doc/src/FAQ/TODO.html

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   9 <h1><a name="section_1">PostgreSQL TODO List</a></h1>
  10 <p>Current maintainer:     Bruce Momjian (<a href="mailto:bruce@momjian.us">bruce@momjian.us</a>)<br/>
  11 Last updated:           Fri May  9 20:24:53 EDT 2008
  12 </p>
  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>.
  15 </p>
  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>
  18 </p>
  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>.
  23 </p>
  24 <h1><a name="section_2">Administration</a></h1>
  25
  26 <ul>
  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>
  32 </p>
  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
  37   owner is correct.
  38 </p>
  39   </li><li>-<em>Add function to report the time of the most recent server reload</em>
  40   </li><li>Allow statistics collector information to be pulled from the collector
  41   process directly, rather than requiring the collector to write a
  42   filesystem file twice a second?
  43   </li><li>Reduce file system activity overhead of statistics file pgstat.stat
  44 <p>  <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00106.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00106.php</a>
  45 </p>
  46   </li><li>Allow statistics last vacuum/analyze execution times to be displayed
  47   without requiring stats_row_level to be enabled
  48 <p>  <a href="http://archives.postgresql.org/pgsql-docs/2007-04/msg00028.php">http://archives.postgresql.org/pgsql-docs/2007-04/msg00028.php</a>
  49 </p>
  50   </li><li>Allow log_min_messages to be specified on a per-module basis
  51 <p>  This would allow administrators to see more detailed information from
  52   specific sections of the backend, e.g. checkpoints, autovacuum, etc.
  53   Another idea is to allow separate configuration files for each module,
  54   or allow arbitrary SET commands to be passed to them.
  55 </p>
  56   </li><li>Simplify ability to create partitioned tables
  57 <p>  This would allow creation of partitioned tables without requiring
  58   creation of triggers or rules for INSERT/UPDATE/DELETE, and constraints
  59   for rapid partition selection.  Options could include range and hash
  60   partition selection.
  61 </p>
  62 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00375.php</a>
  63   <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00151.php</a>
  64   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00028.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00028.php</a>
  65   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00248.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00248.php</a>
  66   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00387.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00387.php</a>
  67   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00413.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00413.php</a>
  68 </p>
  69   </li><li>Allow auto-selection of partitioned tables for min/max() operations
  70   </li><li>Allow more complex user/database default GUC settings
  71 <p>  Currently ALTER USER and ALTER DATABASE support per-user and
  72   per-database defaults.  Consider adding per-user-and-database
  73   defaults so things like search_path can be defaulted for a
  74   specific user connecting to a specific database.
  75 </p>
  76   </li><li>Allow custom variable classes that can restrict who can set the values
  77 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00911.php</a>
  78 </p>
  79   </li><li>Implement the SQL standard mechanism whereby REVOKE ROLE revokes only
  80   the privilege granted by the invoking role, and not those granted
  81   by other roles
  82 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00010.php</a>
  83 </p>
  84   </li><li>Allow SSL authentication/encryption over unix domain sockets
  85 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00924.php</a>
  86 </p>
  87   </li><li>Allow SSL key file permission checks to be optionally disabled when
  88   sharing SSL keys with other applications
  89 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00069.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00069.php</a>
  90 </p>
  91   </li><li>Allow client certificate names to be checked against the client
  92   hostname
  93 <p>  This is already implemented in
  94   libpq/fe-secure.c::verify_peer_name_matches_certificate() but the code
  95   is commented out.
  96 </p>
  97   </li><li>Configuration files
  98   <ul>
  99     <li>Allow pg_hba.conf to specify host names along with IP addresses
 100 <p>          Host name lookup could occur when the postmaster reads the
 101           pg_hba.conf file, or when the backend starts.  Another
 102           solution would be to reverse lookup the connection IP and
 103           check that hostname against the host names in pg_hba.conf.
 104           We could also then check that the host name maps to the IP
 105           address.
 106 </p>
 107     </li><li>%Allow postgresql.conf file values to be changed via an SQL
 108           API, perhaps using SET GLOBAL
 109     </li><li>Allow the server to be stopped/restarted via an SQL API
 110     </li><li>Issue a warning if a change-on-restart-only postgresql.conf value
 111           is modified  and the server config files are reloaded
 112     </li><li>Consider normalizing fractions in postgresql.conf, perhaps
 113           using '%'
 114 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00550.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00550.php</a>
 115 </p>
 116     </li><li>Allow Kerberos to disable stripping of realms so we can
 117           check the username@realm against multiple realms
 118 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00009.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00009.php</a>
 119 </p>
 120   </li></ul>
 121   </li><li>Tablespaces
 122   <ul>
 123     <li>Allow a database in tablespace t1 with tables created in
 124           tablespace t2 to be used as a template for a new database created
 125           with default tablespace t2
 126 <p>          Currently all objects in the default database tablespace must
 127           have default tablespace specifications. This is because new
 128           databases are created by copying directories. If you mix default
 129           tablespace tables and tablespace-specified tables in the same
 130           directory, creating a new database from such a mixed directory
 131           would create a new database with tables that had incorrect
 132           explicit tablespaces.  To fix this would require modifying
 133           pg_class in the newly copied database, which we don't currently
 134           do.
 135 </p>
 136     </li><li>Allow reporting of which objects are in which tablespaces
 137 <p>          This item is difficult because a tablespace can contain objects
 138           from multiple databases. There is a server-side function that
 139           returns the databases which use a specific tablespace, so this
 140           requires a tool that will call that function and connect to each
 141           database to find the objects in each database for that tablespace.
 142 </p>
 143     </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory
 144           structure on the recovery computer is different from the original
 145     </li><li>Allow per-tablespace quotas
 146   </li></ul>
 147   </li><li>Point-In-Time Recovery (PITR)
 148   <ul>
 149     <li>Allow a warm standby system to also allow read-only statements
 150 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php</a>
 151 </p>
 152     </li><li>%Create dump tool for write-ahead logs for use in determining
 153           transaction id for point-in-time recovery
 154 <p>          This is useful for checking PITR recovery.
 155 </p>
 156     </li><li>Allow recovery.conf to support the same syntax as
 157           postgresql.conf, including quoting
 158 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00497.php</a>
 159 </p>
 160     </li><li>Fix server restart problem when the server was shutdown during
 161           a PITR backup
 162 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00800.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00800.php</a>
 163 </p>
 164     </li><li>Recreate pg_xlog/archive_status/ if it doesn't exist after
 165           restoring from a PITR backup
 166 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00487.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00487.php</a>
 167 </p>
 168   </li></ul>
 169 </li></ul>
 170 <h1><a name="section_3">Data Types</a></h1>
 171
 172 <ul>
 173   <li>Change NUMERIC to enforce the maximum precision
 174   </li><li>Reduce storage space for small NUMERICs
 175 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01331.php</a>
 176   <a href="http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php">http://archives.postgresql.org/pgsql-patches/2007-02/msg00505.php</a>
 177   <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00715.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00715.php</a>
 178 </p>
 179   </li><li>Fix data types where equality comparison isn't intuitive, e.g. box
 180   </li><li>Add support for public SYNONYMs
 181 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00519.php</a>
 182 </p>
 183   </li><li>Fix CREATE CAST on DOMAINs
 184 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php">http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php</a>
 185   <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01681.php</a>
 186 </p>
 187   </li><li>Allow domains to be cast
 188 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2003-06/msg01206.php">http://archives.postgresql.org/pgsql-hackers/2003-06/msg01206.php</a>
 189   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00289.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00289.php</a>
 190 </p>
 191   </li><li>Add support for SQL-standard GENERATED/IDENTITY columns
 192 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg00543.php</a>
 193   <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00038.php</a>
 194   <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00344.php</a>
 195   <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00076.php</a>
 196   <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00604.php</a>
 197 </p>
 198   </li><li>Improve XML support
 199 <p>  <a href="http://developer.postgresql.org/index.php/XML_Support">http://developer.postgresql.org/index.php/XML_Support</a>
 200 </p>
 201   </li><li>Consider placing all sequences in a single table, or create a system
 202   view
 203 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
 204 </p>
 205   </li><li>Allow the UUID type to accept non-standard formats
 206 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01214.php</a>
 207 </p>
 208   </li><li>Consider a special data type for regular expressions
 209 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg01067.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg01067.php</a>
 210 </p>
 211   </li><li>Reduce BIT data type overhead using short varlena headers
 212 <p>  <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00273.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00273.php</a>
 213 </p>
 214   </li><li>Allow xml arrays to be cast to other data types
 215 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00981.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00981.php</a>
 216   <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00231.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00231.php</a>
 217   <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00471.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00471.php</a>
 218 </p>
 219   </li><li>Simplify integer cross-data-type operators
 220 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2008-01/msg00189.php">http://archives.postgresql.org/pgsql-bugs/2008-01/msg00189.php</a>
 221 </p>
 222   </li><li>Allow XML to accept more liberal DOCTYPE specifications
 223 <p>  <a href="http://archives.postgresql.org/pgsql-general/2008-02/msg00347.php">http://archives.postgresql.org/pgsql-general/2008-02/msg00347.php</a>
 224 </p>
 225   </li><li>Allow adding/renaming/removing enumerated values to an existing
 226   enumerated data type
 227 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01718.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01718.php</a>
 228 </p>
 229   </li><li>Dates and Times
 230   <ul>
 231     <li>Allow infinite dates and intervals just like infinite timestamps
 232     </li><li>Merge hardwired timezone names with the TZ database; allow either
 233           kind everywhere a TZ name is currently taken
 234     </li><li>Allow TIMESTAMP WITH TIME ZONE to store the original timezone
 235           information, either zone name or offset from UTC
 236 <p>          If the TIMESTAMP value is stored with a time zone name, interval
 237           computations should adjust based on the time zone rules.
 238           <a href="http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php">http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php</a>
 239 </p>
 240     </li><li>Fix SELECT '0.01 years'::interval, '0.01 months'::interval
 241     </li><li>Add a GUC variable to allow output of interval values in ISO8601
 242           format
 243     </li><li>Have timestamp subtraction not call justify_hours()?
 244 <p>          <a href="http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php">http://archives.postgresql.org/pgsql-sql/2006-10/msg00059.php</a>
 245 </p>
 246     </li><li>Improve timestamptz subtraction to be DST-aware
 247 <p>          Currently subtracting one date from another that crosses a
 248           daylight savings time adjustment can return '1 day 1 hour', but
 249           adding that back to the first date returns a time one hour in
 250           the future.  This is caused by the adjustment of '25 hours' to
 251           '1 day 1 hour', and '1 day' is the same time the next day, even
 252           if daylight savings adjustments are involved.
