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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: Tue Mar 11 16:04:51 EDT 2008
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 administrators to safely terminate individual sessions either
30 via an SQL function or SIGTERM
31 <p> Lock table corruption following SIGTERM of an individual backend
32 has been reported in 8.0. A possible cause was fixed in 8.1, but
33 it is unknown whether other problems exist. This item mostly
34 requires additional testing rather than of writing any new code.
36 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00174.php</a>
37 <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00218.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00218.php</a>
39 </li><li>Check for unreferenced table files created by transactions that were
40 in-progress when the server terminated abruptly
41 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.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>Add function to report the time of the most recent server reload
50 </li><li>Allow statistics collector information to be pulled from the collector
51 process directly, rather than requiring the collector to write a
52 filesystem file twice a second?
53 </li><li>Allow statistics last vacuum/analyze execution times to be displayed
54 without requiring stats_row_level to be enabled
55 </li><li>Allow log_min_messages to be specified on a per-module basis
56 <p> This would allow administrators to see more detailed information from
57 specific sections of the backend, e.g. checkpoints, autovacuum, etc.
58 Another idea is to allow separate configuration files for each module,
59 or allow arbitrary SET commands to be passed to them.
61 </li><li>Simplify ability to create partitioned tables
62 <p> This would allow creation of partitioned tables without requiring
63 creation of triggers or rules for INSERT/UPDATE/DELETE, and constraints
64 for rapid partition selection. Options could include range and hash
67 <p> <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>Implement the SQL standard mechanism whereby REVOKE ROLE revokes only
81 the privilege granted by the invoking role, and not those granted
83 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php</a>
85 </li><li>Allow SSL authentication/encryption over unix domain sockets
86 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php</a>
88 </li><li>Allow client certificate names to be checked against the client
90 <p> This is already implemented in
91 libpq/fe-secure.c::verify_peer_name_matches_certificate() but the code
94 </li><li>Configuration files
96 <li>Allow pg_hba.conf to specify host names along with IP addresses
97 <p> Host name lookup could occur when the postmaster reads the
98 pg_hba.conf file, or when the backend starts. Another
99 solution would be to reverse lookup the connection IP and
100 check that hostname against the host names in pg_hba.conf.
101 We could also then check that the host name maps to the IP
104 </li><li>%Allow postgresql.conf file values to be changed via an SQL
105 API, perhaps using SET GLOBAL
106 </li><li>Allow the server to be stopped/restarted via an SQL API
107 </li><li>Issue a warning if a change-on-restart-only postgresql.conf value
108 is modified and the server config files are reloaded
112 <li>Allow a database in tablespace t1 with tables created in
113 tablespace t2 to be used as a template for a new database created
114 with default tablespace t2
115 <p> Currently all objects in the default database tablespace must
116 have default tablespace specifications. This is because new
117 databases are created by copying directories. If you mix default
118 tablespace tables and tablespace-specified tables in the same
119 directory, creating a new database from such a mixed directory
120 would create a new database with tables that had incorrect
121 explicit tablespaces. To fix this would require modifying
122 pg_class in the newly copied database, which we don't currently
125 </li><li>Allow reporting of which objects are in which tablespaces
126 <p> This item is difficult because a tablespace can contain objects
127 from multiple databases. There is a server-side function that
128 returns the databases which use a specific tablespace, so this
129 requires a tool that will call that function and connect to each
130 database to find the objects in each database for that tablespace.
132 </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory
133 structure on the recovery computer is different from the original
134 </li><li>Allow per-tablespace quotas
136 </li><li>Point-In-Time Recovery (PITR)
138 <li>Allow a warm standby system to also allow read-only statements
139 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>]
140 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php</a>
142 </li><li>%Create dump tool for write-ahead logs for use in determining
143 transaction id for point-in-time recovery
144 <p> This is useful for checking PITR recovery.
146 </li><li>Allow recovery.conf to support the same syntax as
147 postgresql.conf, including quoting
148 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php</a>
152 <h1><a name="section_3">Data Types</a></h1>
155 <li>Change NUMERIC to enforce the maximum precision
156 </li><li>Reduce storage space for small NUMERICs
157 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php</a>
158 <a href="http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php">http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php</a>
160 </li><li>Fix data types where equality comparison isn't intuitive, e.g. box
161 </li><li>Add support for public SYNONYMs
162 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php</a>
164 </li><li>Fix CREATE CAST on DOMAINs
165 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php">http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php</a>
166 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php</a>
168 </li><li>Add support for SQL-standard GENERATED/IDENTITY columns
169 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php</a>
170 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php</a>
171 <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php</a>
172 <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php</a>
173 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php</a>
175 </li><li>Improve XML support
176 <p> <a href="http://developer.postgresql.org/index.php/XML_Support">http://developer.postgresql.org/index.php/XML_Support</a>
178 </li><li>Consider placing all sequences in a single table, or create a system
180 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
182 </li><li>Allow the UUID type to accept non-standard formats
183 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php</a>
185 </li><li>Allow text search dictionary to filter out only stop words
186 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php">http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php</a>
188 </li><li>Consider a function-based API for '@@' full text searches
189 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php</a>
191 </li><li>Dates and Times
193 <li>Allow infinite dates and intervals just like infinite timestamps
194 </li><li>Merge hardwired timezone names with the TZ database; allow either
195 kind everywhere a TZ name is currently taken
196 </li><li>Allow TIMESTAMP WITH TIME ZONE to store the original timezone
197 information, either zone name or offset from UTC [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?timezone">timezone</a>]
198 <p> If the TIMESTAMP value is stored with a time zone name, interval
199 computations should adjust based on the time zone rules.
201 </li><li>Fix SELECT '0.01 years'::interval, '0.01 months'::interval
202 </li><li>Add a GUC variable to allow output of interval values in ISO8601
204 </li><li>Have timestamp subtraction not call justify_hours()?
205 <p> <a href="http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php">http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php</a>
207 </li><li>Improve timestamptz subtraction to be DST-aware
208 <p> Currently subtracting one date from another that crosses a
209 daylight savings time adjustment can return '1 day 1 hour', but
210 adding that back to the first date returns a time one hour in
211 the future. This is caused by the adjustment of '25 hours' to
212 '1 day 1 hour', and '1 day' is the same time the next day, even
213 if daylight savings adjustments are involved.
