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9 <h1><a name="section_1">PostgreSQL TODO List</a></h1>
10 <p>Current maintainer: Bruce Momjian (<a href="mailto:bruce@momjian.us">bruce@momjian.us</a>)<br/>
11 Last updated: Fri May 4 23:14:29 EDT 2007
13 <p>The most recent version of this document can be viewed at<br/>
14 <a href="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>.
16 <p><strong>A hyphen, "-", marks changes that will appear in the upcoming 8.3 release.</strong><br/>
17 <strong>A percent sign, "%", marks items that are easier to implement.</strong>
19 <p>Bracketed items, "[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?"></a>]", have more detail.
21 <p>This list contains all known PostgreSQL bugs and feature requests. If<br/>
22 you would like to work on an item, please read the Developer's FAQ<br/>
23 first. There is also a developer's wiki at<br/>
24 <a href="http://developer.postgresql.org">http://developer.postgresql.org</a>.
26 <h1><a name="section_2">Administration</a></h1>
29 <li>Allow major upgrades without dump/reload, perhaps using pg_upgrade
30 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pg_upgrade">pg_upgrade</a>]
31 </li><li>Check for unreferenced table files created by transactions that were
32 in-progress when the server terminated abruptly
33 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php</a>
35 </li><li>Allow administrators to safely terminate individual sessions either
36 via an SQL function or SIGTERM
37 <p> Lock table corruption following SIGTERM of an individual backend
38 has been reported in 8.0. A possible cause was fixed in 8.1, but
39 it is unknown whether other problems exist. This item mostly
40 requires additional testing rather than of writing any new code.
41 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00174.php</a>
43 </li><li>Set proper permissions on non-system schemas during db creation
44 <p> Currently all schemas are owned by the super-user because they are copied
45 from the template1 database. However, since all objects are inherited
46 from the template database, it is not clear that setting schemas to the db
49 </li><li>Support table partitioning that allows a single table to be stored
50 in subtables that are partitioned based on the primary key or a WHERE
52 </li><li>Add function to report the time of the most recent server reload
53 </li><li>Allow statistics collector information to be pulled from the collector
54 process directly, rather than requiring the collector to write a
55 filesystem file twice a second?
56 </li><li>Allow log_min_messages to be specified on a per-module basis
57 <p> This would allow administrators to see more detailed information from
58 specific sections of the backend, e.g. checkpoints, autovacuum, etc.
59 Another idea is to allow separate configuration files for each module,
60 or allow arbitrary SET commands to be passed to them.
62 </li><li>Simplify ability to create partitioned tables
63 <p> This would allow creation of partitioned tables without requiring
64 creation of rules for INSERT/UPDATE/DELETE, and constraints for
65 rapid partition selection. Options could include range and hash
67 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php</a>
68 <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php</a>
70 </li><li>Allow auto-selection of partitioned tables for min/max() operations
71 </li><li>Allow more complex user/database default GUC settings
72 <p> 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 </li><li>Allow custom variable classes that can restrict who can set the values
78 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php</a>
80 </li><li>Improve replication solutions
83 <p> You can use any of the master/slave replication servers to use a
84 standby server for data warehousing. To allow read/write queries to
85 multiple servers, you need multi-master replication like pgcluster.
87 </li><li>Allow replication over unreliable or non-persistent links
89 </li><li>Configuration files
91 <li>-<em>Allow commenting of variables in postgresql.conf to restore them</em>
93 </li><li>Allow pg_hba.conf to specify host names along with IP addresses
94 <p> Host name lookup could occur when the postmaster reads the
95 pg_hba.conf file, or when the backend starts. Another
96 solution would be to reverse lookup the connection IP and
97 check that hostname against the host names in pg_hba.conf.
98 We could also then check that the host name maps to the IP
101 </li><li>%Allow postgresql.conf file values to be changed via an SQL
102 API, perhaps using SET GLOBAL
103 </li><li>Allow the server to be stopped/restarted via an SQL API
104 </li><li>Issue a warning if a change-on-restart-only postgresql.conf value
105 is modified and the server config files are reloaded
106 </li><li>Mark change-on-restart-only values in postgresql.conf
110 <li>Allow a database in tablespace t1 with tables created in
111 tablespace t2 to be used as a template for a new database created
112 with default tablespace t2
113 <p> All objects in the default database tablespace must have default
114 tablespace specifications. This is because new databases are
115 created by copying directories. If you mix default tablespace
116 tables and tablespace-specified tables in the same directory,
117 creating a new database from such a mixed directory would create a
118 new database with tables that had incorrect explicit tablespaces.
119 To fix this would require modifying pg_class in the newly copied
120 database, which we don't currently do.
122 </li><li>Allow reporting of which objects are in which tablespaces
123 <p> This item is difficult because a tablespace can contain objects
124 from multiple databases. There is a server-side function that
125 returns the databases which use a specific tablespace, so this
126 requires a tool that will call that function and connect to each
127 database to find the objects in each database for that tablespace.
129 </li><li>-<em>Add a GUC variable to control the tablespace for temporary objects</em>
131 <p> It could start with a random tablespace from a supplied list and
132 cycle through the list.
134 </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory
135 structure on the recovery computer is different from the original
136 </li><li>Allow per-tablespace quotas
138 </li><li>Point-In-Time Recovery (PITR)
140 <li>Allow a warm standby system to also allow read-only statements
141 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>]
142 <p> This is useful for checking PITR recovery.
143 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php</a>
145 </li><li>%Create dump tool for write-ahead logs for use in determining
146 transaction id for point-in-time recovery
147 </li><li>Allow the PITR process to be debugged and data examined
148 </li><li>Allow recovery.conf to allow the same syntax as
149 postgresql.conf, including quoting
150 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php</a>
154 <h1><a name="section_3">Monitoring</a></h1>
157 <li>Allow server log information to be output as INSERT statements
158 <p> This would allow server log information to be easily loaded into
159 a database for analysis.