 253 </p>
 254     </li><li>Fix interval display to support values exceeding 2^31 hours
 255     </li><li>Add overflow checking to timestamp and interval arithmetic
 256     </li><li>Extend timezone code to allow 64-bit values so we can
 257           represent years beyond 2038
 258 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01363.php</a>
 259 </p>
 260     </li><li>Use LC_TIME for localized weekday/month names, rather than
 261           LC_MESSAGES
 262 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00390.php</a>
 263 </p>
 264     </li><li>Add ISO INTERVAL handling
 265   </li></ul>
 266 </li></ul>
 267 <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/>
 268                   <a href="http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php">http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php</a>
 269 </p>
 270 <ul>
 271   <li>Support ISO INTERVAL syntax if units cannot be determined from
 272                   the string, and are supplied after the string
 273 <p>                  The SQL standard states that the units after the string
 274                   specify the units of the string, e.g. INTERVAL '2' MINUTE
 275                   should return '00:02:00'. The current behavior has the units
 276                   restrict the interval value to the specified unit or unit
 277                   range, INTERVAL '70' SECOND returns '00:00:10'.
 278 </p>
 279 <p>                  For syntax that isn't uniquely ISO or PG syntax, like '1' or
 280                   '1:30', treat as ISO if there is a range specification clause,
 281                   and as PG if there no clause is present, e.g. interpret '1:30'
 282                   MINUTE TO SECOND as '1 minute 30 seconds', and interpret
 283                   '1:30' as '1 hour, 30 minutes'.
 284 </p>
 285 <p>                  This makes common cases like SELECT INTERVAL '1' MONTH
 286                   SQL-standard results. The SQL standard supports a limited
 287                   number of unit combinations and doesn't support unit names in
 288                   the string. The PostgreSQL syntax is more flexible in the
 289                   range of units supported, e.g. PostgreSQL supports '1 year 1
 290                   hour', while the SQL standard does not.
 291 </p>
 292   </li><li>Add support for year-month syntax, INTERVAL '50-6' YEAR
 293                   TO MONTH
 294   </li><li>Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1
 295                   year' AS INTERVAL MONTH), and this should return '12 months'
 296   </li><li>Round or truncate values to the requested precision, e.g.
 297                   INTERVAL '11 months' AS YEAR should return one or zero
 298   </li><li>Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
 299   <ul>
 300     <li>Arrays
 301     <ul>
 302       <li>Delay resolution of array expression's data type so assignment
 303           coercion can be performed on empty array expressions
 304       </li><li>Add support for arrays of domains
 305 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00114.php</a>
 306 </p>
 307       </li><li>Allow single-byte header storage for array elements
 308     </li></ul>
 309     </li><li>Binary Data
 310     <ul>
 311       <li>Improve vacuum of large objects, like contrib/vacuumlo?
 312       </li><li>Add security checking for large objects
 313       </li><li>Auto-delete large objects when referencing row is deleted
 314 <p>          contrib/lo offers this functionality.
 315 </p>
 316       </li><li>Allow read/write into TOAST values like large objects
 317 <p>          This requires the TOAST column to be stored EXTERNAL.
 318 </p>
 319       </li><li>Add API for 64-bit large object access
 320 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00781.php</a>
 321 </p>
 322     </li></ul>
 323     </li><li>MONEY data type
 324     <ul>
 325       <li>Add locale-aware MONEY type, and support multiple currencies
 326 <p>          <a href="http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php">http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php</a>
 327           <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01181.php</a>
 328 </p>
 329       </li><li>MONEY dumps in a locale-specific format making it difficult to
 330           restore to a system with a different locale
 331       </li><li>Allow MONEY to be easily cast to/from other numeric data types
 332     </li></ul>
 333     </li><li>Text Search
 334     <ul>
 335       <li>Allow dictionaries to change the token that is passed on to
 336           later dictionaries
 337 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php">http://archives.postgresql.org/pgsql-patches/2007-11/msg00081.php</a>
 338 </p>
 339       </li><li>Consider a function-based API for '@@' searches
 340 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00511.php</a>
 341 </p>
 342       </li><li>Improve text search error messages
 343 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00966.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00966.php</a>
 344           <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01146.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01146.php</a>
 345 </p>
 346       </li><li>Consider changing error to warning for strings larger than one
 347           megabyte
 348 <p>          <a href="http://archives.postgresql.org/pgsql-bugs/2008-02/msg00190.php">http://archives.postgresql.org/pgsql-bugs/2008-02/msg00190.php</a>
 349           <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00062.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00062.php</a>
 350 </p>
 351     </li></ul>
 352   </li></ul>
 353 </li></ul>
 354 <h1><a name="section_4">Functions</a></h1>
 355
 356 <ul>
 357   <li>Allow INET subnet tests using non-constants to be indexed
 358   </li><li>Allow to_date() and to_timestamp() accept localized month names
 359   </li><li>Fix to_date()-related functions to consistently issue errors
 360 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00915.php</a>
 361 </p>
 362   </li><li>Add missing parameter handling in to_char()
 363 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg00948.php</a>
 364 </p>
 365   </li><li>Allow substring/replace() to get/set bit values
 366   </li><li>Allow to_char() on interval values to accumulate the highest unit
 367   requested
 368 <p>  Some special format flag would be required to request such
 369   accumulation.  Such functionality could also be added to EXTRACT.
 370   Prevent accumulation that crosses the month/day boundary because of
 371   the uneven number of days in a month.
 372 </p>
 373   <ul>
 374     <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') =&gt; 65
 375     </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) =&gt; 2600
 376     </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') =&gt; 0:1:19:20
 377     </li><li>to_char(INTERVAL '3 years 5 months','MM') =&gt; 41
 378   </li></ul>
 379   </li><li>Implement inlining of set-returning functions defined in SQL
 380   </li><li>Allow SQL-language functions to return results from RETURNING queries
 381 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00665.php</a>
 382 </p>
 383   </li><li>Allow SQL-language functions to reference parameters by parameter name
 384 <p>  Currently SQL-language functions can only refer to dollar parameters,
 385   e.g. $1
 386 </p>
 387   </li><li>Add SPI_gettypmod() to return the typemod for a TupleDesc
 388   </li><li>Enforce typmod for function inputs, function results and parameters for
 389   spi_prepare'd statements called from PLs
 390 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01403.php</a>
 391 </p>
 392   </li><li>Allow holdable cursors in SPI
 393   </li><li>Tighten function permission checks
 394 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00568.php</a>
 395 </p>
 396   </li><li>Fix IS OF so it matches the ISO specification, and add documentation
 397 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php">http://archives.postgresql.org/pgsql-patches/2003-08/msg00060.php</a>
 398   <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00060.php</a>
 399 </p>
 400   </li><li>Add missing operators for geometric data types
 401 <p>  Some geometric types do not have the full suite of geometric operators,
 402   e.g. box @&gt; point
 403 </p>
 404   </li><li>Implement Boyer-Moore searching in strpos()
 405 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php">http://archives.postgresql.org/pgsql-patches/2007-08/msg00012.php</a>
 406 </p>
 407   </li><li>Prevent malicious functions from being executed with the permissions
 408   of unsuspecting users
 409 <p>  Index functions are safe, so VACUUM and ANALYZE are safe too.
 410   Triggers, CHECK and DEFAULT expressions, and rules are still vulnerable.
 411   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php</a>
 412 </p>
 413   </li><li>Reduce memory usage of aggregates in set returning functions
 414 <p>  <a href="http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php">http://archives.postgresql.org/pgsql-performance/2008-01/msg00031.php</a>
 415 </p>
 416   </li><li>Add temporal versions of generate_series()
 417 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php</a>
 418 </p>
 419   </li><li>Add array_accum() and array_to_set() functions for arrays
 420 <p>  The standards specify array_agg() and UNNEST.
 421   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00464.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00464.php</a>
 422 </p>
 423   </li><li>Fix /contrib/ltree operator
 424 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-11/msg00044.php">http://archives.postgresql.org/pgsql-bugs/2007-11/msg00044.php</a>
 425 </p>
 426   </li><li>Fix inconsistent precedence of =, &gt;, and &lt; compared to &lt;&gt;, &gt;=, and &lt;=
 427 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00145.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00145.php</a>
 428 </p>
 429   </li><li>Fix regular expression bug when using complex back-references
 430 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00000.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00000.php</a>
 431 </p>
 432   </li><li>Have /contrib/dblink reuse unnamed connections
 433 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00895.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00895.php</a>
 434 </p>
 435   </li><li>Add SQL-standard array_agg() and unnest() array functions
 436 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01017.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01017.php</a>
 437 </p>
 438   </li><li>Allow calling of a procedure outside a SELECT that can control the
 439   transaction state
 440 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01375.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01375.php</a>
 441 </p>
 442 </li></ul>
 443 <h1><a name="section_5">Multi-Language Support</a></h1>
 444
 445 <ul>
 446   <li>Add NCHAR (as distinguished from ordinary varchar),
 447   </li><li>Allow locale to be set at database creation
 448 <p>  Currently locale can only be set during initdb.  No global tables have
 449   locale-aware columns.  However, the database template used during
 450   database creation might have locale-aware indexes.  The indexes would
 451   need to be reindexed to match the new locale.
 452 </p>
 453   </li><li>Allow encoding on a per-column basis optionally using the ICU library;
 454   Add CREATE COLLATE
 455 <p>  Right now only one encoding is allowed per database.
 456 </p>
 457 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php">http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php</a>
 458   <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php</a>
 459   <a href="http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php">http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php</a>
 460   <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php</a>
 461   <a href="http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php">http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php</a>
 462   <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php</a>
 463   <a href="http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php">http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php</a>
 464   <a href="http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php">http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php</a>
 465   <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php</a>
 466   <a href="http://wiki.postgresql.org/wiki/Todo:Collate">http://wiki.postgresql.org/wiki/Todo:Collate</a>
 467   <a href="http://wiki.postgresql.org/wiki/Todo:ICU">http://wiki.postgresql.org/wiki/Todo:ICU</a>
 468 </p>
 469   </li><li>Support multiple simultaneous character sets, per SQL92
 470   </li><li>Improve UTF8 combined character handling?
 471   </li><li>Add octet_length_server() and octet_length_client()
 472   </li><li>Make octet_length_client() the same as octet_length()?
 473   </li><li>Fix problems with wrong runtime encoding conversion for NLS message files
 474   </li><li>Add URL to more complete multi-byte regression tests
 475 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php">http://archives.postgresql.org/pgsql-hackers/2005-07/msg00272.php</a>
 476 </p>
 477   </li><li>Fix ILIKE and regular expressions to handle case insensitivity
 478   properly in multibyte encodings
 479 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php">http://archives.postgresql.org/pgsql-bugs/2005-10/msg00001.php</a>
 480   <a href="http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php">http://archives.postgresql.org/pgsql-patches/2005-11/msg00173.php</a>
 481 </p>
 482   </li><li>Set client encoding based on the client operating system encoding
 483 <p>  Currently client_encoding is set in postgresql.conf, which
 484   defaults to the server encoding.