215 </li><li>Fix interval display to support values exceeding 2^31 hours
216 </li><li>Add overflow checking to timestamp and interval arithmetic
217 </li><li>Extend timezone code to allow 64-bit values so we can
218 represent years beyond 2038
219 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php</a>
221 </li><li>Use LC_TIME for localized weekday/month names, rather than
223 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php</a>
225 </li><li>Add ISO INTERVAL handling
228 <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/>
229 <a href="http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php">http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php</a>
232 <li>Support ISO INTERVAL syntax if units cannot be determined from
233 the string, and are supplied after the string
234 <p> The SQL standard states that the units after the string
235 specify the units of the string, e.g. INTERVAL '2' MINUTE
236 should return '00:02:00'. The current behavior has the units
237 restrict the interval value to the specified unit or unit
238 range, INTERVAL '70' SECOND returns '00:00:10'.
240 <p> For syntax that isn't uniquely ISO or PG syntax, like '1' or
241 '1:30', treat as ISO if there is a range specification clause,
242 and as PG if there no clause is present, e.g. interpret '1:30'
243 MINUTE TO SECOND as '1 minute 30 seconds', and interpret
244 '1:30' as '1 hour, 30 minutes'.
246 <p> This makes common cases like SELECT INTERVAL '1' MONTH
247 SQL-standard results. The SQL standard supports a limited
248 number of unit combinations and doesn't support unit names in
249 the string. The PostgreSQL syntax is more flexible in the
250 range of units supported, e.g. PostgreSQL supports '1 year 1
251 hour', while the SQL standard does not.
253 </li><li>Add support for year-month syntax, INTERVAL '50-6' YEAR
255 </li><li>Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1
256 year' AS INTERVAL MONTH), and this should return '12 months'
257 </li><li>Round or truncate values to the requested precision, e.g.
258 INTERVAL '11 months' AS YEAR should return one or zero
259 </li><li>Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
263 <li>Delay resolution of array expression's data type so assignment
264 coercion can be performed on empty array expressions
265 </li><li>Add support for arrays of domains
266 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php</a>
268 </li><li>Allow single-byte header storage for array elements
272 <li>Improve vacuum of large objects, like contrib/vacuumlo?
273 </li><li>Add security checking for large objects
274 </li><li>Auto-delete large objects when referencing row is deleted
275 <p> contrib/lo offers this functionality.
277 </li><li>Allow read/write into TOAST values like large objects
278 <p> This requires the TOAST column to be stored EXTERNAL.
280 </li><li>Add API for 64-bit large object access
281 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php</a>
284 </li><li>MONEY data type
286 <li>Add locale-aware MONEY type, and support multiple currencies
287 <p> <a href="http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php">http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php</a>
288 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php</a>
290 </li><li>MONEY dumps in a locale-specific format making it difficult to
291 restore to a system with a different locale
292 </li><li>Allow MONEY to be easily cast to/from other numeric data types
296 <h1><a name="section_4">Functions</a></h1>
299 <li>Allow INET subnet tests using non-constants to be indexed
300 </li><li>Allow to_date() and to_timestamp() accept localized month names
301 </li><li>Fix to_date()-related functions to consistently issue errors
302 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php</a>
304 </li><li>Add missing parameter handling in to_char()
305 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php</a>
307 </li><li>Allow substring/replace() to get/set bit values
308 </li><li>Allow to_char() on interval values to accumulate the highest unit
310 <p> Some special format flag would be required to request such
311 accumulation. Such functionality could also be added to EXTRACT.
312 Prevent accumulation that crosses the month/day boundary because of
313 the uneven number of days in a month.
316 <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
317 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
318 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
319 </li><li>to_char(INTERVAL '3 years 5 months','MM') => 41
321 </li><li>Implement inlining of set-returning functions defined in SQL
322 </li><li>Allow SQL-language functions to return results from RETURNING queries
323 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php</a>
325 </li><li>Allow SQL-language functions to reference parameters by parameter name
326 <p> Currently SQL-language functions can only refer to dollar parameters,
329 </li><li>Add SPI_gettypmod() to return the typemod for a TupleDesc
330 </li><li>Enforce typmod for function inputs, function results and parameters for
331 spi_prepare'd statements called from PLs
332 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php</a>
334 </li><li>Allow holdable cursors in SPI
335 </li><li>Tighten function permission checks
336 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php</a>
338 </li><li>Fix IS OF so it matches the ISO specification, and add documentation
339 <p> <a href="http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php">http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php</a>
340 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php</a>
342 </li><li>Add missing operators for geometric data types
343 <p> Some geometric types do not have the full suite of geometric operators,
346 </li><li>Implement Boyer-Moore searching in strpos()
347 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php">http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php</a>
349 </li><li>Prevent malicious functions from being executed with the permissions
350 of unsuspecting users
351 <p> Index functions are safe, so VACUUM and ANALYZE are safe too.
352 Triggers, CHECK and DEFAULT expressions, and rules are still vulnerable.
353 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php</a>
355 </li><li>Reduce memory usage of aggregates in set returning functions
356 <p> <a href="http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php">http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php</a>
358 </li><li>Add temporal versions of generate_series()
359 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php</a>
362 <h1><a name="section_5">Multi-Language Support</a></h1>
365 <li>Add NCHAR (as distinguished from ordinary varchar),
366 </li><li>Allow locale to be set at database creation
367 <p> Currently locale can only be set during initdb. No global tables have
368 locale-aware columns. However, the database template used during
369 database creation might have locale-aware indexes. The indexes would
370 need to be reindexed to match the new locale.
372 </li><li>Allow encoding on a per-column basis optionally using the ICU library:
373 <p> Right now only one encoding is allowed per database. [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?locale">locale</a>]
375 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php">http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php</a>
376 <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php</a>
377 <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php</a>
378 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php</a>
380 </li><li>Add CREATE COLLATE? [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?locale">locale</a>]
381 </li><li>Support multiple simultaneous character sets, per SQL92
382 </li><li>Improve UTF8 combined character handling?
383 </li><li>Add octet_length_server() and octet_length_client()
384 </li><li>Make octet_length_client() the same as octet_length()?
385 </li><li>Fix problems with wrong runtime encoding conversion for NLS message files
386 </li><li>Add URL to more complete multi-byte regression tests
387 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php">http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php</a>
389 </li><li>Fix ILIKE and regular expressions to handle case insensitivity
390 properly in multibyte encodings
391 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php">http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php</a>
392 <a href="http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php">http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php</a>
394 </li><li>Set client encoding based on the client operating system encoding
395 <p> Currently client_encoding is set in postgresql.conf, which
396 defaults to the server encoding.
