1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
5 <title>PostgreSQL TODO List</title>
6 <meta name="generator" content="HTML::TextToHTML v2.25"/>
8 <body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF">
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: Mon May 19 20:35:36 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 8.4 release.</strong><br/>
17 <strong>A percent sign, "%", marks items that are easier to implement.</strong>
19 <p>This list contains all known PostgreSQL bugs and feature requests. If<br/>
20 you would like to work on an item, please read the Developer's FAQ<br/>
21 first. There is also a developer's wiki at<br/>
22 <a href="http://developer.postgresql.org">http://developer.postgresql.org</a>.
24 <h1><a name="section_2">Administration</a></h1>
27 <li>-<em>Allow administrators to safely terminate individual sessions either</em>
28 via an SQL function or SIGTERM
29 </li><li>Check for unreferenced table files created by transactions that were
30 in-progress when the server terminated abruptly
31 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00096.php</a>
33 </li><li>Set proper permissions on non-system schemas during db creation
34 <p> Currently all schemas are owned by the super-user because they are copied
35 from the template1 database. However, since all objects are inherited
36 from the template database, it is not clear that setting schemas to the db
39 </li><li>-<em>Add function to report the time of the most recent server reload</em>
40 </li><li>Allow log_min_messages to be specified on a per-module basis
41 <p> This would allow administrators to see more detailed information from
42 specific sections of the backend, e.g. checkpoints, autovacuum, etc.
43 Another idea is to allow separate configuration files for each module,
44 or allow arbitrary SET commands to be passed to them.
46 </li><li>Simplify ability to create partitioned tables
47 <p> This would allow creation of partitioned tables without requiring
48 creation of triggers or rules for INSERT/UPDATE/DELETE, and constraints
49 for rapid partition selection. Options could include range and hash
52 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php</a>
53 <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php</a>
54 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00028.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00028.php</a>
55 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00248.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00248.php</a>
56 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00387.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00387.php</a>
57 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00413.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00413.php</a>
59 </li><li>Allow auto-selection of partitioned tables for min/max() operations
60 </li><li>Allow more complex user/database default GUC settings
61 <p> Currently ALTER USER and ALTER DATABASE support per-user and
62 per-database defaults. Consider adding per-user-and-database
63 defaults so things like search_path can be defaulted for a
64 specific user connecting to a specific database.
66 </li><li>Allow custom variable classes that can restrict who can set the values
67 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php</a>
69 </li><li>Implement the SQL standard mechanism whereby REVOKE ROLE revokes only
70 the privilege granted by the invoking role, and not those granted
72 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php</a>
74 </li><li>Allow SSL authentication/encryption over unix domain sockets
75 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php</a>
77 </li><li>Allow SSL key file permission checks to be optionally disabled when
78 sharing SSL keys with other applications
79 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00069.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00069.php</a>
81 </li><li>Allow client certificate names to be checked against the client
83 <p> This is already implemented in
84 libpq/fe-secure.c::verify_peer_name_matches_certificate() but the code
87 </li><li>Configuration files
89 <li>Allow pg_hba.conf to specify host names along with IP addresses
90 <p> Host name lookup could occur when the postmaster reads the
91 pg_hba.conf file, or when the backend starts. Another
92 solution would be to reverse lookup the connection IP and
93 check that hostname against the host names in pg_hba.conf.
94 We could also then check that the host name maps to the IP
97 </li><li>%Allow postgresql.conf file values to be changed via an SQL
98 API, perhaps using SET GLOBAL
99 </li><li>Allow the server to be stopped/restarted via an SQL API
100 </li><li>Issue a warning if a change-on-restart-only postgresql.conf value
101 is modified and the server config files are reloaded
102 </li><li>Consider normalizing fractions in postgresql.conf, perhaps
104 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00550.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00550.php</a>
106 </li><li>Allow Kerberos to disable stripping of realms so we can
107 check the username@realm against multiple realms
108 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00009.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00009.php</a>
113 <li>Allow a database in tablespace t1 with tables created in
114 tablespace t2 to be used as a template for a new database created
115 with default tablespace t2
116 <p> Currently all objects in the default database tablespace must
117 have default tablespace specifications. This is because new
118 databases are created by copying directories. If you mix default
119 tablespace tables and tablespace-specified tables in the same
120 directory, creating a new database from such a mixed directory
121 would create a new database with tables that had incorrect
122 explicit tablespaces. To fix this would require modifying
123 pg_class in the newly copied database, which we don't currently
126 </li><li>Allow reporting of which objects are in which tablespaces
127 <p> This item is difficult because a tablespace can contain objects
128 from multiple databases. There is a server-side function that
129 returns the databases which use a specific tablespace, so this
130 requires a tool that will call that function and connect to each
131 database to find the objects in each database for that tablespace.
133 </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory
134 structure on the recovery computer is different from the original
135 </li><li>Allow per-tablespace quotas
137 </li><li>Statistics Collector
139 <li>Allow statistics collector information to be pulled from the collector
140 process directly, rather than requiring the collector to write a
141 filesystem file twice a second?
142 </li><li>Reduce file system activity overhead of statistics file pgstat.stat
143 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00106.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00106.php</a>
145 </li><li>Allow statistics last vacuum/analyze execution times to be displayed
146 without requiring stats_row_level to be enabled
147 <p> <a href="http://archives.postgresql.org/pgsql-docs/2007-04/msg00028.php">http://archives.postgresql.org/pgsql-docs/2007-04/msg00028.php</a>
149 </li><li>Clear table counters on TRUNCATE
150 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00169.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00169.php</a>
153 </li><li>Point-In-Time Recovery (PITR)
155 <li>Allow a warm standby system to also allow read-only statements
156 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php</a>
158 </li><li>%Create dump tool for write-ahead logs for use in determining
159 transaction id for point-in-time recovery
160 <p> This is useful for checking PITR recovery.
162 </li><li>Allow recovery.conf to support the same syntax as
163 postgresql.conf, including quoting
164 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php</a>
166 </li><li>Fix server restart problem when the server was shutdown during
168 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00800.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00800.php</a>
170 </li><li>Recreate pg_xlog/archive_status/ if it doesn't exist after
171 restoring from a PITR backup
172 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00487.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00487.php</a>
176 <h1><a name="section_3">Data Types</a></h1>
179 <li>Change NUMERIC to enforce the maximum precision
180 </li><li>Reduce storage space for small NUMERICs
181 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php</a>
182 <a href="http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php">http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php</a>
183 <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00715.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00715.php</a>
185 </li><li>Fix data types where equality comparison isn't intuitive, e.g. box
186 </li><li>Add support for public SYNONYMs
187 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php</a>
189 </li><li>Fix CREATE CAST on DOMAINs
190 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php">http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php</a>
191 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php</a>
193 </li><li>Allow domains to be cast
194 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2003-06/msg01206.php">http://archives.postgresql.org/pgsql-hackers/2003-06/msg01206.php</a>
195 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00289.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00289.php</a>
197 </li><li>Add support for SQL-standard GENERATED/IDENTITY columns
198 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php</a>
199 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php</a>
200 <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php</a>
201 <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php</a>
202 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php</a>
204 </li><li>Improve XML support
205 <p> <a href="http://developer.postgresql.org/index.php/XML_Support">http://developer.postgresql.org/index.php/XML_Support</a>
207 </li><li>Consider placing all sequences in a single table, or create a system
209 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
211 </li><li>Allow the UUID type to accept non-standard formats
212 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php</a>
214 </li><li>Consider a special data type for regular expressions
215 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg01067.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg01067.php</a>
217 </li><li>Reduce BIT data type overhead using short varlena headers
218 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00273.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00273.php</a>
220 </li><li>Allow xml arrays to be cast to other data types
221 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00981.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00981.php</a>
222 <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00231.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00231.php</a>
223 <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00471.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00471.php</a>
225 </li><li>Simplify integer cross-data-type operators
226 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-01/msg00189.php">http://archives.postgresql.org/pgsql-bugs/2008-01/msg00189.php</a>
228 </li><li>Allow XML to accept more liberal DOCTYPE specifications
229 <p> <a href="http://archives.postgresql.org/pgsql-general/2008-02/msg00347.php">http://archives.postgresql.org/pgsql-general/2008-02/msg00347.php</a>
231 </li><li>Allow adding/renaming/removing enumerated values to an existing
233 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01718.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01718.php</a>
235 </li><li>Dates and Times
237 <li>Allow infinite dates and intervals just like infinite timestamps
238 </li><li>Merge hardwired timezone names with the TZ database; allow either
239 kind everywhere a TZ name is currently taken
240 </li><li>Allow TIMESTAMP WITH TIME ZONE to store the original timezone
241 information, either zone name or offset from UTC
242 <p> If the TIMESTAMP value is stored with a time zone name, interval
243 computations should adjust based on the time zone rules.
