PostgreSQL TODO List
====================
-Last updated: Thu Apr 17 16:56:51 EDT 2008
+Last updated: Sat Apr 19 08:15:19 EDT 2008
The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html.
#A hyphen, "-", marks changes that will appear in the upcoming 8.3 release.#
#A percent sign, "%", marks items that are easier to implement.#
-Bracketed items, "[]", have more detail.
-
This list contains all known PostgreSQL bugs and feature requests. If
you would like to work on an item, please read the Developer's FAQ
first. There is also a developer's wiki at
* Point-In-Time Recovery (PITR)
o Allow a warm standby system to also allow read-only statements
- [pitr]
http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php
o Merge hardwired timezone names with the TZ database; allow either
kind everywhere a TZ name is currently taken
o Allow TIMESTAMP WITH TIME ZONE to store the original timezone
- information, either zone name or offset from UTC [timezone]
+ information, either zone name or offset from UTC
If the TIMESTAMP value is stored with a time zone name, interval
computations should adjust based on the time zone rules.
+ http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php
o Fix SELECT '0.01 years'::interval, '0.01 months'::interval
o Add a GUC variable to allow output of interval values in ISO8601
database creation might have locale-aware indexes. The indexes would
need to be reindexed to match the new locale.
-* Allow encoding on a per-column basis optionally using the ICU library
+* Allow encoding on a per-column basis optionally using the ICU library;
+ Add CREATE COLLATE
- Right now only one encoding is allowed per database. [locale]
+ Right now only one encoding is allowed per database.
http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php
+ http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php
http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php
+ http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php
+ http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php
+ http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php
+ http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php
http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php
http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php
http://wiki.postgresql.org/wiki/Todo:Collate
http://wiki.postgresql.org/wiki/Todo:ICU
-* Add CREATE COLLATE? [locale]
* Support multiple simultaneous character sets, per SQL92
* Improve UTF8 combined character handling?
* Add octet_length_server() and octet_length_client()
http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php
* Add a GUC variable to warn about non-standard SQL usage in queries
-* Add SQL-standard MERGE command, typically used to merge two tables
- [merge]
-
- This is similar to UPDATE, then for unmatched rows, INSERT.
- Whether concurrent access allows modifications which could cause
- row loss is implementation independent.
-
-* Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
- [merge]
+* Add SQL-standard MERGE/REPLACE/UPSERT command
+ MERGE is typically used to merge two tables. REPLACE or UPSERT
+ command does UPDATE, or on failure, INSERT. This is similar to UPDATE,
+ then for unmatched rows, INSERT. Whether concurrent access allows
+ modifications which could cause row loss is implementation independent.
To implement this cleanly requires that the table have a unique index
- so duplicate checking can be easily performed. It is possible to
- do it without a unique index if we require the user to LOCK the table
- before the MERGE.
+ so duplicate checking can be easily performed. It is possible to do it
+ without a unique index if we require the user to LOCK the table before
+ the MERGE.
http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php
http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php
* psql
o Have psql show current values for a sequence
o Move psql backslash database information into the backend, use
- mnemonic commands? [psql]
+ mnemonic commands?
This would allow non-psql clients to pull the same information out
of the database as psql.
+ http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php
o Make psql's \d commands more consistent
Startup Time Improvements
=========================
-* Experiment with multi-threaded backend for backend creation [thread]
+* Experiment with multi-threaded backend for backend creation
This would prevent the overhead associated with process creation. Most
operating systems have trivial process creation time compared to
Write-Ahead Log
===============
-* Eliminate need to write full pages to WAL before page modification [wal]
+* Eliminate need to write full pages to WAL before page modification
Currently, to protect against partial disk page writes, we write
full page images to WAL before they are modified so we can correct any
partial page writes during recovery. These pages can also be
eliminated from point-in-time archive files.
+ http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php
o When off, write CRC to WAL and check file system blocks
on recovery
Currently fsync of WAL requires the disk platter to perform a full
rotation to fsync again. One idea is to write the WAL to different
offsets that might reduce the rotational delay.
+ http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php
* Allow WAL logging to be turned off for a table, but the table
- might be dropped or truncated during crash recovery [walcontrol]
+ might be dropped or truncated during crash recovery
Allow tables to bypass WAL writes and just fsync() dirty pages on
commit. This should be implemented using ALTER TABLE, e.g. ALTER
non-default logging should not use referential integrity with
default-logging tables. A table without dirty buffers during a
crash could perhaps avoid the drop/truncate.
+ http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
* Allow WAL logging to be turned off for a table, but the table would
- avoid being truncated/dropped [walcontrol]
+ avoid being truncated/dropped
To do this, only a single writer can modify the table, and writes
must happen only on new pages so the new pages can be removed during
crash recovery. Readers can continue accessing the table. Such
tables probably cannot have indexes. One complexity is the handling
of indexes on TOAST tables.
+ http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
* Speed WAL recovery by allowing more than one page to be prefetched
-Last updated: Thu Apr 17 16:56:51 EDT 2008
+Last updated: Sat Apr 19 08:15:19 EDT 2008
The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html.
A hyphen, "-", marks changes that will appear in the upcoming 8.3 release.
A percent sign, "%", marks items that are easier to implement.
-
Bracketed items, "[]", have more detail.
-
This list contains all known PostgreSQL bugs and feature requests. If
you would like to work on an item, please read the Developer's FAQ
first. There is also a developer's wiki at
Point-In-Time Recovery (PITR)
Allow a warm standby system to also allow read-only statements
http://archives.postgresql.org/pgsql-hackers/2007-03/msg00050.php
%Create dump tool for write-ahead logs for use in determining
Merge hardwired timezone names with the TZ database; allow either
kind everywhere a TZ name is currently taken
Allow TIMESTAMP WITH TIME ZONE to store the original timezone
- information, either zone name or offset from UTC
[timezone]+ information, either zone name or offset from UTC
If the TIMESTAMP value is stored with a time zone name, interval
computations should adjust based on the time zone rules.
