ac9e14d064
< STABLE | DEFAULT ]. [wallog] > STABLE | DEFAULT ]. Tables using non-default logging should not use > referential integrity with default-logging tables, and tables using > stable logging probably can not have indexes. [wallog]
1101 lines
54 KiB
HTML
1101 lines
54 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
|
|
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html>
|
|
<head>
|
|
<title>PostgreSQL TODO List</title>
|
|
<meta name="generator" content="HTML::TextToHTML v2.25"/>
|
|
</head>
|
|
<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: Thu Jan 5 11:35:12 EST 2006
|
|
</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>.
|
|
</p>
|
|
<p><strong>A hyphen, "-", marks changes that will appear in the upcoming 8.2 release.</strong><br/>
|
|
<strong>A percent sign, "%", marks items that are easier to implement.</strong>
|
|
</p>
|
|
<p>Bracketed items, "[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?"></a>]", have more detail.
|
|
</p>
|
|
<p>This list contains all known PostgreSQL bugs and feature requests. If<br/>
|
|
you would like to work on an item, please read the Developer's FAQ<br/>
|
|
first.
|
|
</p>
|
|
<h1><a name="section_2">Administration</a></h1>
|
|
|
|
<ul>
|
|
<li>%Remove behavior of postmaster -o
|
|
</li><li>%Allow pooled connections to list all prepared statements
|
|
<p> This would allow an application inheriting a pooled connection to know
|
|
the statements 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>Check for unreferenced table files created by transactions that were
|
|
in-progress when the server terminated abruptly
|
|
</li><li>Allow administrators to safely terminate individual sessions either
|
|
via an SQL function or SIGTERM
|
|
<p> Lock table corruption following SIGTERM of an individual backend
|
|
has been reported in 8.0. A possible cause was fixed in 8.1, but
|
|
it is unknown whether other problems exist. This item mostly
|
|
requires additional testing rather than of writing any new code.
|
|
</p>
|
|
</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>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>Add function to report the time of the most recent server reload
|
|
</li><li>Improve replication solutions
|
|
<ul>
|
|
<li>Load balancing
|
|
<p> You can use any of the master/slave replication servers to use a
|
|
standby server for data warehousing. To allow read/write queries to
|
|
multiple servers, you need multi-master replication like pgcluster.
|
|
</p>
|
|
</li><li>Allow replication over unreliable or non-persistent links
|
|
</li></ul>
|
|
</li><li>Configuration files
|
|
<ul>
|
|
<li>%Add "include file" functionality in postgresql.conf
|
|
</li><li>%Allow commenting of variables in postgresql.conf to restore them
|
|
to defaults
|
|
<p> Currently, if a variable is commented out, it keeps the
|
|
previous uncommented value until a server restarted.
|
|
</p>
|
|
</li><li>%Allow pg_hba.conf settings to be controlled via SQL
|
|
<p> This would add a function to load the SQL table from
|
|
pg_hba.conf, and one to writes its contents to the flat file.
|
|
The table should have a line number that is a float so rows
|
|
can be inserted between existing rows, e.g. row 2.5 goes
|
|
between row 2 and row 3.
|
|
</p>
|
|
</li><li>%Allow postgresql.conf file values to be changed via an SQL
|
|
API, perhaps using SET GLOBAL
|
|
</li><li>Allow the server to be stopped/restarted via an SQL API
|
|
</li><li>Issue a warning if a change-on-restart-only postgresql.conf value
|
|
is modified and the server config files are reloaded
|
|
</li><li>Mark change-on-restart-only values in postgresql.conf
|
|
</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 contains 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 statements
|
|
[<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>Allow server logs to be remotely read and removed using SQL commands
|
|
</li><li>Allow protocol-level BIND parameter values to be logged
|
|
</li></ul>
|
|
<h1><a name="section_4">Data Types</a></h1>
|
|
|
|
<ul>
|
|
<li>Improve the MONEY data type
|
|
<p> Change the MONEY data type to use DECIMAL internally, with special
|
|
locale-aware output formatting.