244 <a href="http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php">http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php</a>
246 </li><li>Fix SELECT '0.01 years'::interval, '0.01 months'::interval
247 </li><li>Add a GUC variable to allow output of interval values in ISO8601
249 </li><li>Have timestamp subtraction not call justify_hours()?
250 <p> <a href="http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php">http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php</a>
252 </li><li>Improve timestamptz subtraction to be DST-aware
253 <p> Currently subtracting one date from another that crosses a
254 daylight savings time adjustment can return '1 day 1 hour', but
255 adding that back to the first date returns a time one hour in
256 the future. This is caused by the adjustment of '25 hours' to
257 '1 day 1 hour', and '1 day' is the same time the next day, even
258 if daylight savings adjustments are involved.
260 </li><li>Fix interval display to support values exceeding 2^31 hours
261 </li><li>Add overflow checking to timestamp and interval arithmetic
262 </li><li>Extend timezone code to allow 64-bit values so we can
263 represent years beyond 2038
264 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php</a>
266 </li><li>-<em>Use LC_TIME for localized weekday/month names, rather than</em>
268 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php</a>
270 </li><li>Add ISO INTERVAL handling
273 <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/>
274 <a href="http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php">http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php</a>
277 <li>Support ISO INTERVAL syntax if units cannot be determined from
278 the string, and are supplied after the string
279 <p> The SQL standard states that the units after the string
280 specify the units of the string, e.g. INTERVAL '2' MINUTE
281 should return '00:02:00'. The current behavior has the units
282 restrict the interval value to the specified unit or unit
283 range, INTERVAL '70' SECOND returns '00:00:10'.
285 <p> For syntax that isn't uniquely ISO or PG syntax, like '1' or
286 '1:30', treat as ISO if there is a range specification clause,
287 and as PG if there no clause is present, e.g. interpret '1:30'
288 MINUTE TO SECOND as '1 minute 30 seconds', and interpret
289 '1:30' as '1 hour, 30 minutes'.
291 <p> This makes common cases like SELECT INTERVAL '1' MONTH
292 SQL-standard results. The SQL standard supports a limited
293 number of unit combinations and doesn't support unit names in
294 the string. The PostgreSQL syntax is more flexible in the
295 range of units supported, e.g. PostgreSQL supports '1 year 1
296 hour', while the SQL standard does not.
298 </li><li>Add support for year-month syntax, INTERVAL '50-6' YEAR
300 </li><li>Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1
301 year' AS INTERVAL MONTH), and this should return '12 months'
302 </li><li>Round or truncate values to the requested precision, e.g.
303 INTERVAL '11 months' AS YEAR should return one or zero
304 </li><li>Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
308 <li>Delay resolution of array expression's data type so assignment
309 coercion can be performed on empty array expressions
310 </li><li>Add support for arrays of domains
311 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php</a>
313 </li><li>Allow single-byte header storage for array elements
317 <li>Improve vacuum of large objects, like contrib/vacuumlo?
318 </li><li>Add security checking for large objects
319 </li><li>Auto-delete large objects when referencing row is deleted
320 <p> contrib/lo offers this functionality.
322 </li><li>Allow read/write into TOAST values like large objects
323 <p> This requires the TOAST column to be stored EXTERNAL.
325 </li><li>Add API for 64-bit large object access
326 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php</a>
329 </li><li>MONEY data type
331 <li>Add locale-aware MONEY type, and support multiple currencies
332 <p> <a href="http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php">http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php</a>
333 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php</a>
335 </li><li>MONEY dumps in a locale-specific format making it difficult to
336 restore to a system with a different locale
337 </li><li>Allow MONEY to be easily cast to/from other numeric data types
341 <li>Allow dictionaries to change the token that is passed on to
343 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php">http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php</a>
345 </li><li>Consider a function-based API for '@@' searches
346 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php</a>
348 </li><li>Improve text search error messages
349 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00966.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00966.php</a>
350 <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01146.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01146.php</a>
352 </li><li>Consider changing error to warning for strings larger than one
354 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-02/msg00190.php">http://archives.postgresql.org/pgsql-bugs/2008-02/msg00190.php</a>
355 <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00062.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00062.php</a>
360 <h1><a name="section_4">Functions</a></h1>
363 <li>Allow INET subnet tests using non-constants to be indexed
364 </li><li>Allow to_date() and to_timestamp() accept localized month names
365 </li><li>Fix to_date()-related functions to consistently issue errors
366 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php</a>
368 </li><li>Add missing parameter handling in to_char()
369 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php</a>
371 </li><li>Allow substring/replace() to get/set bit values
372 </li><li>Allow to_char() on interval values to accumulate the highest unit
374 <p> Some special format flag would be required to request such
375 accumulation. Such functionality could also be added to EXTRACT.
376 Prevent accumulation that crosses the month/day boundary because of
377 the uneven number of days in a month.
380 <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
381 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
382 </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
383 </li><li>to_char(INTERVAL '3 years 5 months','MM') => 41
385 </li><li>Implement inlining of set-returning functions defined in SQL
386 </li><li>Allow SQL-language functions to return results from RETURNING queries
387 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php</a>
389 </li><li>Allow SQL-language functions to reference parameters by parameter name
390 <p> Currently SQL-language functions can only refer to dollar parameters,
393 </li><li>Add SPI_gettypmod() to return the typemod for a TupleDesc
394 </li><li>Enforce typmod for function inputs, function results and parameters for
395 spi_prepare'd statements called from PLs
396 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php</a>
398 </li><li>Allow holdable cursors in SPI
399 </li><li>Tighten function permission checks
400 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php</a>
402 </li><li>Fix IS OF so it matches the ISO specification, and add documentation
403 <p> <a href="http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php">http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php</a>
404 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php</a>
406 </li><li>Add missing operators for geometric data types
407 <p> Some geometric types do not have the full suite of geometric operators,
410 </li><li>Implement Boyer-Moore searching in strpos()
411 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php">http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php</a>
413 </li><li>Prevent malicious functions from being executed with the permissions
414 of unsuspecting users
415 <p> Index functions are safe, so VACUUM and ANALYZE are safe too.
416 Triggers, CHECK and DEFAULT expressions, and rules are still vulnerable.
417 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php</a>
419 </li><li>Reduce memory usage of aggregates in set returning functions
420 <p> <a href="http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php">http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php</a>
422 </li><li>Add temporal versions of generate_series()
423 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php</a>
425 </li><li>Add array_accum() and array_to_set() functions for arrays
426 <p> The standards specify array_agg() and UNNEST.
427 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00464.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00464.php</a>
429 </li><li>Fix /contrib/ltree operator
430 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-11/msg00044.php">http://archives.postgresql.org/pgsql-bugs/2007-11/msg00044.php</a>
432 </li><li>Fix inconsistent precedence of =, >, and < compared to <>, >=, and <=
433 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00145.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00145.php</a>
435 </li><li>Fix regular expression bug when using complex back-references
436 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00000.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00000.php</a>
438 </li><li>Have /contrib/dblink reuse unnamed connections
439 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00895.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00895.php</a>
441 </li><li>Add SQL-standard array_agg() and unnest() array functions
442 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01017.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01017.php</a>
444 </li><li>Allow calling of a procedure outside a SELECT that can control the
446 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01375.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01375.php</a>
449 <h1><a name="section_5">Multi-Language Support</a></h1>
452 <li>Add NCHAR (as distinguished from ordinary varchar),
453 </li><li>Allow locale to be set at database creation
454 <p> Currently locale can only be set during initdb. No global tables have
455 locale-aware columns. However, the database template used during
456 database creation might have locale-aware indexes. The indexes would
457 need to be reindexed to match the new locale.
459 </li><li>Allow encoding on a per-column basis optionally using the ICU library;
461 <p> Right now only one encoding is allowed per database.
463 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php">http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php</a>
464 <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php</a>
465 <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php</a>
466 <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php</a>
467 <a href="http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php">http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php</a>
468 <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php</a>
469 <a href="http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php">http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php</a>
470 <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php</a>
471 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php</a>
472 <a href="http://wiki.postgresql.org/wiki/Todo:Collate">http://wiki.postgresql.org/wiki/Todo:Collate</a>
473 <a href="http://wiki.postgresql.org/wiki/Todo:ICU">http://wiki.postgresql.org/wiki/Todo:ICU</a>
475 </li><li>Support multiple simultaneous character sets, per SQL92
476 </li><li>Improve UTF8 combined character handling?