161 </li><li>-<em>Add ability to monitor the use of temporary sort files</em>
163 <h1><a name="section_4">Data Types</a></h1>
166 <li>-<em>Make 64-bit version of the MONEY data type</em>
167 </li><li>Add locale-aware MONEY type, and support multiple currencies
168 <p> <a href="http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php">http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php</a>
169 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php</a>
171 </li><li>Change NUMERIC to enforce the maximum precision
172 </li><li>Reduce storage space for small NUMERICs
173 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php</a>
174 <a href="http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php">http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php</a>
176 </li><li>Fix data types where equality comparison isn't intuitive, e.g. box
177 </li><li>Allow user-defined types to specify a type modifier at table creation
179 </li><li>-<em>Allow user-defined types to accept 'typmod' parameters</em>
180 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-08/msg01142.php">http://archives.postgresql.org/pgsql-hackers/2005-08/msg01142.php</a>
181 <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00012.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00012.php</a>
182 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00149.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00149.php</a>
184 </li><li>Add support for public SYNONYMs
185 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php</a>
187 </li><li>Fix CREATE CAST on DOMAINs
188 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php">http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php</a>
189 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php</a>
191 </li><li>-<em>Add Globally/Universally Unique Identifier (GUID/UUID)</em>
192 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-09/msg00209.php">http://archives.postgresql.org/pgsql-patches/2006-09/msg00209.php</a>
193 <a href="http://archives.postgresql.org/pgsql-general/2007-01/msg00853.php">http://archives.postgresql.org/pgsql-general/2007-01/msg00853.php</a>
195 </li><li>Add support for SQL-standard GENERATED/IDENTITY columns
196 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php</a>
197 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php</a>
199 </li><li>-<em>Support a data type with specific enumerated values (ENUM)</em>
200 </li><li>Improve XML support
201 <p> <a href="http://developer.postgresql.org/index.php/XML_Support">http://developer.postgresql.org/index.php/XML_Support</a>
203 </li><li>Consider placing all sequences in a single table, or create a system
205 </li><li>Allow all data types to cast to and from TEXT
206 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00017.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00017.php</a>
208 </li><li>Dates and Times
210 <li>Allow infinite dates and intervals just like infinite timestamps
211 </li><li>Merge hardwired timezone names with the TZ database; allow either
212 kind everywhere a TZ name is currently taken
213 </li><li>Allow TIMESTAMP WITH TIME ZONE to store the original timezone
214 information, either zone name or offset from UTC [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?timezone">timezone</a>]
215 <p> If the TIMESTAMP value is stored with a time zone name, interval
216 computations should adjust based on the time zone rules.
218 </li><li>Fix SELECT '0.01 years'::interval, '0.01 months'::interval
219 </li><li>Add a GUC variable to allow output of interval values in ISO8601
221 </li><li>Have timestamp subtraction not call justify_hours()?
222 <p> <a href="http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php">http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php</a>
224 </li><li>Improve timestamptz subtraction to be DST-aware
225 <p> Currently subtracting one date from another that crosses a
226 daylight savings time adjustment can return '1 day 1 hour', but
227 adding that back to the first date returns a time one hour in
228 the future. This is caused by the adjustment of '25 hours' to
229 '1 day 1 hour', and '1 day' is the same time the next day, even
230 if daylight savings adjustments are involved.
232 </li><li>Fix interval display to support values exceeding 2^31 hours
233 </li><li>Add overflow checking to timestamp and interval arithmetic
234 </li><li>Extend timezone code to allow 64-bit values so we can
235 represent years beyond 2038
236 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php</a>
238 </li><li>Use LC_TIME for localized weekday/month names, rather than
240 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php</a>
242 </li><li>Add ISO INTERVAL handling
245 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-01/msg00250.php">http://archives.postgresql.org/pgsql-hackers/2006-01/msg00250.php</a><br/>
246 <a href="http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php">http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php</a>
249 <li>Support ISO INTERVAL syntax if units cannot be determined from
250 the string, and are supplied after the string
251 <p> The SQL standard states that the units after the string
252 specify the units of the string, e.g. INTERVAL '2' MINUTE
253 should return '00:02:00'. The current behavior has the units
254 restrict the interval value to the specified unit or unit
255 range, INTERVAL '70' SECOND returns '00:00:10'.
257 <p> For syntax that isn't uniquely ISO or PG syntax, like '1' or
258 '1:30', treat as ISO if there is a range specification clause,
259 and as PG if there no clause is present, e.g. interpret '1:30'
260 MINUTE TO SECOND as '1 minute 30 seconds', and interpret
261 '1:30' as '1 hour, 30 minutes'.
263 <p> This makes common cases like SELECT INTERVAL '1' MONTH
264 SQL-standard results. The SQL standard supports a limited
265 number of unit combinations and doesn't support unit names in
266 the string. The PostgreSQL syntax is more flexible in the
267 range of units supported, e.g. PostgreSQL supports '1 year 1
268 hour', while the SQL standard does not.
270 </li><li>Add support for year-month syntax, INTERVAL '50-6' YEAR TO MONTH
271 </li><li>Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1 year' AS
272 INTERVAL MONTH), and this should return '12 months'
273 </li><li>Round or truncate values to the requested precision, e.g.
274 INTERVAL '11 months' AS YEAR should return one or zero
275 </li><li>Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
279 <li>Delay resolution of array expression's data type so assignment
280 coercion can be performed on empty array expressions
281 </li><li>Add support for arrays of domains
282 </li><li>Add support for arrays of complex types
283 </li><li>Allow single-byte header storage for array elements
287 <li>Improve vacuum of large objects, like /contrib/vacuumlo?
288 </li><li>Add security checking for large objects
289 </li><li>Auto-delete large objects when referencing row is deleted
290 <p> /contrib/lo offers this functionality.
292 </li><li>Allow read/write into TOAST values like large objects
293 <p> This requires the TOAST column to be stored EXTERNAL.
295 </li><li>Add API for 64-bit large object access
296 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php</a>
301 <h1><a name="section_5">Functions</a></h1>
304 <li>Allow INET subnet tests using non-constants to be indexed
305 </li><li>Allow to_date() and to_timestamp() accept localized month names
306 </li><li>Fix to_date()-related functions to consistently issue errors
307 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php</a>
309 </li><li>Add missing parameter handling in to_char()
311 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php</a>
314 <li>Allow functions to have a schema search path specified at creation time
315 </li><li>Allow substring/replace() to get/set bit values
316 </li><li>Allow to_char() on interval values to accumulate the highest unit
318 <p> Some special format flag would be required to request such
319 accumulation. Such functionality could also be added to EXTRACT.
320 Prevent accumulation that crosses the month/day boundary because of
321 the uneven number of days in a month.
324 <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
325 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
326 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
327 </li><li>to_char(INTERVAL '3 years 5 months','MM') => 41
329 </li><li>-<em>Add ISO day of week format 'ID' to to_char() where Monday = 1</em>
330 </li><li>-<em>Add a field 'isoyear' to extract(), based on the ISO week</em>
331 </li><li>Implement inlining of set-returning functions defined in SQL
332 </li><li>Allow SQL-language functions to return results from RETURNING queries
333 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php</a>
335 </li><li>Allow SQL-language functions to reference parameters by parameter name
336 <p> Currently SQL-language functions can only refer to dollar parameters,
339 </li><li>Add SPI_gettypmod() to return the typemod for a TupleDesc
340 </li><li>Enforce typmod for function inputs, function results and parameters for
341 spi_prepare'd statements called from PLs
342 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php</a>
344 </li><li>Allow holdable cursors in SPI
345 </li><li>Tighten function permission checks
346 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php</a>
348 </li><li>Fix IS OF so it matches the ISO specification, and add documentation
349 <p> <a href="http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php">http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php</a>
350 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php</a>
352 </li><li>Add missing operators for geometric data types
353 <p> Some geometric types do not have the full suite of geometric operators,
357 <h1><a name="section_6">Multi-Language Support</a></h1>
360 <li>Add NCHAR (as distinguished from ordinary varchar),
361 </li><li>Allow locale to be set at database creation
362 <p> Currently locale can only be set during initdb. No global tables have
363 locale-aware columns. However, the database template used during
364 database creation might have locale-aware indexes. The indexes would
365 need to be reindexed to match the new locale.
