diff options
| author | Bruce Momjian <bruce@momjian.us> | 2005-07-04 17:00:32 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2005-07-04 17:00:32 +0000 |
| commit | 8ea398513ef287bc25ac08dc7a4d92fb68dc668d (patch) | |
| tree | ee594e9d34d643ce471661a604099aac25b3db40 /doc/src | |
| parent | b9fe8ee225f9fe649dff488e4cdbb3a65003155e (diff) | |
| download | postgresql-8ea398513ef287bc25ac08dc7a4d92fb68dc668d.tar.gz postgresql-8ea398513ef287bc25ac08dc7a4d92fb68dc668d.zip | |
Restructure TODO sections.
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/FAQ/TODO.html | 471 |
1 files changed, 246 insertions, 225 deletions
diff --git a/doc/src/FAQ/TODO.html b/doc/src/FAQ/TODO.html index e37a84b95f4..7f1546e9c4a 100644 --- a/doc/src/FAQ/TODO.html +++ b/doc/src/FAQ/TODO.html @@ -8,7 +8,7 @@ <body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF"> <h1><a name="section_1">PostgreSQL TODO List</a></h1> <p>Current maintainer: Bruce Momjian (<a href="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a>)<br/> -Last updated: Mon Jul 4 08:32:37 EDT 2005 +Last updated: Mon Jul 4 13:00:23 EDT 2005 </p> <p>The most recent version of this document can be viewed at<br/> <a href="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>. @@ -27,94 +27,27 @@ first. <li>Remove behavior of postmaster -o after making postmaster/postgres flags unique </li><li>Allow limits on per-db/role connections - </li><li>Allow server log information to be output as INSERT statements -<p> This would allow server log information to be easily loaded into - a database for analysis. -</p> - </li><li>Prevent dropping user that still owns objects, or auto-drop the objects </li><li>Allow pooled connections to list all prepared queries <p> This would allow an application inheriting a pooled connection to know the queries prepared in the current session. </p> </li><li>Allow major upgrades without dump/reload, perhaps using pg_upgrade [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pg_upgrade">pg_upgrade</a>] - </li><li>Allow GRANT/REVOKE permissions to be applied to all schema objects with one - command -<p> The proposed syntax is: -</p><p> GRANT SELECT ON ALL TABLES IN public TO phpuser; - GRANT SELECT ON NEW TABLES IN public TO phpuser; -</p> - </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on - schema permissions </li><li>Check for unreferenced table files created by transactions that were in-progress when the server terminated abruptly - </li><li>Allow reporting of which objects are in which tablespaces -<p> This item is difficult because a tablespace can contain objects from - multiple databases. There is a server-side function that returns the - databases which use a specific tablespace, so this requires a tool - that will call that function and connect to each database to find the - objects in each database for that tablespace. -</p> - </li><li>Allow a database in tablespace t1 with tables created in tablespace t2 - to be used as a template for a new database created with default - tablespace t2 -<p> All objects in the default database tablespace must have default tablespace - specifications. This is because new databases are created by copying - directories. If you mix default tablespace tables and tablespace-specified - tables in the same directory, creating a new database from such a mixed - directory would create a new database with tables that had incorrect - explicit tablespaces. To fix this would require modifying pg_class in the - newly copied database, which we don't currently do. -</p> - </li><li>Add a GUC variable to control the tablespace for temporary objects and - sort files -<p> It could start with a random tablespace from a supplied list and cycle - through the list. -</p> - </li><li>Add ability to monitor the use of temporary sort files - </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory - structure on the recovery computer is different from the original - </li><li>Add "include file" functionality in postgresql.conf - </li><li>-<em>Add session start time and last statement time to pg_stat_activity</em> - </li><li>Allow server logs to be remotely read using SQL commands - </li><li>Allow pg_hba.conf settings to be controlled via SQL -<p> This would require a new global table that is dumped to flat file for - use by the postmaster. We do a similar thing for pg_shadow currently. -</p> </li><li>Allow administrators to