TODO list for PostgreSQL ======================== Last updated: Mon Sep 6 23:55:43 EDT 1999 Current maintainer: Bruce Momjian (maillist@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 next release. RELIABILITY ----------- RESOURCES * Elog() does not free all its memory(Jan) * spinlock stuck problem when elog(FATAL) and elog(ERROR) inside bufmgr * Recover or force failure when disk space is exhausted PARSER * Disallow inherited columns with the same name as new columns * INSERT INTO ... SELECT with AS columns matching result columns problem * SELECT pg_class FROM pg_class generates strange error * Alter TABLE ADD COLUMN does not honor DEFAULT, add CONSTRAINT * Do not allow bpchar column creation without length * Select a[1] FROM test fails, it needs test.a[1] * -Array index references without table name cause problems * Update table SET table.value = 3 fails * Creating index of TIMESTAMP & RELTIME fails, or rename to DATETIME(Thomas) * SELECT foo UNION SELECT foo is incorrectly simplified to SELECT foo * -INSERT ... SELECT ... GROUP BY groups by target columns not source columns * -CREATE TABLE test (a char(5) DEFAULT text '', b int4) fails on INSERT * UNION with LIMIT fails * Unique index on base column not honored on inserts from inherited table INSERT INTO inherit_table (unique_index_col) VALUES (dup) should fail * CREATE TABLE x AS SELECT 1 UNION SELECT 2 fails * CREATE TABLE test(col char(2) DEFAULT user) fails in length restriction * SELECT ... UNION ... ORDER BY fails when sort expr not in result list * Be smarter about promoting types when UNION merges different data types * SELECT ... UNION ... GROUP BY fails if column types disagree * redesign INSERT ... SELECT to have two levels of target list * -select * from pg_class where oid in (0,-1) * have INTERSECT/EXCEPT prevent duplicates unless ALL is specified VIEWS * Views containing aggregates sometimes fail(Jan) * Views with spaces in view name fail when referenced MISC * User who can create databases can modify pg_database table * Plpgsql does not handle quoted mixed-case identifiers * Fix btree to give a useful elog when key > 1/2 (page - overhead) * pg_dump should preserve primary key information ENHANCEMENTS ------------ URGENT * Add referential integrity(Jan?) * Add OUTER joins, left and right(Thomas, Bruce) * Allow long tuples by chaining or auto-storing outside db (chaining,large objs) * Eliminate limits on query length * Fix memory leak for expressions?, aggregates?(Tom?) ADMIN * Better interface for adding to pg_group * More access control over who can create tables and access the database * Add syslog functionality * Allow elog() to return error codes, not just messages * Allow international error message support and add error codes * Generate postmaster pid file and remove flock/fcntl lock code * Add ability to specifiy location of lock/socket files TYPES * Add BIT, BIT VARYING * 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 Allow large text type to use large objects(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 * Allow pg_descriptions when creating types, tables, columns, and functions * Add IPv6 capability to INET/CIDR types * Make a separate SERIAL type? * Store binary-compatible type information in the system * Allow user to define char1 column * Add support for & operator * Allow LOCALE on a per-column basis, default to ASCII * Allow array on int8[] * 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 * Add index on NUMERIC/DECIMAL type * Make Absolutetime/Relativetime int4 because time_t can be int8 on some ports 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 creation of functional indexes to use default types * Permissions on indexes - prevent them? * Allow SQL function indexes * Add FILLFACTOR to index creation * Allow indexing of LIKE with localle character sets * Allow indexing of more than eight columns COMMANDS * ALTER TABLE ADD COLUMN to inherited table put column in wrong place * Add ALTER TABLE DROP/ALTER COLUMN feature * Allow CLUSTER on all tables at once, and improve CLUSTER * Generate error on CREATE OPERATOR of ~~, ~ and and ~* * 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 * Rewrite the LIKE handling by rewriting the user string with the supplied ESCAPE * Move LIKE index optimization handling to the optimizer * Allow RULE recompilation * Support UNION/INTERSECT/EXCEPT in sub-selects CLIENTS * Make NULL's come out at the beginning or end depending on the ORDER BY direction * Allow flag to control COPY input/output of NULLs * Update reltuples from COPY command * Allow psql \copy to allow delimiters * Add a function to return the last inserted oid, for