367 </li><li>Allow encoding on a per-column basis optionally using the ICU library:
368 <p> Right now only one encoding is allowed per database. [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?locale">locale</a>]
369 <a href="http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php">http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php</a>
370 <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php</a>
371 <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php</a>
372 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php</a>
374 </li><li>Add CREATE COLLATE? [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?locale">locale</a>]
375 </li><li>Support multiple simultaneous character sets, per SQL92
376 </li><li>Improve UTF8 combined character handling?
377 </li><li>Add octet_length_server() and octet_length_client()
378 </li><li>Make octet_length_client() the same as octet_length()?
379 </li><li>Fix problems with wrong runtime encoding conversion for NLS message files
380 </li><li>Add URL to more complete multi-byte regression tests
381 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php">http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php</a>
383 </li><li>Fix ILIKE and regular expressions to handle case insensitivity
384 properly in multibyte encodings
385 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php">http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php</a>
386 <a href="http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php">http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php</a>
388 </li><li>Set client encoding based on the client operating system encoding
389 <p> Currently client_encoding is set in postgresql.conf, which
390 defaults to the server encoding.
391 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php</a>
393 </li><li>Fix cases where invalid byte encodings are accepted by the database,
394 but throw an error on SELECT
395 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00767.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00767.php</a>
398 <h1><a name="section_7">Views / Rules</a></h1>
401 <li>Automatically create rules on views so they are updateable, per SQL99
402 <p> We can only auto-create rules for simple views. For more complex
403 cases users will still have to write rules manually.
404 <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php</a>
405 <a href="http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php">http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php</a>
407 </li><li>Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
408 </li><li>Allow NOTIFY in rules involving conditionals
409 </li><li>Allow VIEW/RULE recompilation when the underlying tables change
410 <p> Another issue is whether underlying table changes should be reflected
411 in the view, e.g. should SELECT * show additional columns if they
412 are added after the view is created.
415 <h1><a name="section_8">SQL Commands</a></h1>
418 <li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
419 </li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
420 </li><li>%Allow SET CONSTRAINTS to be qualified by schema/table name
421 </li><li>%Add a separate TRUNCATE permission
422 <p> Currently only the owner can TRUNCATE a table because triggers are not
423 called, and the table is locked in exclusive mode.
425 </li><li>Allow PREPARE of cursors
426 </li><li>Allow finer control over the caching of prepared query plans
427 <p> Currently queries prepared via the libpq API are planned on first
428 execute using the supplied parameters --- allow SQL PREPARE to do the
429 same. Also, allow control over replanning prepared queries either
430 manually or automatically when statistics for execute parameters
431 differ dramatically from those used during planning.
433 </li><li>Invalidate prepared queries, like INSERT, when the table definition
435 </li><li>Improve logging of prepared statements recovered during startup
436 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php</a>
438 </li><li>Allow LISTEN/NOTIFY to store info in memory rather than tables?
439 <p> Currently LISTEN/NOTIFY information is stored in pg_listener. Storing
440 such information in memory would improve performance.
442 </li><li>Add optional textual message to NOTIFY
443 <p> This would allow an informational message to be added to the notify
444 message, perhaps indicating the row modified or other custom
447 </li><li>Add a GUC variable to warn about non-standard SQL usage in queries
448 </li><li>Add SQL-standard MERGE command, typically used to merge two tables
449 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
450 <p> This is similar to UPDATE, then for unmatched rows, INSERT.
451 Whether concurrent access allows modifications which could cause
452 row loss is implementation independent.
454 </li><li>Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
455 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
456 <p> To implement this cleanly requires that the table have a unique index
457 so duplicate checking can be easily performed. It is possible to
458 do it without a unique index if we require the user to LOCK the table
460 <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php</a>
461 <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php</a>
463 </li><li>Add NOVICE output level for helpful messages like automatic sequence/index
465 </li><li>-<em>Add RESET SESSION command to reset all session state</em>
466 </li><li>Add GUC to issue notice about statements that use unjoined tables
467 </li><li>Allow EXPLAIN to identify tables that were skipped because of
469 </li><li>Allow EXPLAIN output to be more easily processed by scripts
470 </li><li>Enable standard_conforming_strings
471 </li><li>Make standard_conforming_strings the default in 8.4?
472 <p> When this is done, backslash-quote should be prohibited in non-E''
473 strings because of possible confusion over how such strings treat
474 backslashes. Basically, '' is always safe for a literal single
475 quote, while \' might or might not be based on the backslash
478 </li><li>Simplify dropping roles that have objects in several databases
479 </li><li>Allow COMMENT ON to accept an expression rather than just a string
480 </li><li>Allow the count returned by SELECT, etc to be to represent as an int64
481 to allow a higher range of values
482 </li><li>Add SQL99 WITH clause to SELECT
483 </li><li>Add SQL:2003 WITH RECURSIVE (hierarchical) queries to SELECT
484 </li><li>Add DEFAULT .. AS OWNER so permission checks are done as the table
486 <p> This would be useful for SERIAL nextval() calls and CHECK constraints.
488 </li><li>Allow DISTINCT to work in multiple-argument aggregate calls
489 </li><li>Add column to pg_stat_activity that shows the progress of long-running
490 commands like CREATE INDEX and VACUUM
491 </li><li>Implement SQL:2003 window functions
492 </li><li>Improve failure message when DROP DATABASE is used on a database that
493 has prepared transactions
494 </li><li>Allow INSERT/UPDATE ... RETURNING inside a SELECT 'FROM' clause
495 <p> <a href="http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php">http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php</a>
496 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php</a>
498 </li><li>Increase locking when DROPing objects so dependent objects cannot
499 get dropped while the DROP operation is happening
500 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php</a>
504 <li>Allow CREATE TABLE AS to determine column lengths for complex
505 expressions like SELECT col1 || col2
506 </li><li>Use more reliable method for CREATE DATABASE to get a consistent
508 </li><li>Fix transaction restriction checks for CREATE DATABASE and
510 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00133.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00133.php</a>
512 </li><li>Have WITH CONSTRAINTS also create constraint indexes
513 <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php</a>
517 <li>Allow UPDATE tab SET ROW (col, ...) = (SELECT...)
518 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php</a>
519 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php</a>
524 <li>%Have ALTER TABLE RENAME rename SERIAL sequence names
525 </li><li>Add ALTER DOMAIN to modify the underlying data type
526 </li><li>%Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
527 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php</a>
529 </li><li>%Allow ALTER TABLE to change constraint deferrability and actions
530 </li><li>Add missing object types for ALTER ... SET SCHEMA
531 </li><li>Allow ALTER TABLESPACE to move to different directories
532 </li><li>Allow databases to be moved to different tablespaces
533 </li><li>Allow moving system tables to other tablespaces, where possible
534 <p> Currently non-global system tables must be in the default database
535 tablespace. Global system tables can never be moved.