|
|
</p>
|
|
</li><li>Change NUMERIC to enforce the maximum precision
|
|
</li><li>Add NUMERIC division operator that doesn't round?
|
|
<p> Currently NUMERIC _rounds_ the result to the specified precision.
|
|
This means division can return a result that multiplied by the
|
|
divisor is greater than the dividend, e.g. this returns a value > 10:
|
|
</p>
|
|
</li></ul>
|
|
<p> SELECT (10::numeric(2,0) / 6::numeric(2,0))::numeric(2,0) * 6;
|
|
</p>
|
|
<p> The positive modulus result returned by NUMERICs might be considered<br/>
|
|
inaccurate, in one sense.
|
|
</p>
|
|
<ul>
|
|
<li>%Disallow changing default expression of a SERIAL column?
|
|
</li><li>Fix data types where equality comparison isn't intuitive, e.g. box
|
|
</li><li>%Prevent INET cast to CIDR if the unmasked bits are not zero, or
|
|
zero the bits
|
|
</li><li>%Prevent INET cast to CIDR from dropping netmask, SELECT '<a href="telnet://1.1.1.1">1.1.1.1</a>'::inet::cidr
|
|
</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>Allow user-defined types to specify a type modifier at table creation
|
|
time
|
|
</li><li>Dates and Times
|
|
<ul>
|
|
<li>Allow infinite dates just like infinite timestamps
|
|
</li><li>Merge hardwired timezone names with the TZ database; allow either
|
|
kind everywhere a TZ name is currently taken
|
|
</li><li>Allow customization of the known set of TZ names (generalize the
|
|
present australian_timezones hack)
|
|
</li><li>Allow TIMESTAMP WITH TIME ZONE to store the original timezone
|
|
information, either zone name or offset from UTC [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?timezone">timezone</a>]
|
|
<p> If the TIMESTAMP value is stored with a time zone name, interval
|
|
computations should adjust based on the time zone rules.
|
|
</p>
|
|
</li><li>Fix SELECT '0.01 years'::interval, '0.01 months'::interval
|
|
</li><li>Fix SELECT INTERVAL '1' MONTH
|
|
</li><li>Add a GUC variable to allow output of interval values in ISO8601
|
|
format
|
|
</li><li>Improve timestamptz subtraction to be DST-aware
|
|
<p> Currently, subtracting one date from another that crosses a
|
|
daylight savings time adjustment can return '1 day 1 hour', but
|
|
adding that back to the first date returns a time one hour in
|
|
the future. This is caused by the adjustment of '25 hours' to
|
|
'1 day 1 hour', and '1 day' is the same time the next day, even
|
|
if daylight savings adjustments are involved.
|
|
</p>
|
|
</li><li>Fix interval display to support values exceeding 2^31 hours
|
|
</li><li>Add overflow checking to timestamp and interval arithmetic
|
|
</li><li>Add ISO INTERVAL handling
|
|
<ul>
|
|
<li>Add support for day-time syntax, INTERVAL '1 2:03:04' DAY TO
|
|
SECOND
|
|
</li><li>Add support for year-month syntax, INTERVAL '50-6' YEAR TO MONTH
|
|
</li><li>For syntax that isn't uniquely ISO or PG syntax, like '1:30' or
|
|
'1', treat as ISO if there is a range specification clause,
|
|
and as PG if there no clause is present, e.g. interpret
|
|
<p> '1:30' MINUTE TO SECOND as '1 minute 30 seconds', and
|
|
interpret '1:30' as '1 hour, 30 minutes'
|
|
<li>Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1 year' AS
|
|
INTERVAL MONTH), and this should return '12 months'
|
|
</li><li>Round or truncate values to the requested precision, e.g.