 485   <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg01696.php</a>
 486 </p>
 487   </li><li>Change memory allocation for multi-byte functions so memory is
 488   allocated inside conversion functions
 489 <p>  Currently we preallocate memory based on worst-case usage.
 490 </p>
 491 </li></ul>
 492 <h1><a name="section_6">Views / Rules</a></h1>
 493
 494 <ul>
 495   <li>Automatically create rules on views so they are updateable, per SQL99
 496 <p>  We can only auto-create rules for simple views.  For more complex
 497   cases users will still have to write rules manually.
 498 </p>
 499 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php</a>
 500   <a href="http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php">http://archives.postgresql.org/pgsql-patches/2006-08/msg00255.php</a>
 501 </p>
 502   </li><li>Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
 503   </li><li>Allow VIEW/RULE recompilation when the underlying tables change
 504 <p>  Another issue is whether underlying table changes should be reflected
 505   in the view, e.g. should SELECT * show additional columns if they
 506   are added after the view is created.
 507 </p>
 508   </li><li>Make it possible to use RETURNING together with conditional DO INSTEAD
 509   rules, such as for partitioning setups
 510 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00577.php</a>
 511 </p>
 512   </li><li>Add the ability to automatically create materialized views
 513 <p>  Right now materialized views require the user to create triggers on the
 514   main table to keep the summary table current.  SQL syntax should be able
 515   to manager the triggers and summary table automatically.  A more
 516   sophisticated implementation would automatically retrieve from the
 517   summary table when the main table is referenced, if possible.
 518 </p>
 519 </li></ul>
 520 <h1><a name="section_7">SQL Commands</a></h1>
 521
 522 <ul>
 523   <li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
 524   </li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
 525   </li><li>%Allow SET CONSTRAINTS to be qualified by schema/table name
 526   </li><li>%Add a separate TRUNCATE permission
 527 <p>  Currently only the owner can TRUNCATE a table because triggers are not
 528   called, and the table is locked in exclusive mode.
 529 </p>
 530   </li><li>Allow PREPARE of cursors
 531   </li><li>Allow finer control over the caching of prepared query plans
 532 <p>  Currently queries prepared via the libpq API are planned on first
 533   execute using the supplied parameters --- allow SQL PREPARE to do the
 534   same.  Also, allow control over replanning prepared queries either
 535   manually or automatically when statistics for execute parameters
 536   differ dramatically from those used during planning.
 537 </p>
 538   </li><li>Improve logging of prepared transactions recovered during startup
 539 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php</a>
 540 </p>
 541   </li><li>Improve failure message when DROP DATABASE is used on a database that
 542   has prepared transactions
 543   </li><li>Allow prepared transactions with temporary tables created and dropped
 544   in the same transaction, and when an ON COMMIT DELETE ROWS temporary
 545   table is accessed
 546 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00047.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00047.php</a>
 547 </p>
 548   </li><li>Add a GUC variable to warn about non-standard SQL usage in queries
 549   </li><li>Add SQL-standard MERGE/REPLACE/UPSERT command
 550 <p>  MERGE is typically used to merge two tables.  REPLACE or UPSERT
 551   command does UPDATE, or on failure, INSERT. This is similar to UPDATE,
 552   then for unmatched rows, INSERT.  Whether concurrent access allows
 553   modifications which could cause row loss is implementation independent.
 554   To implement this cleanly requires that the table have a unique index
 555   so duplicate checking can be easily performed.  It is possible to do it
 556   without a unique index if we require the user to LOCK the table before
 557   the MERGE.
 558 </p>
 559 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php</a>
 560   <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php</a>
 561   <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01475.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01475.php</a>
 562 </p>
 563   </li><li>Add NOVICE output level for helpful messages like automatic sequence/index
 564   creation
 565   </li><li>Add GUC to issue notice about statements that use unjoined tables
 566   </li><li>Allow EXPLAIN to identify tables that were skipped because of
 567   constraint_exclusion
 568   </li><li>Allow EXPLAIN output to be more easily processed by scripts, perhaps XML
 569   </li><li>Enable standard_conforming_strings
 570   </li><li>Make standard_conforming_strings the default in 8.5?
 571 <p>  When this is done, backslash-quote should be prohibited in non-E''
 572   strings because of possible confusion over how such strings treat
 573   backslashes.  Basically, '' is always safe for a literal single
 574   quote, while \' might or might not be based on the backslash
 575   handling rules.
 576 </p>
 577   </li><li>Simplify dropping roles that have objects in several databases
 578   </li><li>Allow COMMENT ON to accept an expression rather than just a string
 579   </li><li>Allow the count returned by SELECT, etc to be represented as an int64
 580   to allow a higher range of values
 581   </li><li>Add SQL99 WITH clause to SELECT
 582   </li><li>Add SQL:2003 WITH RECURSIVE (hierarchical) queries to SELECT
 583 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01375.php</a>
 584   <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00642.php</a>
 585   <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00139.php</a>
 586   <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01334.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01334.php</a>
 587   <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00105.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00105.php</a>
 588   <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00327.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00327.php</a>
 589 </p>
 590   </li><li>Add DEFAULT .. AS OWNER so permission checks are done as the table
 591   owner
 592 <p>  This would be useful for SERIAL nextval() calls and CHECK constraints.
 593 </p>
 594   </li><li>Allow DISTINCT to work in multiple-argument aggregate calls
 595   </li><li>Add column to pg_stat_activity that shows the progress of long-running
 596   commands like CREATE INDEX and VACUUM
 597   </li><li>Implement SQL:2003 window functions
 598   </li><li>Allow INSERT/UPDATE ... RETURNING inside a SELECT 'FROM' clause
 599 <p>  <a href="http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php">http://archives.postgresql.org/pgsql-general/2006-09/msg00803.php</a>
 600   <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00693.php</a>
 601 </p>
 602   </li><li>Increase locking when DROPing objects so dependent objects cannot
 603   get dropped while the DROP operation is happening
 604 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00937.php</a>
 605 </p>
 606   </li><li>-<em>Allow AS in "SELECT col AS label" to be optional in certain cases</em>
 607   </li><li>Allow INSERT ... DELETE ... RETURNING, namely allow the DELETE ...
 608   RETURNING to supply values to the INSERT
 609   <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>
 610   </li><li>Add comments on system tables/columns using the information in
 611   catalogs.sgml
 612 <p>  Ideally the information would be pulled from the SGML file
 613   automatically.
 614 </p>
 615   </li><li>Improve reporting of UNION type mismatches
 616 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00944.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00944.php</a>
 617   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00597.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00597.php</a>
 618 </p>
 619   </li><li>CREATE
 620   <ul>
 621     <li>Allow CREATE TABLE AS to determine column lengths for complex
 622           expressions like SELECT col1 || col2
 623     </li><li>Have WITH CONSTRAINTS also create constraint indexes
 624 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00149.php</a>
 625 </p>
 626     </li><li>Have CONSTRAINT cname NOT NULL record the contraint name
 627 <p>          Right now pg_attribute.attnotnull records the NOT NULL status
 628           of the column, but does not record the contraint name
 629 </p>
 630     </li><li>Prevent concurrent CREATE TABLE table1 from sometimes returning
 631           a cryptic error message
 632 <p>          <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00169.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00169.php</a>
 633 </p>
 634     </li><li>Add CREATE SCHEMA ... LIKE that copies a schema
 635   </li></ul>
 636   </li><li>UPDATE
 637   <ul>
 638     <li>Allow UPDATE tab SET ROW (col, ...) = (SELECT...)
 639 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php">http://archives.postgresql.org/pgsql-hackers/2006-07/msg01306.php</a>
 640           <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00865.php</a>
 641           <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00315.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00315.php</a>
 642           <a href="http://archives.postgresql.org/pgsql-patches/2008-03/msg00237.php">http://archives.postgresql.org/pgsql-patches/2008-03/msg00237.php</a>
 643 </p>
 644     </li><li>Research self-referential UPDATEs that see inconsistent row versions
 645           in read-committed mode
 646 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php</a>
 647           <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php</a>
 648 </p>
 649     </li><li>Allow GLOBAL temporary tables to exist as empty by default in
 650           all sessions
 651 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00006.php</a>
 652 </p>
 653   </li></ul>
 654   </li><li>ALTER
 655   <ul>
 656     <li>Have ALTER TABLE RENAME rename SERIAL sequence names
 657 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
 658 </p>
 659     </li><li>Have ALTER SEQUENCE RENAME rename the sequence name stored
 660           in the sequence table
 661 <p>          <a href="http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php">http://archives.postgresql.org/pgsql-bugs/2007-09/msg00092.php</a>
 662           <a href="http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php">http://archives.postgresql.org/pgsql-bugs/2007-10/msg00007.php</a>
 663           <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00008.php</a>
 664 </p>
 665     </li><li>Add ALTER DOMAIN to modify the underlying data type
 666     </li><li>%Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
 667 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00168.php</a>
 668 </p>
 669     </li><li>%Allow ALTER TABLE to change constraint deferrability and actions
 670     </li><li>Add missing object types for ALTER ... SET SCHEMA
 671     </li><li>Allow ALTER TABLESPACE to move to different directories
 672     </li><li>Allow databases to be moved to different tablespaces
 673     </li><li>Allow moving system tables to other tablespaces, where possible
 674 <p>          Currently non-global system tables must be in the default database
 675           tablespace. Global system tables can never be moved.
 676 </p>
 677     </li><li>-<em>Prevent parent tables from altering or dropping constraints</em>
 678           like CHECK that are inherited by child tables unless CASCADE
 679           is used
 680     </li><li>-<em>Prevent child tables from altering or dropping constraints</em>
 681           like CHECK that were inherited from the parent table
 682     </li><li>Have ALTER INDEX update the name of a constraint using that index
 683     </li><li>Add ALTER TABLE RENAME CONSTRAINT, update index name also
 684     </li><li>Allow column display reordering by recording a display,
 685           storage, and permanent id for every column?
 686 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00782.php</a>
 687 </p>
 688   </li></ul>
 689   </li><li>CLUSTER
 690   <ul>
 691     <li>Automatically maintain clustering on a table
 692 <p>          This might require some background daemon to maintain clustering
 693           during periods of low usage. It might also require tables to be only
 694           partially filled for easier reorganization.  Another idea would
 695           be to create a merged heap/index data file so an index lookup would
 696           automatically access the heap data too.  A third idea would be to
 697           store heap rows in hashed groups, perhaps using a user-supplied
 698           hash function.