537 </li><li>Prevent parent tables from altering or dropping constraints
538 like CHECK that are inherited by child tables unless CASCADE
540 </li><li>%Prevent child tables from altering or dropping constraints
541 like CHECK that were inherited from the parent table
542 </li><li>Have ALTER INDEX update the name of a constraint using that index
543 </li><li>Add ALTER TABLE RENAME CONSTRAINT, update index name also
544 </li><li>Allow column display reordering by recording a display,
545 storage, and permanent id for every column?
546 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php</a>
551 <li>-<em>Make CLUSTER preserve recently-dead tuples per MVCC requirements</em>
552 </li><li>Automatically maintain clustering on a table
553 <p> This might require some background daemon to maintain clustering
554 during periods of low usage. It might also require tables to be only
555 partially filled for easier reorganization. Another idea would
556 be to create a merged heap/index data file so an index lookup would
557 automatically access the heap data too. A third idea would be to
558 store heap rows in hashed groups, perhaps using a user-supplied
560 <a href="http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php">http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php</a>
562 </li><li>%Add default clustering to system tables
563 <p> To do this, determine the ideal cluster index for each system
564 table and set the cluster setting during initdb.
566 </li><li>%Add VERBOSE option to report tables as they are processed,
568 </li><li>-<em>Add more logical syntax CLUSTER table USING index;</em>
569 support current syntax for backward compatibility
573 <li>Allow COPY to report error lines and continue
574 <p> This requires the use of a savepoint before each COPY line is
575 processed, with ROLLBACK on COPY failure.
577 </li><li>Allow COPY on a newly-created table to skip WAL logging
578 <p> On crash recovery, the table involved in the COPY would
579 be removed or have its heap and index files truncated. One
580 issue is that no other backend should be able to add to
581 the table at the same time, which is something that is
585 </li><li>GRANT/REVOKE
587 <li>Allow column-level privileges
588 </li><li>%Allow GRANT/REVOKE permissions to be applied to all schema objects
590 <p> The proposed syntax is:
591 </p><p> GRANT SELECT ON ALL TABLES IN public TO phpuser;
592 GRANT SELECT ON NEW TABLES IN public TO phpuser;
594 </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on
596 </li><li>Allow SERIAL sequences to inherit permissions from the base table?
600 <li>Allow UPDATE/DELETE WHERE CURRENT OF cursor
601 <p> This requires using the row ctid to map cursor rows back to the
602 original heap row. This become more complicated if WITH HOLD cursors
603 are to be supported because WITH HOLD cursors have a copy of the row
604 and no FOR UPDATE lock.
605 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01014.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01014.php</a>
607 </li><li>Prevent DROP TABLE from dropping a row referenced by its own open
612 <li>Allow INSERT/UPDATE of the system-generated oid value for a row
613 </li><li>In rules, allow VALUES() to contain a mixture of 'old' and 'new'
618 <li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
620 </li><li>Add SET PATH for schemas?
621 <p> This is basically the same as SET search_path.
624 </li><li>Referential Integrity
626 <li>Add MATCH PARTIAL referential integrity
627 </li><li>Change foreign key constraint for array -> element to mean element
629 </li><li>Enforce referential integrity for system tables
630 </li><li>Fix problem when cascading referential triggers make changes on
631 cascaded tables, seeing the tables in an intermediate state
632 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
633 <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
635 </li><li>Allow DEFERRABLE and end-of-statement UNIQUE constraints?
636 <p> This would allow UPDATE tab SET col = col + 1 to work if col has
637 a unique index. Currently, uniqueness checks are done while the
638 command is being executed, rather than at the end of the statement
640 <a href="http://people.planetpostgresql.org/greg/index.php?/archives/2006/06/10.html">http://people.planetpostgresql.org/greg/index.php?/archives/2006/06/10.html</a>
641 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php</a>
644 </li><li>Server-Side Languages
648 <li>Fix RENAME to work on variables other than OLD/NEW
649 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php">http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php</a>
650 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php</a>
651 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php</a>
653 </li><li>Allow function parameters to be passed by name,
654 get_employee_salary(12345 AS emp_id, 2001 AS tax_year)
655 </li><li>Add Oracle-style packages (Pavel)
656 <p> A package would be a schema with session-local variables,
657 public/private functions, and initialization functions. It
658 is also possible to implement these capabilities
659 in all schemas and not use a separate "packages"
661 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php</a>
663 </li><li>Allow handling of %TYPE arrays, e.g. tab.col%TYPE[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?"></a>]
664 </li><li>Allow listing of record column names, and access to
665 record columns via variables, e.g. columns := r.(*),
667 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php</a>
668 <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php</a>
669 <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php</a>
671 </li><li>Add single-step debugging of functions
672 </li><li>-<em>Add support for MOVE cursors</em>
673 </li><li>Add support for SCROLL cursors
674 </li><li>Add support for WITH HOLD cursors
675 </li><li>Allow RETURN to return row or record functions
676 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-11/msg00045.php">http://archives.postgresql.org/pgsql-patches/2005-11/msg00045.php</a>
677 <a href="http://archives.postgresql.org/pgsql-patches/2006-08/msg00397.php">http://archives.postgresql.org/pgsql-patches/2006-08/msg00397.php</a>
678 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00388.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00388.php</a>
680 </li><li>Fix problems with RETURN NEXT on tables with
681 dropped/added columns after function creation
682 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00165.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00165.php</a>
684 </li><li>Allow row and record variables to be set to NULL constants,
685 and allow NULL tests on such variables
686 <p> Because a row is not scalar, do not allow assignment
687 from NULL-valued scalars.
688 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php</a>
693 <li>Add table function support to pltcl, plpythonu
694 </li><li>Add support for polymorphic arguments and return types to
695 languages other than PL/PgSQL
696 </li><li>Add capability to create and call PROCEDURES
697 </li><li>Add support for OUT and INOUT parameters to languages other
699 </li><li>Add PL/PythonU tracebacks
700 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php</a>
702 </li><li>-<em>Allow PL/PythonU to return boolean rather than 1/0</em>
706 <h1><a name="section_9">Clients</a></h1>
709 <li>Have pg_ctl look at PGHOST in case it is a socket directory?
710 </li><li>Allow pg_ctl to work properly with configuration files located outside
712 <p> pg_ctl can not read the pid file because it isn't located in the
713 config directory but in the PGDATA directory. The solution is to
714 allow pg_ctl to read and understand postgresql.conf to find the
715 data_directory value.
717 </li><li>Make consistent use of long/short command options --- pg_ctl needs
718 long ones, pg_config doesn't have short ones, postgres doesn't have
719 enough long ones, etc.