|
|
INTERVAL '11 months' AS YEAR should return one or zero
|
|
</li><li>Support precision, CREATE TABLE foo (a INTERVAL MONTH(3))
|
|
</li></ul>
|
|
</p></ul>
|
|
</li><li>Arrays
|
|
<ul>
|
|
<li>-<em>Allow NULLs in arrays</em>
|
|
</li><li>Delay resolution of array expression's data type so assignment
|
|
coercion can be performed on empty array expressions
|
|
</li></ul>
|
|
</li><li>Binary Data
|
|
<ul>
|
|
<li>Improve vacuum of large objects, like /contrib/vacuumlo?
|
|
</li><li>Add security checking for large objects
|
|
</li><li>Auto-delete large objects when referencing row is deleted
|
|
<p> /contrib/lo offers this functionality.
|
|
</p>
|
|
</li><li>Allow read/write into TOAST values like large objects
|
|
<p> This requires the TOAST column to be stored EXTERNAL.
|
|
</p>
|
|
</li></ul>
|
|
</li></ul>
|
|
<h1><a name="section_5">Functions</a></h1>
|
|
|
|
<ul>
|
|
<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(), pg_get_attrdef(),
|
|
pg_get_tabledef(), pg_get_domaindef(), pg_get_functiondef()
|
|
</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>Add sleep() function, remove from regress.c
|
|
</li><li>Allow user-defined functions retuning a domain value to enforce domain
|
|
constraints
|
|
</li><li>Add SPI_gettypmod() to return the typemod for a TupleDesc
|
|
</li></ul>
|
|
<h1><a name="section_6">Multi-Language Support</a></h1>
|
|
|
|
<ul>
|
|
<li>Add NCHAR (as distinguished from ordinary varchar),
|
|
</li><li>Allow locale to be set at database creation
|
|
<p> Currently locale can only be set during initdb. No global tables have
|
|
locale-aware columns. However, the database template used during
|
|
database creation might have locale-aware indexes. The indexes would
|
|
need to be reindexed to match the new locale.
|
|
</p>
|
|
</li><li>Allow encoding on a per-column basis
|
|
<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>Add octet_length_server() and octet_length_client()
|
|
</li><li>Make octet_length_client() the same as octet_length()?
|
|
</li><li>Fix problems with wrong runtime encoding conversion for NLS message files
|
|
</li></ul>
|
|
<h1><a name="section_7">Views / Rules</a></h1>
|
|
|
|
<ul>
|
|
<li>%Automatically create rules on views so they are updateable, per SQL99
|
|
<p> We can only auto-create rules for simple views. For more complex
|
|
cases users will still have to write rules.
|
|
</p>
|
|
</li><li>Add the functionality for WITH CHECK OPTION clause of CREATE VIEW
|
|
</li><li>Allow NOTIFY in rules involving conditionals
|
|
</li><li>Allow VIEW/RULE recompilation when the underlying tables change
|
|
<p> Another issue is whether underlying table changes should be reflected
|
|
in the view, e.g. should SELECT * show additional columns if they
|
|
are added after the view is created.
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_8">SQL Commands</a></h1>
|
|
|
|
<ul>
|
|
<li>Change LIMIT/OFFSET and FETCH/MOVE to use int8
|
|
</li><li>Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
|
|
</li><li>Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
|
|
</li><li>%Allow SET CONSTRAINTS to be qualified by schema/table name
|
|
</li><li>%Allow TRUNCATE ... CASCADE/RESTRICT
|
|
<p> This is like DELETE CASCADE, but truncates.
|
|
</p>
|
|
</li><li>%Add a separate TRUNCATE permission
|
|
<p> Currently only the owner can TRUNCATE a table because triggers are not
|
|
called, and the table is locked in exclusive mode.