 699           <a href="http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php">http://archives.postgresql.org/pgsql-performance/2004-08/msg00349.php</a>
 700 </p>
 701     </li><li>%Add default clustering to system tables
 702 <p>          To do this, determine the ideal cluster index for each system
 703           table and set the cluster setting during initdb.
 704 </p>
 705     </li><li>%Add VERBOSE option to report tables as they are processed,
 706           like VACUUM VERBOSE
 707   </li></ul>
 708   </li><li>COPY
 709   <ul>
 710     <li>Allow COPY to report error lines and continue
 711 <p>          This requires the use of a savepoint before each COPY line is
 712           processed, with ROLLBACK on COPY failure.
 713           <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00572.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00572.php</a>
 714 </p>
 715     </li><li>Allow COPY on a newly-created table to skip WAL logging
 716 <p>          On crash recovery, the table involved in the COPY would
 717           be removed or have its heap and index files truncated.  One
 718           issue is that no other backend should be able to add to
 719           the table at the same time, which is something that is
 720           currently allowed.  This currently is done if the table is
 721           created inside the same transaction block as the COPY because
 722           no other backends can see the table.
 723 </p>
 724     </li><li>Consider using a ring buffer for COPY FROM
 725 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00140.php</a>
 726           <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01080.php</a>
 727 </p>
 728     </li><li>Allow COPY FROM to create index entries in bulk
 729 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00811.php</a>
 730 </p>
 731     </li><li>Allow COPY in CSV mode to control whether a quoted zero-length
 732           string is treated as NULL
 733 <p>          Currently this is always treated as a zero-length string,
 734           which generates an error when loading into an integer column
 735           <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00905.php</a>
 736 </p>
 737     </li><li>Impove COPY performance
 738 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00954.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00954.php</a>
 739 </p>
 740   </li></ul>
 741   </li><li>GRANT/REVOKE
 742   <ul>
 743     <li>Allow column-level privileges
 744     </li><li>%Allow GRANT/REVOKE permissions to be applied to all schema objects
 745           with one command
 746 <p>          The proposed syntax is:
 747 </p><p>                GRANT SELECT ON ALL TABLES IN public TO phpuser;
 748                 GRANT SELECT ON NEW TABLES IN public TO phpuser;
 749 </p>
 750     </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on
 751           schema permissions
 752     </li><li>Allow SERIAL sequences to inherit permissions from the base table?
 753   </li></ul>
 754   </li><li>CURSOR
 755   <ul>
 756     <li>Prevent DROP TABLE from dropping a row referenced by its own open
 757           cursor?
 758   </li></ul>
 759   </li><li>INSERT
 760   <ul>
 761     <li>Allow INSERT/UPDATE of the system-generated oid value for a row
 762     </li><li>In rules, allow VALUES() to contain a mixture of 'old' and 'new'
 763           references
 764   </li></ul>
 765   </li><li>SHOW/SET
 766   <ul>
 767     <li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
 768           ANALYZE, and CLUSTER
 769   </li></ul>
 770   </li><li>LISTEN/NOTIFY
 771   <ul>
 772     <li>Allow LISTEN/NOTIFY to store info in memory rather than tables?
 773 <p>          Currently LISTEN/NOTIFY information is stored in pg_listener.
 774           Storing such information in memory would improve performance.
 775 </p>
 776     </li><li>Add optional textual message to NOTIFY
 777 <p>          This would allow an informational message to be added to the notify
 778           message, perhaps indicating the row modified or other custom
 779           information.
 780 </p>
 781     </li><li>Allow multiple identical NOTIFY events to always be communicated
 782           to the client, rather than sent as a single notification to the
 783           listener
 784 <p>          <a href="http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php">http://archives.postgresql.org/pgsql-general/2008-01/msg00057.php</a>
 785 </p>
 786     </li><li>Allow NOTIFY in rules involving conditionals
 787     </li><li>Improve LISTEN concurrency
 788 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01106.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01106.php</a>
 789 </p>
 790   </li></ul>
 791 </li></ul>
 792 <h1><a name="section_8">Referential Integrity</a></h1>
 793
 794 <ul>
 795   <li>Add MATCH PARTIAL referential integrity
 796   </li><li>Change foreign key constraint for array -&gt; element to mean element
 797   in array?
 798   </li><li>Fix problem when cascading referential triggers make changes on
 799   cascaded tables, seeing the tables in an intermediate state
 800 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
 801   <a href="http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php">http://archives.postgresql.org/pgsql-hackers/2005-09/msg00174.php</a>
 802 </p>
 803   </li><li>Allow DEFERRABLE and end-of-statement UNIQUE constraints?
 804 <p>  This would allow UPDATE tab SET col = col + 1 to work if col has
 805   a unique index.  Currently, uniqueness checks are done while the
 806   command is being executed, rather than at the end of the statement
 807   or transaction.
 808   <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>
 809   <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01458.php</a>
 810 </p>
 811   </li><li>Optimize referential integrity checks
 812 <p>  <a href="http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php">http://archives.postgresql.org/pgsql-performance/2005-10/msg00458.php</a>
 813   <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00744.php</a>
 814 </p>
 815 </li></ul>
 816 <h1><a name="section_9">Server-Side Languages</a></h1>
 817
 818 <ul>
 819   <li>PL/pgSQL
 820   <ul>
 821     <li>Fix RENAME to work on variables other than OLD/NEW
 822 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php">http://archives.postgresql.org/pgsql-hackers/2002-03/msg00591.php</a>
 823           <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01615.php</a>
 824           <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg01587.php</a>
 825 </p>
 826     </li><li>Allow function parameters to be passed by name,
 827           get_employee_salary(12345 AS emp_id, 2001 AS tax_year)
 828     </li><li>Allow handling of %TYPE arrays, e.g. tab.col%TYPE[]
 829     </li><li>Allow listing of record column names, and access to
 830           record columns via variables, e.g. columns := r.(*),
 831           tval2 := r.(colname)
 832 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00458.php</a>
 833           <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00302.php</a>
 834           <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00031.php</a>
 835 </p>
 836     </li><li>Add support for SCROLL cursors
 837     </li><li>Add support for WITH HOLD cursors
 838     </li><li>Allow row and record variables to be set to NULL constants,
 839           and allow NULL tests on such variables
 840 <p>          Because a row is not scalar, do not allow assignment
 841           from NULL-valued scalars.
 842 </p>
 843 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00070.php</a>
 844 </p>
 845     </li><li>Review handling of MOVE and FETCH
 846 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00527.php</a>
 847 </p>
 848     </li><li>Improve logic of determining if an identifier is a a
 849           variable or column name
 850 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php</a>
 851 </p>
 852     </li><li>Consider keeping seperate cached copies when search_path changes
 853 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01009.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01009.php</a>
 854 </p>
 855     </li><li>Add CASE capability to language (already in SQL)
 856 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00696.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00696.php</a>
 857 </p>
 858   </li></ul>
 859   </li><li>Other
 860   <ul>
 861     <li>Add table function support to pltcl, plpythonu
 862     </li><li>Add support for polymorphic arguments and return types to
 863           languages other than PL/PgSQL
 864     </li><li>Add capability to create and call PROCEDURES
 865     </li><li>Add support for OUT and INOUT parameters to languages other
 866           than PL/PgSQL
 867     </li><li>Add PL/PythonU tracebacks
 868 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php">http://archives.postgresql.org/pgsql-patches/2006-02/msg00288.php</a>
 869 </p>
 870     </li><li>Allow data to be passed in native language formats, rather
 871           than only text
 872 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00289.php</a>
 873 </p>
 874     </li><li>Add ability to obfuscate function bodies
 875 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00125.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00125.php</a>
 876 </p>
 877   </li></ul>
 878 </li></ul>
 879 <h1><a name="section_10">Clients</a></h1>
 880
 881 <ul>
 882   <li>Have pg_ctl look at PGHOST in case it is a socket directory?
 883   </li><li>Allow pg_ctl to work properly with configuration files located outside
 884   the PGDATA directory
 885 <p>  pg_ctl can not read the pid file because it isn't located in the
 886   config directory but in the PGDATA directory.  The solution is to
 887   allow pg_ctl to read and understand postgresql.conf to find the
 888   data_directory value.
 889 </p>
 890   </li><li>Add a function like pg_get_indexdef() that report more detailed index
 891   information
 892 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php">http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php</a>
 893 </p>
 894   </li><li>psql
 895   <ul>
 896     <li>Have psql show current values for a sequence
 897     </li><li>Move psql backslash database information into the backend, use
 898           mnemonic commands?
 899 <p>          This would allow non-psql clients to pull the same information out
 900           of the database as psql.
 901           <a href="http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php">http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php</a>
 902 </p>
 903     </li><li>Make psql's \d commands more consistent
 904 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
 905           <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php</a>
 906 </p>
 907     </li><li>Consistently display privilege information for all objects in psql
 908     </li><li>Add auto-expanded mode so expanded output is used if the row
 909           length is wider than the screen width.
 910 <p>          Consider using auto-expanded mode for backslash commands like \df+.
 911 </p>
 912     </li><li>Prevent tab completion of SET TRANSACTION from querying the
 913           database and therefore preventing the transaction isolation
 914           level from being set.
 915 <p>          Currently SET &lt;tab&gt; causes a database lookup to check all
 916           supported session variables.  This query causes problems
 917           because setting the transaction isolation level must be the
 918           first statement of a transaction.
 919 </p>
 920     </li><li>Add a \set variable to control whether \s displays line numbers
 921 <p>          Another option is to add \# which lists line numbers, and
 922           allows command execution.
 923 </p>
 924 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00255.php</a>
 925 </p>
 926     </li><li>Prevent escape string warnings when object names have
 927           backslashes
 928 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00227.php</a>
 929 </p>
 930     </li><li>Have \d show foreign keys that reference a table's primary key
 931 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php</a>
 932 </p>
 933     </li><li>Have \d show child tables that inherit from the specified parent
 934     </li><li>Have \l+ show database size, if permissions allow
 935 <p>          Ideally it will not generate an error for invalid permissions
 936 </p>
 937     </li><li>Include the symbolic SQLSTATE name in verbose error reports
 938 <p>          <a href="http://archives.postgresql.org/pgsql-general/2007-09/msg00438.php">http://archives.postgresql.org/pgsql-general/2007-09/msg00438.php</a>
 939 </p>
 940     </li><li>-<em>Improve display of enums to show valid enum values</em>
 941     </li><li>Add prompt escape to display the client and server versions
 942   </li></ul>
 943   </li><li>pg_dump / pg_restore
 944   <ul>
 945     <li>%Add dumping of comments on index columns and composite type columns
 946     </li><li>%Add full object name to the tag field.  eg. for operators we need
 947           '=(integer, integer)', instead of just '='.