722 <li>Have psql show current values for a sequence
723 </li><li>Move psql backslash database information into the backend, use
724 mnemonic commands? [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?psql">psql</a>]
725 <p> This would allow non-psql clients to pull the same information out
726 of the database as psql.
728 </li><li>Fix psql's \d commands more consistent
729 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
730 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
732 </li><li>-<em>Allow psql \pset boolean variables to set to fixed values, rather</em>
734 </li><li>Consistently display privilege information for all objects in psql
735 </li><li>Add auto-expanded mode so expanded output is used if the row
736 length is wider than the screen width.
737 <p> Consider using auto-expanded mode for backslash commands like \df+.
739 </li><li>Prevent tab completion of SET TRANSACTION from querying the
740 database and therefore preventing the transaction isolation
741 level from being set.
742 <p> Currently SET <tab> causes a database lookup to check all
743 supported session variables. This query causes problems
744 because setting the transaction isolation level must be the
745 first statement of a transaction.
747 </li><li>Consider parsing the -c string into individual queries so each
748 is run in its own transaction
749 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00291.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00291.php</a>
751 </li><li>Add a \set variable to control whether \s displays line numbers
752 <p> Another option is to add \# which lists line numbers, and
753 allows command execution.
755 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php</a>
760 <li>%Add dumping of comments on index columns and composite type columns
761 </li><li>%Add full object name to the tag field. eg. for operators we need
762 '=(integer, integer)', instead of just '='.
763 </li><li>Add pg_dumpall custom format dumps?
764 </li><li>Remove unnecessary function pointer abstractions in pg_dump source
766 </li><li>Allow selection of individual object(s) of all types, not just
768 </li><li>In a selective dump, allow dumping of an object and all its
770 </li><li>Add options like pg_restore -l and -L to pg_dump
771 </li><li>Stop dumping CASCADE on DROP TYPE commands in clean mode
772 </li><li>Allow pg_dump --clean to drop roles that own objects or have
774 </li><li>-<em>Add -f to pg_dumpall</em>
779 <p> Document differences between ecpg and the SQL standard and
780 information about the Informix-compatibility module.
782 </li><li>Solve cardinality > 1 for input descriptors / variables?
783 </li><li>Add a semantic check level, e.g. check if a table really exists
784 </li><li>fix handling of DB attributes that are arrays
785 </li><li>Use backend PREPARE/EXECUTE facility for ecpg where possible
786 </li><li>Implement SQLDA
787 </li><li>Fix nested C comments
788 </li><li>%sqlwarn[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?6">6</a>] should be 'W' if the PRECISION or SCALE value specified
789 </li><li>Make SET CONNECTION thread-aware, non-standard?
790 </li><li>Allow multidimensional arrays
791 </li><li>Add internationalized message strings
792 </li><li>Implement COPY FROM STDIN
796 <li>Add PQescapeIdentifierConn()
797 </li><li>Prevent PQfnumber() from lowercasing unquoted the column name
798 <p> PQfnumber() should never have been doing lowercasing, but
799 historically it has so we need a way to prevent it
801 </li><li>Allow statement results to be automatically batched to the client
802 <p> Currently all statement results are transferred to the libpq
803 client before libpq makes the results available to the
804 application. This feature would allow the application to make
805 use of the first result rows while the rest are transferred, or
806 held on the server waiting for them to be requested by libpq.
807 One complexity is that a statement like SELECT 1/col could error
808 out mid-way through the result set.
809 <li>Fix SSL retry to avoid useless repeated connection attempts and
810 ensuing misleading error messages
811 </li><li>Consider disallowing multiple queries in PQexec() as an
812 additional barrier to SQL injection attacks
813 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php</a>
815 </li><li>Add PQexecf() that allows complex parameter substitution
816 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php</a>
820 <h1><a name="section_10">Triggers</a></h1>
823 <li>Add deferred trigger queue file
824 <p> Right now all deferred trigger information is stored in backend
825 memory. This could exhaust memory for very large trigger queues.
826 This item involves dumping large queues into files.
828 </li><li>Allow triggers to be disabled in only the current session.
829 <p> This is currently possible by starting a multi-statement transaction,
830 modifying the system tables, performing the desired SQL, restoring the
831 system tables, and committing the transaction. ALTER TABLE ...
832 TRIGGER requires a table lock so it is not ideal for this usage.
834 </li><li>With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
835 <p> If the dump is known to be valid, allow foreign keys to be added
836 without revalidating the data.
838 </li><li>Allow statement-level triggers to access modified rows
839 </li><li>Support triggers on columns
840 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php</a>
842 </li><li>Allow AFTER triggers on system tables
843 <p> System tables are modified in many places in the backend without going
844 through the executor and therefore not causing triggers to fire. To
845 complete this item, the functions that modify system tables will have
848 </li><li>Tighten trigger permission checks
849 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php</a>
851 </li><li>Allow BEFORE INSERT triggers on views
852 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php">http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php</a>
855 <h1><a name="section_11">Dependency Checking</a></h1>
858 <li>Flush cached query plans when the dependent objects change,
859 when the cardinality of parameters changes dramatically, or
860 when new ANALYZE statistics are available
861 <p> A more complex solution would be to save multiple plans for different
862 cardinality and use the appropriate plan based on the EXECUTE values.
864 </li><li>Track dependencies in function bodies and recompile/invalidate
865 <p> This is particularly important for references to temporary tables
866 in PL/PgSQL because PL/PgSQL caches query plans. The only workaround
867 in PL/PgSQL is to use EXECUTE. One complexity is that a function
868 might itself drop and recreate dependent tables, causing it to
869 invalidate its own query plan.
872 <h1><a name="section_12">Indexes</a></h1>
875 <li>Add UNIQUE capability to non-btree indexes
876 </li><li>Prevent index uniqueness checks when UPDATE does not modify the column
877 <p> Uniqueness (index) checks are done when updating a column even if the
878 column is not modified by the UPDATE.
880 </li><li>Allow the creation of on-disk bitmap indexes which can be quickly
881 combined with other bitmap indexes
882 <p> Such indexes could be more compact if there are only a few distinct values.
883 Such indexes can also be compressed. Keeping such indexes updated can be
886 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php</a>
887 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php</a>
889 </li><li>-<em>Allow use of indexes to search for NULLs</em>
890 </li><li>Allow accurate statistics to be collected on indexes with more than
891 one column or expression indexes, perhaps using per-index statistics
892 <p> <a href="http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php">http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php</a>
893 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php</a>
895 </li><li>-<em>Allow the creation of indexes with mixed ascending/descending</em>
897 </li><li>Consider compressing indexes by storing key values duplicated in
898 several rows as a single index entry
899 <p> This is difficult because it requires datatype-specific knowledge.
