3 Current maintainer: Bruce Momjian (bruce@momjian.us)
4 Last updated: Fri May 9 20:24:53 EDT 2008
6 The most recent version of this document can be viewed at
7 http://www.postgresql.org/docs/faqs.TODO.html.
9 #A hyphen, "-", marks changes that will appear in the upcoming 8.4 release.#
10 #A percent sign, "%", marks items that are easier to implement.#
12 This list contains all known PostgreSQL bugs and feature requests. If
13 you would like to work on an item, please read the Developer's FAQ
14 first. There is also a developer's wiki at
15 http://developer.postgresql.org.
21 * -Allow administrators to safely terminate individual sessions either
22 via an SQL function or SIGTERM
23 * Check for unreferenced table files created by transactions that were
24 in-progress when the server terminated abruptly
26 http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php
28 * Set proper permissions on non-system schemas during db creation
30 Currently all schemas are owned by the super-user because they are copied
31 from the template1 database. However, since all objects are inherited
32 from the template database, it is not clear that setting schemas to the db
35 * -Add function to report the time of the most recent server reload
36 * Allow statistics collector information to be pulled from the collector
37 process directly, rather than requiring the collector to write a
38 filesystem file twice a second?
39 * Reduce file system activity overhead of statistics file pgstat.stat
41 http://archives.postgresql.org/pgsql-general/2007-12/msg00106.php
43 * Allow statistics last vacuum/analyze execution times to be displayed
44 without requiring stats_row_level to be enabled
46 http://archives.postgresql.org/pgsql-docs/2007-04/msg00028.php
48 * Allow log_min_messages to be specified on a per-module basis
50 This would allow administrators to see more detailed information from
51 specific sections of the backend, e.g. checkpoints, autovacuum, etc.
52 Another idea is to allow separate configuration files for each module,
53 or allow arbitrary SET commands to be passed to them.
55 * Simplify ability to create partitioned tables
57 This would allow creation of partitioned tables without requiring
58 creation of triggers or rules for INSERT/UPDATE/DELETE, and constraints
59 for rapid partition selection. Options could include range and hash
62 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php
63 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php
64 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00028.php
65 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00248.php
66 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00387.php
67 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00413.php
69 * Allow auto-selection of partitioned tables for min/max() operations
70 * Allow more complex user/database default GUC settings
72 Currently ALTER USER and ALTER DATABASE support per-user and
73 per-database defaults. Consider adding per-user-and-database
74 defaults so things like search_path can be defaulted for a
75 specific user connecting to a specific database.
77 * Allow custom variable classes that can restrict who can set the values
79 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php
81 * Implement the SQL standard mechanism whereby REVOKE ROLE revokes only
82 the privilege granted by the invoking role, and not those granted
85 http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php
87 * Allow SSL authentication/encryption over unix domain sockets
89 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php
91 * Allow SSL key file permission checks to be optionally disabled when
92 sharing SSL keys with other applications
94 http://archives.postgresql.org/pgsql-bugs/2007-12/msg00069.php
96 * Allow client certificate names to be checked against the client
99 This is already implemented in
100 libpq/fe-secure.c::verify_peer_name_matches_certificate() but the code
103 * Configuration files
105 o Allow pg_hba.conf to specify host names along with IP addresses
107 Host name lookup could occur when the postmaster reads the
108 pg_hba.conf file, or when the backend starts. Another
109 solution would be to reverse lookup the connection IP and
110 check that hostname against the host names in pg_hba.conf.
111 We could also then check that the host name maps to the IP
114 o %Allow postgresql.conf file values to be changed via an SQL
115 API, perhaps using SET GLOBAL
116 o Allow the server to be stopped/restarted via an SQL API
117 o Issue a warning if a change-on-restart-only postgresql.conf value
118 is modified and the server config files are reloaded
119 o Consider normalizing fractions in postgresql.conf, perhaps
122 http://archives.postgresql.org/pgsql-hackers/2007-06/msg00550.php
124 o Allow Kerberos to disable stripping of realms so we can
125 check the username@realm against multiple realms
127 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00009.php
132 o Allow a database in tablespace t1 with tables created in
133 tablespace t2 to be used as a template for a new database created
134 with default tablespace t2
136 Currently all objects in the default database tablespace must
137 have default tablespace specifications. This is because new
138 databases are created by copying directories. If you mix default
139 tablespace tables and tablespace-specified tables in the same
140 directory, creating a new database from such a mixed directory
141 would create a new database with tables that had incorrect
142 explicit tablespaces. To fix this would require modifying
143 pg_class in the newly copied database, which we don't currently
146 o Allow reporting of which objects are in which tablespaces
148 This item is difficult because a tablespace can contain objects
149 from multiple databases. There is a server-side function that
150 returns the databases which use a specific tablespace, so this
151 requires a tool that will call that function and connect to each
152 database to find the objects in each database for that tablespace.
154 o Allow WAL replay of CREATE TABLESPACE to work when the directory
155 structure on the recovery computer is different from the original
157 o Allow per-tablespace quotas
160 * Point-In-Time Recovery (PITR)
162 o Allow a warm standby system to also allow read-only statements
164 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php
166 o %Create dump tool for write-ahead logs for use in determining
167 transaction id for point-in-time recovery
169 This is useful for checking PITR recovery.
171 o Allow recovery.conf to support the same syntax as
172 postgresql.conf, including quoting
174 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php
176 o Fix server restart problem when the server was shutdown during
179 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00800.php
181 o Recreate pg_xlog/archive_status/ if it doesn't exist after
182 restoring from a PITR backup
184 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00487.php
190 * Change NUMERIC to enforce the maximum precision
191 * Reduce storage space for small NUMERICs
193 http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php
194 http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php
195 http://archives.postgresql.org/pgsql-hackers/2007-06/msg00715.php
197 * Fix data types where equality comparison isn't intuitive, e.g. box
198 * Add support for public SYNONYMs
200 http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php
202 * Fix CREATE CAST on DOMAINs
204 http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php
205 http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php
207 * Allow domains to be cast
209 http://archives.postgresql.org/pgsql-hackers/2003-06/msg01206.php
210 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00289.php
212 * Add support for SQL-standard GENERATED/IDENTITY columns
214 http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php
215 http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php
216 http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php
217 http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php
218 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php
220 * Improve XML support
222 http://developer.postgresql.org/index.php/XML_Support
224 * Consider placing all sequences in a single table, or create a system
227 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php
229 * Allow the UUID type to accept non-standard formats
231 http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php
233 * Consider a special data type for regular expressions
235 http://archives.postgresql.org/pgsql-hackers/2007-08/msg01067.php
237 * Reduce BIT data type overhead using short varlena headers
239 http://archives.postgresql.org/pgsql-general/2007-12/msg00273.php
241 * Allow xml arrays to be cast to other data types
243 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00981.php
244 http://archives.postgresql.org/pgsql-hackers/2007-10/msg00231.php
245 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00471.php
247 * Simplify integer cross-data-type operators
249 http://archives.postgresql.org/pgsql-bugs/2008-01/msg00189.php
251 * Allow XML to accept more liberal DOCTYPE specifications
253 http://archives.postgresql.org/pgsql-general/2008-02/msg00347.php
255 * Allow adding/renaming/removing enumerated values to an existing
258 http://archives.postgresql.org/pgsql-hackers/2008-04/msg01718.php
262 o Allow infinite dates and intervals just like infinite timestamps
263 o Merge hardwired timezone names with the TZ database; allow either
264 kind everywhere a TZ name is currently taken
265 o Allow TIMESTAMP WITH TIME ZONE to store the original timezone
266 information, either zone name or offset from UTC
268 If the TIMESTAMP value is stored with a time zone name, interval
269 computations should adjust based on the time zone rules.