use in psql scripts * Allow psql to print nulls as distinct from ""(?) * PQrequestCancel() be able to terminate backend waiting for lock EXOTIC FEATURES * Add sql3 recursive unions * Add the concept of dataspaces * Add replication of distributed databases * Allow queries across multiple databases 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 * Restore unused oid's on backend exit if no one else has gotten oids * Have UPDATE/DELETE clean out indexes * Allow WHERE restriction on ctid * Allow cursors to be DECLAREd/OPENed/CLOSEed outside transactions * Allow PQrequestCancel() to terminate when in waiting-for-lock state * Transaction log, so re-do log can be on a separate disk by with after-row images(Vadim) * Populate backend status area and write program to dump status data * Make oid use unsigned int more reliably, pg_atoi() * Allow subqueries in target list * Put sort files, large objects in their on directory * Do autocommit so always in a transaction block * Show location of syntax error in query * Redesign the function call interface to handle NULLs better(Jan) * Document/trigger/rule so changes to pg_shadow create pg_pwd * Missing optimizer selectivities for date, r-tree, etc. * Overhaul mdmgr/smgr to fix double unlinking and double opens, cleanup * Overhaul bufmgr/lockmgr/transaction manager * Add PL/Perl(Mark Hollomon) * Make postgres user have a password by default * Add configure test to check for C++ need for *.h and namespaces * Allow BLCKSZ <= 64k, not <= 32k * redesign UNION structures to have separarate target lists PERFORMANCE ----------- FSYNC * Allow transaction commits with rollback with no-fsync performance * Prevent fsync in SELECT-only queries INDEXES * Use indexes in ORDER BY for restrictive data sets, min(), max() * Pull requested data directly from indexes, bypassing heap data * Use index to restrict rows returned by multi-key index when used with non-consecutive keys or OR clauses, so fewer heap accesses * Convert function(constant) into a constant for index use * Allow LIMIT ability on single-table queries that have no ORDER BY to use a matching index * Improve LIMIT processing by using index to limit rows processed * Have optimizer take LIMIT into account when considering index scans * Make index creation use psort code, because it is now faster(Vadim) * Allow creation of sort temp tables > 1 Gig * Create more system table indexes for faster cache lookups * fix indexscan() so it does leak memory by not requiring caller to free * Improve _bt_binsrch() to handle equal keys better, remove _bt_firsteq()(Tom) * Allow SELECT * FROM tab WHERE int2col = 4 use int2col index * Allow optimizer to prefer plans that match ORDER BY CACHE * Cache most recent query plan(s?) * Shared catalog cache, reduce lseek()'s by caching table size in shared area * elog() flushes cache, try invalidating just entries from current xact, perhaps using invalidation cache MISC * Allow compression of log and meta data * Update pg_statistic table to remove operator column * Allow char() not to use variable-sized header to reduce disk size * Do async I/O to do better read-ahead of data * -Fix memory exhaustion when using many OR's * Get faster regex() code from Henry Spencer when it is available * Use mmap() rather than SYSV shared memory(?) * Process const = const parts of OR clause in separate pass * 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 * 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 * fix memory leak in cache code when non-existant table is referenced * In WHERE tab1.x=3 AND tab1.x=tab2.y, add tab2.y=3 * pass atttypmod through parser in more cases(Bruce) * remove duplicate type in/out functions for disk and net SOURCE CODE ----------- * Add use of 'const' for varibles in source tree * Fix C optimizer problem where fmgr_ptr calls return different types * Add needed includes and removed unneede include files(Bruce) * Make configure --enable-debug add -g on compile line --------------------------------------------------------------------------- Developers who have claimed items are: -------------------------------------- * Billy is Billy G. Allie * Brook is Brook Milligan * Bruce is Bruce Momjian * Bryan is Bryan Henderson * D'Arcy is D'Arcy J.M. Cain * David is David Hartwig * Edmund is Edmund Mergl * Goran is Goran Thyni * Hiroshi is Hiroshi Inoue * Jan is Jan Wieck * Marc is Marc Fournier * Massimo Dal Zotto * Michael is Michael Meskes * Oleg is Oleg Bartunov * Peter is Peter T Mount * Ryan is Ryan Bradetich * Stefan Simkovics * Tatsuo is Tatsuo Ishii * Tom is Tom Lane * Thomas is Thomas Lockhart * TomH is Tom I Helbekkmo * Vadim is "Vadim B. Mikheev"