901 </li><li>Add REINDEX CONCURRENTLY, like CREATE INDEX CONCURRENTLY
902 <p> This is difficult because you must upgrade to an exclusive table lock
903 to replace the existing index file. CREATE INDEX CONCURRENTLY does not
904 have this complication. This would allow index compaction without
909 <li>Allow inherited tables to inherit indexes, UNIQUE constraints,
910 and primary/foreign keys
911 </li><li>Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
912 on inherited table, e.g. INSERT INTO inherit_table
913 (unique_index_col) VALUES (dup) should fail
914 <p> The main difficulty with this item is the problem of
915 creating an index that can span multiple tables.
917 </li><li>Allow SELECT ... FOR UPDATE on inherited tables
921 <li>Add more GIST index support for geometric data types
922 </li><li>Allow GIST indexes to create certain complex index types, like
923 digital trees (see Aoki)
927 <li>Pack hash index buckets onto disk pages more efficiently
928 <p> Currently only one hash bucket can be stored on a page. Ideally
929 several hash buckets could be stored on a single page and greater
930 granularity used for the hash algorithm.
932 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php">http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php</a>
934 </li><li>Consider sorting hash buckets so entries can be found using a
935 binary search, rather than a linear scan
936 </li><li>In hash indexes, consider storing the hash value with or instead
938 </li><li>Add WAL logging for crash recovery
939 </li><li>Allow multi-column hash indexes
940 </li><li>During index creation, pre-sort the tuples to improve build speed
941 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01199.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01199.php</a>
945 <h1><a name="section_13">Fsync</a></h1>
948 <li>Improve commit_delay handling to reduce fsync()
949 </li><li>Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
950 <p> Ideally this requires a separate test program that can be run
951 at initdb time or optionally later. Consider O_SYNC when
954 </li><li>%Add an option to sync() before fsync()'ing checkpoint files
955 </li><li>Add program to test if fsync has a delay compared to non-fsync
956 </li><li>Reduce checkpoint performance degredation by forcing data to disk
958 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-12/msg00104.php">http://archives.postgresql.org/pgsql-patches/2006-12/msg00104.php</a>
959 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00337.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00337.php</a>
960 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00079.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00079.php</a>
963 <h1><a name="section_14">Cache Usage</a></h1>
966 <li>Allow free-behind capability for large sequential scans, perhaps using
968 <p> Posix_fadvise() can control both sequential/random file caching and
969 free-behind behavior, but it is unclear how the setting affects other
970 backends that also have the file open, and the feature is not supported
971 on all operating systems.
973 </li><li>Speed up COUNT(*)
974 <p> We could use a fixed row count and a +/- count to follow MVCC
975 visibility rules, or a single cached value could be used and
976 invalidated if anyone modifies the table. Another idea is to
977 get a count directly from a unique index, but for this to be
978 faster than a sequential scan it must avoid access to the heap
979 to obtain tuple visibility information.
981 </li><li>Provide a way to calculate an "estimated COUNT(*)"
982 <p> Perhaps by using the optimizer's cardinality estimates or random
985 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php</a>
987 </li><li>Allow data to be pulled directly from indexes
988 <p> Currently indexes do not have enough tuple visibility information
989 to allow data to be pulled from the index without also accessing
990 the heap. One way to allow this is to set a bit on index tuples
991 to indicate if a tuple is currently visible to all transactions
992 when the first valid heap lookup happens. This bit would have to
993 be cleared when a heap tuple is expired.
995 <p> Another idea is to maintain a bitmap of heap pages where all rows
996 are visible to all backends, and allow index lookups to reference
997 that bitmap to avoid heap lookups, perhaps the same bitmap we might
998 add someday to determine which heap pages need vacuuming. Frequently
999 accessed bitmaps would have to be stored in shared memory. One 8k
1000 page of bitmaps could track 512MB of heap pages.
1002 </li><li>Consider automatic caching of statements at various levels:
1004 <li>Parsed query tree
1005 </li><li>Query execute plan
1006 </li><li>Query results
1008 </li><li>Allow sequential scans to take advantage of other concurrent
1009 sequential scans, also called "Synchronised Scanning"
1010 <p> One possible implementation is to start sequential scans from the lowest
1011 numbered buffer in the shared cache, and when reaching the end wrap
1012 around to the beginning, rather than always starting sequential scans
1013 at the start of the table.
1015 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-12/msg00076.php">http://archives.postgresql.org/pgsql-patches/2006-12/msg00076.php</a>
1016 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00408.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00408.php</a>
1017 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00784.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00784.php</a>
1018 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00415.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00415.php</a>
1020 </li><li>Consider increasing internal areas when shared buffers is increased
1021 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php">http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php</a>
1023 </li><li>Consider decreasing the amount of memory used by PrivateRefCount
1024 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php</a>
1025 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php</a>
1028 <h1><a name="section_15">Vacuum</a></h1>
1031 <li>Improve speed with indexes
1032 <p> For large table adjustments during VACUUM FULL, it is faster to cluster
1033 or reindex rather than update the index. Also, index updates can bloat
1036 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php</a>
1038 </li><li>Reduce lock time during VACUUM FULL by moving tuples with read lock,
1039 then write lock and truncate table
1040 <p> Moved tuples are invisible to other backends so they don't require a
1041 write lock. However, the read lock promotion to write lock could lead
1042 to deadlock situations.
1044 </li><li>Auto-fill the free space map by scanning the buffer cache or by
1045 checking pages written by the background writer
1046 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php">http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php</a>
1047 <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php</a>
1049 </li><li>Create a bitmap of pages that need vacuuming
1050 <p> Instead of sequentially scanning the entire table, have the background
1051 writer or some other process record pages that have expired rows, then
1052 VACUUM can look at just those pages rather than the entire table. In
1053 the event of a system crash, the bitmap would probably be invalidated.
1054 One complexity is that index entries still have to be vacuumed, and
1055 doing this without an index scan (by using the heap values to find the
1056 index entry) might be slow and unreliable, especially for user-defined
1059 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php</a>
1060 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php</a>
1062 </li><li>Allow FSM to return free space toward the beginning of the heap file,
1063 in hopes that empty pages at the end can be truncated by VACUUM
1064 </li><li>Allow FSM page return free space based on table clustering, to assist
1065 in maintaining clustering?
1066 </li><li>Consider shrinking expired tuples to just their headers
1067 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php</a>
1068 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01025.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01025.php</a>
1070 </li><li>Allow heap reuse of UPDATEd rows if no indexed columns are changed,
1071 and old and new versions are on the same heap page?
1072 <p> While vacuum handles DELETEs fine, updating of non-indexed columns, like
1073 counters, are difficult for VACUUM to handle efficiently. This method
1074 is possible for same-page updates because a single index row can be
1075 used to point to both old and new values.