477 </li><li>Add octet_length_server() and octet_length_client()
478 </li><li>Make octet_length_client() the same as octet_length()?
479 </li><li>Fix problems with wrong runtime encoding conversion for NLS message files
480 </li><li>Add URL to more complete multi-byte regression tests
481 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php">http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php</a>
483 </li><li>Fix ILIKE and regular expressions to handle case insensitivity
484 properly in multibyte encodings
485 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php">http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php</a>
486 <a href="http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php">http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php</a>
488 </li><li>Set client encoding based on the client operating system encoding
489 <p> Currently client_encoding is set in postgresql.conf, which
490 defaults to the server encoding.
491 <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php</a>
493 </li><li>Change memory allocation for multi-byte functions so memory is
494 allocated inside conversion functions
495 <p> Currently we preallocate memory based on worst-case usage.
498 <h1><a name="section_6">Views / Rules</a></h1>
501 <li>Automatically create rules on views so they are updateable, per SQL99
502 <p> We can only auto-create rules for simple views. For more complex
503 cases users will still have to write rules manually.
505 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php</a>
506 <a href="http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php">http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php</a>
508 </li><li>Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
509 </li><li>Allow VIEW/RULE recompilation when the underlying tables change
510 <p> Another issue is whether underlying table changes should be reflected
511 in the view, e.g. should SELECT * show additional columns if they
512 are added after the view is created.
514 </li><li>Make it possible to use RETURNING together with conditional DO INSTEAD
515 rules, such as for partitioning setups
516 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php</a>
518 </li><li>Add the ability to automatically create materialized views
519 <p> Right now materialized views require the user to create triggers on the
520 main table to keep the summary table current. SQL syntax should be able
521 to manager the triggers and summary table automatically. A more
522 sophisticated implementation would automatically retrieve from the
523 summary table when the main table is referenced, if possible.
526 <h1><a name="section_7">SQL Commands</a></h1>
529 <li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
530 </li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
531 </li><li>%Allow SET CONSTRAINTS to be qualified by schema/table name
532 </li><li>%Add a separate TRUNCATE permission
533 <p> Currently only the owner can TRUNCATE a table because triggers are not
534 called, and the table is locked in exclusive mode.
536 </li><li>Allow PREPARE of cursors
537 </li><li>Allow finer control over the caching of prepared query plans
538 <p> Currently queries prepared via the libpq API are planned on first
539 execute using the supplied parameters --- allow SQL PREPARE to do the
540 same. Also, allow control over replanning prepared queries either
541 manually or automatically when statistics for execute parameters
542 differ dramatically from those used during planning.
544 </li><li>Improve logging of prepared transactions recovered during startup
545 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php</a>
547 </li><li>Improve failure message when DROP DATABASE is used on a database that
548 has prepared transactions
549 </li><li>Allow prepared transactions with temporary tables created and dropped
550 in the same transaction, and when an ON COMMIT DELETE ROWS temporary
552 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00047.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00047.php</a>
554 </li><li>Add a GUC variable to warn about non-standard SQL usage in queries
555 </li><li>Add SQL-standard MERGE/REPLACE/UPSERT command
556 <p> MERGE is typically used to merge two tables. REPLACE or UPSERT
557 command does UPDATE, or on failure, INSERT. This is similar to UPDATE,
558 then for unmatched rows, INSERT. Whether concurrent access allows
559 modifications which could cause row loss is implementation independent.
560 To implement this cleanly requires that the table have a unique index
561 so duplicate checking can be easily performed. It is possible to do it
562 without a unique index if we require the user to LOCK the table before
565 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php</a>
566 <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php</a>
567 <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01475.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01475.php</a>
569 </li><li>Add NOVICE output level for helpful messages like automatic sequence/index
571 </li><li>Add GUC to issue notice about statements that use unjoined tables
572 </li><li>Allow EXPLAIN to identify tables that were skipped because of
574 </li><li>Allow EXPLAIN output to be more easily processed by scripts, perhaps XML
575 </li><li>Enable standard_conforming_strings
576 </li><li>Make standard_conforming_strings the default in 8.5?
577 <p> When this is done, backslash-quote should be prohibited in non-E''
578 strings because of possible confusion over how such strings treat
579 backslashes. Basically, '' is always safe for a literal single
580 quote, while \' might or might not be based on the backslash
583 </li><li>Simplify dropping roles that have objects in several databases
584 </li><li>Allow COMMENT ON to accept an expression rather than just a string
585 </li><li>Allow the count returned by SELECT, etc to be represented as an int64
586 to allow a higher range of values
587 </li><li>Add SQL99 WITH clause to SELECT
588 </li><li>Add SQL:2003 WITH RECURSIVE (hierarchical) queries to SELECT
589 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php</a>
590 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php</a>
591 <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php</a>
592 <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01334.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01334.php</a>
593 <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00105.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00105.php</a>
594 <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00327.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00327.php</a>
596 </li><li>Add DEFAULT .. AS OWNER so permission checks are done as the table
598 <p> This would be useful for SERIAL nextval() calls and CHECK constraints.
600 </li><li>Allow DISTINCT to work in multiple-argument aggregate calls
601 </li><li>Add column to pg_stat_activity that shows the progress of long-running
602 commands like CREATE INDEX and VACUUM
603 <p> <a href="http://archives.postgresql.org/pgsql-patches/2008-04/msg00203.php">http://archives.postgresql.org/pgsql-patches/2008-04/msg00203.php</a>
605 </li><li>Implement SQL:2003 window functions
606 </li><li>Allow INSERT/UPDATE ... RETURNING inside a SELECT 'FROM' clause
607 <p> <a href="http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php">http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php</a>
608 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php</a>
610 </li><li>Increase locking when DROPing objects so dependent objects cannot
611 get dropped while the DROP operation is happening
612 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php</a>
614 </li><li>-<em>Allow AS in "SELECT col AS label" to be optional in certain cases</em>
615 </li><li>Allow INSERT ... DELETE ... RETURNING, namely allow the DELETE ...
616 RETURNING to supply values to the INSERT
617 <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>
618 </li><li>Add comments on system tables/columns using the information in
620 <p> Ideally the information would be pulled from the SGML file
623 </li><li>Improve reporting of UNION type mismatches
624 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00944.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00944.php</a>
625 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00597.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00597.php</a>
629 <li>Allow CREATE TABLE AS to determine column lengths for complex
630 expressions like SELECT col1 || col2
631 </li><li>Have WITH CONSTRAINTS also create constraint indexes
632 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php</a>
634 </li><li>Have CONSTRAINT cname NOT NULL record the contraint name
635 <p> Right now pg_attribute.attnotnull records the NOT NULL status
636 of the column, but does not record the contraint name
638 </li><li>Prevent concurrent CREATE TABLE table1 from sometimes returning
639 a cryptic error message
640 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00169.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00169.php</a>
642 </li><li>Add CREATE SCHEMA ... LIKE that copies a schema
646 <li>Allow UPDATE tab SET ROW (col, ...) = (SELECT...)
647 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php</a>
648 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php</a>
649 <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00315.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00315.php</a>
650 <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00237.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00237.php</a>
652 </li><li>Research self-referential UPDATEs that see inconsistent row versions
653 in read-committed mode
654 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php</a>
655 <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php</a>
657 </li><li>Allow GLOBAL temporary tables to exist as empty by default in
659 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php</a>
664 <li>Have ALTER TABLE RENAME rename SERIAL sequence names
665 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
667 </li><li>Have ALTER SEQUENCE RENAME rename the sequence name stored
668 in the sequence table
669 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php">http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php</a>
670 <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php</a>
671 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
673 </li><li>Add ALTER DOMAIN to modify the underlying data type
674 </li><li>%Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
675 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php</a>
677 </li><li>%Allow ALTER TABLE to change constraint deferrability and actions
678 </li><li>Add missing object types for ALTER ... SET SCHEMA
679 </li><li>Allow ALTER TABLESPACE to move to different directories
680 </li><li>Allow databases to be moved to different tablespaces
681 </li><li>Allow moving system tables to other tablespaces, where possible
682 <p> Currently non-global system tables must be in the default database
683 tablespace. Global system tables can never be moved.