270 http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php
272 o Fix SELECT '0.01 years'::interval, '0.01 months'::interval
273 o Add a GUC variable to allow output of interval values in ISO8601
275 o Have timestamp subtraction not call justify_hours()?
277 http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php
279 o Improve timestamptz subtraction to be DST-aware
281 Currently subtracting one date from another that crosses a
282 daylight savings time adjustment can return '1 day 1 hour', but
283 adding that back to the first date returns a time one hour in
284 the future. This is caused by the adjustment of '25 hours' to
285 '1 day 1 hour', and '1 day' is the same time the next day, even
286 if daylight savings adjustments are involved.
288 o Fix interval display to support values exceeding 2^31 hours
289 o Add overflow checking to timestamp and interval arithmetic
290 o Extend timezone code to allow 64-bit values so we can
291 represent years beyond 2038
293 http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php
295 o Use LC_TIME for localized weekday/month names, rather than
298 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php
300 o Add ISO INTERVAL handling
302 http://archives.postgresql.org/pgsql-hackers/2006-01/msg00250.php
303 http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php
305 o Support ISO INTERVAL syntax if units cannot be determined from
306 the string, and are supplied after the string
308 The SQL standard states that the units after the string
309 specify the units of the string, e.g. INTERVAL '2' MINUTE
310 should return '00:02:00'. The current behavior has the units
311 restrict the interval value to the specified unit or unit
312 range, INTERVAL '70' SECOND returns '00:00:10'.
314 For syntax that isn't uniquely ISO or PG syntax, like '1' or
315 '1:30', treat as ISO if there is a range specification clause,
316 and as PG if there no clause is present, e.g. interpret '1:30'
317 MINUTE TO SECOND as '1 minute 30 seconds', and interpret
318 '1:30' as '1 hour, 30 minutes'.
320 This makes common cases like SELECT INTERVAL '1' MONTH
321 SQL-standard results. The SQL standard supports a limited
322 number of unit combinations and doesn't support unit names in
323 the string. The PostgreSQL syntax is more flexible in the
324 range of units supported, e.g. PostgreSQL supports '1 year 1
325 hour', while the SQL standard does not.
327 o Add support for year-month syntax, INTERVAL '50-6' YEAR
329 o Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1
330 year' AS INTERVAL MONTH), and this should return '12 months'
331 o Round or truncate values to the requested precision, e.g.
332 INTERVAL '11 months' AS YEAR should return one or zero
333 o Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
338 o Delay resolution of array expression's data type so assignment
339 coercion can be performed on empty array expressions
340 o Add support for arrays of domains
342 http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php
344 o Allow single-byte header storage for array elements
349 o Improve vacuum of large objects, like contrib/vacuumlo?
350 o Add security checking for large objects
351 o Auto-delete large objects when referencing row is deleted
353 contrib/lo offers this functionality.
355 o Allow read/write into TOAST values like large objects
357 This requires the TOAST column to be stored EXTERNAL.
359 o Add API for 64-bit large object access
361 http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php
365 * Add locale-aware MONEY type, and support multiple currencies
367 http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php
368 http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php
370 * MONEY dumps in a locale-specific format making it difficult to
371 restore to a system with a different locale
372 * Allow MONEY to be easily cast to/from other numeric data types
376 o Allow dictionaries to change the token that is passed on to
379 http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php
381 o Consider a function-based API for '@@' searches
383 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php
385 o Improve text search error messages
387 http://archives.postgresql.org/pgsql-hackers/2007-10/msg00966.php
388 http://archives.postgresql.org/pgsql-hackers/2007-11/msg01146.php
390 o Consider changing error to warning for strings larger than one
393 http://archives.postgresql.org/pgsql-bugs/2008-02/msg00190.php
394 http://archives.postgresql.org/pgsql-patches/2008-03/msg00062.php
401 * Allow INET subnet tests using non-constants to be indexed
402 * Allow to_date() and to_timestamp() accept localized month names
403 * Fix to_date()-related functions to consistently issue errors
405 http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php
407 * Add missing parameter handling in to_char()
409 http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php
411 * Allow substring/replace() to get/set bit values
412 * Allow to_char() on interval values to accumulate the highest unit
415 Some special format flag would be required to request such
416 accumulation. Such functionality could also be added to EXTRACT.
417 Prevent accumulation that crosses the month/day boundary because of
418 the uneven number of days in a month.
420 o to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
421 o to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
422 o to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
423 o to_char(INTERVAL '3 years 5 months','MM') => 41
425 * Implement inlining of set-returning functions defined in SQL
426 * Allow SQL-language functions to return results from RETURNING queries
428 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php
430 * Allow SQL-language functions to reference parameters by parameter name
432 Currently SQL-language functions can only refer to dollar parameters,
435 * Add SPI_gettypmod() to return the typemod for a TupleDesc
436 * Enforce typmod for function inputs, function results and parameters for
437 spi_prepare'd statements called from PLs
439 http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php
441 * Allow holdable cursors in SPI
442 * Tighten function permission checks
444 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php
446 * Fix IS OF so it matches the ISO specification, and add documentation
448 http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php
449 http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php
451 * Add missing operators for geometric data types
453 Some geometric types do not have the full suite of geometric operators,
456 * Implement Boyer-Moore searching in strpos()
458 http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php
460 * Prevent malicious functions from being executed with the permissions
461 of unsuspecting users
463 Index functions are safe, so VACUUM and ANALYZE are safe too.
464 Triggers, CHECK and DEFAULT expressions, and rules are still vulnerable.
465 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php
467 * Reduce memory usage of aggregates in set returning functions
469 http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php
471 * Add temporal versions of generate_series()
473 http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php
475 * Add array_accum() and array_to_set() functions for arrays
477 The standards specify array_agg() and UNNEST.
478 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00464.php
480 * Fix /contrib/ltree operator
482 http://archives.postgresql.org/pgsql-bugs/2007-11/msg00044.php
484 * Fix inconsistent precedence of =, >, and < compared to <>, >=, and <=
486 http://archives.postgresql.org/pgsql-bugs/2007-12/msg00145.php
488 * Fix regular expression bug when using complex back-references
490 http://archives.postgresql.org/pgsql-bugs/2007-10/msg00000.php
492 * Have /contrib/dblink reuse unnamed connections
494 http://archives.postgresql.org/pgsql-hackers/2007-10/msg00895.php
496 * Add SQL-standard array_agg() and unnest() array functions
498 http://archives.postgresql.org/pgsql-hackers/2008-01/msg01017.php
500 * Allow calling of a procedure outside a SELECT that can control the
503 http://archives.postgresql.org/pgsql-hackers/2007-10/msg01375.php
507 Multi-Language Support
508 ======================
510 * Add NCHAR (as distinguished from ordinary varchar),
511 * Allow locale to be set at database creation
513 Currently locale can only be set during initdb. No global tables have
514 locale-aware columns. However, the database template used during
515 database creation might have locale-aware indexes. The indexes would
516 need to be reindexed to match the new locale.