1076 <a href="http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php">http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php</a>
1077 <a href="http://archives.postgresql.org/pgsql-hackers/2006-06/msg01534.php">http://archives.postgresql.org/pgsql-hackers/2006-06/msg01534.php</a>
1079 </li><li>Reuse index tuples that point to heap tuples that are not visible to
1081 </li><li>Improve dead row detection during multi-statement transactions usage
1082 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php</a>
1084 </li><li>Auto-vacuum
1086 <li>Use free-space map information to guide refilling
1087 </li><li>%Issue log message to suggest VACUUM FULL if a table is nearly
1089 </li><li>Consider logging activity either to the logs or a system view
1090 </li><li>-<em>Turn on by default</em>
1091 </li><li>Allow multiple vacuums so large tables do not starve small
1093 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-01/msg00031.php">http://archives.postgresql.org/pgsql-general/2007-01/msg00031.php</a>
1095 </li><li>Improve control of auto-vacuum
1096 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php</a>
1100 <h1><a name="section_16">Locking</a></h1>
1103 <li>Fix priority ordering of read and write light-weight locks (Neil)
1104 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php</a>
1105 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php</a>
1107 </li><li>Fix problem when multiple subtransactions of the same outer transaction
1108 hold different types of locks, and one subtransaction aborts
1109 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php</a>
1110 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php</a>
1111 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php</a>
1113 </li><li>Allow UPDATEs on only non-referential integrity columns not to conflict
1114 with referential integrity locks
1115 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php</a>
1117 </li><li>Add idle_in_transaction_timeout GUC so locks are not held for long
1120 <h1><a name="section_17">Startup Time Improvements</a></h1>
1123 <li>Experiment with multi-threaded backend for backend creation [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?thread">thread</a>]
1124 <p> This would prevent the overhead associated with process creation. Most
1125 operating systems have trivial process creation time compared to
1126 database startup overhead, but a few operating systems (Win32,
1127 Solaris) might benefit from threading. Also explore the idea of
1128 a single session using multiple threads to execute a statement faster.
1130 </li><li>Experiment with multi-threaded backend better resource utilization
1131 <p> This would allow a single query to make use of multiple CPU's or
1132 multiple I/O channels simultaneously. One idea is to create a
1133 background reader that can pre-fetch sequential and index scan
1134 pages needed by other backends. This could be expanded to allow
1135 concurrent reads from multiple devices in a partitioned table.
1137 </li><li>Add connection pooling
1138 <p> It is unclear if this should be done inside the backend code or done
1139 by something external like pgpool. The passing of file descriptors to
1140 existing backends is one of the difficulties with a backend approach.
1143 <h1><a name="section_18">Write-Ahead Log</a></h1>
1146 <li>Eliminate need to write full pages to WAL before page modification [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?wal">wal</a>]
1147 <p> Currently, to protect against partial disk page writes, we write
1148 full page images to WAL before they are modified so we can correct any
1149 partial page writes during recovery. These pages can also be
1150 eliminated from point-in-time archive files.
1153 <li>When off, write CRC to WAL and check file system blocks
1155 <p> If CRC check fails during recovery, remember the page in case
1156 a later CRC for that page properly matches.
1158 </li><li>Write full pages during file system write and not when
1159 the page is modified in the buffer cache
1160 <p> This allows most full page writes to happen in the background
1161 writer. It might cause problems for applying WAL on recovery
1162 into a partially-written page, but later the full page will be
1166 </li><li>Allow WAL traffic to be streamed to another server for stand-by
1168 </li><li>Reduce WAL traffic so only modified values are written rather than
1170 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php</a>
1172 </li><li>-<em>Allow the pg_xlog directory location to be specified during initdb</em>
1173 with a symlink back to the /data location
1174 </li><li>Allow WAL information to recover corrupted pg_controldata
1175 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php</a>
1177 </li><li>Find a way to reduce rotational delay when repeatedly writing
1179 <p> Currently fsync of WAL requires the disk platter to perform a full
1180 rotation to fsync again. One idea is to write the WAL to different
1181 offsets that might reduce the rotational delay.
1183 </li><li>Allow buffered WAL writes and fsync
1184 <p> Instead of guaranteeing recovery of all committed transactions, this
1185 would provide improved performance by delaying WAL writes and fsync
1186 so an abrupt operating system restart might lose a few seconds of
1187 committed transactions but still be consistent. We could perhaps
1188 remove the 'fsync' parameter (which results in an an inconsistent
1189 database) in favor of this capability.
1191 </li><li>Allow WAL logging to be turned off for a table, but the table
1192 might be dropped or truncated during crash recovery [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?walcontrol">walcontrol</a>]
1193 <p> Allow tables to bypass WAL writes and just fsync() dirty pages on
1194 commit. This should be implemented using ALTER TABLE, e.g. ALTER
1195 TABLE PERSISTENCE [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo? DROP | TRUNCATE | DEFAULT "> DROP | TRUNCATE | DEFAULT </a>]. Tables using
1196 non-default logging should not use referential integrity with
1197 default-logging tables. A table without dirty buffers during a
1198 crash could perhaps avoid the drop/truncate.
1200 </li><li>Allow WAL logging to be turned off for a table, but the table would
1201 avoid being truncated/dropped [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?walcontrol">walcontrol</a>]
1202 <p> To do this, only a single writer can modify the table, and writes
1203 must happen only on new pages so the new pages can be removed during
1204 crash recovery. Readers can continue accessing the table. Such
1205 tables probably cannot have indexes. One complexity is the handling
1206 of indexes on TOAST tables.
1209 <h1><a name="section_19">Optimizer / Executor</a></h1>
1212 <li>Improve selectivity functions for geometric operators
1213 </li><li>-<em>Allow ORDER BY ... LIMIT # to select high/low value without sort or</em>
1214 index using a sequential scan for highest/lowest values
1215 </li><li>Precompile SQL functions to avoid overhead
1216 </li><li>Create utility to compute accurate random_page_cost value
1217 </li><li>Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
1218 </li><li>Have EXPLAIN ANALYZE issue NOTICE messages when the estimated and
1219 actual row counts differ by a specified percentage
1220 </li><li>Consider using hash buckets to do DISTINCT, rather than sorting
1221 <p> This would be beneficial when there are few distinct values. This is
1222 already used by GROUP BY.
1224 </li><li>Log statements where the optimizer row estimates were dramatically
1225 different from the number of rows actually found?
1226 </li><li>Consider compressed annealing to search for query plans
1227 <p> This might replace GEQO, <a href="http://sixdemonbag.org/Djinni">http://sixdemonbag.org/Djinni</a>.
1229 </li><li>Improve merge join performance by allowing mark/restore of
1231 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php</a>
1234 <h1><a name="section_20">Miscellaneous Performance</a></h1>
1237 <li>Do async I/O for faster random read-ahead of data
1238 <p> Async I/O allows multiple I/O requests to be sent to the disk with
1239 results coming back asynchronously.
1240 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php</a>
1242 </li><li>Use mmap() rather than SYSV shared memory or to write WAL files?
1243 <p> This would remove the requirement for SYSV SHM but would introduce
1244 portability issues. Anonymous mmap (or mmap to /dev/zero) is required
1245 to prevent I/O overhead.