safely terminate individual sessions either via an SQL function or SIGTERM <p> Currently SIGTERM of a backend can lead to lock table corruption. </p> - </li><li>Un-comment all variables in postgresql.conf -<p> By not showing commented-out variables, we discourage people from - thinking that re-commenting a variable returns it to its default. - This has to address environment variables that are then overridden - by config file values. Another option is to allow commented values - to return to their default values. -</p> - </li><li>Allow point-in-time recovery to archive partially filled write-ahead - logs [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>] -<p> Currently only full WAL files are archived. This means that the most - recent transactions aren't available for recovery in case of a disk - failure. This could be triggered by a user command or a timer. -</p> - </li><li>Automatically force archiving of partially-filled WAL files when - pg_stop_backup() is called or the server is stopped -<p> Doing this will allow administrators to know more easily when the - archive contins all the files needed for point-in-time recovery. -</p> - </li><li>Create dump tool for write-ahead logs for use in determining - transaction id for point-in-time recovery + </li><li>Prevent dropping user that still owns objects, or auto-drop the objects </li><li>Set proper permissions on non-system schemas during db creation <p> Currently all schemas are owned by the super-user because they are copied from the template1 database. </p> - </li><li>Add a function that returns the 'uptime' of the postmaster - </li><li>Allow a warm standby system to also allow read-only queries [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>] -<p> This is useful for checking PITR recovery. -</p> - </li><li>Allow the PITR process to be debugged and data examined </li><li>-<em>Add the client IP address and port to pg_stat_activity</em> + </li><li>Support table partitioning that allows a single table to be stored + in subtables that are partitioned based on the primary key or a WHERE + clause </li><li>Improve replication solutions <ul> <li>Load balancing @@ -124,14 +57,87 @@ first. </p> </li><li>Allow replication over unreliable or non-persistent links </li></ul> - </li><li>Support table partitioning that allows a single table to be stored - in subtables that are partitioned based on the primary key or a WHERE - clause - </li><li>Allow postgresql.conf values to be set so they can not be changed by - the user - </li><li>Allow per-tablespace quotas + </li><li>Configuration files + <ul> + <li>Add "include file" functionality in postgresql.conf + </li><li>Allow postgresql.conf values to be set so they can not be changed + by the user + </li><li>Allow commenting of variables in postgresql.conf to restore them + to defaults + </li><li>Allow pg_hba.conf settings to be controlled via SQL +<p> This would require a new global table that is dumped to flat file for + use by the postmaster. We do a similar thing for pg_shadow currently. +</p> + </li></ul> + </li><li>Tablespaces + <ul> + <li>Allow a database in tablespace t1 with tables created in + tablespace t2 to be used as a template for a new database created + with default tablespace t2 +<p> All objects in the default database tablespace must have default + tablespace specifications. This is because new databases are + created by copying directories. If you mix default tablespace + tables and tablespace-specified tables in the same directory, + creating a new database from such a mixed directory would create a + new database with tables that had incorrect explicit tablespaces. + To fix this would require modifying pg_class in the newly copied + database, which we don't currently do. +</p> + </li><li>Allow reporting of which objects are in which tablespaces +<p> This item is difficult because a tablespace can contain objects + from multiple databases. There is a server-side function that + returns the databases which use a specific tablespace, so this + requires a tool that will call that function and connect to each + database to find the objects in each database for that tablespace. +</p> + <ul> + <li>Add a GUC variable to control the tablespace for temporary objects + and sort files +<p> It could start with a random tablespace from a supplied list and + cycle through the list. +</p> + </li><li>Allow WAL replay of