397 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php</a>
399 </li><li>Change memory allocation for multi-byte functions so memory is
400 allocated inside conversion functions
401 <p> Currently we preallocate memory based on worst-case usage.
404 <h1><a name="section_6">Views / Rules</a></h1>
407 <li>Automatically create rules on views so they are updateable, per SQL99
408 <p> We can only auto-create rules for simple views. For more complex
409 cases users will still have to write rules manually.
411 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php</a>
412 <a href="http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php">http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php</a>
414 </li><li>Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
415 </li><li>Allow NOTIFY in rules involving conditionals
416 </li><li>Allow VIEW/RULE recompilation when the underlying tables change
417 <p> Another issue is whether underlying table changes should be reflected
418 in the view, e.g. should SELECT * show additional columns if they
419 are added after the view is created.
421 </li><li>Make it possible to use RETURNING together with conditional DO INSTEAD
422 rules, such as for partitioning setups
423 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php</a>
425 </li><li>Add the ability to automatically create materialized views
426 <p> Right now materialized views require the user to create triggers on the
427 main table to keep the summary table current. SQL syntax should be able
428 to manager the triggers and summary table automatically. A more
429 sophisticated implementation would automatically retrieve from the
430 summary table when the main table is referenced, if possible.
433 <h1><a name="section_7">SQL Commands</a></h1>
436 <li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
437 </li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
438 </li><li>%Allow SET CONSTRAINTS to be qualified by schema/table name
439 </li><li>%Add a separate TRUNCATE permission
440 <p> Currently only the owner can TRUNCATE a table because triggers are not
441 called, and the table is locked in exclusive mode.
443 </li><li>Allow PREPARE of cursors
444 </li><li>Allow finer control over the caching of prepared query plans
445 <p> Currently queries prepared via the libpq API are planned on first
446 execute using the supplied parameters --- allow SQL PREPARE to do the
447 same. Also, allow control over replanning prepared queries either
448 manually or automatically when statistics for execute parameters
449 differ dramatically from those used during planning.
451 </li><li>Improve logging of prepared transactions recovered during startup
452 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php</a>
454 </li><li>Allow LISTEN/NOTIFY to store info in memory rather than tables?
455 <p> Currently LISTEN/NOTIFY information is stored in pg_listener. Storing
456 such information in memory would improve performance.
458 </li><li>Add optional textual message to NOTIFY
459 <p> This would allow an informational message to be added to the notify
460 message, perhaps indicating the row modified or other custom
463 </li><li>Allow multiple identical NOTIFY events to always be communicated to the
464 client, rather than sent as a single notification to the listener
465 <p> <a href="http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php">http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php</a>
467 </li><li>Add a GUC variable to warn about non-standard SQL usage in queries
468 </li><li>Add SQL-standard MERGE command, typically used to merge two tables
469 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
470 <p> This is similar to UPDATE, then for unmatched rows, INSERT.
471 Whether concurrent access allows modifications which could cause
472 row loss is implementation independent.
474 </li><li>Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
475 [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
476 <p> To implement this cleanly requires that the table have a unique index
477 so duplicate checking can be easily performed. It is possible to
478 do it without a unique index if we require the user to LOCK the table
481 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php</a>
482 <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php</a>
484 </li><li>Add NOVICE output level for helpful messages like automatic sequence/index
486 </li><li>Add GUC to issue notice about statements that use unjoined tables
487 </li><li>Allow EXPLAIN to identify tables that were skipped because of
489 </li><li>Allow EXPLAIN output to be more easily processed by scripts, perhaps XML
490 </li><li>Enable standard_conforming_strings
491 </li><li>Make standard_conforming_strings the default in 8.5?
492 <p> When this is done, backslash-quote should be prohibited in non-E''
493 strings because of possible confusion over how such strings treat
494 backslashes. Basically, '' is always safe for a literal single
495 quote, while \' might or might not be based on the backslash
498 </li><li>Simplify dropping roles that have objects in several databases
499 </li><li>Allow COMMENT ON to accept an expression rather than just a string
500 </li><li>Allow the count returned by SELECT, etc to be represented as an int64
501 to allow a higher range of values
502 </li><li>Add SQL99 WITH clause to SELECT
503 </li><li>Add SQL:2003 WITH RECURSIVE (hierarchical) queries to SELECT
504 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php</a>
505 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php</a>
506 <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php</a>
508 </li><li>Add DEFAULT .. AS OWNER so permission checks are done as the table
510 <p> This would be useful for SERIAL nextval() calls and CHECK constraints.
512 </li><li>Allow DISTINCT to work in multiple-argument aggregate calls
513 </li><li>Add column to pg_stat_activity that shows the progress of long-running
514 commands like CREATE INDEX and VACUUM
515 </li><li>Implement SQL:2003 window functions
516 </li><li>Improve failure message when DROP DATABASE is used on a database that
517 has prepared transactions
518 </li><li>Allow INSERT/UPDATE ... RETURNING inside a SELECT 'FROM' clause
519 <p> <a href="http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php">http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php</a>
520 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php</a>
522 </li><li>Increase locking when DROPing objects so dependent objects cannot
523 get dropped while the DROP operation is happening
524 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php</a>
526 </li><li>-<em>Allow AS in "SELECT col AS label" to be optional in certain cases</em>
527 </li><li>Allow INSERT ... DELETE ... RETURNING, namely allow the DELETE ...
528 RETURNING to supply values to the INSERT
529 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/thrd2.php#00979">http://archives.postgresql.org/pgsql-hackers/2008-02/thrd2.php#00979</a>
530 </li><li>Add comments on system tables/columns using the information in
532 <p> Ideally the information would be pulled from the SGML file
537 <li>Allow CREATE TABLE AS to determine column lengths for complex
538 expressions like SELECT col1 || col2
539 </li><li>Have WITH CONSTRAINTS also create constraint indexes
540 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php</a>
542 </li><li>Have CONSTRAINT cname NOT NULL record the contraint name
543 <p> Right now pg_attribute.attnotnull records the NOT NULL status
544 of the column, but does not record the contraint name
549 <li>Allow UPDATE tab SET ROW (col, ...) = (SELECT...)