 948     </li><li>Add pg_dumpall custom format dumps?
 949     </li><li>Allow selection of individual object(s) of all types, not just
 950           tables
 951     </li><li>In a selective dump, allow dumping of an object and all its
 952           dependencies
 953     </li><li>Add options like pg_restore -l and -L to pg_dump
 954     </li><li>Stop dumping CASCADE on DROP TYPE commands in clean mode
 955     </li><li>Allow pg_dump --clean to drop roles that own objects or have
 956           privileges
 957     </li><li>Change pg_dump so that a comment on the dumped database is
 958           applied to the loaded database, even if the database has a
 959           different name.  This will require new backend syntax, perhaps
 960           COMMENT ON CURRENT DATABASE.
 961     </li><li>Remove unnecessary function pointer abstractions in pg_dump source
 962           code
 963     </li><li>Allow pg_dump to utilize multiple CPUs and I/O channels by dumping
 964           multiple objects simultaneously
 965 <p>          The difficulty with this is getting multiple dump processes to
 966           produce a single dump output file.  It also would require
 967           several sessions to share the same snapshot.
 968           <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php</a>
 969 </p>
 970     </li><li>Allow pg_restore to utilize multiple CPUs and I/O channels by
 971           restoring multiple objects simultaneously
 972 <p>          This might require a pg_restore flag to indicate how many
 973           simultaneous operations should be performed.  Only pg_dump's
 974           -Fc format has the necessary dependency information.
 975           <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00963.php</a>
 976 </p>
 977     </li><li>To better utilize resources, allow pg_restore to check foreign
 978           keys simultaneously, where possible
 979     </li><li>Allow pg_restore to create all indexes of a table
 980           concurrently, via a single heap scan
 981 <p>          This requires a pg_dump -Fc file because that format contains
 982           the required dependency information.
 983           <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01274.php</a>
 984 </p>
 985     </li><li>Allow pg_restore to load different parts of the COPY data
 986           simultaneously
 987     </li><li>Prevent pg_dump/pg_restore from being affected by
 988           statement_timeout
 989 <p>          Using psql to restore a pg_dump dump is also affected.
 990 </p>
 991     </li><li>Remove pre-7.3 pg_dump code that assumes pg_depend does not exit
 992     </li><li>Allow pre/data/post files when schema and data are dumped
 993           separately, for performance reasons
 994 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00205.php</a>
 995 </p>
 996   </li></ul>
 997   </li><li>ecpg
 998   <ul>
 999     <li>Docs
1000 <p>          Document differences between ecpg and the SQL standard and
1001           information about the Informix-compatibility module.
1002 </p>
1003     </li><li>Solve cardinality &gt; 1 for input descriptors / variables?
1004     </li><li>Add a semantic check level, e.g. check if a table really exists
1005     </li><li>fix handling of DB attributes that are arrays
1006     </li><li>Use backend PREPARE/EXECUTE facility for ecpg where possible
1007     </li><li>Implement SQLDA
1008     </li><li>Fix nested C comments
1009     </li><li>%sqlwarn[6] should be 'W' if the PRECISION or SCALE value specified
1010     </li><li>Make SET CONNECTION thread-aware, non-standard?
1011     </li><li>Allow multidimensional arrays
1012     </li><li>Add internationalized message strings
1013     </li><li>Implement COPY FROM STDIN
1014   </li></ul>
1015   </li><li>libpq
1016   <ul>
1017     <li>Add PQescapeIdentifierConn()
1018     </li><li>Prevent PQfnumber() from lowercasing unquoted the column name
1019 <p>          PQfnumber() should never have been doing lowercasing, but
1020           historically it has so we need a way to prevent it
1021 </p>
1022     </li><li>Allow statement results to be automatically batched to the client
1023 <p>          Currently all statement results are transferred to the libpq
1024           client before libpq makes the results available to the
1025           application.  This feature would allow the application to make
1026           use of the first result rows while the rest are transferred, or
1027           held on the server waiting for them to be requested by libpq.
1028           One complexity is that a statement like SELECT 1/col could error
1029           out mid-way through the result set.
1030 </p>
1031     </li><li>Consider disallowing multiple queries in PQexec() as an
1032           additional barrier to SQL injection attacks
1033 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00184.php</a>
1034 </p>
1035     </li><li>Add PQexecf() that allows complex parameter substitution
1036 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01803.php</a>
1037 </p>
1038     </li><li>Add SQLSTATE severity to PGconn return status
1039 <p>          <a href="http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php">http://archives.postgresql.org/pgsql-interfaces/2007-11/msg00015.php</a>
1040 </p>
1041   </li></ul>
1042 </li></ul>
1043 <h1><a name="section_11">Triggers</a></h1>
1044
1045 <ul>
1046   <li>Add deferred trigger queue file
1047 <p>  Right now all deferred trigger information is stored in backend
1048   memory.  This could exhaust memory for very large trigger queues.
1049   This item involves dumping large queues into files.
1050 </p>
1051   </li><li>Allow triggers to be disabled in only the current session.
1052 <p>  This is currently possible by starting a multi-statement transaction,
1053   modifying the system tables, performing the desired SQL, restoring the
1054   system tables, and committing the transaction.  ALTER TABLE ...
1055   TRIGGER requires a table lock so it is not ideal for this usage.
1056 </p>
1057   </li><li>With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
1058 <p>  If the dump is known to be valid, allow foreign keys to be added
1059   without revalidating the data.
1060 </p>
1061   </li><li>Allow statement-level triggers to access modified rows
1062   </li><li>Support triggers on columns
1063 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00107.php</a>
1064 </p>
1065   </li><li>Allow AFTER triggers on system tables
1066 <p>  System tables are modified in many places in the backend without going
1067   through the executor and therefore not causing triggers to fire. To
1068   complete this item, the functions that modify system tables will have
1069   to fire triggers.
1070 </p>
1071   </li><li>Tighten trigger permission checks
1072 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00564.php</a>
1073 </p>
1074   </li><li>Allow BEFORE INSERT triggers on views
1075 <p>  <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php">http://archives.postgresql.org/pgsql-general/2007-02/msg01466.php</a>
1076 </p>
1077   </li><li>-<em>Add ability to trigger on TRUNCATE</em>
1078   </li><li>Add database and transaction-level triggers
1079 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00451.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00451.php</a>
1080 </p>
1081 </li></ul>
1082 <h1><a name="section_12">Indexes</a></h1>
1083
1084 <ul>
1085   <li>Add UNIQUE capability to non-btree indexes
1086   </li><li>Prevent index uniqueness checks when UPDATE does not modify the column
1087 <p>  Uniqueness (index) checks are done when updating a column even if the
1088   column is not modified by the UPDATE.
1089 </p>
1090   </li><li>Allow the creation of on-disk bitmap indexes which can be quickly
1091   combined with other bitmap indexes
1092 <p>  Such indexes could be more compact if there are only a few distinct values.
1093   Such indexes can also be compressed.  Keeping such indexes updated can be
1094   costly.
1095 </p>
1096 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php">http://archives.postgresql.org/pgsql-patches/2005-07/msg00512.php</a>
1097   <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01107.php</a>
1098   <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00265.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00265.php</a>
1099   <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01214.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01214.php</a>
1100   <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00013.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00013.php</a>
1101   <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00741.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00741.php</a>
1102 </p>
1103   </li><li>Allow accurate statistics to be collected on indexes with more than
1104   one column or expression indexes, perhaps using per-index statistics
1105 <p>  <a href="http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php">http://archives.postgresql.org/pgsql-performance/2006-10/msg00222.php</a>
1106   <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01131.php</a>
1107 </p>
1108   </li><li>Consider increasing the default and maximum number of statistics targets,
1109   and reduce statistics target overhead
1110 <p>  Also consider having a larger statistics target for indexed columns
1111   and expression indexes.
1112   <a href="http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php">http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php</a>
1113   <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php">http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php</a>
1114   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01066.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01066.php</a>
1115   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00188.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00188.php</a>
1116 </p>
1117   </li><li>Consider smaller indexes that record a range of values per heap page,
1118   rather than having one index entry for every heap row
1119 <p>  This is useful if the heap is clustered by the indexed values.
1120   <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php</a>
1121   <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php</a>
1122   <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php</a>
1123   <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00163.php</a>
1124   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00014.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00014.php</a>
1125   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00487.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00487.php</a>
1126   <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01589.php</a>
1127 </p>
1128   </li><li>Add REINDEX CONCURRENTLY, like CREATE INDEX CONCURRENTLY
1129 <p>  This is difficult because you must upgrade to an exclusive table lock
1130   to replace the existing index file.  CREATE INDEX CONCURRENTLY does not
1131   have this complication.  This would allow index compaction without
1132   downtime.
1133   <a href="http://archives.postgresql.org/pgsql-performance/2007-08/msg00289.php">http://archives.postgresql.org/pgsql-performance/2007-08/msg00289.php</a>
1134 </p>
1135   </li><li>Allow multiple indexes to be created concurrently, ideally via a
1136   single heap scan, and have pg_restore use it
1137   </li><li>Consider sorting entries before inserting into btree index
1138 <p>  <a href="http://archives.postgresql.org/pgsql-general/2008-01/msg01010.php">http://archives.postgresql.org/pgsql-general/2008-01/msg01010.php</a>
1139 </p>
1140   </li><li>Allow index scans to return matching index keys, not just the matching
1141   heap locations
1142 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg01657.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg01657.php</a>
1143 </p>
1144   </li><li>Inheritance
1145   <ul>
1146     <li>Allow inherited tables to inherit indexes, UNIQUE constraints,
1147           and primary/foreign keys
1148     </li><li>Honor UNIQUE INDEX on base column in INSERTs/UPDATEs
1149           on inherited table, e.g.  INSERT INTO inherit_table
1150           (unique_index_col) VALUES (dup) should fail
1151 <p>          The main difficulty with this item is the problem of
1152           creating an index that can span multiple tables.
1153 </p>
1154     </li><li>Allow SELECT ... FOR UPDATE on inherited tables
1155     </li><li>Require all CHECK constraints to be inherited
1156 <p>          <a href="http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php">http://archives.postgresql.org/pgsql-bugs/2007-04/msg00026.php</a>
1157 </p>
1158     </li><li>Add checks to prevent a CREATE RULE views on inherited tables
1159 <p>          <a href="http://archives.postgresql.org/pgsql-general/2008-02/msg01420.php">http://archives.postgresql.org/pgsql-general/2008-02/msg01420.php</a>
1160           <a href="http://archives.postgresql.org/pgsql-general/2008-03/msg00077.php">http://archives.postgresql.org/pgsql-general/2008-03/msg00077.php</a>
1161 </p>
1162   </li></ul>
1163   </li><li>GIST
1164   <ul>
1165     <li>Add more GIST index support for geometric data types
1166     </li><li>Allow GIST indexes to create certain complex index types, like
1167           digital trees (see Aoki)
1168   </li></ul>
1169   </li><li>Hash
1170 </li></ul>
1171 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php</a>
1172 </p>
1173 <ul>
1174   <li>Pack hash index buckets onto disk pages more efficiently
1175 <p>          Currently only one hash bucket can be stored on a page. Ideally
1176           several hash buckets could be stored on a single page and greater
1177           granularity used for the hash algorithm.