518 * Allow encoding on a per-column basis optionally using the ICU library;
521 Right now only one encoding is allowed per database.
523 http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php
524 http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php
525 http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php
526 http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php
527 http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php
528 http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php
529 http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php
530 http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php
531 http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php
532 http://wiki.postgresql.org/wiki/Todo:Collate
533 http://wiki.postgresql.org/wiki/Todo:ICU
535 * Support multiple simultaneous character sets, per SQL92
536 * Improve UTF8 combined character handling?
537 * Add octet_length_server() and octet_length_client()
538 * Make octet_length_client() the same as octet_length()?
539 * Fix problems with wrong runtime encoding conversion for NLS message files
540 * Add URL to more complete multi-byte regression tests
542 http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php
544 * Fix ILIKE and regular expressions to handle case insensitivity
545 properly in multibyte encodings
547 http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php
548 http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php
550 * Set client encoding based on the client operating system encoding
552 Currently client_encoding is set in postgresql.conf, which
553 defaults to the server encoding.
554 http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php
556 * Change memory allocation for multi-byte functions so memory is
557 allocated inside conversion functions
559 Currently we preallocate memory based on worst-case usage.
566 * Automatically create rules on views so they are updateable, per SQL99
568 We can only auto-create rules for simple views. For more complex
569 cases users will still have to write rules manually.
571 http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php
572 http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php
574 * Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
575 * Allow VIEW/RULE recompilation when the underlying tables change
577 Another issue is whether underlying table changes should be reflected
578 in the view, e.g. should SELECT * show additional columns if they
579 are added after the view is created.
581 * Make it possible to use RETURNING together with conditional DO INSTEAD
582 rules, such as for partitioning setups
584 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php
586 * Add the ability to automatically create materialized views
588 Right now materialized views require the user to create triggers on the
589 main table to keep the summary table current. SQL syntax should be able
590 to manager the triggers and summary table automatically. A more
591 sophisticated implementation would automatically retrieve from the
592 summary table when the main table is referenced, if possible.
599 * Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
600 * Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
601 * %Allow SET CONSTRAINTS to be qualified by schema/table name
602 * %Add a separate TRUNCATE permission
604 Currently only the owner can TRUNCATE a table because triggers are not
605 called, and the table is locked in exclusive mode.
607 * Allow PREPARE of cursors
608 * Allow finer control over the caching of prepared query plans
610 Currently queries prepared via the libpq API are planned on first
611 execute using the supplied parameters --- allow SQL PREPARE to do the
612 same. Also, allow control over replanning prepared queries either
613 manually or automatically when statistics for execute parameters
614 differ dramatically from those used during planning.
616 * Improve logging of prepared transactions recovered during startup
618 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php
620 * Improve failure message when DROP DATABASE is used on a database that
621 has prepared transactions
622 * Allow prepared transactions with temporary tables created and dropped
623 in the same transaction, and when an ON COMMIT DELETE ROWS temporary
626 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00047.php
628 * Add a GUC variable to warn about non-standard SQL usage in queries
629 * Add SQL-standard MERGE/REPLACE/UPSERT command
631 MERGE is typically used to merge two tables. REPLACE or UPSERT
632 command does UPDATE, or on failure, INSERT. This is similar to UPDATE,
633 then for unmatched rows, INSERT. Whether concurrent access allows
634 modifications which could cause row loss is implementation independent.
635 To implement this cleanly requires that the table have a unique index
636 so duplicate checking can be easily performed. It is possible to do it
637 without a unique index if we require the user to LOCK the table before
640 http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php
641 http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php
642 http://archives.postgresql.org/pgsql-hackers/2008-04/msg01475.php
644 * Add NOVICE output level for helpful messages like automatic sequence/index
646 * Add GUC to issue notice about statements that use unjoined tables
647 * Allow EXPLAIN to identify tables that were skipped because of
649 * Allow EXPLAIN output to be more easily processed by scripts, perhaps XML
650 * Enable standard_conforming_strings
651 * Make standard_conforming_strings the default in 8.5?
653 When this is done, backslash-quote should be prohibited in non-E''
654 strings because of possible confusion over how such strings treat
655 backslashes. Basically, '' is always safe for a literal single
656 quote, while \' might or might not be based on the backslash
659 * Simplify dropping roles that have objects in several databases
660 * Allow COMMENT ON to accept an expression rather than just a string
661 * Allow the count returned by SELECT, etc to be represented as an int64
662 to allow a higher range of values
663 * Add SQL99 WITH clause to SELECT
664 * Add SQL:2003 WITH RECURSIVE (hierarchical) queries to SELECT
666 http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php
667 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php
668 http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php
669 http://archives.postgresql.org/pgsql-hackers/2007-11/msg01334.php
670 http://archives.postgresql.org/pgsql-patches/2008-01/msg00105.php
671 http://archives.postgresql.org/pgsql-patches/2008-03/msg00327.php
673 * Add DEFAULT .. AS OWNER so permission checks are done as the table
676 This would be useful for SERIAL nextval() calls and CHECK constraints.
678 * Allow DISTINCT to work in multiple-argument aggregate calls
679 * Add column to pg_stat_activity that shows the progress of long-running
680 commands like CREATE INDEX and VACUUM
681 * Implement SQL:2003 window functions
682 * Allow INSERT/UPDATE ... RETURNING inside a SELECT 'FROM' clause
684 http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php
685 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php
687 * Increase locking when DROPing objects so dependent objects cannot
688 get dropped while the DROP operation is happening
690 http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php
692 * -Allow AS in "SELECT col AS label" to be optional in certain cases
694 * Allow INSERT ... DELETE ... RETURNING, namely allow the DELETE ...
695 RETURNING to supply values to the INSERT
696 http://archives.postgresql.org/pgsql-hackers/2008-02/thrd2.php#00979
698 * Add comments on system tables/columns using the information in
701 Ideally the information would be pulled from the SGML file
704 * Improve reporting of UNION type mismatches
706 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00944.php
707 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00597.php
712 o Allow CREATE TABLE AS to determine column lengths for complex
713 expressions like SELECT col1 || col2
715 o Have WITH CONSTRAINTS also create constraint indexes
717 http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php
719 o Have CONSTRAINT cname NOT NULL record the contraint name
721 Right now pg_attribute.attnotnull records the NOT NULL status
722 of the column, but does not record the contraint name
724 o Prevent concurrent CREATE TABLE table1 from sometimes returning
725 a cryptic error message
727 http://archives.postgresql.org/pgsql-bugs/2007-10/msg00169.php
729 o Add CREATE SCHEMA ... LIKE that copies a schema
734 o Allow UPDATE tab SET ROW (col, ...) = (SELECT...)
736 http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php
737 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php
738 http://archives.postgresql.org/pgsql-patches/2007-04/msg00315.php
739 http://archives.postgresql.org/pgsql-patches/2008-03/msg00237.php
741 o Research self-referential UPDATEs that see inconsistent row versions
742 in read-committed mode
744 http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php
745 http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php
747 o Allow GLOBAL temporary tables to exist as empty by default in
750 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php
755 o Have ALTER TABLE RENAME rename SERIAL sequence names
757 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php
759 o Have ALTER SEQUENCE RENAME rename the sequence name stored
760 in the sequence table
762 http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php
763 http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php
764 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php
766 o Add ALTER DOMAIN to modify the underlying data type
767 o %Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
769 http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php
771 o %Allow ALTER TABLE to change constraint deferrability and actions
772 o Add missing object types for ALTER ... SET SCHEMA
773 o Allow ALTER TABLESPACE to move to different directories
774 o Allow databases to be moved to different tablespaces
775 o Allow moving system tables to other tablespaces, where possible
777 Currently non-global system tables must be in the default database
778 tablespace. Global system tables can never be moved.