CREATE TABLESPACE to work when the directory + structure on the recovery computer is different from the original + </li><li>Allow per-tablespace quotas + </li></ul> + </li></ul> + </li><li>Point-in-time Recovery (PITR) + <ul> + <li>Allow point-in-time recovery to archive partially filled + write-ahead logs [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>] +<p> Currently only full WAL files are archived. This means that the + most recent transactions aren't available for recovery in case + of a disk failure. This could be triggered by a user command or + a timer. +</p> + </li><li>Automatically force archiving of partially-filled WAL files when + pg_stop_backup() is called or the server is stopped +<p> Doing this will allow administrators to know more easily when + the archive contins all the files needed for point-in-time + recovery. +</p> + </li><li>Create dump tool for write-ahead logs for use in determining + transaction id for point-in-time recovery + </li><li>Allow a warm standby system to also allow read-only queries + [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pitr">pitr</a>] +<p> This is useful for checking PITR recovery. +</p> + </li><li>Allow the PITR process to be debugged and data examined + </li></ul> +</li></ul> +<h1><a name="section_3">Monitoring</a></h1> + +<ul> + <li>Allow server log information to be output as INSERT statements +<p> This would allow server log information to be easily loaded into + a database for analysis. +</p> + </li><li>Add ability to monitor the use of temporary sort files + </li><li>-<em>Add session start time and last statement time to pg_stat_activity</em> + </li><li>Allow server logs to be remotely read using SQL commands + </li><li>-<em>Add a function that returns the start time of the postmaster</em> </li></ul> -<h1><a name="section_3">Data Types</a></h1> +<h1><a name="section_4">Data Types</a></h1> <ul> <li>Remove Money type, add money formatting for decimal type @@ -148,24 +154,10 @@ first. inaccurate, in one sense. </p> <ul> - <li>Add function to return compressed length of TOAST data values - </li><li>Allow INET subnet tests using non-constants to be indexed - </li><li>Add transaction_timestamp(), statement_timestamp(), clock_timestamp() - functionality -<p> Current CURRENT_TIMESTAMP returns the start time of the current - transaction, and gettimeofday() returns the wallclock time. This will - make time reporting more consistent and will allow reporting of - the statement start time. -</p> - </li><li>Have sequence dependency track use of DEFAULT sequences, - seqname.nextval (?) - </li><li>Disallow changing default expression of a SERIAL column (?) + <li>Have sequence dependency track use of DEFAULT sequences, + seqname.nextval? + </li><li>Disallow changing default expression of a SERIAL column? </li><li>Allow infinite dates just like infinite timestamps - </li><li>Have initdb set DateStyle based on locale? - </li><li>Add pg_get_acldef(), pg_get_typedefault(), and pg_get_attrdef() - </li><li>Allow to_char() to print localized month names - </li><li>Allow functions to have a schema search path specified at creation time - </li><li>Allow substring/replace() to get/set bit values </li><li>Add a GUC variable to allow output of interval values in ISO8601 format </li><li>Fix data types where equality comparison isn't intuitive, e.g. box </li><li>Merge hardwired timezone names with the TZ database; allow either kind @@ -185,24 +177,6 @@ first. </li><li>Allow INET + INT4 to increment the host part of the address, or throw an error on overflow </li><li>Add 'tid != tid ' operator for use in corruption recovery - </li><li>Prevent to_char() on interval from returning meaningless values -<p> For example, to_char('1 month', 'mon') is meaningless. Basically, - most date-related parameters to to_char() are meaningless for - intervals because interval is not anchored to a date. -</p> - </li><li>Allow to_char() on interval values to accumulate the highest unit - requested -<p> Some special format flag would be required to request such - accumulation. Such functionality could also be added to EXTRACT. - Prevent accumulation that crosses the month/day boundary because of - the uneven number of days in a month. -</p> - <ul> - <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65 - </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600 - </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20 - </li><li>to_char(INTERVAL '3 years 5 months','MM') => 41 - </li></ul> </li><li>Add ISO INTERVAL handling <ul> <li>Add support for day-time syntax, INTERVAL '1 2:03:04' DAY TO SECOND @@ -229,7 +203,7 @@ first. </li></ul> </li><li>BINARY DATA <ul> - <li>Improve vacuum of large objects, like /contrib/vacuumlo (?) + <li>Improve vacuum of large objects, like /contrib/vacuumlo? </li><li>Add security checking for large objects <p> Currently large objects entries do not have owners. Permissions can only be set at the pg_largeobject table level. @@ -240,7 +214,42 @@ first. </p> </li></ul> </li></ul> -<h1><a name="section_4">Multi-Language Support</a></h1> +<h1><a name="section_5">Functions</a></h1> + +<ul> + <li>Add function to return compressed length of TOAST data values + </li><li>Allow INET subnet tests using non-constants to be indexed + </li><li>Add transaction_timestamp(), statement_timestamp(), clock_timestamp() + functionality +<p> Current CURRENT_TIMESTAMP returns the start time of the current + transaction, and gettimeofday() returns the wallclock time. This will + make time reporting more consistent and will allow reporting of + the statement start time. +</p> + </li><li>Add pg_get_acldef(), pg_get_typedefault(), and pg_get_attrdef() + </li><li>Allow to_char() to print localized month names + </li><li>Allow functions to have a schema search path specified at creation time + </li><li>Allow substring/replace() to get/set bit values + </li><li>Allow to_char() on interval values to accumulate the highest unit + requested +<p> Some special format flag would be required to request such + accumulation. Such functionality could also be added to EXTRACT. + Prevent accumulation that crosses the month/day boundary because of + the uneven number of days in a month. +</p> + <ul> + <li>to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65 + </li><li>to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600 + </li><li>to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20 + </li><li>to_char(INTERVAL '3 years 5 months','MM') => 41 + </li></ul> + </li><li>Prevent to_char() on interval from returning meaningless values +<p> For example, to_char('1 month', 'mon') is meaningless. Basically, + most date-related parameters to to_char() are meaningless for + intervals because interval is not anchored to a date. +</p> +</li></ul> +<h1><a name="section_6">Multi-Language Support</a></h1> <ul> <li>Add NCHAR (as distinguished from ordinary varchar), @@ -254,11 +263,11 @@ first. <p> Right now only one encoding is allowed per database. </p> </li><li>Support multiple simultaneous character sets, per SQL92 - </li><li>Improve UTF8 combined character handling (?) + </li><li>Improve UTF8 combined character handling? </li><li>Add octet_length_server() and octet_length_client() </li><li>Make octet_length_client() the same as octet_length()? </li></ul> -<h1><a name="section_5">Views / Rules</a></h1> +<h1><a name="section_7">Views / Rules</a></h1> <ul> <li>Automatically create rules on views so they are updateable, per SQL99 @@ -271,90 +280,16 @@ first. </li><li>Allow temporary views on non-temporary tables </li><li>Allow RULE recompilation </li></ul> -<h1><a name="section_6">Indexes</a></h1> - -<ul> - <li>Allow inherited tables to inherit index, UNIQUE constraint, and primary - key, foreign key - </li><li>UNIQUE INDEX on base column not honored on INSERTs/UPDATEs from - inherited table: INSERT INTO inherit_table (unique_index_col) VALUES - (dup) should fail -<p> The main difficulty with this item is the problem of creating an index - that can span more than one table. -</p> - </li><li>Add UNIQUE capability to non-btree indexes - </li><li>Add more gist index support for geometric data types - </li><li>-<em>Use indexes for MIN() and MAX()</em> -<p> MIN/MAX queries can already be rewritten as SELECT col FROM tab ORDER - BY col {DESC} LIMIT 1. Completing this item involves doing this - transformation automatically. -</p> - </li><li>-<em>Use index to restrict rows returned by multi-key index when used with</em> - non-consecutive keys to reduce heap accesses -<p> For an index on col1,col2,col3, and a WHERE clause of col1 = 5 and - col3 = 9, spin though the index checking for col1 and col3 matches, - rather than just col1; also called skip-scanning. -</p> - </li><li>Prevent index uniqueness checks when UPDATE does not modify the column -<p> Uniqueness (index) checks are done when updating a column even if the - column is not modified by the UPDATE. -</p> - </li><li>Fetch heap pages matching index entries in sequential order -<p> Rather than randomly accessing heap pages based on index entries, mark - heap pages needing access in a bitmap and do the lookups in sequential - order. Another method would be to sort heap ctids matching the index - before accessing the heap rows. -</p> - </li><li>-<em>Allow non-bitmap indexes to be combined by creating bitmaps in memory</em> -<p> This feature allows separate indexes to be ANDed or ORed together. This - is particularly useful for data warehousing applications that need to - query the database in an many permutations. This feature scans an index - and creates an in-memory bitmap, and allows that bitmap to be combined - with other bitmap created in a similar way. The bitmap can either index - all TIDs, or be lossy, meaning it records just page numbers and each - page tuple has to be checked for validity in a separate pass. -</p> - </li><li>Allow the creation of on-disk bitmap indexes which can be quickly - combined with other bitmap indexes -<p> Such indexes could be more compact if there are only a few distinct values. - Such indexes can also be compressed. Keeping such indexes updated can be - costly. -</p> - </li><li>Allow use of indexes to search for NULLs -<p> One solution is to create a partial index on an IS NULL expression. -</p> - </li><li>-<em>Add concurrency to GIST</em> - </li><li>Pack hash index buckets onto disk pages more efficiently -<p> Currently no only one hash bucket can be stored on a page. Ideally - several hash buckets could be stored on a single page and greater - granularity used for the hash algorithm. -</p> - </li><li>Consider sorting hash buckets so entries can be found using a binary - search, rather than a linear scan - </li><li>In hash indexes, consider storing the hash value with or instead - of the key itself - </li><li>Allow accurate statistics to be collected on indexes with more than - one column or expression indexes, perhaps using per-index statistics - </li><li>Add fillfactor to control reserved free space during index creation - </li><li>Allow the creation of indexes with mixed ascending/descending specifiers - </li><li>-<em>Fix incorrect rtree results due to wrong assumptions about "over"</em> - operator semantics - </li><li>Allow GIST indexes to create certain complex index types, like digital - trees (see Aoki) -</li></ul> -<h1><a name="section_7">Commands</a></h1> +<h1><a name="section_8">Commands</a></h1> <ul> <li>-<em>Add BETWEEN SYMMETRIC/ASYMMETRIC</em> </li><li>Change LIMIT/OFFSET and FETCH/MOVE to use int8 </li><li>Allow CREATE TABLE AS to determine column lengths for complex expressions like SELECT col1 || col2 - </li><li>Allow UPDATE to handle complex aggregates [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?update">update</a>] (?) - </li><li>Allow backslash handling in quoted strings to be disabled for portability -<p> The use of C-style backslashes (.e.g. \n, \r) in quoted strings is not - SQL-spec compliant, so allow such handling to be disabled. However, - disabling backslashes could break many third-party applications and tools. -</p> + </li><li>Allow UPDATE to handle complex aggregates [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?update">update</a>]? + </li><li>-<em>Add E'' escape string marker so eventually ordinary strings can treat</em> + backslashes literally, for portability </li><li>Allow an alias to be provided for the target table in UPDATE/DELETE <p> This is not SQL-spec but many DBMSs allow it. </p> @@ -363,6 +298,7 @@ first. functionality in DELETE. It's been agreed that the keyword should be USING, to avoid anything as confusing as DELETE FROM a FROM b. </p> + </li><li>Have initdb set DateStyle based on locale? </li><li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT </li><li>-<em>Allow REINDEX to rebuild all database indexes</em> </li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY @@ -394,7 +330,7 @@ first. <p> Currently the system uses the operating system COPY command to create a new database. </p> - </li><li>Add C code to copy directories for use in creating new databases + </li><li>Add C code on Unix to copy directories for use in creating new databases </li><li>Have pg_ctl look at PGHOST in case it is a socket