1178 </p>
1179 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php">http://archives.postgresql.org/pgsql-hackers/2004-06/msg00168.php</a>
1180 </p>
1181   </li><li>Consider sorting hash buckets so entries can be found using a
1182           binary search, rather than a linear scan
1183   </li><li>In hash indexes, consider storing the hash value with or instead
1184           of the key itself
1185   </li><li>Add WAL logging for crash recovery
1186   </li><li>Allow multi-column hash indexes
1187   </li><li>-<em>During index creation, pre-sort the tuples to improve build speed</em>
1188 </li></ul>
1189 <h1><a name="section_13">Fsync</a></h1>
1190
1191 <ul>
1192   <li>Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
1193 <p>  Ideally this requires a separate test program that can be run
1194   at initdb time or optionally later.  Consider O_SYNC when
1195   O_DIRECT exists.
1196 </p>
1197   </li><li>Add program to test if fsync has a delay compared to non-fsync
1198   </li><li>Consider sorting writes during checkpoint
1199 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg00541.php</a>
1200 </p>
1201 </li></ul>
1202 <h1><a name="section_14">Cache Usage</a></h1>
1203
1204 <ul>
1205   <li>Speed up COUNT(*)
1206 <p>  We could use a fixed row count and a +/- count to follow MVCC
1207   visibility rules, or a single cached value could be used and
1208   invalidated if anyone modifies the table.  Another idea is to
1209   get a count directly from a unique index, but for this to be
1210   faster than a sequential scan it must avoid access to the heap
1211   to obtain tuple visibility information.
1212 </p>
1213   </li><li>Provide a way to calculate an "estimated COUNT(*)"
1214 <p>  Perhaps by using the optimizer's cardinality estimates or random
1215   sampling.
1216 </p>
1217 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php">http://archives.postgresql.org/pgsql-hackers/2005-11/msg00943.php</a>
1218 </p>
1219   </li><li>Allow data to be pulled directly from indexes
1220 <p>  Currently indexes do not have enough tuple visibility information
1221   to allow data to be pulled from the index without also accessing
1222   the heap.  One way to allow this is to set a bit on index tuples
1223   to indicate if a tuple is currently visible to all transactions
1224   when the first valid heap lookup happens.  This bit would have to
1225   be cleared when a heap tuple is expired.
1226 </p>
1227 <p>  Another idea is to maintain a bitmap of heap pages where all rows
1228   are visible to all backends, and allow index lookups to reference
1229   that bitmap to avoid heap lookups, perhaps the same bitmap we might
1230   add someday to determine which heap pages need vacuuming.  Frequently
1231   accessed bitmaps would have to be stored in shared memory.  One 8k
1232   page of bitmaps could track 512MB of heap pages.
1233 </p>
1234 <p>  A third idea would be for a heap scan to check if all rows are visible
1235   and if so set a per-table flag which can be checked by index scans.
1236   Any change to the table would have to clear the flag.  To detect
1237   changes during the heap scan a counter could be set at the start and
1238   checked at the end --- if it is the same, the table has not been
1239   modified --- any table change would increment the counter.
1240 </p>
1241 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-10/msg00166.php">http://archives.postgresql.org/pgsql-patches/2007-10/msg00166.php</a>
1242   <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00049.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00049.php</a>
1243 </p>
1244   </li><li>Consider automatic caching of statements at various levels:
1245   <ul>
1246     <li>Parsed query tree
1247     </li><li>Query execute plan
1248     </li><li>Query results
1249         <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00823.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00823.php</a>
1250   </li></ul>
1251   </li><li>Consider increasing internal areas when shared buffers is increased
1252 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php">http://archives.postgresql.org/pgsql-hackers/2005-10/msg01419.php</a>
1253 </p>
1254   </li><li>Consider decreasing the amount of memory used by PrivateRefCount
1255 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00797.php</a>
1256   <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00752.php</a>
1257 </p>
1258   </li><li>Consider allowing higher priority queries to have referenced buffer
1259   cache pages stay in memory longer
1260 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00562.php</a>
1261 </p>
1262 </li></ul>
1263 <h1><a name="section_15">Vacuum</a></h1>
1264
1265 <ul>
1266   <li>Improve speed with indexes
1267 <p>  For large table adjustments during VACUUM FULL, it is faster to cluster
1268   or reindex rather than update the index.  Also, index updates can bloat
1269   the index.
1270 </p>
1271 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg00024.php</a>
1272   <a href="http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php">http://archives.postgresql.org/pgsql-performance/2007-05/msg00296.php</a>
1273   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00307.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00307.php</a>
1274 </p>
1275   </li><li>Auto-fill the free space map by scanning the buffer cache or by
1276   checking pages written by the background writer
1277 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php">http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php</a>
1278   <a href="http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php">http://archives.postgresql.org/pgsql-hackers/2006-03/msg00011.php</a>
1279 </p>
1280   </li><li>Create a bitmap of pages that need vacuuming
1281 <p>  Instead of sequentially scanning the entire table, have the background
1282   writer or some other process record pages that have expired rows, then
1283   VACUUM can look at just those pages rather than the entire table.  In
1284   the event of a system crash, the bitmap would probably be invalidated.
1285   One complexity is that index entries still have to be vacuumed, and
1286   doing this without an index scan (by using the heap values to find the
1287   index entry) might be slow and unreliable, especially for user-defined
1288   index functions.
1289 </p>
1290 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01188.php</a>
1291   <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00121.php</a>
1292   <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00508.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00508.php</a>
1293   <a href="http://archives.postgresql.org/pgsql-patches/2007-04/msg00347.php">http://archives.postgresql.org/pgsql-patches/2007-04/msg00347.php</a>
1294   <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00156.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00156.php</a>
1295   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00546.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00546.php</a>
1296   <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00416.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00416.php</a>
1297 </p>
1298   </li><li>Allow FSM to return free space toward the beginning of the heap file,
1299   in hopes that empty pages at the end can be truncated by VACUUM
1300   </li><li>Allow FSM page return free space based on table clustering, to assist
1301   in maintaining clustering?
1302   </li><li>Improve dead row detection during multi-statement transactions usage
1303 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php">http://archives.postgresql.org/pgsql-patches/2007-03/msg00358.php</a>
1304 </p>
1305   </li><li>Consider a more compact data representation for dead tuples
1306 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00143.php</a>
1307 </p>
1308   </li><li>Auto-vacuum
1309   <ul>
1310     <li>%Issue log message to suggest VACUUM FULL if a table is nearly
1311           empty?
1312     </li><li>Improve control of auto-vacuum
1313 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00876.php</a>
1314 </p>
1315     </li><li>Prevent long-lived temporary tables from causing frozen-xid
1316           advancement starvation
1317 <p>          The problem is that autovacuum cannot vacuum them to set frozen xids;
1318           only the session that created them can do that.
1319           <a href="http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php">http://archives.postgresql.org/pgsql-general/2007-06/msg01645.php</a>
1320 </p>
1321     </li><li>Store per-table autovacuum settings in pg_class.reloptions.
1322 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php</a>
1323           <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php</a>
1324 </p>
1325     </li><li>Prevent autovacuum from running if an old transaction is still
1326           running from the last vacuum
1327 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php</a>
1328 </p>
1329   </li></ul>
1330 </li></ul>
1331 <h1><a name="section_16">Locking</a></h1>
1332
1333 <ul>
1334   <li>Fix priority ordering of read and write light-weight locks (Neil)
1335 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00893.php</a>
1336   <a href="http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php">http://archives.postgresql.org/pgsql-hackers/2004-11/msg00905.php</a>
1337 </p>
1338   </li><li>Fix problem when multiple subtransactions of the same outer transaction
1339   hold different types of locks, and one subtransaction aborts
1340 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg01011.php</a>
1341   <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg00001.php</a>
1342   <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00435.php</a>
1343   <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00773.php</a>
1344 </p>
1345   </li><li>Allow UPDATEs on only non-referential integrity columns not to conflict
1346   with referential integrity locks
1347 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00073.php</a>
1348 </p>
1349   </li><li>Add idle_in_transaction_timeout GUC so locks are not held for long
1350   periods of time
1351   </li><li>Improve deadlock detection when a page cleaning lock conflicts
1352   with a shared buffer that is pinned
1353 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php">http://archives.postgresql.org/pgsql-bugs/2008-01/msg00138.php</a>
1354   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php</a>
1355   <a href="http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php">http://archives.postgresql.org/pgsql-committers/2008-01/msg00365.php</a>
1356 </p>
1357   </li><li>Detect deadlocks involving LockBufferForCleanup()
1358 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00873.php</a>
1359 </p>
1360 </li></ul>
1361 <h1><a name="section_17">Startup Time Improvements</a></h1>
1362
1363 <ul>
1364   <li>Experiment with multi-threaded backend for backend creation
1365 <p>  This would prevent the overhead associated with process creation. Most
1366   operating systems have trivial process creation time compared to
1367   database startup overhead, but a few operating systems (Win32,
1368   Solaris) might benefit from threading.  Also explore the idea of
1369   a single session using multiple threads to execute a statement faster.
1370 </p>
1371 </li></ul>
1372 <h1><a name="section_18">Write-Ahead Log</a></h1>
1373
1374 <ul>
1375   <li>Eliminate need to write full pages to WAL before page modification
1376 <p>  Currently, to protect against partial disk page writes, we write
1377   full page images to WAL before they are modified so we can correct any
1378   partial page writes during recovery.  These pages can also be
1379   eliminated from point-in-time archive files.
1380   <a href="http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php">http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php</a>
1381 </p>
1382   <ul>
1383     <li>When off, write CRC to WAL and check file system blocks
1384            on recovery
1385 <p>           If CRC check fails during recovery, remember the page in case
1386            a later CRC for that page properly matches.
1387 </p>
1388     </li><li>Write full pages during file system write and not when
1389            the page is modified in the buffer cache
1390 <p>           This allows most full page writes to happen in the background
1391            writer.  It might cause problems for applying WAL on recovery
1392            into a partially-written page, but later the full page will be
1393            replaced from WAL.