780 o -Prevent parent tables from altering or dropping constraints
781 like CHECK that are inherited by child tables unless CASCADE
783 o -Prevent child tables from altering or dropping constraints
784 like CHECK that were inherited from the parent table
785 o Have ALTER INDEX update the name of a constraint using that index
786 o Add ALTER TABLE RENAME CONSTRAINT, update index name also
787 o Allow column display reordering by recording a display,
788 storage, and permanent id for every column?
790 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php
796 o Automatically maintain clustering on a table
798 This might require some background daemon to maintain clustering
799 during periods of low usage. It might also require tables to be only
800 partially filled for easier reorganization. Another idea would
801 be to create a merged heap/index data file so an index lookup would
802 automatically access the heap data too. A third idea would be to
803 store heap rows in hashed groups, perhaps using a user-supplied
805 http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php
807 o %Add default clustering to system tables
809 To do this, determine the ideal cluster index for each system
810 table and set the cluster setting during initdb.
812 o %Add VERBOSE option to report tables as they are processed,
818 o Allow COPY to report error lines and continue
820 This requires the use of a savepoint before each COPY line is
821 processed, with ROLLBACK on COPY failure.
822 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00572.php
824 o Allow COPY on a newly-created table to skip WAL logging
826 On crash recovery, the table involved in the COPY would
827 be removed or have its heap and index files truncated. One
828 issue is that no other backend should be able to add to
829 the table at the same time, which is something that is
830 currently allowed. This currently is done if the table is
831 created inside the same transaction block as the COPY because
832 no other backends can see the table.
834 o Consider using a ring buffer for COPY FROM
836 http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php
837 http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php
839 o Allow COPY FROM to create index entries in bulk
841 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php
843 o Allow COPY in CSV mode to control whether a quoted zero-length
844 string is treated as NULL
846 Currently this is always treated as a zero-length string,
847 which generates an error when loading into an integer column
848 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00905.php
850 o Impove COPY performance
852 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00954.php
858 o Allow column-level privileges
859 o %Allow GRANT/REVOKE permissions to be applied to all schema objects
862 The proposed syntax is:
863 GRANT SELECT ON ALL TABLES IN public TO phpuser;
864 GRANT SELECT ON NEW TABLES IN public TO phpuser;
866 o Allow GRANT/REVOKE permissions to be inherited by objects based on
869 o Allow SERIAL sequences to inherit permissions from the base table?
874 o Prevent DROP TABLE from dropping a row referenced by its own open
880 o Allow INSERT/UPDATE of the system-generated oid value for a row
881 o In rules, allow VALUES() to contain a mixture of 'old' and 'new'
887 o Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
893 o Allow LISTEN/NOTIFY to store info in memory rather than tables?
895 Currently LISTEN/NOTIFY information is stored in pg_listener.
896 Storing such information in memory would improve performance.
898 o Add optional textual message to NOTIFY
900 This would allow an informational message to be added to the notify
901 message, perhaps indicating the row modified or other custom
904 o Allow multiple identical NOTIFY events to always be communicated
905 to the client, rather than sent as a single notification to the
908 http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php
910 o Allow NOTIFY in rules involving conditionals
911 o Improve LISTEN concurrency
913 http://archives.postgresql.org/pgsql-hackers/2008-02/msg01106.php
917 Referential Integrity
918 =====================
920 * Add MATCH PARTIAL referential integrity
921 * Change foreign key constraint for array -> element to mean element
923 * Fix problem when cascading referential triggers make changes on
924 cascaded tables, seeing the tables in an intermediate state
926 http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php
927 http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php
929 * Allow DEFERRABLE and end-of-statement UNIQUE constraints?
931 This would allow UPDATE tab SET col = col + 1 to work if col has
932 a unique index. Currently, uniqueness checks are done while the
933 command is being executed, rather than at the end of the statement
935 http://people.planetpostgresql.org/greg/index.php?/archives/2006/06/10.html
936 http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php
938 * Optimize referential integrity checks
940 http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php
941 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php
944 Server-Side Languages
945 =====================
948 o Fix RENAME to work on variables other than OLD/NEW
950 http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php
951 http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php
952 http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php
954 o Allow function parameters to be passed by name,
955 get_employee_salary(12345 AS emp_id, 2001 AS tax_year)
956 o Allow handling of %TYPE arrays, e.g. tab.col%TYPE[]
957 o Allow listing of record column names, and access to
958 record columns via variables, e.g. columns := r.(*),
961 http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php
962 http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php
963 http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php
965 o Add support for SCROLL cursors
966 o Add support for WITH HOLD cursors
967 o Allow row and record variables to be set to NULL constants,
968 and allow NULL tests on such variables
970 Because a row is not scalar, do not allow assignment
971 from NULL-valued scalars.
973 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php
975 o Review handling of MOVE and FETCH
977 http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php
979 o Improve logic of determining if an identifier is a a
980 variable or column name
982 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php
984 o Consider keeping seperate cached copies when search_path changes
986 http://archives.postgresql.org/pgsql-hackers/2008-01/msg01009.php
988 o Add CASE capability to language (already in SQL)
990 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00696.php
996 o Add table function support to pltcl, plpythonu
997 o Add support for polymorphic arguments and return types to
998 languages other than PL/PgSQL
999 o Add capability to create and call PROCEDURES
1000 o Add support for OUT and INOUT parameters to languages other
1002 o Add PL/PythonU tracebacks
1004 http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php
1006 o Allow data to be passed in native language formats, rather
1009 http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php
1011 o Add ability to obfuscate function bodies
1013 http://archives.postgresql.org/pgsql-patches/2008-01/msg00125.php
1020 * Have pg_ctl look at PGHOST in case it is a socket directory?
1021 * Allow pg_ctl to work properly with configuration files located outside
1022 the PGDATA directory
1024 pg_ctl can not read the pid file because it isn't located in the
1025 config directory but in the PGDATA directory. The solution is to
1026 allow pg_ctl to read and understand postgresql.conf to find the
1027 data_directory value.
1029 * Add a function like pg_get_indexdef() that report more detailed index
1032 http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php
1035 o Have psql show current values for a sequence
1036 o Move psql backslash database information into the backend, use
1039 This would allow non-psql clients to pull the same information out
1040 of the database as psql.
1041 http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php
1043 o Make psql's \d commands more consistent
1045 http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php
1046 http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php
1048 o Consistently display privilege information for all objects in psql
1049 o Add auto-expanded mode so expanded output is used if the row
1050 length is wider than the screen width.
1052 Consider using auto-expanded mode for backslash commands like \df+.
1054 o Prevent tab completion of SET TRANSACTION from querying the
1055 database and therefore preventing the transaction isolation
1056 level from being set.
1058 Currently SET <tab> causes a database lookup to check all
1059 supported session variables. This query causes problems
1060 because setting the transaction isolation level must be the
1061 first statement of a transaction.
1063 o Add a \set variable to control whether \s displays line numbers
1065 Another option is to add \# which lists line numbers, and
1066 allows command execution.