550 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php</a>
551 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php</a>
553 </li><li>Research self-referential UPDATEs that see inconsistent row versions
554 in read-committed mode
555 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php</a>
556 <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php</a>
558 </li><li>Allow GLOBAL temporary tables to exist as empty by default in
560 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php</a>
565 <li>Have ALTER TABLE RENAME rename SERIAL sequence names
566 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
568 </li><li>Have ALTER SEQUENCE RENAME rename the sequence name stored
569 in the sequence table
570 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php">http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php</a>
571 <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php</a>
572 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
574 </li><li>Add ALTER DOMAIN to modify the underlying data type
575 </li><li>%Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
576 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php</a>
578 </li><li>%Allow ALTER TABLE to change constraint deferrability and actions
579 </li><li>Add missing object types for ALTER ... SET SCHEMA
580 </li><li>Allow ALTER TABLESPACE to move to different directories
581 </li><li>Allow databases to be moved to different tablespaces
582 </li><li>Allow moving system tables to other tablespaces, where possible
583 <p> Currently non-global system tables must be in the default database
584 tablespace. Global system tables can never be moved.
586 </li><li>Prevent parent tables from altering or dropping constraints
587 like CHECK that are inherited by child tables unless CASCADE
589 </li><li>%Prevent child tables from altering or dropping constraints
590 like CHECK that were inherited from the parent table
591 </li><li>Have ALTER INDEX update the name of a constraint using that index
592 </li><li>Add ALTER TABLE RENAME CONSTRAINT, update index name also
593 </li><li>Allow column display reordering by recording a display,
594 storage, and permanent id for every column?
595 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php</a>
600 <li>Automatically maintain clustering on a table
601 <p> This might require some background daemon to maintain clustering
602 during periods of low usage. It might also require tables to be only
603 partially filled for easier reorganization. Another idea would
604 be to create a merged heap/index data file so an index lookup would
605 automatically access the heap data too. A third idea would be to
606 store heap rows in hashed groups, perhaps using a user-supplied
608 <a href="http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php">http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php</a>
610 </li><li>%Add default clustering to system tables
611 <p> To do this, determine the ideal cluster index for each system
612 table and set the cluster setting during initdb.
614 </li><li>%Add VERBOSE option to report tables as they are processed,
619 <li>Allow COPY to report error lines and continue
620 <p> This requires the use of a savepoint before each COPY line is
621 processed, with ROLLBACK on COPY failure.
623 </li><li>Allow COPY on a newly-created table to skip WAL logging
624 <p> On crash recovery, the table involved in the COPY would
625 be removed or have its heap and index files truncated. One
626 issue is that no other backend should be able to add to
627 the table at the same time, which is something that is
628 currently allowed. This currently is done if the table is
629 created inside the same transaction block as the COPY because
630 no other backends can see the table.
632 </li><li>Consider using a ring buffer for COPY FROM
633 <p> <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php</a>
634 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php</a>
636 </li><li>Allow COPY FROM to create index entries in bulk
637 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php</a>
640 </li><li>GRANT/REVOKE
642 <li>Allow column-level privileges
643 </li><li>%Allow GRANT/REVOKE permissions to be applied to all schema objects
645 <p> The proposed syntax is:
646 </p><p> GRANT SELECT ON ALL TABLES IN public TO phpuser;
647 GRANT SELECT ON NEW TABLES IN public TO phpuser;
649 </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on
651 </li><li>Allow SERIAL sequences to inherit permissions from the base table?
655 <li>Prevent DROP TABLE from dropping a row referenced by its own open
660 <li>Allow INSERT/UPDATE of the system-generated oid value for a row
661 </li><li>In rules, allow VALUES() to contain a mixture of 'old' and 'new'
666 <li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
670 <h1><a name="section_8">Referential Integrity</a></h1>
673 <li>Add MATCH PARTIAL referential integrity
674 </li><li>Change foreign key constraint for array -> element to mean element
676 </li><li>Fix problem when cascading referential triggers make changes on
677 cascaded tables, seeing the tables in an intermediate state
678 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
679 <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
681 </li><li>Allow DEFERRABLE and end-of-statement UNIQUE constraints?
682 <p> This would allow UPDATE tab SET col = col + 1 to work if col has
683 a unique index. Currently, uniqueness checks are done while the
684 command is being executed, rather than at the end of the statement
686 <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>
687 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php</a>
689 </li><li>Optimize referential integrity checks
690 <p> <a href="http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php">http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php</a>
691 <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php</a>
694 <h1><a name="section_9">Server-Side Languages</a></h1>
699 <li>Fix RENAME to work on variables other than OLD/NEW
700 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php">http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php</a>
701 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php</a>
702 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php</a>
704 </li><li>Allow function parameters to be passed by name,
705 get_employee_salary(12345 AS emp_id, 2001 AS tax_year)
706 </li><li>Allow handling of %TYPE arrays, e.g. tab.col%TYPE[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?"></a>]
707 </li><li>Allow listing of record column names, and access to
708 record columns via variables, e.g. columns := r.(*),
710 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php</a>
711 <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php</a>
712 <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php</a>
714 </li><li>Add support for SCROLL cursors
715 </li><li>Add support for WITH HOLD cursors
716 </li><li>Allow row and record variables to be set to NULL constants,
717 and allow NULL tests on such variables
718 <p> Because a row is not scalar, do not allow assignment
719 from NULL-valued scalars.
721 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php</a>
723 </li><li>Review handling of MOVE and FETCH
724 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php</a>
729 <li>Add table function support to pltcl, plpythonu
730 </li><li>Add support for polymorphic arguments and return types to
731 languages other than PL/PgSQL
732 </li><li>Add capability to create and call PROCEDURES
733 </li><li>Add support for OUT and INOUT parameters to languages other
735 </li><li>Add PL/PythonU tracebacks
736 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php</a>
738 </li><li>Allow data to be passed in native language formats, rather
740 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php</a>
744 <h1><a name="section_10">Clients</a></h1>
747 <li>Have pg_ctl look at PGHOST in case it is a socket directory?
748 </li><li>Allow pg_ctl to work properly with configuration files located outside
750 <p> pg_ctl can not read the pid file because it isn't located in the
751 config directory but in the PGDATA directory. The solution is to
752 allow pg_ctl to read and understand postgresql.conf to find the
753 data_directory value.
755 </li><li>Add a function like pg_get_indexdef() that report more detailed index
757 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php</a>
759 </li><li>Prefix command-line utilities like createuser with 'pg_'
760 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00025.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00025.php</a>
764 <li>Have psql show current values for a sequence
765 </li><li>Move psql backslash database information into the backend, use
766 mnemonic commands? [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?psql">psql</a>]
767 <p> This would allow non-psql clients to pull the same information out
768 of the database as psql.
