postgresql/doc/TODO

TODO list for PostgreSQL
========================
Last updated:		Sat May  6 23:21:34 EDT 2000

Current maintainer:	Bruce Momjian (pgman@candle.pha.pa.us)

The most recent version of this document can be viewed at
the PostgreSQL web site, http://www.PostgreSQL.org.

A dash(-) marks changes that will appear in the upcoming 7.0 release.

Names in brackets "[]" indicate more detailed information is available in
the directory pgsql/doc/TODO.detail/ under that name.


RELIABILITY
-----------

PARSER

* SELECT pg_class FROM pg_class generates strange error
* Alter TABLE ADD COLUMN does not honor DEFAULT, add CONSTRAINT
* Creating index of TIMESTAMP & RELTIME fails, or rename to DATETIME(Thomas)
* SELECT foo UNION SELECT foo is incorrectly simplified to SELECT foo
* Unique index on base column not honored on inserts from inherited table
  INSERT INTO inherit_table (unique_index_col) VALUES (dup) should fail
  [inherit] 
* Be smarter about promoting types when UNION merges different data types
* redesign INSERT ... SELECT to have two levels of target list
* have INTERSECT/EXCEPT prevent duplicates unless ALL is specified
* SELECT DISTINCT ON col1 col1 col2 FROM tab1 is broken [distinct]
* SELECT col::DECIMAL(12,10); fails

VIEWS

* Views containing aggregates sometimes fail(Jan)
* Creating view and inheriting the view causes view* to show
  duplicates(inherit) 
* Disallow LOCK on view

MISC

* Plpgsql does not handle quoted mixed-case identifiers
* Buffer reference counting bugfixes
* Fix libpq bug that causes it to drop backend error message sent
  just before connection closure (ie, any FATAL error message)
* SELECT ... UNION ... ORDER BY fails when sort expr not in result list
* SELECT ... UNION ... GROUP BY fails if column types disagree, no type
  promotion occurs
* Modification  of  pg_class  can  happen while table in use by
  another backend.  Might  lead  to  MVCC  inside  of  syscache
* Permission to UPDATE table allows DELETE also
* Some database schema's are not dumpable;  do dumps in oid order


ENHANCEMENTS
------------

URGENT

* Add OUTER joins, left and right[outer](Thomas, Bruce)
* Allow long tuples by chaining or auto-storing outside db (TOAST)(Jan)
* Fix memory leak for expressions[memory](Tom?) 

ADMIN

* More access control over who can create tables and access the database
* Test syslog functionality
* Allow elog() to return error codes, not just messages
* Allow international error message support and add error codes
* Add ability to specifiy location of lock/socket files [flock]
* Unify configuration into one configuration file (Peter E)

TYPES

* Nchar (as distinguished from ordinary varchar),
* Domain capability
* Add STDDEV/VARIANCE() function for standard deviation computation/variance
* Allow compression of large fields or a compressed field type
* Large objects
	o Fix large object mapping scheme, own typeid or reltype(Peter)
	o Not to stuff everything as files in a single directory, hash dirs
	o Allow large object vacuuming
	o Tables that start with xinv confused to be large objects
* Add IPv6 capability to INET/CIDR types
* Make a separate SERIAL type?
* Store binary-compatible type information in the system
* Add support for & operator
* Allow LOCALE on a per-column basis, default to ASCII
* Allow nulls in arrays
* Allow arrays to be ORDER'ed
* Remove Money type, add money formatting for decimal type
* Declare typein/out functions in pg_proc with a special "C string" data type
* Add non-large-object binary field
* Functions returning sets don't really work right[function]

VIEWS

* Allow DISTINCT on views
* Allow views of aggregate columns
* Allow views with subselects

INDEXES

* Allow CREATE INDEX zman_index ON test (date_trunc( 'day', zman ) datetime_ops)
  fails index can't store constant parameters
* Allow SQL function indexes
* Add FILLFACTOR to index creation

COMMANDS

* ALTER TABLE ADD COLUMN to inherited table put column in wrong place [inherit]
* Add ALTER TABLE DROP/ALTER COLUMN feature(Peter E)
* Add ALTER TABLE command to change table ownership
* Allow CLUSTER on all tables at once, and improve CLUSTER, loses NOT
	NULL specification, indexes, permissions, etc on table[cluster]
* Add SIMILAR TO to allow character classes, 'pg_[a-c]%'
* Auto-destroy sequence on DROP of table with SERIAL(Ryan)
* Allow LOCK TABLE tab1, tab2, tab3 so all tables locked in unison
* Allow INSERT/UPDATE of system-generated oid value for a row
* Allow ESCAPE '\' at the end of LIKE for ANSI compliance [like]
* Rewrite the LIKE handling by rewriting the user string with the 
  supplied ESCAPE [like]
* Allow RULE recompilation
* Support UNION/INTERSECT/EXCEPT in sub-selects
* Allow DELETE and UPDATE to use inheritance using tablename*
* Allow INSERT INTO my_table VALUES (a, b, c, DEFAULT, x, y, z, ...)
* Allow BINARY option to SELECT, like we do with DECLARE
  
CLIENTS

* Make NULL's come out at the beginning or end depending on the 
  ORDER BY direction
* Update reltuples from COPY command
* fix array handling for ECPG
* add pg_dump option to dump type names as standard ANSI types
* allow psql \d to show primary and foreign keys
* allow psql \d to show temporary table schema

REFERENTIAL INTEGRITY

* Add MATCH PARTIAL referential integrity
* Foreign key does not check that columns referenced form a primary key
  or constrained by UNIQUE 
* Check that primary key exists at foreign key definition time
* Prevent column dropping if column is used by foreign key
* Propagate column or table renaming to foreign key constraints
* Emit a warning at foreign key creation time if no UNIQUE index
  exists on referenced primary key attributes