1068 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php
1070 o Prevent escape string warnings when object names have
1073 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php
1075 o Have \d show foreign keys that reference a table's primary key
1077 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php
1079 o Have \d show child tables that inherit from the specified parent
1080 o Have \l+ show database size, if permissions allow
1082 Ideally it will not generate an error for invalid permissions
1084 o Include the symbolic SQLSTATE name in verbose error reports
1086 http://archives.postgresql.org/pgsql-general/2007-09/msg00438.php
1088 o -Improve display of enums to show valid enum values
1089 o Add prompt escape to display the client and server versions
1092 * pg_dump / pg_restore
1093 o %Add dumping of comments on index columns and composite type columns
1094 o %Add full object name to the tag field. eg. for operators we need
1095 '=(integer, integer)', instead of just '='.
1096 o Add pg_dumpall custom format dumps?
1097 o Allow selection of individual object(s) of all types, not just
1099 o In a selective dump, allow dumping of an object and all its
1101 o Add options like pg_restore -l and -L to pg_dump
1102 o Stop dumping CASCADE on DROP TYPE commands in clean mode
1103 o Allow pg_dump --clean to drop roles that own objects or have
1105 o Change pg_dump so that a comment on the dumped database is
1106 applied to the loaded database, even if the database has a
1107 different name. This will require new backend syntax, perhaps
1108 COMMENT ON CURRENT DATABASE.
1109 o Remove unnecessary function pointer abstractions in pg_dump source
1111 o Allow pg_dump to utilize multiple CPUs and I/O channels by dumping
1112 multiple objects simultaneously
1114 The difficulty with this is getting multiple dump processes to
1115 produce a single dump output file. It also would require
1116 several sessions to share the same snapshot.
1117 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php
1119 o Allow pg_restore to utilize multiple CPUs and I/O channels by
1120 restoring multiple objects simultaneously
1122 This might require a pg_restore flag to indicate how many
1123 simultaneous operations should be performed. Only pg_dump's
1124 -Fc format has the necessary dependency information.
1125 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php
1127 o To better utilize resources, allow pg_restore to check foreign
1128 keys simultaneously, where possible
1129 o Allow pg_restore to create all indexes of a table
1130 concurrently, via a single heap scan
1132 This requires a pg_dump -Fc file because that format contains
1133 the required dependency information.
1134 http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php
1136 o Allow pg_restore to load different parts of the COPY data
1138 o Prevent pg_dump/pg_restore from being affected by
1141 Using psql to restore a pg_dump dump is also affected.
1143 o Remove pre-7.3 pg_dump code that assumes pg_depend does not exit
1144 o Allow pre/data/post files when schema and data are dumped
1145 separately, for performance reasons
1147 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php
1154 Document differences between ecpg and the SQL standard and
1155 information about the Informix-compatibility module.
1157 o Solve cardinality > 1 for input descriptors / variables?
1158 o Add a semantic check level, e.g. check if a table really exists
1159 o fix handling of DB attributes that are arrays
1160 o Use backend PREPARE/EXECUTE facility for ecpg where possible
1162 o Fix nested C comments
1163 o %sqlwarn[6] should be 'W' if the PRECISION or SCALE value specified
1164 o Make SET CONNECTION thread-aware, non-standard?
1165 o Allow multidimensional arrays
1166 o Add internationalized message strings
1167 o Implement COPY FROM STDIN
1171 o Add PQescapeIdentifierConn()
1172 o Prevent PQfnumber() from lowercasing unquoted the column name
1174 PQfnumber() should never have been doing lowercasing, but
1175 historically it has so we need a way to prevent it
1177 o Allow statement results to be automatically batched to the client
1179 Currently all statement results are transferred to the libpq
1180 client before libpq makes the results available to the
1181 application. This feature would allow the application to make
1182 use of the first result rows while the rest are transferred, or
1183 held on the server waiting for them to be requested by libpq.
1184 One complexity is that a statement like SELECT 1/col could error
1185 out mid-way through the result set.
1187 o Consider disallowing multiple queries in PQexec() as an
1188 additional barrier to SQL injection attacks
1190 http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php
1192 o Add PQexecf() that allows complex parameter substitution
1194 http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php
1196 o Add SQLSTATE severity to PGconn return status
1198 http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php
1204 * Add deferred trigger queue file
1206 Right now all deferred trigger information is stored in backend
1207 memory. This could exhaust memory for very large trigger queues.
1208 This item involves dumping large queues into files.
1210 * Allow triggers to be disabled in only the current session.
1212 This is currently possible by starting a multi-statement transaction,
1213 modifying the system tables, performing the desired SQL, restoring the
1214 system tables, and committing the transaction. ALTER TABLE ...
1215 TRIGGER requires a table lock so it is not ideal for this usage.
1217 * With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
1219 If the dump is known to be valid, allow foreign keys to be added
1220 without revalidating the data.
1222 * Allow statement-level triggers to access modified rows
1223 * Support triggers on columns
1225 http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php
1227 * Allow AFTER triggers on system tables
1229 System tables are modified in many places in the backend without going
1230 through the executor and therefore not causing triggers to fire. To
1231 complete this item, the functions that modify system tables will have
1234 * Tighten trigger permission checks
1236 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php
1238 * Allow BEFORE INSERT triggers on views
1240 http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php
1242 * -Add ability to trigger on TRUNCATE
1243 * Add database and transaction-level triggers
1245 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00451.php
1252 * Add UNIQUE capability to non-btree indexes
1253 * Prevent index uniqueness checks when UPDATE does not modify the column
1255 Uniqueness (index) checks are done when updating a column even if the
1256 column is not modified by the UPDATE.
1258 * Allow the creation of on-disk bitmap indexes which can be quickly
1259 combined with other bitmap indexes
1261 Such indexes could be more compact if there are only a few distinct values.
1262 Such indexes can also be compressed. Keeping such indexes updated can be
1265 http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php
1266 http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php
1267 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00265.php
1268 http://archives.postgresql.org/pgsql-hackers/2007-03/msg01214.php
1269 http://archives.postgresql.org/pgsql-patches/2007-05/msg00013.php
1270 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00741.php
1272 * Allow accurate statistics to be collected on indexes with more than
1273 one column or expression indexes, perhaps using per-index statistics
1275 http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php
1276 http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php
1278 * Consider increasing the default and maximum number of statistics targets,
1279 and reduce statistics target overhead
1281 Also consider having a larger statistics target for indexed columns
1282 and expression indexes.
1283 http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php
1284 http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php
1285 http://archives.postgresql.org/pgsql-hackers/2008-01/msg01066.php
1286 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00188.php
1288 * Consider smaller indexes that record a range of values per heap page,
1289 rather than having one index entry for every heap row
1291 This is useful if the heap is clustered by the indexed values.
1292 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php
1293 http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php
1294 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php
1295 http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php
1296 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00014.php
1297 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00487.php
1298 http://archives.postgresql.org/pgsql-hackers/2008-04/msg01589.php
1300 * Add REINDEX CONCURRENTLY, like CREATE INDEX CONCURRENTLY
1302 This is difficult because you must upgrade to an exclusive table lock
1303 to replace the existing index file. CREATE INDEX CONCURRENTLY does not
1304 have this complication. This would allow index compaction without
1306 http://archives.postgresql.org/pgsql-performance/2007-08/msg00289.php
1308 * Allow multiple indexes to be created concurrently, ideally via a
1309 single heap scan, and have pg_restore use it
1311 * Consider sorting entries before inserting into btree index
1313 http://archives.postgresql.org/pgsql-general/2008-01/msg01010.php
1315 * Allow index scans to return matching index keys, not just the matching
1318 http://archives.postgresql.org/pgsql-hackers/2008-04/msg01657.php
1324 o Allow inherited tables to inherit indexes, UNIQUE constraints,
1325 and primary/foreign keys
1326 o Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
1327 on inherited table, e.g. INSERT INTO inherit_table
1328 (unique_index_col) VALUES (dup) should fail
1330 The main difficulty with this item is the problem of
1331 creating an index that can span multiple tables.