|
|
</p>
|
|
</li><li>Allow PREPARE of cursors
|
|
</li><li>Allow PREPARE to automatically determine parameter types based on the SQL
|
|
statement
|
|
</li><li>Allow finer control over the caching of prepared query plans
|
|
<p> Currently, queries prepared via the libpq API are planned on first
|
|
execute using the supplied parameters --- allow SQL PREPARE to do the
|
|
same. Also, allow control over replanning prepared queries either
|
|
manually or automatically when statistics for execute parameters
|
|
differ dramatically from those used during planning.
|
|
</p>
|
|
</li><li>Allow LISTEN/NOTIFY to store info in memory rather than tables?
|
|
<p> Currently LISTEN/NOTIFY information is stored in pg_listener. Storing
|
|
such information in memory would improve performance.
|
|
</p>
|
|
</li><li>Add optional textual message to NOTIFY
|
|
<p> This would allow an informational message to be added to the notify
|
|
message, perhaps indicating the row modified or other custom
|
|
information.
|
|
</p>
|
|
</li><li>Add a GUC variable to warn about non-standard SQL usage in queries
|
|
</li><li>Add SQL-standard MERGE command, typically used to merge two tables
|
|
[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
|
|
<p> This is similar to UPDATE, then for unmatched rows, INSERT.
|
|
Whether concurrent access allows modifications which could cause
|
|
row loss is implementation independent.
|
|
</p>
|
|
</li><li>Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
|
|
[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?merge">merge</a>]
|
|
<p> 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.
|
|
</p>
|
|
</li><li>Add NOVICE output level for helpful messages like automatic sequence/index
|
|
creation
|
|
</li><li>%Add COMMENT ON for all cluster global objects (roles, databases
|
|
and tablespaces)
|
|
</li><li>-<em>Make row-wise comparisons work per SQL spec</em>
|
|
<p> Right now, '(a, b) < (1, 2)' is processed as 'a < 1 and b < 2', but
|
|
the SQL standard requires it to be processed as a column-by-column
|
|
comparison, so the proper comparison is '(a < 1) OR (a = 1 AND b < 2)'.
|
|
</p>
|
|
</li><li>Add RESET CONNECTION command to reset all session state
|
|
<p> This would include resetting of all variables (RESET ALL), dropping of
|
|
temporary tables, removing any NOTIFYs, cursors, open transactions,
|
|
prepared queries, currval()s, etc. This could be used for connection
|
|
pooling. We could also change RESET ALL to have this functionality.
|
|
The difficult of this features is allowing RESET ALL to not affect
|
|
changes made by the interface driver for its internal use. One idea
|
|
is for this to be a protocol-only feature. Another approach is to
|
|
notify the protocol when a RESET CONNECTION command is used.
|
|
</p>
|
|
</li><li>Add GUC to issue notice about statements that use unjoined tables
|
|
</li><li>Allow EXPLAIN to identify tables that were skipped because of
|
|
constraint_exclusion
|
|
</li><li>Allow EXPLAIN output to be more easily processed by scripts
|
|
</li><li>Eventually enable escape_string<u>warning and standard</u>conforming_strings
|
|
</li><li>Simplify dropping roles that have objects in several databases
|
|
</li><li>Allow COMMENT ON to accept an expression rather than just a string
|
|
</li><li>Allow the count returned by SELECT, etc to be to represent as an int64
|
|
to allow a higher range of values
|
|
</li><li>Make CLUSTER preserve recently-dead tuples per MVCC requirements
|
|
</li><li>CREATE
|
|
<ul>
|
|
<li>Allow CREATE TABLE AS to determine column lengths for complex
|
|
expressions like SELECT col1 || col2
|
|
</li><li>Use more reliable method for CREATE DATABASE to get a consistent
|
|
copy of db?
|
|
</li><li>Add ON COMMIT capability to CREATE TABLE AS ... SELECT
|
|
</li></ul>
|
|
</li><li>UPDATE
|
|
<ul>
|
|
<li>Allow UPDATE to handle complex aggregates [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?update">update</a>]?