EXOTIC FEATURES

* Add sql3 recursive unions
* Add the concept of dataspaces
* Add replication of distributed databases
* Allow queries across multiple databases
* Allow nested transactions (Vadim)

MISC

* Increase identifier length(NAMEDATALEN) if small performance hit
* Allow row re-use without vacuum(Vadim)
* Create a background process for each database that runs while
  database is idle, finding superceeded rows, gathering stats and vacuuming
* Add UNIQUE capability to non-btree indexes
* Certain indexes will not shrink, i.e. oid indexes with many inserts(Vadim)
* Restore unused oid's on backend exit if no one else has gotten oids
* Have UPDATE/DELETE clean out indexes
* Allow cursors to be DECLAREd/OPENed/CLOSEed outside transactions
* Allow DELETE WHERE CURRENT OF cursor
* Transaction log, so re-do log can be on a separate disk by
  with after-row images(Vadim) [logging](Vadim)(in-progress)
* Populate backend status area and write program to dump status data
* Make oid use unsigned int more reliably, pg_atoi()
* Put sort files, large objects in their own directory
* Do autocommit so always in a transaction block(?)
* Show location of syntax error in query [yacc]
* Redesign the function call interface to handle NULLs better[function](Tom)
* Missing optimizer selectivities for date, r-tree, etc. [optimizer]
* Overhaul bufmgr/lockmgr/transaction manager
* Allow BLCKSZ <= 64k, not <= 32k
* redesign UNION structures to have separarate target lists
* Allow multi-level query trees for INSERT INTO ... SELECT
* Use IPC_EXCL when creating shared memory and semaphores
* have pg_upgrade use pg_ctl to stop/start postmaster
* Encrpyt passwords in pg_shadow table using MD5

PERFORMANCE
-----------

FSYNC

* Allow transaction commits with rollback with no-fsync performance [fsync](Vadim)

INDEXES

* Use indexes in ORDER BY for min(), max()
* Use index to restrict rows returned by multi-key index when used with
  non-consecutive keys or OR clauses, so fewer heap accesses
* Allow SELECT * FROM tab WHERE int2col = 4 use int2col index, int8,
  float4, numeric/decimal too [optimizer]
* Include heap CTID in btree index keys, remove equal-key cruft from btree

CACHE

* Cache most recent query plan(s) [prepare]
* Shared catalog cache, reduce lseek()'s by caching table size in shared area

MISC

* Allow compression of log and meta data
* Allow char() not to use variable-sized header to reduce disk size
* Do async I/O to do better read-ahead of data
* Get faster regex() code from Henry Spencer <henry@zoo.utoronto.ca>
  when it is available
* Use mmap() rather than SYSV shared memory(?)
* Make oid use oidin/oidout not int4in/int4out in pg_type.h
* Improve Subplan list handling
* Allow Subplans to use efficient joins(hash, merge) with upper variable
  [subquery]
* use fmgr_info()/fmgr_faddr() instead of fmgr() calls in high-traffic
  places, like GROUP BY, UNIQUE, index processing, etc.
* improve dynamic memory allocation by introducing tuple-context memory
  allocation [memory]
* In WHERE tab1.x=3 AND tab1.x=tab2.y, add tab2.y=3
* Allow persistent backends [persistent]
* prevent labels from being output for stored rules (Tom)
* allow configuration of maximum number of open files


SOURCE CODE
-----------
* Add use of 'const' for variables in source tree
* Fix C optimizer problem where fmgr_ptr calls return different types [alpha]
* Does Mariposa source contain any other bug fixes?
* Remove SET KSQO option now that OR processing is improved(Tom)
* Use macros to define NT open() file parameters, remove NT-specific defines
* Change CURRENT to OLD internally for rules

---------------------------------------------------------------------------


Developers who have claimed items are:
--------------------------------------
	* Billy is Billy G. Allie <Bill.Allie@mug.org>
	* Brook is Brook Milligan <brook@trillium.NMSU.Edu>
	* Bruce is Bruce Momjian<pgman@candle.pha.pa.us>
	* Bryan is Bryan Henderson<bryanh@giraffe.netgate.net>
	* D'Arcy is D'Arcy J.M. Cain <darcy@druid.net>
	* David is David Hartwig <daveh@insightdist.com>
	* Edmund is Edmund Mergl <E.Mergl@bawue.de>
	* Goran is Goran Thyni <goran@kyla.kiruna.se>
	* Hiroshi is Hiroshi Inoue<Inoue@tpf.co.jp>
	* Jan is Jan Wieck <wieck@sapserv.debis.de>
 	* Marc is Marc Fournier <scrappy@hub.org>
	* Massimo Dal Zotto <dz@cs.unitn.it>
	* Michael is Michael Meskes <meskes@postgresql.org>
	* Oleg is Oleg Bartunov <oleg@sai.msu.su>
	* Peter is Peter T Mount <peter@retep.org.uk>
	* Peter E is Peter Eisentraut<peter_e@gmx.net>
	* Ryan is Ryan Bradetich <rbrad@hpb50023.boi.hp.com>
	* Stefan Simkovics <ssimkovi@rainbow.studorg.tuwien.ac.at>
	* Tatsuo is Tatsuo Ishii <t-ishii@sra.co.jp>
	* Tom is Tom Lane <tgl@sss.pgh.pa.us>
	* Thomas is Thomas Lockhart <lockhart@alumni.caltech.edu>
	* TomH is Tom I Helbekkmo <tih@Hamartun.Priv.NO>
	* Vadim is "Vadim B. Mikheev" <vadim@krs.ru>