1333 o Allow SELECT ... FOR UPDATE on inherited tables
1334 o Require all CHECK constraints to be inherited
1336 http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php
1338 o Add checks to prevent a CREATE RULE views on inherited tables
1340 http://archives.postgresql.org/pgsql-general/2008-02/msg01420.php
1341 http://archives.postgresql.org/pgsql-general/2008-03/msg00077.php
1346 o Add more GIST index support for geometric data types
1347 o Allow GIST indexes to create certain complex index types, like
1348 digital trees (see Aoki)
1353 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php
1355 o Pack hash index buckets onto disk pages more efficiently
1357 Currently only one hash bucket can be stored on a page. Ideally
1358 several hash buckets could be stored on a single page and greater
1359 granularity used for the hash algorithm.
1361 http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php
1363 o Consider sorting hash buckets so entries can be found using a
1364 binary search, rather than a linear scan
1365 o In hash indexes, consider storing the hash value with or instead
1367 o Add WAL logging for crash recovery
1368 o Allow multi-column hash indexes
1369 o -During index creation, pre-sort the tuples to improve build speed
1376 * Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
1378 Ideally this requires a separate test program that can be run
1379 at initdb time or optionally later. Consider O_SYNC when
1382 * Add program to test if fsync has a delay compared to non-fsync
1383 * Consider sorting writes during checkpoint
1385 http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php
1394 We could use a fixed row count and a +/- count to follow MVCC
1395 visibility rules, or a single cached value could be used and
1396 invalidated if anyone modifies the table. Another idea is to
1397 get a count directly from a unique index, but for this to be
1398 faster than a sequential scan it must avoid access to the heap
1399 to obtain tuple visibility information.
1401 * Provide a way to calculate an "estimated COUNT(*)"
1403 Perhaps by using the optimizer's cardinality estimates or random
1406 http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php
1408 * Allow data to be pulled directly from indexes
1410 Currently indexes do not have enough tuple visibility information
1411 to allow data to be pulled from the index without also accessing
1412 the heap. One way to allow this is to set a bit on index tuples
1413 to indicate if a tuple is currently visible to all transactions
1414 when the first valid heap lookup happens. This bit would have to
1415 be cleared when a heap tuple is expired.
1417 Another idea is to maintain a bitmap of heap pages where all rows
1418 are visible to all backends, and allow index lookups to reference
1419 that bitmap to avoid heap lookups, perhaps the same bitmap we might
1420 add someday to determine which heap pages need vacuuming. Frequently
1421 accessed bitmaps would have to be stored in shared memory. One 8k
1422 page of bitmaps could track 512MB of heap pages.
1424 A third idea would be for a heap scan to check if all rows are visible
1425 and if so set a per-table flag which can be checked by index scans.
1426 Any change to the table would have to clear the flag. To detect
1427 changes during the heap scan a counter could be set at the start and
1428 checked at the end --- if it is the same, the table has not been
1429 modified --- any table change would increment the counter.
1431 http://archives.postgresql.org/pgsql-patches/2007-10/msg00166.php
1432 http://archives.postgresql.org/pgsql-patches/2008-01/msg00049.php
1434 * Consider automatic caching of statements at various levels:
1437 o Query execute plan
1439 http://archives.postgresql.org/pgsql-hackers/2008-04/msg00823.php
1441 * Consider increasing internal areas when shared buffers is increased
1443 http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php
1445 * Consider decreasing the amount of memory used by PrivateRefCount
1447 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php
1448 http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php
1450 * Consider allowing higher priority queries to have referenced buffer
1451 cache pages stay in memory longer
1453 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php
1460 * Improve speed with indexes
1462 For large table adjustments during VACUUM FULL, it is faster to cluster
1463 or reindex rather than update the index. Also, index updates can bloat
1466 http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php
1467 http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php
1468 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00307.php
1470 * Auto-fill the free space map by scanning the buffer cache or by
1471 checking pages written by the background writer
1473 http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php
1474 http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php
1476 * Create a bitmap of pages that need vacuuming
1478 Instead of sequentially scanning the entire table, have the background
1479 writer or some other process record pages that have expired rows, then
1480 VACUUM can look at just those pages rather than the entire table. In
1481 the event of a system crash, the bitmap would probably be invalidated.
1482 One complexity is that index entries still have to be vacuumed, and
1483 doing this without an index scan (by using the heap values to find the
1484 index entry) might be slow and unreliable, especially for user-defined
1487 http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php
1488 http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php
1489 http://archives.postgresql.org/pgsql-patches/2007-03/msg00508.php
1490 http://archives.postgresql.org/pgsql-patches/2007-04/msg00347.php
1491 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00156.php
1492 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00546.php
1493 http://archives.postgresql.org/pgsql-hackers/2008-04/msg00416.php
1495 * Allow FSM to return free space toward the beginning of the heap file,
1496 in hopes that empty pages at the end can be truncated by VACUUM
1497 * Allow FSM page return free space based on table clustering, to assist
1498 in maintaining clustering?
1499 * Improve dead row detection during multi-statement transactions usage
1501 http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php
1503 * Consider a more compact data representation for dead tuples
1505 http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php
1510 o %Issue log message to suggest VACUUM FULL if a table is nearly
1512 o Improve control of auto-vacuum
1514 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php
1516 o Prevent long-lived temporary tables from causing frozen-xid
1517 advancement starvation
1519 The problem is that autovacuum cannot vacuum them to set frozen xids;
1520 only the session that created them can do that.
1521 http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php
1523 o Store per-table autovacuum settings in pg_class.reloptions.
1525 http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php
1526 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php
1528 o Prevent autovacuum from running if an old transaction is still
1529 running from the last vacuum
1531 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php
1538 * Fix priority ordering of read and write light-weight locks (Neil)
1540 http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php
1541 http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php
1543 * Fix problem when multiple subtransactions of the same outer transaction
1544 hold different types of locks, and one subtransaction aborts
1546 http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php
1547 http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php
1548 http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php
1549 http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php
1551 * Allow UPDATEs on only non-referential integrity columns not to conflict
1552 with referential integrity locks
1554 http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php
1556 * Add idle_in_transaction_timeout GUC so locks are not held for long
1559 * Improve deadlock detection when a page cleaning lock conflicts
1560 with a shared buffer that is pinned
1562 http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php
1563 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php
1564 http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php
1566 * Detect deadlocks involving LockBufferForCleanup()
1568 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php
1572 Startup Time Improvements
1573 =========================
1575 * Experiment with multi-threaded backend for backend creation
1577 This would prevent the overhead associated with process creation. Most
1578 operating systems have trivial process creation time compared to
1579 database startup overhead, but a few operating systems (Win32,
1580 Solaris) might benefit from threading. Also explore the idea of
1581 a single session using multiple threads to execute a statement faster.