directory? </li><li>Allow pg_ctl to work properly with configuration files located outside the PGDATA directory @@ -403,7 +339,6 @@ first. allow pg_ctl to read and understand postgresql.conf to find the data_directory value. </p> - </li><li>Allow column-level GRANT/REVOKE privileges </li><li>Add a GUC variable to warn about non-standard SQL usage in queries </li><li>Add MERGE command that does UPDATE/DELETE, or on failure, INSERT (rules, triggers?) @@ -412,7 +347,7 @@ first. creation </li><li>Add COMMENT ON for all cluster global objects (roles, databases and tablespaces) - </li><li>Add an option to automatically use savepoints for each statement in a + </li><li>-<em>Add an option to automatically use savepoints for each statement in a</em> multi-statement transaction. <p> When enabled, this would allow errors in multi-statement transactions to be automatically ignored. @@ -470,11 +405,25 @@ first. processed, with ROLLBACK on COPY failure. </p> </li><li>-<em>Allow COPY to understand \x as a hex byte</em> - </li><li>Have COPY return the number of rows loaded/unloaded (?) + </li><li>Have COPY return the number of rows loaded/unloaded? </li><li>-<em>Allow COPY to optionally include column headings in the first line</em> </li><li>-<em>Allow COPY FROM ... CSV to interpret newlines and carriage</em> returns in data </li></ul> + </li><li>GRANT/REVOKE + <ul> + <li>Allow column-level privileges + <ul> + <li>Allow GRANT/REVOKE permissions to be applied to all schema objects with one + command +<p> The proposed syntax is: +</p><p> GRANT SELECT ON ALL TABLES IN public TO phpuser; + GRANT SELECT ON NEW TABLES IN public TO phpuser; +</p> + </li><li>Allow GRANT/REVOKE permissions to be inherited by objects based on + schema permissions + </li></ul> + </li></ul> </li><li>CURSOR <ul> <li>Allow UPDATE/DELETE WHERE CURRENT OF cursor @@ -484,7 +433,7 @@ first. and no FOR UPDATE lock. </p> </li><li>Prevent DROP TABLE from dropping a row referenced by its own open - cursor (?) + cursor? </li><li>Allow pooled connections to list all open WITH HOLD cursors <p> Because WITH HOLD cursors exist outside transactions, this allows them to be listed so they can be closed. @@ -505,7 +454,7 @@ first. <li>-<em>Have SHOW ALL show descriptions for server-side variables</em> </li><li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM ANALYZE, and CLUSTER - </li><li>Add SET PATH for schemas (?) + </li><li>Add SET PATH for schemas? <p> This is basically the same as SET search_path. </p> </li></ul> @@ -524,7 +473,7 @@ first. </li><li>Allow function parameters to be passed by name, get_employee_salary(emp_id => 12345, tax_year => 2001) </li><li>Add Oracle-style packages - </li><li>Add table function support to pltcl, plperl, plpython (?) + </li><li>Add table function support to pltcl, plperl, plpython? </li><li>Allow PL/pgSQL to name columns by ordinal position, e.g. rec.(3) </li><li>-<em>Allow PL/pgSQL EXECUTE query_var INTO record_var;</em> </li><li>Add capability to create and call PROCEDURES @@ -534,11 +483,11 @@ first. </li><li>Add support for polymorphic arguments and return types to plperl </li></ul> </li></ul> -<h1><a name="section_8">Clients</a></h1> +<h1><a name="section_9">Clients</a></h1> <ul> <li>Add a libpq function to support Parse/DescribeStatement capability - </li><li>Prevent libpq's PQfnumber() from lowercasing the column name (?) + </li><li>Prevent libpq's PQfnumber() from lowercasing the column name? </li><li>Allow libpq to access SQLSTATE so pg_ctl can test for connection failure <p> This would be used for checking if the server is up. </p> @@ -577,7 +526,7 @@ first. <p> Document differences between ecpg and the SQL standard and information about the Informix-compatibility module. </p> - </li><li>Solve cardinality > 1 for input descriptors / variables (?) + </li><li>Solve cardinality > 1 for input descriptors / variables? </li><li>Add a semantic check level, e.g. check if a table really exists </li><li>fix handling of DB attributes that are arrays </li><li>Use backend PREPARE/EXECUTE facility for ecpg where possible @@ -589,7 +538,7 @@ first. </li><li>Add internationalized message strings </li></ul> </li></ul> -<h1><a name="section_9">Referential Integrity</a></h1> +<h1><a name="section_10">Referential Integrity</a></h1> <ul> <li>Add MATCH PARTIAL referential integrity @@ -601,8 +550,8 @@ first. </li><li>-<em>Implement shared row locks