+
http://archives.postgresql.org/pgsql-hackers/2004-10/msg00705.php
Fix SELECT '0.01 years'::interval, '0.01 months'::interval
Add a GUC variable to allow output of interval values in ISO8601
database creation might have locale-aware indexes. The indexes would
need to be reindexed to match the new locale.
-
Allow encoding on a per-column basis optionally using the ICU library
-
Right now only one encoding is allowed per database. [locale]
+
Allow encoding on a per-column basis optionally using the ICU library;
+ Add CREATE COLLATE
+
Right now only one encoding is allowed per database.
http://archives.postgresql.org/pgsql-hackers/2005-03/msg00932.php
+
http://archives.postgresql.org/pgsql-patches/2005-08/msg00039.php http://archives.postgresql.org/pgsql-patches/2005-08/msg00309.php
+
http://archives.postgresql.org/pgsql-hackers/2005-09/msg00110.php+
http://archives.postgresql.org/pgsql-patches/2005-09/msg00020.php+
http://archives.postgresql.org/pgsql-hackers/2005-12/msg01121.php+
http://archives.postgresql.org/pgsql-hackers/2006-01/msg00767.php http://archives.postgresql.org/pgsql-patches/2006-03/msg00233.php
http://archives.postgresql.org/pgsql-hackers/2006-09/msg00662.php
http://wiki.postgresql.org/wiki/Todo:Collate
http://wiki.postgresql.org/wiki/Todo:ICU
-
Add CREATE COLLATE? [locale]
Support multiple simultaneous character sets, per SQL92
Improve UTF8 combined character handling?
Add octet_length_server() and octet_length_client()
http://archives.postgresql.org/pgsql-hackers/2006-11/msg00092.php
Add a GUC variable to warn about non-standard SQL usage in queries
-
Add SQL-standard MERGE command, typically used to merge two tables
-
This is similar to UPDATE, then for unmatched rows, INSERT.
- Whether concurrent access allows modifications which could cause
- row loss is implementation independent.
-
-
Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
-
To implement this cleanly requires that the table have a unique index
- so duplicate checking can be easily performed. It is possible to
- do it without a unique index if we require the user to LOCK the table
- before the MERGE.
+
Add SQL-standard MERGE/REPLACE/UPSERT command
+
MERGE is typically used to merge two tables. REPLACE or UPSERT
+ command does UPDATE, or on failure, INSERT. This is similar to UPDATE,
+ then for unmatched rows, INSERT. Whether concurrent access allows
+ modifications which could cause row loss is implementation independent.
+ To implement this cleanly requires that the table have a unique index
+ so duplicate checking can be easily performed. It is possible to do it
+ without a unique index if we require the user to LOCK the table before
+ the MERGE.
http://archives.postgresql.org/pgsql-hackers/2005-11/msg00501.php
http://archives.postgresql.org/pgsql-hackers/2005-11/msg00536.php
Have psql show current values for a sequence
Move psql backslash database information into the backend, use
- mnemonic commands?
[psql]+ mnemonic commands?
This would allow non-psql clients to pull the same information out
of the database as psql.
+
http://archives.postgresql.org/pgsql-hackers/2004-01/msg00191.php
Make psql's \d commands more consistent
http://archives.postgresql.org/pgsql-hackers/2004-11/msg00014.php
Startup Time Improvements
-
Experiment with multi-threaded backend for backend creation [thread]+
Experiment with multi-threaded backend for backend creation
This would prevent the overhead associated with process creation. Most
operating systems have trivial process creation time compared to
database startup overhead, but a few operating systems (Win32,
-
Eliminate need to write full pages to WAL before page modification [wal]+
Eliminate need to write full pages to WAL before page modification
Currently, to protect against partial disk page writes, we write
full page images to WAL before they are modified so we can correct any
partial page writes during recovery. These pages can also be
eliminated from point-in-time archive files.
+
http://archives.postgresql.org/pgsql-hackers/2002-06/msg00655.php
When off, write CRC to WAL and check file system blocks
Currently fsync of WAL requires the disk platter to perform a full
rotation to fsync again. One idea is to write the WAL to different
offsets that might reduce the rotational delay.
+
http://archives.postgresql.org/pgsql-hackers/2002-11/msg00483.php
Allow WAL logging to be turned off for a table, but the table
- might be dropped or truncated during crash recovery
[walcontrol]+ might be dropped or truncated during crash recovery
Allow tables to bypass WAL writes and just fsync() dirty pages on
commit. This should be implemented using ALTER TABLE, e.g. ALTER
TABLE PERSISTENCE [
DROP | TRUNCATE | DEFAULT ]. Tables using non-default logging should not use referential integrity with
default-logging tables. A table without dirty buffers during a
crash could perhaps avoid the drop/truncate.
+
http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
Allow WAL logging to be turned off for a table, but the table would
- avoid being truncated/dropped
[walcontrol]+ avoid being truncated/dropped
To do this, only a single writer can modify the table, and writes
must happen only on new pages so the new pages can be removed during
crash recovery. Readers can continue accessing the table. Such
tables probably cannot have indexes. One complexity is the handling
of indexes on TOAST tables.
+
http://archives.postgresql.org/pgsql-hackers/2005-12/msg01016.php
Speed WAL recovery by allowing more than one page to be prefetched
This should be done utilizing the same infrastructure used for
projects / postgresql.git / commitdiff