1394 </p>
1395   </li></ul>
1396   </li><li>Allow WAL traffic to be streamed to another server for stand-by
1397   replication
1398   </li><li>Reduce WAL traffic so only modified values are written rather than
1399   entire rows
1400 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php">http://archives.postgresql.org/pgsql-hackers/2007-03/msg01589.php</a>
1401 </p>
1402   </li><li>Allow WAL information to recover corrupted pg_controldata
1403 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php">http://archives.postgresql.org/pgsql-patches/2006-06/msg00025.php</a>
1404 </p>
1405   </li><li>Find a way to reduce rotational delay when repeatedly writing
1406   last WAL page
1407 <p>  Currently fsync of WAL requires the disk platter to perform a full
1408   rotation to fsync again. One idea is to write the WAL to different
1409   offsets that might reduce the rotational delay.
1410   <a href="http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php">http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php</a>
1411 </p>
1412   </li><li>Allow WAL logging to be turned off for a table, but the table
1413   might be dropped or truncated during crash recovery
1414 <p>  Allow tables to bypass WAL writes and just fsync() dirty pages on
1415   commit.  This should be implemented using ALTER TABLE, e.g. ALTER
1416   TABLE PERSISTENCE [ DROP | TRUNCATE | DEFAULT ].  Tables using
1417   non-default logging should not use referential integrity with
1418   default-logging tables.  A table without dirty buffers during a
1419   crash could perhaps avoid the drop/truncate.
1420   <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php</a>
1421 </p>
1422   </li><li>Allow WAL logging to be turned off for a table, but the table would
1423   avoid being truncated/dropped
1424 <p>  To do this, only a single writer can modify the table, and writes
1425   must happen only on new pages so the new pages can be removed during
1426   crash recovery.  Readers can continue accessing the table.  Such
1427   tables probably cannot have indexes.  One complexity is the handling
1428   of indexes on TOAST tables.
1429   <a href="http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php">http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php</a>
1430 </p>
1431   </li><li>Speed WAL recovery by allowing more than one page to be prefetched
1432 <p>  This should be done utilizing the same infrastructure used for
1433   prefetching in general to avoid introducing complex error-prone code
1434   in WAL replay.
1435   <a href="http://archives.postgresql.org/pgsql-general/2007-12/msg00683.php">http://archives.postgresql.org/pgsql-general/2007-12/msg00683.php</a>
1436   <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00497.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00497.php</a>
1437   <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg01279.php</a>
1438 </p>
1439   </li><li>Improve WAL concurrency by increasing lock granularity
1440 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00556.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00556.php</a>
1441 </p>
1442   </li><li>Be more aggressive about creating WAL files
1443 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01325.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01325.php</a>
1444   <a href="http://archives.postgresql.org/pgsql-hackers/2004-07/msg01075.php">http://archives.postgresql.org/pgsql-hackers/2004-07/msg01075.php</a>
1445   <a href="http://archives.postgresql.org/pgsql-hackers/2005-04/msg00556.php">http://archives.postgresql.org/pgsql-hackers/2005-04/msg00556.php</a>
1446 </p>
1447   </li><li>Have resource managers report the duration of their status changes
1448 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg01468.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg01468.php</a>
1449 </p>
1450   </li><li>Move pgfoundry's xlogdump to /contrib and have it rely more closely
1451   on the WAL backend code
1452 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00035.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00035.php</a>
1453 </p>
1454 </li></ul>
1455 <h1><a name="section_19">Optimizer / Executor</a></h1>
1456
1457 <ul>
1458   <li>Improve selectivity functions for geometric operators
1459   </li><li>Precompile SQL functions to avoid overhead
1460   </li><li>Create utility to compute accurate random_page_cost value
1461   </li><li>Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
1462   </li><li>Have EXPLAIN ANALYZE issue NOTICE messages when the estimated and
1463   actual row counts differ by a specified percentage
1464   </li><li>Improve how ANALYZE computes in-doubt tuples
1465 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg00771.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg00771.php</a>
1466 </p>
1467   </li><li>Consider using hash buckets to do DISTINCT, rather than sorting
1468 <p>  This would be beneficial when there are few distinct values.  This is
1469   already used by GROUP BY.
1470 </p>
1471   </li><li>Log statements where the optimizer row estimates were dramatically
1472   different from the number of rows actually found?
1473   </li><li>Consider compressed annealing to search for query plans
1474 <p>  This might replace GEQO, <a href="http://sixdemonbag.org/Djinni">http://sixdemonbag.org/Djinni</a>.
1475 </p>
1476   </li><li>Improve merge join performance by allowing mark/restore of
1477   tuple sources
1478 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php">http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php</a>
1479 </p>
1480   </li><li>Consider using a hash for joining to a large IN (VALUES ...) list
1481 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php">http://archives.postgresql.org/pgsql-hackers/2007-05/msg00450.php</a>
1482 </p>
1483 </li></ul>
1484 <h1><a name="section_20">Background Writer</a></h1>
1485
1486 <ul>
1487   <li>Consider having the background writer update the transaction status
1488   hint bits before writing out the page
1489 <p>  Implementing this requires the background writer to have access to system
1490   catalogs and the transaction status log.
1491 </p>
1492   </li><li>Consider adding buffers the background writer finds reusable to the
1493   free list
1494 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1495 </p>
1496   </li><li>Automatically tune bgwriter_delay based on activity rather then using a
1497   fixed interval
1498 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php">http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php</a>
1499 </p>
1500   </li><li>Consider wither increasing BM_MAX_USAGE_COUNT improves performance
1501 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php">http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php</a>
1502 </p>
1503   </li><li>Test to see if calling PreallocXlogFiles() from the background writer
1504   will help with WAL segment creation latency
1505 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-06/msg00340.php">http://archives.postgresql.org/pgsql-patches/2007-06/msg00340.php</a>
1506 </p>
1507 </li></ul>
1508 <h1><a name="section_21">Miscellaneous Performance</a></h1>
1509
1510 <ul>
1511   <li>Do async I/O for faster random read-ahead of data
1512 <p>  Async I/O allows multiple I/O requests to be sent to the disk with
1513   results coming back asynchronously.
1514 </p>
1515 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00820.php</a>
1516   <a href="http://archives.postgresql.org/pgsql-performance/2007-09/msg00255.php">http://archives.postgresql.org/pgsql-performance/2007-09/msg00255.php</a>
1517   <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00027.php</a>
1518   <a href="http://archives.postgresql.org/pgsql-patches/2008-01/msg00170.php">http://archives.postgresql.org/pgsql-patches/2008-01/msg00170.php</a>
1519 </p>
1520   </li><li>Use mmap() rather than SYSV shared memory or to write WAL files?
1521 <p>  This would remove the requirement for SYSV SHM but would introduce
1522   portability issues. Anonymous mmap (or mmap to /dev/zero) is required
1523   to prevent I/O overhead.
1524 </p>
1525   </li><li>Consider mmap()'ing files into a backend?
1526 <p>  Doing I/O to large tables would consume a lot of address space or
1527   require frequent mapping/unmapping.  Extending the file also causes
1528   mapping problems that might require mapping only individual pages,
1529   leading to thousands of mappings.  Another problem is that there is no
1530   way to <u>prevent</u> I/O to disk from the dirty shared buffers so changes
1531   could hit disk before WAL is written.
1532 </p>
1533   </li><li>Add a script to ask system configuration questions and tune postgresql.conf
1534   </li><li>Consider ways of storing rows more compactly on disk
1535   <ul>
1536     <li>Reduce the row header size?
1537     </li><li>Consider reducing on-disk varlena length from four bytes to
1538           two because a heap row cannot be more than 64k in length
1539   </li></ul>
1540   </li><li>Consider increasing NUM_CLOG_BUFFERS
1541 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00030.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00030.php</a>
1542   <a href="http://archives.postgresql.org/pgsql-performance/2007-08/msg00024.php">http://archives.postgresql.org/pgsql-performance/2007-08/msg00024.php</a>
1543 </p>
1544   </li><li>Consider transaction start/end performance improvements
1545 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00948.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00948.php</a>
1546   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php</a>
1547 </p>
1548   </li><li>Allow user configuration of TOAST thresholds
1549 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php">http://archives.postgresql.org/pgsql-hackers/2007-02/msg00213.php</a>
1550   <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php</a>
1551 </p>
1552   </li><li>Allow configuration of backend priorities via the operating system
1553 <p>  Though backend priorities make priority inversion during lock
1554   waits possible, research shows that this is not a huge problem.
1555 </p>
1556 <p>  <a href="http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php">http://archives.postgresql.org/pgsql-general/2007-02/msg00493.php</a>
1557 </p>
1558   </li><li>Experiment with multi-threaded backend better I/O utilization
1559 <p>  This would allow a single query to make use of multiple I/O channels
1560   simultaneously.  One idea is to create a background reader that can
1561   pre-fetch sequential and index scan pages needed by other backends.
1562   This could be expanded to allow concurrent reads from multiple devices
1563   in a partitioned table.
1564 </p>
1565   </li><li>Experiment with multi-threaded backend better CPU utilization
1566 <p>  This would allow several CPUs to be used for a single query, such as
1567   for sorting or query execution.
1568 </p>
1569   </li><li>Consider increasing the minimum allowed number of shared buffers
1570 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php">http://archives.postgresql.org/pgsql-bugs/2008-02/msg00157.php</a>
1571 </p>
1572   </li><li>Expire published xmin for read-only and idle transactions
1573 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00343.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00343.php</a>
1574 </p>
1575   </li><li>Consider if CommandCounterIncrement() can avoid its
1576   AcceptInvalidationMessages() call
1577 <p>  <a href="http://archives.postgresql.org/pgsql-committers/2007-11/msg00585.php">http://archives.postgresql.org/pgsql-committers/2007-11/msg00585.php</a>
1578 </p>
1579   </li><li>Improve performance of shared invalidation queue for multiple CPUs
1580 <p>  <a href="http://archives.postgresql.org/pgsql-performance/2008-01/msg00023.php">http://archives.postgresql.org/pgsql-performance/2008-01/msg00023.php</a>
1581 </p>
1582   </li><li>Consider Cartesian joins when both relations are needed to form an
1583   indexscan qualification for a third relation
1584 <p>  <a href="http://archives.postgresql.org/pgsql-performance/2007-12/msg00090.php">http://archives.postgresql.org/pgsql-performance/2007-12/msg00090.php</a>
1585 </p>
1586   </li><li>Consider not storing a NULL bitmap on disk if all the NULLs are
1587   trailing
1588 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00624.php</a>
1589   <a href="http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php">http://archives.postgresql.org/pgsql-patches/2007-12/msg00109.php</a>
1590 </p>
1591   </li><li>Sort large UPDATE/DELETEs so it is done in heap order
1592 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg01119.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg01119.php</a>
1593 </p>
1594   </li><li>-<em>Avoid tuple some tuple copying in sort routines</em>
1595   </li><li>SMP scalability improvements
1596 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00439.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00439.php</a>
1597   <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00206.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00206.php</a>
1598   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00361.php</a>
1599 </p>
1600   </li><li>Research reducing deTOASTing in more places
1601 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-09/msg00895.php">http://archives.postgresql.org/pgsql-hackers/2007-09/msg00895.php</a>
1602 </p>
1603   </li><li>Consider being smarter about memory and external files used during
1604   sorts
1605 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-11/msg01101.php">http://archives.postgresql.org/pgsql-hackers/2007-11/msg01101.php</a>
1606   <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00045.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00045.php</a>
1607 </p>
1608   </li><li>Allow one transaction to see tuples using the snapshot of another
1609   transaction
1610 <p>  This would assist multiple backends in working together.