770 </li><li>Fix psql's \d commands more consistent
771 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
772 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
774 </li><li>Consistently display privilege information for all objects in psql
775 </li><li>Add auto-expanded mode so expanded output is used if the row
776 length is wider than the screen width.
777 <p> Consider using auto-expanded mode for backslash commands like \df+.
779 </li><li>Prevent tab completion of SET TRANSACTION from querying the
780 database and therefore preventing the transaction isolation
781 level from being set.
782 <p> Currently SET <tab> causes a database lookup to check all
783 supported session variables. This query causes problems
784 because setting the transaction isolation level must be the
785 first statement of a transaction.
787 </li><li>Add a \set variable to control whether \s displays line numbers
788 <p> Another option is to add \# which lists line numbers, and
789 allows command execution.
791 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php</a>
793 </li><li>Prevent escape string warnings when object names have
795 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php</a>
797 </li><li>Have \d show foreign keys that reference a table's primary key
798 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php</a>
800 </li><li>Have \d show child tables that inherit from the specified parent
801 </li><li>Have \l+ show database size, if permissions allow
802 <p> Ideally it will not generate an error for invalid permissions
805 </li><li>pg_dump / pg_restore
807 <li>%Add dumping of comments on index columns and composite type columns
808 </li><li>%Add full object name to the tag field. eg. for operators we need
809 '=(integer, integer)', instead of just '='.
810 </li><li>Add pg_dumpall custom format dumps?
811 </li><li>Allow selection of individual object(s) of all types, not just
813 </li><li>In a selective dump, allow dumping of an object and all its
815 </li><li>Add options like pg_restore -l and -L to pg_dump
816 </li><li>Stop dumping CASCADE on DROP TYPE commands in clean mode
817 </li><li>Allow pg_dump --clean to drop roles that own objects or have
819 </li><li>Change pg_dump so that a comment on the dumped database is
820 applied to the loaded database, even if the database has a
821 different name. This will require new backend syntax, perhaps
822 COMMENT ON CURRENT DATABASE.
823 </li><li>Remove unnecessary function pointer abstractions in pg_dump source
825 </li><li>Allow pg_dump to utilize multiple CPUs and I/O channels by dumping
826 multiple objects simultaneously
827 <p> The difficulty with this is getting multiple dump processes to
828 produce a single dump output file. It also would require
829 several sessions to share the same snapshot.
830 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php</a>
832 </li><li>Allow pg_restore to utilize multiple CPUs and I/O channels by
833 restoring multiple objects simultaneously
834 <p> This might require a pg_restore flag to indicate how many
835 simultaneous operations should be performed. Only pg_dump's
836 -Fc format has the necessary dependency information.
837 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php</a>
839 </li><li>To better utilize resources, allow pg_restore to check foreign
840 keys simultaneously, where possible
841 </li><li>Allow pg_restore to create all indexes of a table
842 concurrently, via a single heap scan
843 <p> This requires a pg_dump -Fc file because that format contains
844 the required dependency information.
845 <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php</a>
847 </li><li>Allow pg_restore to load different parts of the COPY data
849 </li><li>Prevent pg_dump/pg_restore from being affected by
851 <p> Using psql to restore a pg_dump dump is also affected.
857 <p> Document differences between ecpg and the SQL standard and
858 information about the Informix-compatibility module.
860 </li><li>Solve cardinality > 1 for input descriptors / variables?
861 </li><li>Add a semantic check level, e.g. check if a table really exists
862 </li><li>fix handling of DB attributes that are arrays
863 </li><li>Use backend PREPARE/EXECUTE facility for ecpg where possible
864 </li><li>Implement SQLDA
865 </li><li>Fix nested C comments
866 </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
867 </li><li>Make SET CONNECTION thread-aware, non-standard?
868 </li><li>Allow multidimensional arrays
869 </li><li>Add internationalized message strings
870 </li><li>Implement COPY FROM STDIN
874 <li>Add PQescapeIdentifierConn()
875 </li><li>Prevent PQfnumber() from lowercasing unquoted the column name
876 <p> PQfnumber() should never have been doing lowercasing, but
877 historically it has so we need a way to prevent it
879 </li><li>Allow statement results to be automatically batched to the client
880 <p> Currently all statement results are transferred to the libpq
881 client before libpq makes the results available to the
882 application. This feature would allow the application to make
883 use of the first result rows while the rest are transferred, or
884 held on the server waiting for them to be requested by libpq.
885 One complexity is that a statement like SELECT 1/col could error
886 out mid-way through the result set.
888 </li><li>Consider disallowing multiple queries in PQexec() as an
889 additional barrier to SQL injection attacks
890 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php</a>
892 </li><li>Add PQexecf() that allows complex parameter substitution
893 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php</a>
895 </li><li>Add SQLSTATE severity to PGconn return status
896 <p> <a href="http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php">http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php</a>
900 <h1><a name="section_11">Triggers</a></h1>
903 <li>Add deferred trigger queue file
904 <p> Right now all deferred trigger information is stored in backend
905 memory. This could exhaust memory for very large trigger queues.
906 This item involves dumping large queues into files.
908 </li><li>Allow triggers to be disabled in only the current session.
909 <p> This is currently possible by starting a multi-statement transaction,
910 modifying the system tables, performing the desired SQL, restoring the
911 system tables, and committing the transaction. ALTER TABLE ...
912 TRIGGER requires a table lock so it is not ideal for this usage.
914 </li><li>With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
915 <p> If the dump is known to be valid, allow foreign keys to be added
916 without revalidating the data.
918 </li><li>Allow statement-level triggers to access modified rows
919 </li><li>Support triggers on columns
920 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php</a>
922 </li><li>Allow AFTER triggers on system tables
923 <p> System tables are modified in many places in the backend without going
924 through the executor and therefore not causing triggers to fire. To
925 complete this item, the functions that modify system tables will have
928 </li><li>Tighten trigger permission checks
929 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php</a>
931 </li><li>Allow BEFORE INSERT triggers on views
932 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php">http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php</a>
934 </li><li>Add ability to trigger on TRUNCATE
935 <p> <a href="http://archives.postgresql.org/pgsql-sql/2008-01/msg00050.php">http://archives.postgresql.org/pgsql-sql/2008-01/msg00050.php</a>
938 <h1><a name="section_12">Indexes</a></h1>
941 <li>Add UNIQUE capability to non-btree indexes
942 </li><li>Prevent index uniqueness checks when UPDATE does not modify the column
943 <p> Uniqueness (index) checks are done when updating a column even if the
944 column is not modified by the UPDATE.