685 </li><li>-<em>Prevent parent tables from altering or dropping constraints</em>
686 like CHECK that are inherited by child tables unless CASCADE
688 </li><li>-<em>Prevent child tables from altering or dropping constraints</em>
689 like CHECK that were inherited from the parent table
690 </li><li>Have ALTER INDEX update the name of a constraint using that index
691 </li><li>Add ALTER TABLE RENAME CONSTRAINT, update index name also
692 </li><li>Allow column display reordering by recording a display,
693 storage, and permanent id for every column?
694 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php</a>
696 </li><li>Allow an existing index to be marked as a table's primary key
697 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00500.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00500.php</a>
702 <li>Automatically maintain clustering on a table
703 <p> This might require some background daemon to maintain clustering
704 during periods of low usage. It might also require tables to be only
705 partially filled for easier reorganization. Another idea would
706 be to create a merged heap/index data file so an index lookup would
707 automatically access the heap data too. A third idea would be to
708 store heap rows in hashed groups, perhaps using a user-supplied
710 <a href="http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php">http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php</a>
712 </li><li>%Add default clustering to system tables
713 <p> To do this, determine the ideal cluster index for each system
714 table and set the cluster setting during initdb.
716 </li><li>%Add VERBOSE option to report tables as they are processed,
721 <li>Allow COPY to report error lines and continue
722 <p> This requires the use of a savepoint before each COPY line is
723 processed, with ROLLBACK on COPY failure.
724 <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00572.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00572.php</a>
726 </li><li>Allow COPY on a newly-created table to skip WAL logging
727 <p> On crash recovery, the table involved in the COPY would
728 be removed or have its heap and index files truncated. One
729 issue is that no other backend should be able to add to
730 the table at the same time, which is something that is
731 currently allowed. This currently is done if the table is
732 created inside the same transaction block as the COPY because
733 no other backends can see the table.
735 </li><li>Consider using a ring buffer for COPY FROM
736 <p> <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php</a>
737 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php</a>
739 </li><li>Allow COPY FROM to create index entries in bulk
740 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php</a>
742 </li><li>Allow COPY in CSV mode to control whether a quoted zero-length
743 string is treated as NULL
744 <p> Currently this is always treated as a zero-length string,
745 which generates an error when loading into an integer column
746 <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00905.php</a>
748 </li><li>Impove COPY performance
749 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00954.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00954.php</a>
752 </li><li>GRANT/REVOKE
754 <li>Allow column-level privileges
755 </li><li>%Allow GRANT/REVOKE permissions to be applied to all schema objects
757 <p> The proposed syntax is:
758 </p><p> GRANT SELECT ON ALL TABLES IN public TO phpuser;
759 GRANT SELECT ON NEW TABLES IN public TO phpuser;
761 </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on
763 </li><li>Allow SERIAL sequences to inherit permissions from the base table?
767 <li>Prevent DROP TABLE from dropping a row referenced by its own open
772 <li>Allow INSERT/UPDATE of the system-generated oid value for a row
773 </li><li>In rules, allow VALUES() to contain a mixture of 'old' and 'new'
778 <li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
781 </li><li>LISTEN/NOTIFY
783 <li>Allow LISTEN/NOTIFY to store info in memory rather than tables?
784 <p> Currently LISTEN/NOTIFY information is stored in pg_listener.
785 Storing such information in memory would improve performance.
787 </li><li>Add optional textual message to NOTIFY
788 <p> This would allow an informational message to be added to the notify
789 message, perhaps indicating the row modified or other custom
792 </li><li>Allow multiple identical NOTIFY events to always be communicated
793 to the client, rather than sent as a single notification to the
795 <p> <a href="http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php">http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php</a>
797 </li><li>Allow NOTIFY in rules involving conditionals
798 </li><li>Improve LISTEN concurrency
799 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01106.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01106.php</a>
803 <h1><a name="section_8">Referential Integrity</a></h1>
806 <li>Add MATCH PARTIAL referential integrity
807 </li><li>Change foreign key constraint for array -> element to mean element
809 </li><li>Fix problem when cascading referential triggers make changes on
810 cascaded tables, seeing the tables in an intermediate state
811 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
812 <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
814 </li><li>Allow DEFERRABLE and end-of-statement UNIQUE constraints?
815 <p> This would allow UPDATE tab SET col = col + 1 to work if col has
816 a unique index. Currently, uniqueness checks are done while the
817 command is being executed, rather than at the end of the statement
819 <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>
820 <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php</a>
822 </li><li>Optimize referential integrity checks
823 <p> <a href="http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php">http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php</a>
824 <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php</a>
827 <h1><a name="section_9">Server-Side Languages</a></h1>
832 <li>Fix RENAME to work on variables other than OLD/NEW
833 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php">http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php</a>
834 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php</a>
835 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php</a>
837 </li><li>Allow function parameters to be passed by name,
838 get_employee_salary(12345 AS emp_id, 2001 AS tax_year)
839 </li><li>Allow handling of %TYPE arrays, e.g. tab.col%TYPE[]
840 </li><li>Allow listing of record column names, and access to
841 record columns via variables, e.g. columns := r.(*),
843 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php</a>
844 <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php</a>
845 <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php</a>
847 </li><li>Add support for SCROLL cursors
848 </li><li>Add support for WITH HOLD cursors
849 </li><li>Allow row and record variables to be set to NULL constants,
850 and allow NULL tests on such variables
851 <p> Because a row is not scalar, do not allow assignment
852 from NULL-valued scalars.
854 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php</a>
856 </li><li>Review handling of MOVE and FETCH
857 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php</a>
859 </li><li>Improve logic of determining if an identifier is a a
860 variable or column name
861 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php</a>
863 </li><li>Consider keeping seperate cached copies when search_path changes
864 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01009.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01009.php</a>
866 </li><li>-<em>Add CASE capability to language (already in SQL)</em>
867 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00696.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00696.php</a>
872 <li>Add table function support to pltcl, plpythonu
873 </li><li>Add support for polymorphic arguments and return types to
874 languages other than PL/PgSQL
875 </li><li>Add capability to create and call PROCEDURES
876 </li><li>Add support for OUT and INOUT parameters to languages other
878 </li><li>Add PL/PythonU tracebacks
879 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php</a>
881 </li><li>Allow data to be passed in native language formats, rather
883 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php</a>
885 </li><li>Add ability to obfuscate function bodies
886 <p> <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00125.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00125.php</a>
890 <h1><a name="section_10">Clients</a></h1>
893 <li>Have pg_ctl look at PGHOST in case it is a socket directory?
894 </li><li>Allow pg_ctl to work properly with configuration files located outside
896 <p> pg_ctl can not read the pid file because it isn't located in the
897 config directory but in the PGDATA directory. The solution is to
898 allow pg_ctl to read and understand postgresql.conf to find the
899 data_directory value.
901 </li><li>Add a function like pg_get_indexdef() that report more detailed index
903 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php</a>
907 <li>Have psql show current values for a sequence
908 </li><li>Move psql backslash database information into the backend, use
910 <p> This would allow non-psql clients to pull the same information out
911 of the database as psql.
912 <a href="http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php">http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php</a>
914 </li><li>Make psql's \d commands more consistent
915 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
916 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
918 </li><li>Consistently display privilege information for all objects in psql
919 </li><li>Add auto-expanded mode so expanded output is used if the row
920 length is wider than the screen width.
921 <p> Consider using auto-expanded mode for backslash commands like \df+.
923 </li><li>Prevent tab completion of SET TRANSACTION from querying the
924 database and therefore preventing the transaction isolation
925 level from being set.
926 <p> Currently SET <tab> causes a database lookup to check all
927 supported session variables. This query causes problems
928 because setting the transaction isolation level must be the
929 first statement of a transaction.
931 </li><li>Add a \set variable to control whether \s displays line numbers
932 <p> Another option is to add \# which lists line numbers, and
933 allows command execution.
935 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php</a>
937 </li><li>Prevent escape string warnings when object names have
939 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php</a>
941 </li><li>Have \d show foreign keys that reference a table's primary key
942 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php</a>
944 </li><li>Have \d show child tables that inherit from the specified parent
945 </li><li>-<em>Have \l+ show database size, if permissions allow</em>
946 <p> Ideally it will not generate an error for invalid permissions
948 </li><li>Include the symbolic SQLSTATE name in verbose error reports
949 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-09/msg00438.php">http://archives.postgresql.org/pgsql-general/2007-09/msg00438.php</a>
951 </li><li>-<em>Improve display of enums to show valid enum values</em>
952 </li><li>Add prompt escape to display the client and server versions
954 </li><li>pg_dump / pg_restore
956 <li>%Add dumping of comments on index columns and composite type columns
957 </li><li>%Add full object name to the tag field. eg. for operators we need
958 '=(integer, integer)', instead of just '='.