1588 * Eliminate need to write full pages to WAL before page modification
1590 Currently, to protect against partial disk page writes, we write
1591 full page images to WAL before they are modified so we can correct any
1592 partial page writes during recovery. These pages can also be
1593 eliminated from point-in-time archive files.
1594 http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php
1596 o When off, write CRC to WAL and check file system blocks
1599 If CRC check fails during recovery, remember the page in case
1600 a later CRC for that page properly matches.
1602 o Write full pages during file system write and not when
1603 the page is modified in the buffer cache
1605 This allows most full page writes to happen in the background
1606 writer. It might cause problems for applying WAL on recovery
1607 into a partially-written page, but later the full page will be
1610 * Allow WAL traffic to be streamed to another server for stand-by
1612 * Reduce WAL traffic so only modified values are written rather than
1615 http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php
1617 * Allow WAL information to recover corrupted pg_controldata
1619 http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php
1621 * Find a way to reduce rotational delay when repeatedly writing
1624 Currently fsync of WAL requires the disk platter to perform a full
1625 rotation to fsync again. One idea is to write the WAL to different
1626 offsets that might reduce the rotational delay.
1627 http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php
1629 * Allow WAL logging to be turned off for a table, but the table
1630 might be dropped or truncated during crash recovery
1632 Allow tables to bypass WAL writes and just fsync() dirty pages on
1633 commit. This should be implemented using ALTER TABLE, e.g. ALTER
1634 TABLE PERSISTENCE [ DROP | TRUNCATE | DEFAULT ]. Tables using
1635 non-default logging should not use referential integrity with
1636 default-logging tables. A table without dirty buffers during a
1637 crash could perhaps avoid the drop/truncate.
1638 http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
1640 * Allow WAL logging to be turned off for a table, but the table would
1641 avoid being truncated/dropped
1643 To do this, only a single writer can modify the table, and writes
1644 must happen only on new pages so the new pages can be removed during
1645 crash recovery. Readers can continue accessing the table. Such
1646 tables probably cannot have indexes. One complexity is the handling
1647 of indexes on TOAST tables.
1648 http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
1650 * Speed WAL recovery by allowing more than one page to be prefetched
1652 This should be done utilizing the same infrastructure used for
1653 prefetching in general to avoid introducing complex error-prone code
1655 http://archives.postgresql.org/pgsql-general/2007-12/msg00683.php
1656 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00497.php
1657 http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php
1659 * Improve WAL concurrency by increasing lock granularity
1661 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00556.php
1663 * Be more aggressive about creating WAL files
1665 http://archives.postgresql.org/pgsql-hackers/2007-10/msg01325.php
1666 http://archives.postgresql.org/pgsql-hackers/2004-07/msg01075.php
1667 http://archives.postgresql.org/pgsql-hackers/2005-04/msg00556.php
1669 * Have resource managers report the duration of their status changes
1671 http://archives.postgresql.org/pgsql-hackers/2007-10/msg01468.php
1673 * Move pgfoundry's xlogdump to /contrib and have it rely more closely
1674 on the WAL backend code
1676 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00035.php
1681 Optimizer / Executor
1682 ====================
1684 * Improve selectivity functions for geometric operators
1685 * Precompile SQL functions to avoid overhead
1686 * Create utility to compute accurate random_page_cost value
1687 * Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
1688 * Have EXPLAIN ANALYZE issue NOTICE messages when the estimated and
1689 actual row counts differ by a specified percentage
1690 * Improve how ANALYZE computes in-doubt tuples
1692 http://archives.postgresql.org/pgsql-hackers/2007-11/msg00771.php
1694 * Consider using hash buckets to do DISTINCT, rather than sorting
1696 This would be beneficial when there are few distinct values. This is
1697 already used by GROUP BY.
1699 * Log statements where the optimizer row estimates were dramatically
1700 different from the number of rows actually found?
1701 * Consider compressed annealing to search for query plans
1703 This might replace GEQO, http://sixdemonbag.org/Djinni.
1705 * Improve merge join performance by allowing mark/restore of
1708 http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php
1710 * Consider using a hash for joining to a large IN (VALUES ...) list
1712 http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php
1719 * Consider having the background writer update the transaction status
1720 hint bits before writing out the page
1722 Implementing this requires the background writer to have access to system
1723 catalogs and the transaction status log.
1725 * Consider adding buffers the background writer finds reusable to the
1728 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php
1730 * Automatically tune bgwriter_delay based on activity rather then using a
1733 http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php
1735 * Consider wither increasing BM_MAX_USAGE_COUNT improves performance
1737 http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php
1739 * Test to see if calling PreallocXlogFiles() from the background writer
1740 will help with WAL segment creation latency
1742 http://archives.postgresql.org/pgsql-patches/2007-06/msg00340.php
1746 Miscellaneous Performance
1747 =========================
1749 * Do async I/O for faster random read-ahead of data
1751 Async I/O allows multiple I/O requests to be sent to the disk with
1752 results coming back asynchronously.
1754 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php
1755 http://archives.postgresql.org/pgsql-performance/2007-09/msg00255.php
1756 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php
1757 http://archives.postgresql.org/pgsql-patches/2008-01/msg00170.php
1759 * Use mmap() rather than SYSV shared memory or to write WAL files?
1761 This would remove the requirement for SYSV SHM but would introduce
1762 portability issues. Anonymous mmap (or mmap to /dev/zero) is required
1763 to prevent I/O overhead.
1765 * Consider mmap()'ing files into a backend?
1767 Doing I/O to large tables would consume a lot of address space or
1768 require frequent mapping/unmapping. Extending the file also causes
1769 mapping problems that might require mapping only individual pages,
1770 leading to thousands of mappings. Another problem is that there is no
1771 way to _prevent_ I/O to disk from the dirty shared buffers so changes
1772 could hit disk before WAL is written.
1774 * Add a script to ask system configuration questions and tune postgresql.conf
1775 * Consider ways of storing rows more compactly on disk
1777 o Reduce the row header size?
1778 o Consider reducing on-disk varlena length from four bytes to
1779 two because a heap row cannot be more than 64k in length
1781 * Consider increasing NUM_CLOG_BUFFERS
1783 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00030.php
1784 http://archives.postgresql.org/pgsql-performance/2007-08/msg00024.php
1786 * Consider transaction start/end performance improvements
1788 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00948.php
1789 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php
1791 * Allow user configuration of TOAST thresholds
1793 http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php
1794 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php
1796 * Allow configuration of backend priorities via the operating system
1798 Though backend priorities make priority inversion during lock
1799 waits possible, research shows that this is not a huge problem.
1801 http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php
1803 * Experiment with multi-threaded backend better I/O utilization
1805 This would allow a single query to make use of multiple I/O channels
1806 simultaneously. One idea is to create a background reader that can
1807 pre-fetch sequential and index scan pages needed by other backends.
1808 This could be expanded to allow concurrent reads from multiple devices
1809 in a partitioned table.
1811 * Experiment with multi-threaded backend better CPU utilization
1813 This would allow several CPUs to be used for a single query, such as
1814 for sorting or query execution.