946 </li><li>Allow the creation of on-disk bitmap indexes which can be quickly
947 combined with other bitmap indexes
948 <p> Such indexes could be more compact if there are only a few distinct values.
949 Such indexes can also be compressed. Keeping such indexes updated can be
952 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php</a>
953 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php</a>
955 </li><li>Allow accurate statistics to be collected on indexes with more than
956 one column or expression indexes, perhaps using per-index statistics
957 <p> <a href="http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php">http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php</a>
958 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php</a>
960 </li><li>Consider increasing the number of default statistics target, and
961 reduce statistics target overhead
962 <p> Also consider having a larger statistics target for indexed columns
963 and expression indexes
964 <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php</a>
965 <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php">http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php</a>
967 </li><li>Consider compressing indexes by storing key values duplicated in
968 several rows as a single index entry
969 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php</a>
970 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php</a>
971 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php</a>
972 <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php</a>
974 </li><li>Add REINDEX CONCURRENTLY, like CREATE INDEX CONCURRENTLY
975 <p> This is difficult because you must upgrade to an exclusive table lock
976 to replace the existing index file. CREATE INDEX CONCURRENTLY does not
977 have this complication. This would allow index compaction without
980 </li><li>Allow multiple indexes to be created concurrently, ideally via a
981 single heap scan, and have pg_restore use it
984 <li>Allow inherited tables to inherit indexes, UNIQUE constraints,
985 and primary/foreign keys
986 </li><li>Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
987 on inherited table, e.g. INSERT INTO inherit_table
988 (unique_index_col) VALUES (dup) should fail
989 <p> The main difficulty with this item is the problem of
990 creating an index that can span multiple tables.
992 </li><li>Allow SELECT ... FOR UPDATE on inherited tables
993 </li><li>Require all CHECK constraints to be inherited
994 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php">http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php</a>
999 <li>Add more GIST index support for geometric data types
1000 </li><li>Allow GIST indexes to create certain complex index types, like
1001 digital trees (see Aoki)
1005 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php</a>
1008 <li>Pack hash index buckets onto disk pages more efficiently
1009 <p> Currently only one hash bucket can be stored on a page. Ideally
1010 several hash buckets could be stored on a single page and greater
1011 granularity used for the hash algorithm.
1013 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php">http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php</a>
1015 </li><li>Consider sorting hash buckets so entries can be found using a
1016 binary search, rather than a linear scan
1017 </li><li>In hash indexes, consider storing the hash value with or instead
1019 </li><li>Add WAL logging for crash recovery
1020 </li><li>Allow multi-column hash indexes
1021 </li><li>During index creation, pre-sort the tuples to improve build speed
1022 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01199.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01199.php</a>
1025 <h1><a name="section_13">Fsync</a></h1>
1028 <li>Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
1029 <p> Ideally this requires a separate test program that can be run
1030 at initdb time or optionally later. Consider O_SYNC when
1033 </li><li>Add program to test if fsync has a delay compared to non-fsync
1034 </li><li>Consider sorting writes during checkpoint
1035 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php</a>
1038 <h1><a name="section_14">Cache Usage</a></h1>
1041 <li>Speed up COUNT(*)
1042 <p> We could use a fixed row count and a +/- count to follow MVCC
1043 visibility rules, or a single cached value could be used and
1044 invalidated if anyone modifies the table. Another idea is to
1045 get a count directly from a unique index, but for this to be
1046 faster than a sequential scan it must avoid access to the heap
1047 to obtain tuple visibility information.
1049 </li><li>Provide a way to calculate an "estimated COUNT(*)"
1050 <p> Perhaps by using the optimizer's cardinality estimates or random
1053 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php</a>
1055 </li><li>Allow data to be pulled directly from indexes
1056 <p> Currently indexes do not have enough tuple visibility information
1057 to allow data to be pulled from the index without also accessing
1058 the heap. One way to allow this is to set a bit on index tuples
1059 to indicate if a tuple is currently visible to all transactions
1060 when the first valid heap lookup happens. This bit would have to
1061 be cleared when a heap tuple is expired.
1063 <p> Another idea is to maintain a bitmap of heap pages where all rows
1064 are visible to all backends, and allow index lookups to reference
1065 that bitmap to avoid heap lookups, perhaps the same bitmap we might
1066 add someday to determine which heap pages need vacuuming. Frequently
1067 accessed bitmaps would have to be stored in shared memory. One 8k
1068 page of bitmaps could track 512MB of heap pages.
1070 <p> A third idea would be for a heap scan to check if all rows are visible
1071 and if so set a per-table flag which can be checked by index scans.
1072 Any change to the table would have to clear the flag. To detect
1073 changes during the heap scan a counter could be set at the start and
1074 checked at the end --- if it is the same, the table has not been
1075 modified --- any table change would increment the counter.
1077 </li><li>Consider automatic caching of statements at various levels:
1079 <li>Parsed query tree
1080 </li><li>Query execute plan
1081 </li><li>Query results
1083 </li><li>Consider increasing internal areas when shared buffers is increased
1084 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php">http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php</a>
1086 </li><li>Consider decreasing the amount of memory used by PrivateRefCount
1087 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php</a>
1088 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php</a>
1090 </li><li>Consider allowing higher priority queries to have referenced buffer
1091 cache pages stay in memory longer
1092 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php</a>
1095 <h1><a name="section_15">Vacuum</a></h1>
1098 <li>Improve speed with indexes
1099 <p> For large table adjustments during VACUUM FULL, it is faster to cluster
1100 or reindex rather than update the index. Also, index updates can bloat
1103 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php</a>
1104 <a href="http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php">http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php</a>
1106 </li><li>Auto-fill the free space map by scanning the buffer cache or by
1107 checking pages written by the background writer
1108 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php">http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php</a>
1109 <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php</a>
1111 </li><li>Create a bitmap of pages that need vacuuming
1112 <p> Instead of sequentially scanning the entire table, have the background
1113 writer or some other process record pages that have expired rows, then
1114 VACUUM can look at just those pages rather than the entire table. In
1115 the event of a system crash, the bitmap would probably be invalidated.
1116 One complexity is that index entries still have to be vacuumed, and
1117 doing this without an index scan (by using the heap values to find the
1118 index entry) might be slow and unreliable, especially for user-defined
1121 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php</a>
1122 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php</a>
1124 </li><li>Allow FSM to return free space toward the beginning of the heap file,
1125 in hopes that empty pages at the end can be truncated by VACUUM
1126 </li><li>Allow FSM page return free space based on table clustering, to assist
1127 in maintaining clustering?