959 </li><li>Add pg_dumpall custom format dumps?
960 </li><li>Allow selection of individual object(s) of all types, not just
962 </li><li>In a selective dump, allow dumping of an object and all its
964 </li><li>Add options like pg_restore -l and -L to pg_dump
965 </li><li>Stop dumping CASCADE on DROP TYPE commands in clean mode
966 </li><li>Allow pg_dump --clean to drop roles that own objects or have
968 </li><li>Change pg_dump so that a comment on the dumped database is
969 applied to the loaded database, even if the database has a
970 different name. This will require new backend syntax, perhaps
971 COMMENT ON CURRENT DATABASE.
972 </li><li>Remove unnecessary function pointer abstractions in pg_dump source
974 </li><li>Allow pg_dump to utilize multiple CPUs and I/O channels by dumping
975 multiple objects simultaneously
976 <p> The difficulty with this is getting multiple dump processes to
977 produce a single dump output file. It also would require
978 several sessions to share the same snapshot.
979 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php</a>
981 </li><li>Allow pg_restore to utilize multiple CPUs and I/O channels by
982 restoring multiple objects simultaneously
983 <p> This might require a pg_restore flag to indicate how many
984 simultaneous operations should be performed. Only pg_dump's
985 -Fc format has the necessary dependency information.
986 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php</a>
988 </li><li>To better utilize resources, allow pg_restore to check foreign
989 keys simultaneously, where possible
990 </li><li>Allow pg_restore to create all indexes of a table
991 concurrently, via a single heap scan
992 <p> This requires a pg_dump -Fc file because that format contains
993 the required dependency information.
994 <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php</a>
996 </li><li>Allow pg_restore to load different parts of the COPY data
998 </li><li>Prevent pg_dump/pg_restore from being affected by
1000 <p> Using psql to restore a pg_dump dump is also affected.
1002 </li><li>Remove pre-7.3 pg_dump code that assumes pg_depend does not exit
1003 </li><li>Allow pre/data/post files when schema and data are dumped
1004 separately, for performance reasons
1005 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php</a>
1011 <p> Document differences between ecpg and the SQL standard and
1012 information about the Informix-compatibility module.
1014 </li><li>Solve cardinality > 1 for input descriptors / variables?
1015 </li><li>Add a semantic check level, e.g. check if a table really exists
1016 </li><li>fix handling of DB attributes that are arrays
1017 </li><li>Use backend PREPARE/EXECUTE facility for ecpg where possible
1018 </li><li>Implement SQLDA
1019 </li><li>Fix nested C comments
1020 </li><li>%sqlwarn[6] should be 'W' if the PRECISION or SCALE value specified
1021 </li><li>Make SET CONNECTION thread-aware, non-standard?
1022 </li><li>Allow multidimensional arrays
1023 </li><li>Add internationalized message strings
1024 </li><li>Implement COPY FROM STDIN
1028 <li>Add PQescapeIdentifierConn()
1029 </li><li>Prevent PQfnumber() from lowercasing unquoted the column name
1030 <p> PQfnumber() should never have been doing lowercasing, but
1031 historically it has so we need a way to prevent it
1033 </li><li>Allow statement results to be automatically batched to the client
1034 <p> Currently all statement results are transferred to the libpq
1035 client before libpq makes the results available to the
1036 application. This feature would allow the application to make
1037 use of the first result rows while the rest are transferred, or
1038 held on the server waiting for them to be requested by libpq.
1039 One complexity is that a statement like SELECT 1/col could error
1040 out mid-way through the result set.
1042 </li><li>Consider disallowing multiple queries in PQexec() as an
1043 additional barrier to SQL injection attacks
1044 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php</a>
1046 </li><li>Add PQexecf() that allows complex parameter substitution
1047 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php</a>
1049 </li><li>Add SQLSTATE severity to PGconn return status
1050 <p> <a href="http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php">http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php</a>
1054 <h1><a name="section_11">Triggers</a></h1>
1057 <li>Add deferred trigger queue file
1058 <p> Right now all deferred trigger information is stored in backend
1059 memory. This could exhaust memory for very large trigger queues.
1060 This item involves dumping large queues into files.
1062 </li><li>Allow triggers to be disabled in only the current session.
1063 <p> This is currently possible by starting a multi-statement transaction,
1064 modifying the system tables, performing the desired SQL, restoring the
1065 system tables, and committing the transaction. ALTER TABLE ...
1066 TRIGGER requires a table lock so it is not ideal for this usage.
1068 </li><li>With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
1069 <p> If the dump is known to be valid, allow foreign keys to be added
1070 without revalidating the data.
1072 </li><li>Allow statement-level triggers to access modified rows
1073 </li><li>Support triggers on columns
1074 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php</a>
1076 </li><li>Allow AFTER triggers on system tables
1077 <p> System tables are modified in many places in the backend without going
1078 through the executor and therefore not causing triggers to fire. To
1079 complete this item, the functions that modify system tables will have
1082 </li><li>Tighten trigger permission checks
1083 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php</a>
1085 </li><li>Allow BEFORE INSERT triggers on views
1086 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php">http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php</a>
1088 </li><li>-<em>Add ability to trigger on TRUNCATE</em>
1089 </li><li>Add database and transaction-level triggers
1090 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00451.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00451.php</a>
1093 <h1><a name="section_12">Indexes</a></h1>
1096 <li>Add UNIQUE capability to non-btree indexes
1097 </li><li>Prevent index uniqueness checks when UPDATE does not modify the column
1098 <p> Uniqueness (index) checks are done when updating a column even if the
1099 column is not modified by the UPDATE.
1101 </li><li>Allow the creation of on-disk bitmap indexes which can be quickly
1102 combined with other bitmap indexes
1103 <p> Such indexes could be more compact if there are only a few distinct values.
1104 Such indexes can also be compressed. Keeping such indexes updated can be
1107 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php</a>
1108 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php</a>
1109 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00265.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00265.php</a>
1110 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01214.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01214.php</a>
1111 <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00013.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00013.php</a>
1112 <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00741.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00741.php</a>
1114 </li><li>Allow accurate statistics to be collected on indexes with more than
1115 one column or expression indexes, perhaps using per-index statistics
1116 <p> <a href="http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php">http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php</a>
1117 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php</a>
1119 </li><li>Consider increasing the default and maximum number of statistics targets,
1120 and reduce statistics target overhead
1121 <p> Also consider having a larger statistics target for indexed columns
1122 and expression indexes.
1123 <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php</a>
1124 <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php">http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php</a>
1125 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01066.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01066.php</a>
1126 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00188.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00188.php</a>
1128 </li><li>Consider smaller indexes that record a range of values per heap page,
1129 rather than having one index entry for every heap row
1130 <p> This is useful if the heap is clustered by the indexed values.
1131 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php</a>
1132 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php</a>
1133 <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php</a>
1134 <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php</a>
1135 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00014.php</a>
1136 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00487.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00487.php</a>
1137 <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01589.php</a>
1139 </li><li>Add REINDEX CONCURRENTLY, like CREATE INDEX CONCURRENTLY
1140 <p> This is difficult because you must upgrade to an exclusive table lock
1141 to replace the existing index file. CREATE INDEX CONCURRENTLY does not
1142 have this complication. This would allow index compaction without
1144 <a href="http://archives.postgresql.org/pgsql-performance/2007-08/msg00289.php">http://archives.postgresql.org/pgsql-performance/2007-08/msg00289.php</a>
1146 </li><li>Allow multiple indexes to be created concurrently, ideally via a
1147 single heap scan, and have pg_restore use it
1148 </li><li>Consider sorting entries before inserting into btree index
1149 <p> <a href="http://archives.postgresql.org/pgsql-general/2008-01/msg01010.php">http://archives.postgresql.org/pgsql-general/2008-01/msg01010.php</a>
1151 </li><li>Allow index scans to return matching index keys, not just the matching
1153 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01657.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01657.php</a>
1155 </li><li>Inheritance
1157 <li>Allow inherited tables to inherit indexes, UNIQUE constraints,
1158 and primary/foreign keys
1159 </li><li>Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
1160 on inherited table, e.g. INSERT INTO inherit_table
1161 (unique_index_col) VALUES (dup) should fail
1162 <p> The main difficulty with this item is the problem of
1163 creating an index that can span multiple tables.