and use them in RI triggers</em> </li><li>Enforce referential integrity for system tables </li><li>Change foreign key constraint for array -> element to mean element - in array (?) - </li><li>Allow DEFERRABLE UNIQUE constraints (?) + in array? + </li><li>Allow DEFERRABLE UNIQUE constraints? </li><li>Allow triggers to be disabled [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?trigger">trigger</a>] <p> Currently the only way to disable triggers is to modify the system tables. @@ -624,13 +573,13 @@ first. to fire triggers. </p> </li></ul> -<h1><a name="section_10">Dependency Checking</a></h1> +<h1><a name="section_11">Dependency Checking</a></h1> <ul> <li>Flush cached query plans when the dependent objects change </li><li>Track dependencies in function bodies and recompile/invalidate </li></ul> -<h1><a name="section_11">Exotic Features</a></h1> +<h1><a name="section_12">Exotic Features</a></h1> <ul> <li>Add SQL99 WITH clause to SELECT @@ -658,9 +607,81 @@ first. </li><li>Allow nested schemas </li></ul> </li></ul> -<h2><a name="section_11_1">PERFORMANCE</a></h2> +<h1><a name="section_13">Indexes</a></h1> -<h1><a name="section_12">Fsync</a></h1> +<ul> + <li>Allow inherited tables to inherit index, UNIQUE constraint, and primary + key, foreign key + </li><li>UNIQUE INDEX on base column not honored on INSERTs/UPDATEs from + inherited table: INSERT INTO inherit_table (unique_index_col) VALUES + (dup) should fail +<p> The main difficulty with this item is the problem of creating an index + that can span more than one table. +</p> + </li><li>Add UNIQUE capability to non-btree indexes + </li><li>Add more GIST index support for geometric data types + </li><li>-<em>Use indexes for MIN() and MAX()</em> +<p> MIN/MAX queries can already be rewritten as SELECT col FROM tab ORDER + BY col {DESC} LIMIT 1. Completing this item involves doing this + transformation automatically. +</p> + </li><li>-<em>Use index to restrict rows returned by multi-key index when used with</em> + non-consecutive keys to reduce heap accesses +<p> For an index on col1,col2,col3, and a WHERE clause of col1 = 5 and + col3 = 9, spin though the index checking for col1 and col3 matches, + rather than just col1; also called skip-scanning. +</p> + </li><li>Prevent index uniqueness checks when UPDATE does not modify the column +<p> Uniqueness (index) checks are done when updating a column even if the + column is not modified by the UPDATE. +</p> + </li><li>Fetch heap pages matching index entries in sequential order +<p> Rather than randomly accessing heap pages based on index entries, mark + heap pages needing access in a bitmap and do the lookups in sequential + order. Another method would be to sort heap ctids matching the index + before accessing the heap rows. +</p> + </li><li>-<em>Allow non-bitmap indexes to be combined by creating bitmaps in memory</em> +<p> This feature allows separate indexes to be ANDed or ORed together. This + is particularly useful for data warehousing applications that need to + query the database in an many permutations. This feature scans an index + and creates an in-memory bitmap, and allows that bitmap to be combined + with other bitmap created in a similar way. The bitmap can either index + all TIDs, or be lossy, meaning it records just page numbers and each + page tuple has to be checked for validity in a separate pass. +</p> + </li><li>Allow the creation of on-disk bitmap indexes which can be quickly + combined with other bitmap indexes +<p> Such indexes could be more compact if there are only a few distinct values. + Such indexes can also be compressed. Keeping such indexes updated can be + costly. +</p> + </li><li>Allow use of indexes to search for NULLs +<p> One solution is to create a partial index on an IS NULL expression. +</p> + </li><li>-<em>Add concurrency to GIST</em> + </li><li>Allow accurate statistics to be collected on indexes with more than + one column or expression indexes, perhaps using per-index statistics + </li><li>Add fillfactor to control reserved free space during index creation + </li><li>Allow the creation of indexes with mixed ascending/descending specifiers + </li><li>-<em>Fix incorrect rtree results due to wrong assumptions about "over"</em> + operator semantics + </li><li>Allow GIST indexes to create certain complex index types, like digital + trees (see Aoki) + </li><li>Hash + <ul> + <li>Pack hash index