1247 </li><li>Consider mmap()'ing files into a backend?
1248 <p> Doing I/O to large tables would consume a lot of address space or
1249 require frequent mapping/unmapping. Extending the file also causes
1250 mapping problems that might require mapping only individual pages,
1251 leading to thousands of mappings. Another problem is that there is no
1252 way to <u>prevent</u> I/O to disk from the dirty shared buffers so changes
1253 could hit disk before WAL is written.
1255 </li><li>Add a script to ask system configuration questions and tune postgresql.conf
1256 </li><li>-<em>Merge xmin/xmax/cmin/cmax back into three header fields</em>
1257 </li><li>Consider ways of storing rows more compactly on disk
1259 <li>-<em>Support a smaller header for short variable-length fields</em>
1260 </li><li>Reduce the row header size?
1261 </li><li>Consider reducing on-disk varlena length from four bytes to
1262 two because a heap row cannot be more than 64k in length
1264 </li><li>Consider increasing NUM_CLOG_BUFFERS
1265 </li><li>Consider having the background writer update the transaction status
1266 hint bits before writing out the page
1267 </li><li>Allow user configuration of TOAST thresholds
1268 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php</a>
1270 </li><li>Allow configuration of backend priorities via the operating system
1271 <p> Though backend priorities make priority inversion during lock
1272 waits possible, research shows that this is not a huge problem.
1273 <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php">http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php</a>
1275 </li><li>Consider reducing memory used for shared buffer reference count
1276 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php</a>
1279 <h1><a name="section_21">Source Code</a></h1>
1282 <li>Add use of 'const' for variables in source tree
1283 </li><li>Move some things from /contrib into main tree
1284 </li><li>%Remove warnings created by -Wcast-align
1285 </li><li>Move platform-specific ps status display info from ps_status.c to ports
1286 </li><li>Add optional CRC checksum to heap and index pages
1287 </li><li>Improve documentation to build only interfaces (Marc)
1288 </li><li>Remove or relicense modules that are not under the BSD license, if possible
1289 </li><li>%Remove memory/file descriptor freeing before ereport(ERROR)
1290 </li><li>Acquire lock on a relation before building a relcache entry for it
1291 </li><li>%Promote debug_query_string into a server-side function current_query()
1292 </li><li>Allow cross-compiling by generating the zic database on the target system
1293 </li><li>Improve NLS maintenance of libpgport messages linked onto applications
1294 </li><li>Allow ecpg to work with MSVC and BCC
1295 </li><li>Add xpath_array() to /contrib/xml2 to return results as an array
1296 </li><li>Clean up casting in /contrib/isn
1297 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php</a>
1299 </li><li>Allow building in directories containing spaces
1300 <p> This is probably not possible because 'gmake' and other compiler tools
1301 do not fully support quoting of paths with spaces.
1303 </li><li>Fix sgmltools so PDFs can be generated with bookmarks
1304 </li><li>Use UTF8 encoding for NLS messages so all server encodings can
1306 </li><li>Update Bonjour to work with newer cross-platform SDK
1307 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php</a>
1308 <a href="http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php">http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php</a>
1310 </li><li>Split out libpq pgpass and environment documentation sections to make
1311 it easier for non-developers to find
1312 </li><li>Consider detoasting keys before sorting
1313 </li><li>Consider GnuTLS if OpenSSL license becomes a problem
1314 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php</a>
1315 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php</a>
1317 </li><li>Use strlcpy() rather than our StrNCpy() macro
1318 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg02108.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg02108.php</a>
1320 </li><li>Consider changing documentation format from SGML to XML
1321 <p> <a href="http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php">http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php</a>
1323 </li><li>-<em>Move NAMEDATALEN from postgres_ext.h to pg_config_manual.h</em>
1324 </li><li>Consider making NAMEDATALEN more configurable in future releases
1325 </li><li>Update our code to handle 64-bit timezone files to match the zic
1326 source code, which now uses them
1329 <li>Remove configure.in check for link failure when cause is found
1330 </li><li>Remove readdir() errno patch when runtime/mingwex/dirent.c rev
1332 </li><li>Remove psql newline patch when we find out why mingw outputs an
1334 </li><li>Allow psql to use readline once non-US code pages work with
1336 </li><li>Re-enable timezone output on log_line_prefix '%t' when a
1337 shorter timezone string is available
1338 </li><li>Fix problem with shared memory on the Win32 Terminal Server
1339 </li><li>Improve signal handling
1340 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php">http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php</a>
1342 </li><li>-<em>Add long file support for binary pg_dump output</em>
1343 </li><li>Check WSACancelBlockingCall() for interrupts [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?win32intr">win32intr</a>]
1345 </li><li>Wire Protocol Changes
1347 <li>Allow dynamic character set handling
1348 </li><li>Add decoded type, length, precision
1349 </li><li>Use compression?
1350 </li><li>Update clients to use data types, typmod, schema.table.column names
1351 of result sets using new statement protocol
1354 <h1><a name="section_22">Exotic Features</a></h1>
1357 <li>Add pre-parsing phase that converts non-ISO syntax to supported
1359 <p> This could allow SQL written for other databases to run without
1362 </li><li>Allow plug-in modules to emulate features from other databases
1363 </li><li>SQL*Net listener that makes PostgreSQL appear as an Oracle database
1365 </li><li>Allow statements across databases or servers with transaction
1367 <p> This can be done using dblink and two-phase commit.
1369 </li><li>Add the features of packages
1371 <li>Make private objects accessible only to objects in the same schema
1372 </li><li>Allow current_schema.objname to access current schema objects
1373 </li><li>Add session variables
1374 </li><li>Allow nested schemas
1376 </li><li>Consider allowing control of upper/lower case folding of unquoted
1378 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php">http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php</a>
1379 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php</a>
1382 <h1><a name="section_23">Features We Do <u>Not</u> Want</a></h1>
1385 <li>All backends running as threads in a single process (not wanted)
1386 <p> This eliminates the process protection we get from the current setup.
1387 Thread creation is usually the same overhead as process creation on
1388 modern systems, so it seems unwise to use a pure threaded model.
1390 </li><li>Optimizer hints (not wanted)
1391 <p> Optimizer hints are used to work around problems in the optimizer. We
1392 would rather have the problems reported and fixed.
1393 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php</a>
1394 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php</a>
1395 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php</a>
1397 </li><li>Allow AS in "SELECT col AS label" to be optional (not wanted)
1398 <p> Because we support postfix operators, it isn't possible to make AS
1399 optional and continue to use bison.
1400 <a href="http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php">http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php</a>
1402 </li><li>Embedded server (not wanted)
1403 <p> While PostgreSQL clients runs fine in limited-resource environments, the
1404 server requires multiple processes and a stable pool of resources to
1405 run reliabily and efficiently. Stripping down the PostgreSQL server
1406 to run in the same process address space as the client application
1407 would add too much complexity and failure cases.</p>
1409 </li></ul></li></ul>