1165 </li><li>Allow SELECT ... FOR UPDATE on inherited tables
1166 </li><li>Require all CHECK constraints to be inherited
1167 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php">http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php</a>
1169 </li><li>Add checks to prevent a CREATE RULE views on inherited tables
1170 <p> <a href="http://archives.postgresql.org/pgsql-general/2008-02/msg01420.php">http://archives.postgresql.org/pgsql-general/2008-02/msg01420.php</a>
1171 <a href="http://archives.postgresql.org/pgsql-general/2008-03/msg00077.php">http://archives.postgresql.org/pgsql-general/2008-03/msg00077.php</a>
1176 <li>Add more GIST index support for geometric data types
1177 </li><li>Allow GIST indexes to create certain complex index types, like
1178 digital trees (see Aoki)
1182 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php</a>
1185 <li>Pack hash index buckets onto disk pages more efficiently
1186 <p> Currently only one hash bucket can be stored on a page. Ideally
1187 several hash buckets could be stored on a single page and greater
1188 granularity used for the hash algorithm.
1190 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php">http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php</a>
1192 </li><li>Consider sorting hash buckets so entries can be found using a
1193 binary search, rather than a linear scan
1194 </li><li>In hash indexes, consider storing the hash value with or instead
1196 </li><li>Add WAL logging for crash recovery
1197 </li><li>Allow multi-column hash indexes
1198 </li><li>-<em>During index creation, pre-sort the tuples to improve build speed</em>
1200 <h1><a name="section_13">Fsync</a></h1>
1203 <li>Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
1204 <p> Ideally this requires a separate test program that can be run
1205 at initdb time or optionally later. Consider O_SYNC when
1208 </li><li>Add program to test if fsync has a delay compared to non-fsync
1209 </li><li>Consider sorting writes during checkpoint
1210 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php</a>
1213 <h1><a name="section_14">Cache Usage</a></h1>
1216 <li>Speed up COUNT(*)
1217 <p> We could use a fixed row count and a +/- count to follow MVCC
1218 visibility rules, or a single cached value could be used and
1219 invalidated if anyone modifies the table. Another idea is to
1220 get a count directly from a unique index, but for this to be
1221 faster than a sequential scan it must avoid access to the heap
1222 to obtain tuple visibility information.
1224 </li><li>Provide a way to calculate an "estimated COUNT(*)"
1225 <p> Perhaps by using the optimizer's cardinality estimates or random
1228 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php</a>
1230 </li><li>Allow data to be pulled directly from indexes
1231 <p> Currently indexes do not have enough tuple visibility information
1232 to allow data to be pulled from the index without also accessing
1233 the heap. One way to allow this is to set a bit on index tuples
1234 to indicate if a tuple is currently visible to all transactions
1235 when the first valid heap lookup happens. This bit would have to
1236 be cleared when a heap tuple is expired.
1238 <p> Another idea is to maintain a bitmap of heap pages where all rows
1239 are visible to all backends, and allow index lookups to reference
1240 that bitmap to avoid heap lookups, perhaps the same bitmap we might
1241 add someday to determine which heap pages need vacuuming. Frequently
1242 accessed bitmaps would have to be stored in shared memory. One 8k
1243 page of bitmaps could track 512MB of heap pages.
1245 <p> A third idea would be for a heap scan to check if all rows are visible
1246 and if so set a per-table flag which can be checked by index scans.
1247 Any change to the table would have to clear the flag. To detect
1248 changes during the heap scan a counter could be set at the start and
1249 checked at the end --- if it is the same, the table has not been
1250 modified --- any table change would increment the counter.
1252 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-10/msg00166.php">http://archives.postgresql.org/pgsql-patches/2007-10/msg00166.php</a>
1253 <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00049.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00049.php</a>
1255 </li><li>Consider automatic caching of statements at various levels:
1257 <li>Parsed query tree
1258 </li><li>Query execute plan
1259 </li><li>Query results
1260 <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00823.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00823.php</a>
1262 </li><li>Consider increasing internal areas when shared buffers is increased
1263 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php">http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php</a>
1265 </li><li>Consider decreasing the amount of memory used by PrivateRefCount
1266 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php</a>
1267 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php</a>
1269 </li><li>Consider allowing higher priority queries to have referenced buffer
1270 cache pages stay in memory longer
1271 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php</a>
1274 <h1><a name="section_15">Vacuum</a></h1>
1277 <li>Improve speed with indexes
1278 <p> For large table adjustments during VACUUM FULL, it is faster to cluster
1279 or reindex rather than update the index. Also, index updates can bloat
1282 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php</a>
1283 <a href="http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php">http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php</a>
1284 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00307.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00307.php</a>
1286 </li><li>Auto-fill the free space map by scanning the buffer cache or by
1287 checking pages written by the background writer
1288 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php">http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php</a>
1289 <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php</a>
1291 </li><li>Create a bitmap of pages that need vacuuming
1292 <p> Instead of sequentially scanning the entire table, have the background
1293 writer or some other process record pages that have expired rows, then
1294 VACUUM can look at just those pages rather than the entire table. In
1295 the event of a system crash, the bitmap would probably be invalidated.
1296 One complexity is that index entries still have to be vacuumed, and
1297 doing this without an index scan (by using the heap values to find the
1298 index entry) might be slow and unreliable, especially for user-defined
1301 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php</a>
1302 <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php</a>
1303 <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00508.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00508.php</a>
1304 <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00347.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00347.php</a>
1305 <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00156.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00156.php</a>
1306 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00546.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00546.php</a>
1307 <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00416.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00416.php</a>
1309 </li><li>Allow FSM to return free space toward the beginning of the heap file,
1310 in hopes that empty pages at the end can be truncated by VACUUM
1311 </li><li>Allow FSM page return free space based on table clustering, to assist
1312 in maintaining clustering?
1313 </li><li>-<em>Improve dead row detection during multi-statement transactions usage</em>
1314 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php</a>
1316 </li><li>Consider a more compact data representation for dead tuples
1317 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php</a>
1319 </li><li>Auto-vacuum
1321 <li>%Issue log message to suggest VACUUM FULL if a table is nearly
1323 </li><li>Improve control of auto-vacuum
1324 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php</a>
1326 </li><li>Prevent long-lived temporary tables from causing frozen-xid
1327 advancement starvation
1328 <p> The problem is that autovacuum cannot vacuum them to set frozen xids;
1329 only the session that created them can do that.
1330 <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php">http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php</a>
1332 </li><li>Store per-table autovacuum settings in pg_class.reloptions.
1333 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php</a>
1334 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php</a>
1336 </li><li>Prevent autovacuum from running if an old transaction is still
1337 running from the last vacuum
1338 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php</a>
1342 <h1><a name="section_16">Locking</a></h1>
1345 <li>Fix priority ordering of read and write light-weight locks (Neil)
1346 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php</a>
1347 <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php</a>
1349 </li><li>Fix problem when multiple subtransactions of the same outer transaction
1350 hold different types of locks, and one subtransaction aborts
1351 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php</a>
1352 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php</a>
1353 <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php</a>
1354 <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php</a>
1356 </li><li>Allow UPDATEs on only non-referential integrity columns not to conflict
1357 with referential integrity locks
1358 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php</a>
1360 </li><li>Add idle_in_transaction_timeout GUC so locks are not held for long
1362 </li><li>Improve deadlock detection when a page cleaning lock conflicts
1363 with a shared buffer that is pinned
1364 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php">http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php</a>
1365 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php</a>
1366 <a href="http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php">http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php</a>
1368 </li><li>Detect deadlocks involving LockBufferForCleanup()
1369 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php</a>
1372 <h1><a name="section_17">Startup Time Improvements</a></h1>
1375 <li>Experiment with multi-threaded backend for backend creation
1376 <p> This would prevent the overhead associated with process creation. Most
1377 operating systems have trivial process creation time compared to
1378 database startup overhead, but a few operating systems (Win32,
1379 Solaris) might benefit from threading. Also explore the idea of
1380 a single session using multiple threads to execute a statement faster.
1383 <h1><a name="section_18">Write-Ahead Log</a></h1>
1386 <li>Eliminate need to write full pages to WAL before page modification
1387 <p> Currently, to protect against partial disk page writes, we write
1388 full page images to WAL before they are modified so we can correct any
1389 partial page writes during recovery. These pages can also be
1390 eliminated from point-in-time archive files.