buckets onto disk pages more efficiently +<p> Currently no only one hash bucket can be stored on a page. Ideally + several hash buckets could be stored on a single page and greater + granularity used for the hash algorithm. +</p> + </li><li>Consider sorting hash buckets so entries can be found using a + binary search, rather than a linear scan + </li><li>In hash indexes, consider storing the hash value with or instead + of the key itself + </li></ul> +</li></ul> +<h1><a name="section_14">Fsync</a></h1> <ul> <li>Improve commit_delay handling to reduce fsync() @@ -669,7 +690,7 @@ first. </li><li>Add an option to sync() before fsync()'ing checkpoint files </li><li>Add program to test if fsync has a delay compared to non-fsync </li></ul> -<h1><a name="section_13">Cache</a></h1> +<h1><a name="section_15">Cache Usage</a></h1> <ul> <li>Allow free-behind capability for large sequential scans, perhaps using @@ -725,7 +746,7 @@ first. at the start of the table. </p> </li></ul> -<h1><a name="section_14">Vacuum</a></h1> +<h1><a name="section_16">Vacuum</a></h1> <ul> <li>Improve speed with indexes @@ -758,7 +779,7 @@ first. </li><li>Do VACUUM FULL if table is nearly empty? </li></ul> </li></ul> -<h1><a name="section_15">Locking</a></h1> +<h1><a name="section_17">Locking</a></h1> <ul> <li>Make locking of shared data structures more fine-grained @@ -780,7 +801,7 @@ first. </li><li>Research use of sched_yield() for spinlock acquisition failure </li><li>Fix priority ordering of read and write light-weight locks (Neil) </li></ul> -<h1><a name="section_16">Startup Time</a></h1> +<h1><a name="section_18">Startup Time Improvements</a></h1> <ul> <li>Experiment with multi-threaded backend [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?thread">thread</a>] @@ -796,7 +817,7 @@ first. existing backends is one of the difficulties with a backend approach. </p> </li></ul> -<h1><a name="section_17">Write-Ahead Log</a></h1> +<h1><a name="section_19">Write-Ahead Log</a></h1> <ul> <li>Eliminate need to write full pages to WAL before page modification [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?wal">wal</a>] @@ -806,7 +827,7 @@ first. eliminated from point-in-time archive files. </p> </li><li>Reduce WAL traffic so only modified values are written rather than - entire rows (?) + entire rows? </li><li>Turn off full page writes if fsync is disabled <p> If fsync is off, there is no purpose in writing full pages to WAL </p> @@ -831,7 +852,7 @@ first. </li><li>Eliminate WAL logging for CREATE TABLE AS when not doing WAL archiving </li><li>-<em>Change WAL to use 32-bit CRC, for performance reasons</em> </li></ul> -<h1><a name="section_18">Optimizer / Executor</a></h1> +<h1><a name="section_20">Optimizer / Executor</a></h1> <ul> <li>Add missing optimizer selectivities for date, r-tree, etc @@ -856,16 +877,16 @@ first. </p> </li><li>ANALYZE should record a pg_statistic entry for an all-NULL column </li><li>Log queries where the optimizer row estimates were dramatically - different from the number of rows actually found (?) + different from the number of rows actually found? </li></ul> -<h1><a name="section_19">Miscellaneous</a></h1> +<h1><a name="section_21">Miscellaneous Performance</a></h1> <ul> <li>Do async I/O for faster random read-ahead of data <p> Async I/O allows multiple I/O requests to be sent to the disk with results coming back asynchronously. </p> - </li><li>Use mmap() rather than SYSV shared memory or to write WAL files (?) + </li><li>Use mmap() rather than SYSV shared memory or to write WAL files? <p> This would remove the requirement for SYSV SHM but would introduce portability issues. Anonymous mmap (or mmap to /dev/zero) is required to prevent I/O overhead. @@ -882,7 +903,7 @@ first. </li><li>Use a phantom command counter for nested subtransactions to reduce per-tuple overhead </li></ul> -<h1><a name="section_20">Source Code</a></h1> +<h1><a name="section_22">Source Code</a></h1> <ul> <li>Add use of 'const' for variables in source tree @@ -948,7 +969,7 @@ first. </li></ul> <hr/> -<h3><a name="section_20_1_1">Developers who have claimed items are:</a></h3> +<h2><a name="section_22_1">Developers who have claimed items are:</a></h2> <ul> <li>Alvaro is Alvaro Herrera <<a href="mailto:alvherre@dcc.uchile.cl">alvherre@dcc.uchile.cl</a>> </li><li>Andrew is Andrew Dunstan <<a href="mailto:andrew@dunslane.net">andrew@dunslane.net</a>> |