1816 * Consider increasing the minimum allowed number of shared buffers
1818 http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php
1820 * Expire published xmin for read-only and idle transactions
1822 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00343.php
1824 * Consider if CommandCounterIncrement() can avoid its
1825 AcceptInvalidationMessages() call
1827 http://archives.postgresql.org/pgsql-committers/2007-11/msg00585.php
1829 * Improve performance of shared invalidation queue for multiple CPUs
1831 http://archives.postgresql.org/pgsql-performance/2008-01/msg00023.php
1833 * Consider Cartesian joins when both relations are needed to form an
1834 indexscan qualification for a third relation
1836 http://archives.postgresql.org/pgsql-performance/2007-12/msg00090.php
1838 * Consider not storing a NULL bitmap on disk if all the NULLs are
1841 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php
1842 http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php
1844 * Sort large UPDATE/DELETEs so it is done in heap order
1846 http://archives.postgresql.org/pgsql-hackers/2008-01/msg01119.php
1848 * -Avoid tuple some tuple copying in sort routines
1849 * SMP scalability improvements
1851 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00439.php
1852 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00206.php
1853 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php
1855 * Research reducing deTOASTing in more places
1857 http://archives.postgresql.org/pgsql-hackers/2007-09/msg00895.php
1859 * Consider being smarter about memory and external files used during
1862 http://archives.postgresql.org/pgsql-hackers/2007-11/msg01101.php
1863 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00045.php
1865 * Allow one transaction to see tuples using the snapshot of another
1868 This would assist multiple backends in working together.
1869 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php
1875 * Add use of 'const' for variables in source tree
1876 * Move some things from contrib into main tree
1877 * %Remove warnings created by -Wcast-align
1878 * Move platform-specific ps status display info from ps_status.c to ports
1879 * Add optional CRC checksum to heap and index pages
1880 * Improve documentation to build only interfaces (Marc)
1881 * Remove or relicense modules that are not under the BSD license, if possible
1882 * Acquire lock on a relation before building a relcache entry for it
1883 * Allow cross-compiling by generating the zic database on the target system
1884 * Improve NLS maintenance of libpgport messages linked onto applications
1885 * Clean up casting in contrib/isn
1887 http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php
1889 * Improve the /contrib installation experience
1891 http://archives.postgresql.org/pgsql-hackers/2008-04/msg00132.php
1893 * Use UTF8 encoding for NLS messages so all server encodings can
1895 * Update Bonjour to work with newer cross-platform SDK
1897 http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php
1898 http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php
1900 * Consider detoasting keys before sorting
1901 * Consider GnuTLS if OpenSSL license becomes a problem
1903 http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php
1904 http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php
1906 * Consider changing documentation format from SGML to XML
1908 http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php
1910 * Consider making NAMEDATALEN more configurable in future releases
1911 * Update our code to handle 64-bit timezone files to match the zic
1912 source code, which now uses them
1913 * Have configure choose integer datetimes by default
1915 http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php
1917 * Support scoped IPv6 addresses
1919 http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php
1921 * Consider allowing 64-bit integers and floats to be passed by value on
1924 Also change 32-bit floats (float4) to be passed by value at the same
1927 * Research use of signals and sleep wake ups
1929 http://archives.postgresql.org/pgsql-hackers/2007-07/msg00003.php
1931 * Add automated check for invalid C++ source code constructs
1933 http://archives.postgresql.org/pgsql-patches/2007-07/msg00056.php
1935 * Consider simplifying how memory context resets handle child contexts
1937 http://archives.postgresql.org/pgsql-patches/2007-08/msg00067.php
1939 * Remove use of MAKE_PTR and MAKE_OFFSET macros
1941 http://archives.postgresql.org/pgsql-general/2007-08/msg01510.php
1943 * Convert single quotes to apostrophes in the PDF documentation
1945 http://archives.postgresql.org/pgsql-docs/2007-12/msg00059.php
1947 * Create three versions of libpgport to simplify client code
1949 http://archives.postgresql.org/pgsql-hackers/2007-10/msg00154.php
1951 * Remove old-style routines for manipulating tuples
1953 http://archives.postgresql.org/pgsql-hackers/2007-10/msg00851.php
1955 * Improve detection of shared memory segments being used by others
1956 by checking the SysV shared memory field 'nattch'
1958 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00656.php
1959 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00673.php
1961 * Implement the non-threaded Avahi service discovery protocol
1963 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00939.php
1964 http://archives.postgresql.org/pgsql-patches/2008-02/msg00097.php
1965 http://archives.postgresql.org/pgsql-hackers/2008-03/msg01211.php
1966 http://archives.postgresql.org/pgsql-patches/2008-04/msg00001.php
1970 o Remove configure.in check for link failure when cause is found
1971 o Remove readdir() errno patch when runtime/mingwex/dirent.c rev
1973 o Remove psql newline patch when we find out why mingw outputs an
1975 o Allow psql to use readline once non-US code pages work with
1977 o Fix problem with shared memory on the Win32 Terminal Server
1978 o Diagnose problem where shared memory can sometimes not be
1979 attached by postmaster children
1981 http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php
1983 o Improve signal handling
1985 http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php
1987 o Convert MSVC build system to remove most batch files
1989 http://archives.postgresql.org/pgsql-hackers/2007-08/msg00961.php
1991 o Prevent SSL from sending network packets to avoid interference
1992 with Win32 signal emulation
1994 http://archives.postgresql.org/pgsql-hackers/2007-12/msg00455.php
1996 o Support pgxs when using MSVC
1998 o Fix MSVC NLS support, like for to_char()
2000 http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php
2001 http://archives.postgresql.org/pgsql-patches/2008-02/msg00038.php
2003 o Find a correct rint() substitute on Windows
2005 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00808.php
2009 * Wire Protocol Changes
2011 o Allow dynamic character set handling
2012 o Add decoded type, length, precision
2014 o Update clients to use data types, typmod, schema.table.column names
2015 of result sets using new statement protocol
2021 * Add pre-parsing phase that converts non-ISO syntax to supported
2024 This could allow SQL written for other databases to run without
2027 * Allow plug-in modules to emulate features from other databases
2028 * Add features of Oracle-style packages (Pavel)
2030 A package would be a schema with session-local variables,
2031 public/private functions, and initialization functions. It
2032 is also possible to implement these capabilities
2033 in any schema and not use a separate "packages"
2036 http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php
2038 * Consider allowing control of upper/lower case folding of unquoted
2041 http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php
2042 http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php
2043 http://archives.postgresql.org/pgsql-hackers/2008-03/msg00849.php
2045 * Add autonomous transactions
2047 http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php
2051 Features We Do _Not_ Want
2052 =========================
2054 * All backends running as threads in a single process (not wanted)
2056 This eliminates the process protection we get from the current setup.
2057 Thread creation is usually the same overhead as process creation on
2058 modern systems, so it seems unwise to use a pure threaded model.
2060 * Optimizer hints (not wanted)
2062 Optimizer hints are used to work around problems in the optimizer. We
2063 would rather have the problems reported and fixed.
2065 http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php
2066 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php
2067 http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php
2070 Because we support postfix operators, it isn't possible to make AS
2071 optional and continue to use bison.
2072 http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php
2074 http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php
2076 * Embedded server (not wanted)
2078 While PostgreSQL clients runs fine in limited-resource environments, the
2079 server requires multiple processes and a stable pool of resources to
2080 run reliabily and efficiently. Stripping down the PostgreSQL server
2081 to run in the same process address space as the client application
2082 would add too much complexity and failure cases.