1391 <a href="http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php">http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php</a>
1394 <li>When off, write CRC to WAL and check file system blocks
1396 <p> If CRC check fails during recovery, remember the page in case
1397 a later CRC for that page properly matches.
1399 </li><li>Write full pages during file system write and not when
1400 the page is modified in the buffer cache
1401 <p> This allows most full page writes to happen in the background
1402 writer. It might cause problems for applying WAL on recovery
1403 into a partially-written page, but later the full page will be
1407 </li><li>Allow WAL traffic to be streamed to another server for stand-by
1409 </li><li>Reduce WAL traffic so only modified values are written rather than
1411 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php</a>
1413 </li><li>Allow WAL information to recover corrupted pg_controldata
1414 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php</a>
1416 </li><li>Find a way to reduce rotational delay when repeatedly writing
1418 <p> Currently fsync of WAL requires the disk platter to perform a full
1419 rotation to fsync again. One idea is to write the WAL to different
1420 offsets that might reduce the rotational delay.
1421 <a href="http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php">http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php</a>
1423 </li><li>Allow WAL logging to be turned off for a table, but the table
1424 might be dropped or truncated during crash recovery
1425 <p> Allow tables to bypass WAL writes and just fsync() dirty pages on
1426 commit. This should be implemented using ALTER TABLE, e.g. ALTER
1427 TABLE PERSISTENCE [ DROP | TRUNCATE | DEFAULT ]. Tables using
1428 non-default logging should not use referential integrity with
1429 default-logging tables. A table without dirty buffers during a
1430 crash could perhaps avoid the drop/truncate.
1431 <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php</a>
1433 </li><li>Allow WAL logging to be turned off for a table, but the table would
1434 avoid being truncated/dropped
1435 <p> To do this, only a single writer can modify the table, and writes
1436 must happen only on new pages so the new pages can be removed during
1437 crash recovery. Readers can continue accessing the table. Such
1438 tables probably cannot have indexes. One complexity is the handling
1439 of indexes on TOAST tables.
1440 <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php</a>
1442 </li><li>Speed WAL recovery by allowing more than one page to be prefetched
1443 <p> This should be done utilizing the same infrastructure used for
1444 prefetching in general to avoid introducing complex error-prone code
1446 <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00683.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00683.php</a>
1447 <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00497.php</a>
1448 <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php</a>
1450 </li><li>Improve WAL concurrency by increasing lock granularity
1451 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00556.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00556.php</a>
1453 </li><li>Be more aggressive about creating WAL files
1454 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01325.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01325.php</a>
1455 <a href="http://archives.postgresql.org/pgsql-hackers/2004-07/msg01075.php">http://archives.postgresql.org/pgsql-hackers/2004-07/msg01075.php</a>
1456 <a href="http://archives.postgresql.org/pgsql-hackers/2005-04/msg00556.php">http://archives.postgresql.org/pgsql-hackers/2005-04/msg00556.php</a>
1458 </li><li>Have resource managers report the duration of their status changes
1459 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01468.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01468.php</a>
1461 </li><li>Move pgfoundry's xlogdump to /contrib and have it rely more closely
1462 on the WAL backend code
1463 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00035.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00035.php</a>
1466 <h1><a name="section_19">Optimizer / Executor</a></h1>
1469 <li>Improve selectivity functions for geometric operators
1470 </li><li>Precompile SQL functions to avoid overhead
1471 </li><li>Create utility to compute accurate random_page_cost value
1472 </li><li>Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
1473 </li><li>Have EXPLAIN ANALYZE issue NOTICE messages when the estimated and
1474 actual row counts differ by a specified percentage
1475 </li><li>Improve how ANALYZE computes in-doubt tuples
1476 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00771.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00771.php</a>
1478 </li><li>Consider using hash buckets to do DISTINCT, rather than sorting
1479 <p> This would be beneficial when there are few distinct values. This is
1480 already used by GROUP BY.
1482 </li><li>Log statements where the optimizer row estimates were dramatically
1483 different from the number of rows actually found?
1484 </li><li>Consider compressed annealing to search for query plans
1485 <p> This might replace GEQO, <a href="http://sixdemonbag.org/Djinni">http://sixdemonbag.org/Djinni</a>.
1487 </li><li>Improve merge join performance by allowing mark/restore of
1489 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php</a>
1491 </li><li>Consider using a hash for joining to a large IN (VALUES ...) list
1492 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php</a>
1495 <h1><a name="section_20">Background Writer</a></h1>
1498 <li>Consider having the background writer update the transaction status
1499 hint bits before writing out the page
1500 <p> Implementing this requires the background writer to have access to system
1501 catalogs and the transaction status log.
1503 </li><li>Consider adding buffers the background writer finds reusable to the
1505 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1507 </li><li>Automatically tune bgwriter_delay based on activity rather then using a
1509 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1511 </li><li>Consider wither increasing BM_MAX_USAGE_COUNT improves performance
1512 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php</a>
1514 </li><li>Test to see if calling PreallocXlogFiles() from the background writer
1515 will help with WAL segment creation latency
1516 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-06/msg00340.php">http://archives.postgresql.org/pgsql-patches/2007-06/msg00340.php</a>
1519 <h1><a name="section_21">Miscellaneous Performance</a></h1>
1522 <li>Do async I/O for faster random read-ahead of data
1523 <p> Async I/O allows multiple I/O requests to be sent to the disk with
1524 results coming back asynchronously.
1526 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php</a>
1527 <a href="http://archives.postgresql.org/pgsql-performance/2007-09/msg00255.php">http://archives.postgresql.org/pgsql-performance/2007-09/msg00255.php</a>
1528 <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php</a>
1529 <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00170.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00170.php</a>
1531 </li><li>Use mmap() rather than SYSV shared memory or to write WAL files?
1532 <p> This would remove the requirement for SYSV SHM but would introduce
1533 portability issues. Anonymous mmap (or mmap to /dev/zero) is required
1534 to prevent I/O overhead.
1536 </li><li>Consider mmap()'ing files into a backend?
1537 <p> Doing I/O to large tables would consume a lot of address space or
1538 require frequent mapping/unmapping. Extending the file also causes
1539 mapping problems that might require mapping only individual pages,
1540 leading to thousands of mappings. Another problem is that there is no
1541 way to <u>prevent</u> I/O to disk from the dirty shared buffers so changes
1542 could hit disk before WAL is written.
1544 </li><li>Add a script to ask system configuration questions and tune postgresql.conf
1545 </li><li>Consider ways of storing rows more compactly on disk
1547 <li>Reduce the row header size?
1548 </li><li>Consider reducing on-disk varlena length from four bytes to
1549 two because a heap row cannot be more than 64k in length
1551 </li><li>Consider increasing NUM_CLOG_BUFFERS
1552 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00030.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00030.php</a>
1553 <a href="http://archives.postgresql.org/pgsql-performance/2007-08/msg00024.php">http://archives.postgresql.org/pgsql-performance/2007-08/msg00024.php</a>
1555 </li><li>Consider transaction start/end performance improvements
1556 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00948.php</a>
1557 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php</a>
1559 </li><li>Allow user configuration of TOAST thresholds
1560 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php</a>
1561 <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php</a>
1563 </li><li>Allow configuration of backend priorities via the operating system
1564 <p> Though backend priorities make priority inversion during lock
1565 waits possible, research shows that this is not a huge problem.
1567 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php">http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php</a>
1569 </li><li>Experiment with multi-threaded backend better I/O utilization
1570 <p> This would allow a single query to make use of multiple I/O channels
1571 simultaneously. One idea is to create a background reader that can
1572 pre-fetch sequential and index scan pages needed by other backends.
1573 This could be expanded to allow concurrent reads from multiple devices
1574 in a partitioned table.
1576 </li><li>Experiment with multi-threaded backend better CPU utilization
1577 <p> This would allow several CPUs to be used for a single query, such as
1578 for sorting or query execution.