1128 </li><li>Improve dead row detection during multi-statement transactions usage
1129 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php</a>
1131 </li><li>Consider a more compact data representation for dead tuples
1132 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php</a>
1134 </li><li>Auto-vacuum
1136 <li>%Issue log message to suggest VACUUM FULL if a table is nearly
1138 </li><li>Improve control of auto-vacuum
1139 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php</a>
1141 </li><li>Prevent long-lived temporary tables from causing frozen-xid
1142 advancement starvation
1143 <p> The problem is that autovacuum cannot vacuum them to set frozen xids;
1144 only the session that created them can do that.
1145 <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php">http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php</a>
1147 </li><li>Store per-table autovacuum settings in pg_class.reloptions.
1148 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php</a>
1149 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php</a>
1151 </li><li>Prevent autovacuum from running if an old transaction is still
1152 running from the last vacuum
1153 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php</a>
1157 <h1><a name="section_16">Locking</a></h1>
1160 <li>Fix priority ordering of read and write light-weight locks (Neil)
1161 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php</a>
1162 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php</a>
1164 </li><li>Fix problem when multiple subtransactions of the same outer transaction
1165 hold different types of locks, and one subtransaction aborts
1166 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php</a>
1167 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php</a>
1168 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php</a>
1169 <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php</a>
1171 </li><li>Allow UPDATEs on only non-referential integrity columns not to conflict
1172 with referential integrity locks
1173 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php</a>
1175 </li><li>Add idle_in_transaction_timeout GUC so locks are not held for long
1177 </li><li>Improve deadlock detection when a page cleaning lock conflicts
1178 with a shared buffer that is pinned
1179 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php">http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php</a>
1180 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php</a>
1181 <a href="http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php">http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php</a>
1184 <h1><a name="section_17">Startup Time Improvements</a></h1>
1187 <li>Experiment with multi-threaded backend for backend creation [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?thread">thread</a>]
1188 <p> This would prevent the overhead associated with process creation. Most
1189 operating systems have trivial process creation time compared to
1190 database startup overhead, but a few operating systems (Win32,
1191 Solaris) might benefit from threading. Also explore the idea of
1192 a single session using multiple threads to execute a statement faster.
1195 <h1><a name="section_18">Write-Ahead Log</a></h1>
1198 <li>Eliminate need to write full pages to WAL before page modification [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?wal">wal</a>]
1199 <p> Currently, to protect against partial disk page writes, we write
1200 full page images to WAL before they are modified so we can correct any
1201 partial page writes during recovery. These pages can also be
1202 eliminated from point-in-time archive files.
1205 <li>When off, write CRC to WAL and check file system blocks
1207 <p> If CRC check fails during recovery, remember the page in case
1208 a later CRC for that page properly matches.
1210 </li><li>Write full pages during file system write and not when
1211 the page is modified in the buffer cache
1212 <p> This allows most full page writes to happen in the background
1213 writer. It might cause problems for applying WAL on recovery
1214 into a partially-written page, but later the full page will be
1218 </li><li>Allow WAL traffic to be streamed to another server for stand-by
1220 </li><li>Reduce WAL traffic so only modified values are written rather than
1222 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php</a>
1224 </li><li>Allow WAL information to recover corrupted pg_controldata
1225 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php</a>
1227 </li><li>Find a way to reduce rotational delay when repeatedly writing
1229 <p> Currently fsync of WAL requires the disk platter to perform a full
1230 rotation to fsync again. One idea is to write the WAL to different
1231 offsets that might reduce the rotational delay.
1233 </li><li>Allow WAL logging to be turned off for a table, but the table
1234 might be dropped or truncated during crash recovery [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?walcontrol">walcontrol</a>]
1235 <p> Allow tables to bypass WAL writes and just fsync() dirty pages on
1236 commit. This should be implemented using ALTER TABLE, e.g. ALTER
1237 TABLE PERSISTENCE [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo? DROP | TRUNCATE | DEFAULT "> DROP | TRUNCATE | DEFAULT </a>]. Tables using
1238 non-default logging should not use referential integrity with
1239 default-logging tables. A table without dirty buffers during a
1240 crash could perhaps avoid the drop/truncate.
1242 </li><li>Allow WAL logging to be turned off for a table, but the table would
1243 avoid being truncated/dropped [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?walcontrol">walcontrol</a>]
1244 <p> To do this, only a single writer can modify the table, and writes
1245 must happen only on new pages so the new pages can be removed during
1246 crash recovery. Readers can continue accessing the table. Such
1247 tables probably cannot have indexes. One complexity is the handling
1248 of indexes on TOAST tables.
1250 </li><li>Speed WAL recovery by allowing more than one page to be prefetched
1251 <p> This involves having a separate process that can be told which pages
1252 the recovery process will need in the near future.
1253 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php</a>
1256 <h1><a name="section_19">Optimizer / Executor</a></h1>
1259 <li>Improve selectivity functions for geometric operators
1260 </li><li>Precompile SQL functions to avoid overhead
1261 </li><li>Create utility to compute accurate random_page_cost value
1262 </li><li>Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
1263 </li><li>Have EXPLAIN ANALYZE issue NOTICE messages when the estimated and
1264 actual row counts differ by a specified percentage
1265 </li><li>Consider using hash buckets to do DISTINCT, rather than sorting
1266 <p> This would be beneficial when there are few distinct values. This is
1267 already used by GROUP BY.
1269 </li><li>Log statements where the optimizer row estimates were dramatically
1270 different from the number of rows actually found?
1271 </li><li>Consider compressed annealing to search for query plans
1272 <p> This might replace GEQO, <a href="http://sixdemonbag.org/Djinni">http://sixdemonbag.org/Djinni</a>.
1274 </li><li>Improve merge join performance by allowing mark/restore of
1276 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php</a>
1278 </li><li>Consider using a hash for joining to a large IN (VALUES ...) list
1279 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php</a>
1282 <h1><a name="section_20">Miscellaneous Performance</a></h1>
1285 <li>Do async I/O for faster random read-ahead of data
1286 <p> Async I/O allows multiple I/O requests to be sent to the disk with
1287 results coming back asynchronously.
1289 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php</a>
1290 <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php</a>
1292 </li><li>Use mmap() rather than SYSV shared memory or to write WAL files?
