type, source , min_val,
+ * Add new columns in pg_settings: context, type, source, min_val,
max_val (Joe)
* New pg_hba.conf 'hostnossl' to prevent SSL connections (Jon
Jensen)
Utility Commands
- * Add ON COMMIT PRESERVE ROWS for temp tables (Gavin)
+ * Add ON COMMIT clause to CREATE TABLE for temp tables (Gavin)
* Allow cursors outside transactions using WITH HOLD (Neil)
* Make MOVE/FETCH 0 actually move/fetch 0 (Bruce)
- * Cause FETCH 1 to return the current cursor row, or zero if at
+ * Cause FETCH 1 to return the next cursor row number, or zero if at
beginning/end of cursor, per SQL spec (Bruce)
* Have MOVE return 0 or 1 depending on cursor position (Bruce)
* Properly handle SCROLL with cursors, or report an error (Neil)
* Improve VACUUM performance on indexes by reducing WAL traffic
(Tom)
* Allow pg_ctl to better handle non-standard ports (Greg)
- * Functional indexes now support indexes on column expressions (Tom)
+ * Functional indexes have been generalized into expressional indexes
+ (Tom)
* Syntax errors now reported as 'syntax error' rather than 'parse
error' (Tom)
* Have SHOW TRANSACTION_ISOLATION match input to SET
indexes (Tom)
* pg_dump --use-set-session-authorization and --no-reconnect now do
nothing, all dumps use SET SESSION AUTHORIZATION
+ * Long options for pg_dump are now available on all platforms
_________________________________________________________________
Data Types and Functions
* Allow the creation of special LIKE indexes for non-C locales
(Peter)
* Disallow invalid timezone names (Tom)
- * Trim trailing spaces when CHAR() data is cast to VARCHAR or TEXT
- (Tom)
+ * Trim trailing spaces when CHAR() is cast to VARCHAR or TEXT (Tom)
* Make FLOAT(p) measure the precision p in bits, not decimal digits
(Tom)
* Add IPv6 support to the inet and cidr data types (Michael Graff)
(Michael Graff)
* Have SHOW DATESTYLE generate output similar to that used by SET
DATESTYLE (Tom)
- * Change DATESTYLE to output its value in a more common format (Tom)
* Make EXTRACT(TIMEZONE) and SET/SHOW TIMEZONE follow the SQL
convention for the sign of timezone offsets, ie, positive is east
from UTC (Tom)
* Add "\pset pager always" to always use pager (Greg)
* Improve tab completion (Rod, Ross Reedstrom, Ian Barwick)
* Reorder \? help into groupings (Harald Armin Massa, Bruce)
- * Add schema, cast, and conversion backslash commands (Christopher)
+ * Add backslash commands for listing schemas, casts, and conversions
+ (Christopher)
* \encoding now changes based on client_encoding server variable
(Tom)
* Save edit history into readline history (Ross)
* New '\set AUTOCOMMIT off' capability (Tom)
* New '\set VERBOSITY' to control error detail (Tom)
* New %T prompt string to show transaction status (Tom)
+ * Long options for psql are now available on all platforms
_________________________________________________________________
Libpq
files (Tom)
* Improved PPC locking primitive (Reinhard Max)
* Embed LD_LIBRARY_PATH used for build process into binaries (Billy)
- * New palloc0 to allocate and clear memory (Bruce)
+ * New palloc0 function to allocate and clear memory (Bruce)
* Fix locking code for s390x CPU (64-bit) (Tom)
* Allow OpenBSD to use local ident credentials (William Ahern)
* Make query plan trees read-only to executor (Tom)
Karl Waclawek)
* Use our own version of getopt_long() if needed (Peter)
* Convert administration scripts to C (Peter)
- * Bison >=1.85 is now required for grammar changes
+ * Bison >= 1.85 is now required to build the PostgreSQL grammar, if
+ building from CVS
* Merge documentation into one book (Peter)
* Add Win32 compatibility functions (Bruce)
* Allow client interfaces to compile under MinGW/Win32 (Bruce)
* Support Intel Linux compiler (Peter)
* Improve Linux startup scripts (Slawomir Sudnik, Darko Prenosil)
* Add support for AMD Opteron and Itanium (Jeffrey W. Baker, Bruce)
- * Remove configure --enable-recode
+ * Remove --enable-recode option to configure
* Generate a compile error if spinlock code is not found (Bruce)
_________________________________________________________________
Other Uncategorized
- * EXTRACT(TIMEZONE) and "SET/SHOW TIMEZONE " now follow SQL sign
- convention (positive = east of UTC)
* "DATESTYLE" can now be set to DMY, YMD, or MDY to specify input
field order
* Input date order must now be YYYY-MM-DD (with 4-digit year) or
match DATESTYLE
- * Output of "SHOW DATESTYLE" is now in the same format accepted by
- "SET DATESTYLE"
- * PL/Python is now an untrusted language, and is renamed to
- plpythonu
- * Dollar sign ($) is no longer allowed in operator names
- * Dollar sign ($) can be a non-first character in identifiers
- * Precision in FLOAT(p) is now interpreted as bits, not decimal
- digits
- * Functional indexes have been generalized into expressional indexes
- * CHAR(n) to TEXT conversion automatically strips trailing blanks
* Pattern matching operations can use indexes regardless of locale
- * New frontend/backend protocol supports many long-requested
- features
- * "SET AUTOCOMMIT TO OFF" is no longer supported; psql has an
- AUTOCOMMIT variable
- * Reimplementation of NUMERIC datatype for more speed
- * New regular expression package, many more regexp features (most of
- Perl5)
- * Can now do " EXPLAIN" ... "EXECUTE" to see plan used for a
- prepared query
- * Explicit "JOIN"s no longer constrain query plan, unless
- "JOIN_COLLAPSE_LIMIT = 1"
- * Performance of "foo IN (SELECT ...)" queries has been considerably
- improved
- * "FETCH 0" now re-fetches cursor's current row, per SQL spec
- * Revised executor state representation; plan trees are read-only to
- executor now
- * Information schema
- * Domains now support "CHECK" constraints
- * psql backslash commands for listing conversions, casts, and
- schemas
- * "TRUNCATE TABLE" is transaction-safe
- * "CLUSTER" can re-cluster a previously clustered table, or all such
- tables
- * Statement-level triggers
- * System can use either hash- or sort-based strategy for grouped
- aggregation
- * "ON COMMIT" options for temp tables
- * extra_float_digits option allows pg_dump to dump float data
- accurately
- * Long options for psql and pg_dump are now available on all
- platforms
- * Read-only transactions
- * Object owners can allow grantees to grant the privilege to others
- (grant option)
- * Added "contrib" module for pg_autovacuum which monitors inserts
- and deletes, and does "ANALYZE" or " VACUUM ANALYZE " when
- quantities exceed specified thresholds.
_________________________________________________________________
Release 7.3.4
projects / postgresql.git / commitdiff