1580 </li><li>Consider increasing the minimum allowed number of shared buffers
1581 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php">http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php</a>
1583 </li><li>Expire published xmin for read-only and idle transactions
1584 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00343.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00343.php</a>
1586 </li><li>Consider if CommandCounterIncrement() can avoid its
1587 AcceptInvalidationMessages() call
1588 <p> <a href="http://archives.postgresql.org/pgsql-committers/2007-11/msg00585.php">http://archives.postgresql.org/pgsql-committers/2007-11/msg00585.php</a>
1590 </li><li>Improve performance of shared invalidation queue for multiple CPUs
1591 <p> <a href="http://archives.postgresql.org/pgsql-performance/2008-01/msg00023.php">http://archives.postgresql.org/pgsql-performance/2008-01/msg00023.php</a>
1593 </li><li>Consider Cartesian joins when both relations are needed to form an
1594 indexscan qualification for a third relation
1595 <p> <a href="http://archives.postgresql.org/pgsql-performance/2007-12/msg00090.php">http://archives.postgresql.org/pgsql-performance/2007-12/msg00090.php</a>
1597 </li><li>Consider not storing a NULL bitmap on disk if all the NULLs are
1599 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php</a>
1600 <a href="http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php">http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php</a>
1602 </li><li>Sort large UPDATE/DELETEs so it is done in heap order
1603 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01119.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01119.php</a>
1605 </li><li>-<em>Avoid tuple some tuple copying in sort routines</em>
1606 </li><li>SMP scalability improvements
1607 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00439.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00439.php</a>
1608 <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00206.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00206.php</a>
1609 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php</a>
1611 </li><li>Research reducing deTOASTing in more places
1612 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00895.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00895.php</a>
1614 </li><li>Consider being smarter about memory and external files used during
1616 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01101.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01101.php</a>
1617 <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00045.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00045.php</a>
1619 </li><li>Allow one transaction to see tuples using the snapshot of another
1621 <p> This would assist multiple backends in working together.
1622 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php</a>
1625 <h1><a name="section_22">Source Code</a></h1>
1628 <li>Add use of 'const' for variables in source tree
1629 </li><li>Move some things from contrib into main tree
1630 </li><li>%Remove warnings created by -Wcast-align
1631 </li><li>Move platform-specific ps status display info from ps_status.c to ports
1632 </li><li>Add optional CRC checksum to heap and index pages
1633 </li><li>Improve documentation to build only interfaces (Marc)
1634 </li><li>Remove or relicense modules that are not under the BSD license, if possible
1635 </li><li>Acquire lock on a relation before building a relcache entry for it
1636 </li><li>Allow cross-compiling by generating the zic database on the target system
1637 </li><li>Improve NLS maintenance of libpgport messages linked onto applications
1638 </li><li>Clean up casting in contrib/isn
1639 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php</a>
1641 </li><li>Improve the /contrib installation experience
1642 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00132.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00132.php</a>
1644 </li><li>Use UTF8 encoding for NLS messages so all server encodings can
1646 </li><li>Update Bonjour to work with newer cross-platform SDK
1647 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php</a>
1648 <a href="http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php">http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php</a>
1650 </li><li>Consider detoasting keys before sorting
1651 </li><li>Consider GnuTLS if OpenSSL license becomes a problem
1652 <p> <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php</a>
1653 <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php</a>
1655 </li><li>Consider changing documentation format from SGML to XML
1656 <p> <a href="http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php">http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php</a>
1658 </li><li>Consider making NAMEDATALEN more configurable in future releases
1659 </li><li>Update our code to handle 64-bit timezone files to match the zic
1660 source code, which now uses them
1661 </li><li>Have configure choose integer datetimes by default
1662 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php</a>
1664 </li><li>Support scoped IPv6 addresses
1665 <p> <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php</a>
1667 </li><li>Consider allowing 64-bit integers and floats to be passed by value on
1669 <p> Also change 32-bit floats (float4) to be passed by value at the same
1672 </li><li>Research use of signals and sleep wake ups
1673 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00003.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00003.php</a>
1675 </li><li>Add automated check for invalid C++ source code constructs
1676 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-07/msg00056.php">http://archives.postgresql.org/pgsql-patches/2007-07/msg00056.php</a>
1678 </li><li>Consider simplifying how memory context resets handle child contexts
1679 <p> <a href="http://archives.postgresql.org/pgsql-patches/2007-08/msg00067.php">http://archives.postgresql.org/pgsql-patches/2007-08/msg00067.php</a>
1681 </li><li>Remove use of MAKE_PTR and MAKE_OFFSET macros
1682 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-08/msg01510.php">http://archives.postgresql.org/pgsql-general/2007-08/msg01510.php</a>
1684 </li><li>Convert single quotes to apostrophes in the PDF documentation
1685 <p> <a href="http://archives.postgresql.org/pgsql-docs/2007-12/msg00059.php">http://archives.postgresql.org/pgsql-docs/2007-12/msg00059.php</a>
1687 </li><li>Create three versions of libpgport to simplify client code
1688 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00154.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00154.php</a>
1690 </li><li>Remove old-style routines for manipulating tuples
1691 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00851.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00851.php</a>
1693 </li><li>Improve detection of shared memory segments being used by others
1694 by checking the SysV shared memory field 'nattch'
1695 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00656.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00656.php</a>
1696 <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00673.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00673.php</a>
1698 </li><li>Implement the non-threaded Avahi service discovery protocol
1699 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00939.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00939.php</a>
1700 <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00097.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00097.php</a>
1701 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg01211.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg01211.php</a>
1702 <a href="http://archives.postgresql.org/pgsql-patches/2008-04/msg00001.php">http://archives.postgresql.org/pgsql-patches/2008-04/msg00001.php</a>
1706 <li>Remove configure.in check for link failure when cause is found
1707 </li><li>Remove readdir() errno patch when runtime/mingwex/dirent.c rev
1709 </li><li>Remove psql newline patch when we find out why mingw outputs an
1711 </li><li>Allow psql to use readline once non-US code pages work with
1713 </li><li>Fix problem with shared memory on the Win32 Terminal Server
1714 </li><li>Diagnose problem where shared memory can sometimes not be
1715 attached by postmaster children
1716 <p> <a href="http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php">http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php</a>
1718 </li><li>Improve signal handling
1719 <p> <a href="http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php">http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php</a>
1721 </li><li>Convert MSVC build system to remove most batch files
1722 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00961.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00961.php</a>
1724 </li><li>Prevent SSL from sending network packets to avoid interference
1725 with Win32 signal emulation
1726 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00455.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00455.php</a>
1728 </li><li>Support pgxs when using MSVC
1729 </li><li>Fix MSVC NLS support, like for to_char()
1730 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php</a>
1731 <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00038.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00038.php</a>
1733 </li><li>Find a correct rint() substitute on Windows
1734 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00808.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00808.php</a>
1737 </li><li>Wire Protocol Changes
1739 <li>Allow dynamic character set handling
1740 </li><li>Add decoded type, length, precision
1741 </li><li>Use compression?
1742 </li><li>Update clients to use data types, typmod, schema.table.column names
1743 of result sets using new statement protocol
1746 <h1><a name="section_23">Exotic Features</a></h1>
1749 <li>Add pre-parsing phase that converts non-ISO syntax to supported
1751 <p> This could allow SQL written for other databases to run without
1754 </li><li>Allow plug-in modules to emulate features from other databases
1755 </li><li>Add features of Oracle-style packages (Pavel)
1756 <p> A package would be a schema with session-local variables,
1757 public/private functions, and initialization functions. It
1758 is also possible to implement these capabilities
1759 in any schema and not use a separate "packages"
1762 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php</a>
1764 </li><li>Consider allowing control of upper/lower case folding of unquoted
1766 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php">http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php</a>
1767 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php</a>
1768 <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00849.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00849.php</a>
1770 </li><li>Add autonomous transactions
1771 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php</a>
1774 <h1><a name="section_24">Features We Do <u>Not</u> Want</a></h1>
1777 <li>All backends running as threads in a single process (not wanted)
1778 <p> This eliminates the process protection we get from the current setup.
1779 Thread creation is usually the same overhead as process creation on
1780 modern systems, so it seems unwise to use a pure threaded model.
1782 </li><li>Optimizer hints (not wanted)
1783 <p> Optimizer hints are used to work around problems in the optimizer. We
1784 would rather have the problems reported and fixed.
1786 <p> <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php</a>
1787 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php</a>
1788 <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php</a>
1790 <p> Because we support postfix operators, it isn't possible to make AS
1791 optional and continue to use bison.
1792 <a href="http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php">http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php</a>
1794 <p> <a href="http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php">http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php</a>
1796 </li><li>Embedded server (not wanted)
1797 <p> While PostgreSQL clients runs fine in limited-resource environments, the
1798 server requires multiple processes and a stable pool of resources to
1799 run reliabily and efficiently. Stripping down the PostgreSQL server
1800 to run in the same process address space as the client application
1801 would add too much complexity and failure cases.</p>