1293 <p> This would remove the requirement for SYSV SHM but would introduce
1294 portability issues. Anonymous mmap (or mmap to /dev/zero) is required
1295 to prevent I/O overhead.
1297 </li><li>Consider mmap()'ing files into a backend?
1298 <p> Doing I/O to large tables would consume a lot of address space or
1299 require frequent mapping/unmapping. Extending the file also causes
1300 mapping problems that might require mapping only individual pages,
1301 leading to thousands of mappings. Another problem is that there is no
1302 way to <u>prevent</u> I/O to disk from the dirty shared buffers so changes
1303 could hit disk before WAL is written.
1305 </li><li>Add a script to ask system configuration questions and tune postgresql.conf
1306 </li><li>Consider ways of storing rows more compactly on disk
1308 <li>Reduce the row header size?
1309 </li><li>Consider reducing on-disk varlena length from four bytes to
1310 two because a heap row cannot be more than 64k in length
1312 </li><li>Consider increasing NUM_CLOG_BUFFERS
1313 </li><li>Consider having the background writer update the transaction status
1314 hint bits before writing out the page
1315 <p> Implementing this requires the background writer to have access to system
1316 catalogs and the transaction status log.
1318 </li><li>Consider adding buffers the BGW finds reusable to the free list
1319 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1321 </li><li>Automatically tune bgwriter_delay based on activity rather then using a
1323 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1325 </li><li>Allow user configuration of TOAST thresholds
1326 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php</a>
1328 </li><li>Allow configuration of backend priorities via the operating system
1329 <p> Though backend priorities make priority inversion during lock
1330 waits possible, research shows that this is not a huge problem.
1332 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php">http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php</a>
1334 </li><li>Experiment with multi-threaded backend better resource utilization
1335 <p> This would allow a single query to make use of multiple CPU's or
1336 multiple I/O channels simultaneously. One idea is to create a
1337 background reader that can pre-fetch sequential and index scan
1338 pages needed by other backends. This could be expanded to allow
1339 concurrent reads from multiple devices in a partitioned table.
1341 </li><li>Consider increasing the minimum allowed number of shared buffers
1342 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php">http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php</a>
1345 <h1><a name="section_21">Source Code</a></h1>
1348 <li>Add use of 'const' for variables in source tree
1349 </li><li>Move some things from contrib into main tree
1350 </li><li>%Remove warnings created by -Wcast-align
1351 </li><li>Move platform-specific ps status display info from ps_status.c to ports
1352 </li><li>Add optional CRC checksum to heap and index pages
1353 </li><li>Improve documentation to build only interfaces (Marc)
1354 </li><li>Remove or relicense modules that are not under the BSD license, if possible
1355 </li><li>Acquire lock on a relation before building a relcache entry for it
1356 </li><li>Allow cross-compiling by generating the zic database on the target system
1357 </li><li>Improve NLS maintenance of libpgport messages linked onto applications
1358 </li><li>Clean up casting in contrib/isn
1359 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php</a>
1361 </li><li>Use UTF8 encoding for NLS messages so all server encodings can
1363 </li><li>Update Bonjour to work with newer cross-platform SDK
1364 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php</a>
1365 <a href="http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php">http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php</a>
1367 </li><li>Consider detoasting keys before sorting
1368 </li><li>Consider GnuTLS if OpenSSL license becomes a problem
1369 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php</a>
1370 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php</a>
1372 </li><li>Consider changing documentation format from SGML to XML
1373 <p> <a href="http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php">http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php</a>
1375 </li><li>Consider making NAMEDATALEN more configurable in future releases
1376 </li><li>Update our code to handle 64-bit timezone files to match the zic
1377 source code, which now uses them
1378 </li><li>Have configure choose integer datetimes by default
1379 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php</a>
1381 </li><li>Support scoped IPv6 addresses
1382 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php</a>
1384 </li><li>Consider allowing 64-bit integers and floats to be passed by value on
1386 <p> Also change 32-bit floats (float4) to be passed by value at the same
1391 <li>Remove configure.in check for link failure when cause is found
1392 </li><li>Remove readdir() errno patch when runtime/mingwex/dirent.c rev
1394 </li><li>Remove psql newline patch when we find out why mingw outputs an
1396 </li><li>Allow psql to use readline once non-US code pages work with
1398 </li><li>Fix problem with shared memory on the Win32 Terminal Server
1399 </li><li>Improve signal handling
1400 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php">http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php</a>
1403 </li><li>Wire Protocol Changes
1405 <li>Allow dynamic character set handling
1406 </li><li>Add decoded type, length, precision
1407 </li><li>Use compression?
1408 </li><li>Update clients to use data types, typmod, schema.table.column names
1409 of result sets using new statement protocol
1412 <h1><a name="section_22">Exotic Features</a></h1>
1415 <li>Add pre-parsing phase that converts non-ISO syntax to supported
1417 <p> This could allow SQL written for other databases to run without
1420 </li><li>Allow plug-in modules to emulate features from other databases
1421 </li><li>Add features of Oracle-style packages (Pavel)
1422 <p> A package would be a schema with session-local variables,
1423 public/private functions, and initialization functions. It
1424 is also possible to implement these capabilities
1425 in any schema and not use a separate "packages"
1428 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php</a>
1430 </li><li>Consider allowing control of upper/lower case folding of unquoted
1432 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php">http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php</a>
1433 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php</a>
1435 </li><li>Add autonomous transactions
1436 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php</a>
1439 <h1><a name="section_23">Features We Do <u>Not</u> Want</a></h1>
1442 <li>All backends running as threads in a single process (not wanted)
1443 <p> This eliminates the process protection we get from the current setup.
1444 Thread creation is usually the same overhead as process creation on
1445 modern systems, so it seems unwise to use a pure threaded model.
1447 </li><li>Optimizer hints (not wanted)
1448 <p> Optimizer hints are used to work around problems in the optimizer. We
1449 would rather have the problems reported and fixed.
1451 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php</a>
1452 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php</a>
1453 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php</a>
1455 <p> Because we support postfix operators, it isn't possible to make AS
1456 optional and continue to use bison.
1457 <a href="http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php">http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php</a>
1459 <p> <a href="http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php">http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php</a>
1461 </li><li>Embedded server (not wanted)
1462 <p> While PostgreSQL clients runs fine in limited-resource environments, the
1463 server requires multiple processes and a stable pool of resources to
1464 run reliabily and efficiently. Stripping down the PostgreSQL server
1465 to run in the same process address space as the client application
1466 would add too much complexity and failure cases.</p>