1611   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00400.php</a>
1612 </p>
1613 </li></ul>
1614 <h1><a name="section_22">Source Code</a></h1>
1615
1616 <ul>
1617   <li>Add use of 'const' for variables in source tree
1618   </li><li>Move some things from contrib into main tree
1619   </li><li>%Remove warnings created by -Wcast-align
1620   </li><li>Move platform-specific ps status display info from ps_status.c to ports
1621   </li><li>Add optional CRC checksum to heap and index pages
1622   </li><li>Improve documentation to build only interfaces (Marc)
1623   </li><li>Remove or relicense modules that are not under the BSD license, if possible
1624   </li><li>Acquire lock on a relation before building a relcache entry for it
1625   </li><li>Allow cross-compiling by generating the zic database on the target system
1626   </li><li>Improve NLS maintenance of libpgport messages linked onto applications
1627   </li><li>Clean up casting in contrib/isn
1628 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php">http://archives.postgresql.org/pgsql-hackers/2006-11/msg00245.php</a>
1629 </p>
1630   </li><li>Improve the /contrib installation experience
1631 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-04/msg00132.php">http://archives.postgresql.org/pgsql-hackers/2008-04/msg00132.php</a>
1632 </p>
1633   </li><li>Use UTF8 encoding for NLS messages so all server encodings can
1634   read them properly
1635   </li><li>Update Bonjour to work with newer cross-platform SDK
1636 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg02238.php</a>
1637   <a href="http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php">http://archives.postgresql.org/pgsql-patches/2006-10/msg00048.php</a>
1638 </p>
1639   </li><li>Consider detoasting keys before sorting
1640   </li><li>Consider GnuTLS if OpenSSL license becomes a problem
1641 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php">http://archives.postgresql.org/pgsql-patches/2006-05/msg00040.php</a>
1642   <a href="http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php">http://archives.postgresql.org/pgsql-hackers/2006-12/msg01213.php</a>
1643 </p>
1644   </li><li>Consider changing documentation format from SGML to XML
1645 <p>  <a href="http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php">http://archives.postgresql.org/pgsql-docs/2006-12/msg00152.php</a>
1646 </p>
1647   </li><li>Consider making NAMEDATALEN more configurable in future releases
1648   </li><li>Update our code to handle 64-bit timezone files to match the zic
1649   source code, which now uses them
1650   </li><li>Have configure choose integer datetimes by default
1651 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php">http://archives.postgresql.org/pgsql-patches/2007-05/msg00046.php</a>
1652 </p>
1653   </li><li>Support scoped IPv6 addresses
1654 <p>  <a href="http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php">http://archives.postgresql.org/pgsql-bugs/2007-05/msg00111.php</a>
1655 </p>
1656   </li><li>Consider allowing 64-bit integers and floats to be passed by value on
1657   64-bit platforms
1658 <p>  Also change 32-bit floats (float4) to be passed by value at the same
1659   time.
1660 </p>
1661   </li><li>Research use of signals and sleep wake ups
1662 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-07/msg00003.php">http://archives.postgresql.org/pgsql-hackers/2007-07/msg00003.php</a>
1663 </p>
1664   </li><li>Add automated check for invalid C++ source code constructs
1665 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-07/msg00056.php">http://archives.postgresql.org/pgsql-patches/2007-07/msg00056.php</a>
1666 </p>
1667   </li><li>Consider simplifying how memory context resets handle child contexts
1668 <p>  <a href="http://archives.postgresql.org/pgsql-patches/2007-08/msg00067.php">http://archives.postgresql.org/pgsql-patches/2007-08/msg00067.php</a>
1669 </p>
1670   </li><li>Remove use of MAKE_PTR and MAKE_OFFSET macros
1671 <p>  <a href="http://archives.postgresql.org/pgsql-general/2007-08/msg01510.php">http://archives.postgresql.org/pgsql-general/2007-08/msg01510.php</a>
1672 </p>
1673   </li><li>Convert single quotes to apostrophes in the PDF documentation
1674 <p>  <a href="http://archives.postgresql.org/pgsql-docs/2007-12/msg00059.php">http://archives.postgresql.org/pgsql-docs/2007-12/msg00059.php</a>
1675 </p>
1676   </li><li>Create three versions of libpgport to simplify client code
1677 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00154.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00154.php</a>
1678 </p>
1679   </li><li>Remove old-style routines for manipulating tuples
1680 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2007-10/msg00851.php">http://archives.postgresql.org/pgsql-hackers/2007-10/msg00851.php</a>
1681 </p>
1682   </li><li>Improve detection of shared memory segments being used by others
1683   by checking the SysV shared memory field 'nattch'
1684 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00656.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00656.php</a>
1685   <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00673.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00673.php</a>
1686 </p>
1687   </li><li>Implement the non-threaded Avahi service discovery protocol
1688 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00939.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00939.php</a>
1689   <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00097.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00097.php</a>
1690   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg01211.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg01211.php</a>
1691   <a href="http://archives.postgresql.org/pgsql-patches/2008-04/msg00001.php">http://archives.postgresql.org/pgsql-patches/2008-04/msg00001.php</a>
1692 </p>
1693   </li><li>Win32
1694   <ul>
1695     <li>Remove configure.in check for link failure when cause is found
1696     </li><li>Remove readdir() errno patch when runtime/mingwex/dirent.c rev
1697           1.4 is released
1698     </li><li>Remove psql newline patch when we find out why mingw outputs an
1699           extra newline
1700     </li><li>Allow psql to use readline once non-US code pages work with
1701           backslashes
1702     </li><li>Fix problem with shared memory on the Win32 Terminal Server
1703     </li><li>Diagnose problem where shared memory can sometimes not be
1704           attached by postmaster children
1705 <p>          <a href="http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php">http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php</a>
1706 </p>
1707     </li><li>Improve signal handling
1708 <p>          <a href="http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php">http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php</a>
1709 </p>
1710     </li><li>Convert MSVC build system to remove most batch files
1711 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-08/msg00961.php">http://archives.postgresql.org/pgsql-hackers/2007-08/msg00961.php</a>
1712 </p>
1713     </li><li>Prevent SSL from sending network packets to avoid interference
1714           with Win32 signal emulation
1715 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2007-12/msg00455.php">http://archives.postgresql.org/pgsql-hackers/2007-12/msg00455.php</a>
1716 </p>
1717     </li><li>Support pgxs when using MSVC
1718     </li><li>Fix MSVC NLS support, like for to_char()
1719 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php">http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php</a>
1720           <a href="http://archives.postgresql.org/pgsql-patches/2008-02/msg00038.php">http://archives.postgresql.org/pgsql-patches/2008-02/msg00038.php</a>
1721 </p>
1722     </li><li>Find a correct rint() substitute on Windows
1723 <p>          <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00808.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00808.php</a>
1724 </p>
1725   </li></ul>
1726   </li><li>Wire Protocol Changes
1727   <ul>
1728     <li>Allow dynamic character set handling
1729     </li><li>Add decoded type, length, precision
1730     </li><li>Use compression?
1731     </li><li>Update clients to use data types, typmod, schema.table.column names
1732           of result sets using new statement protocol
1733   </li></ul>
1734 </li></ul>
1735 <h1><a name="section_23">Exotic Features</a></h1>
1736
1737 <ul>
1738   <li>Add pre-parsing phase that converts non-ISO syntax to supported
1739   syntax
1740 <p>  This could allow SQL written for other databases to run without
1741   modification.
1742 </p>
1743   </li><li>Allow plug-in modules to emulate features from other databases
1744   </li><li>Add features of Oracle-style packages  (Pavel)
1745 <p>  A package would be a schema with session-local variables,
1746   public/private functions, and initialization functions.  It
1747   is also possible to implement these capabilities
1748   in any schema and not use a separate "packages"
1749   syntax at all.
1750 </p>
1751 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00384.php</a>
1752 </p>
1753   </li><li>Consider allowing control of upper/lower case folding of unquoted
1754   identifiers
1755 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php">http://archives.postgresql.org/pgsql-hackers/2004-04/msg00818.php</a>
1756   <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg01527.php</a>
1757   <a href="http://archives.postgresql.org/pgsql-hackers/2008-03/msg00849.php">http://archives.postgresql.org/pgsql-hackers/2008-03/msg00849.php</a>
1758 </p>
1759   </li><li>Add autonomous transactions
1760 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php">http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php</a>
1761 </p>
1762 </li></ul>
1763 <h1><a name="section_24">Features We Do <u>Not</u> Want</a></h1>
1764
1765 <ul>
1766   <li>All backends running as threads in a single process (not wanted)
1767 <p>  This eliminates the process protection we get from the current setup.
1768   Thread creation is usually the same overhead as process creation on
1769   modern systems, so it seems unwise to use a pure threaded model.
1770 </p>
1771   </li><li>Optimizer hints (not wanted)
1772 <p>  Optimizer hints are used to work around problems in the optimizer.  We
1773   would rather have the problems reported and fixed.
1774 </p>
1775 <p>  <a href="http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php">http://archives.postgresql.org/pgsql-hackers/2006-08/msg00506.php</a>
1776   <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00517.php</a>
1777   <a href="http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php">http://archives.postgresql.org/pgsql-hackers/2006-10/msg00663.php</a>
1778 </p>
1779 <p>  Because we support postfix operators, it isn't possible to make AS
1780   optional and continue to use bison.
1781   <a href="http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php">http://archives.postgresql.org/pgsql-hackers/2003-04/msg00436.php</a>
1782 </p>
1783 <p>  <a href="http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php">http://archives.postgresql.org/pgsql-sql/2006-08/msg00164.php</a>
1784 </p>
1785   </li><li>Embedded server (not wanted)
1786 <p>  While PostgreSQL clients runs fine in limited-resource environments, the
1787   server requires multiple processes and a stable pool of resources to
1788   run reliabily and efficiently.  Stripping down the PostgreSQL server
1789   to run in the same process address space as the client application
1790   would add too much complexity and failure cases.</p>
1791 </li></ul>
1792
1793 </body>
1794 </html>