|
|
</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>
|
|
</li><li>Allow UPDATE tab SET ROW (col, ...) = (...) for updating multiple
|
|
columns
|
|
</li></ul>
|
|
</li><li>ALTER
|
|
<ul>
|
|
<li>%Have ALTER TABLE RENAME rename SERIAL sequence names
|
|
</li><li>Add ALTER DOMAIN to modify the underlying data type
|
|
</li><li>%Allow ALTER TABLE ... ALTER CONSTRAINT ... RENAME
|
|
</li><li>%Allow ALTER TABLE to change constraint deferrability and actions
|
|
</li><li>Add missing object types for ALTER ... SET SCHEMA
|
|
</li><li>Allow ALTER TABLESPACE to move to different directories
|
|
</li><li>Allow databases to be moved to different tablespaces
|
|
</li><li>Allow moving system tables to other tablespaces, where possible
|
|
<p> Currently non-global system tables must be in the default database
|
|
tablespace. Global system tables can never be moved.
|
|
</p>
|
|
</li><li>%Disallow dropping of an inherited constraint
|
|
</li><li>%Prevent child tables from altering or dropping constraints
|
|
like CHECK that were inherited from the parent table
|
|
</li><li>Have ALTER INDEX update the name of a constraint using that index
|
|
</li><li>Add ALTER TABLE RENAME CONSTRAINT, update index name also
|
|
</li></ul>
|
|
</li><li>CLUSTER
|
|
<ul>
|
|
<li>Automatically maintain clustering on a table
|
|
<p> This might require some background daemon to maintain clustering
|
|
during periods of low usage. It might also require tables to be only
|
|
partially filled for easier reorganization. Another idea would
|
|
be to create a merged heap/index data file so an index lookup would
|
|
automatically access the heap data too. A third idea would be to
|
|
store heap rows in hashed groups, perhaps using a user-supplied
|
|
hash function.
|
|
</p>
|
|
</li><li>%Add default clustering to system tables
|
|
<p> To do this, determine the ideal cluster index for each system
|
|
table and set the cluster setting during initdb.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>COPY
|
|
<ul>
|
|
<li>Allow COPY to report error lines and continue
|
|
<p> This requires the use of a savepoint before each COPY line is
|
|
processed, with ROLLBACK on COPY failure.
|
|
</p>
|
|
</li><li>%Have COPY return the number of rows loaded/unloaded?
|
|
</li><li>Allow COPY on a newly-created table to skip WAL logging
|
|
<p> On crash recovery, the table involved in the COPY would
|
|
be removed or have its heap and index files truncated. One
|
|
issue is that no other backend should be able to add to
|
|
the table at the same time, which is something that is
|
|
currently allowed.
|
|
</p>
|
|
</li><li>Allow COPY to output from views
|
|
<p> Another idea would be to allow actual SELECT statements in a COPY.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>GRANT/REVOKE
|
|
<ul>
|
|
<li>Allow column-level privileges
|
|
</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>
|
|
<ul>
|
|
<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
|
|
<p> This requires using the row ctid to map cursor rows back to the
|
|
original heap row. This become more complicated if WITH HOLD cursors
|
|
are to be supported because WITH HOLD cursors have a copy of the row
|
|
and no FOR UPDATE lock.
|
|
</p>
|
|
</li><li>Prevent DROP TABLE from dropping a row referenced by its own open
|
|
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.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>INSERT
|
|
<ul>
|
|
<li>Allow INSERT/UPDATE of the system-generated oid value for a row
|
|
</li><li>Allow INSERT INTO tab (col1, ..) VALUES (val1, ..), (val2, ..)
|
|
</li><li>Allow INSERT/UPDATE ... RETURNING new.col or old.col
|
|
<p> This is useful for returning the auto-generated key for an INSERT.
|
|
One complication is how to handle rules that run as part of
|
|
the insert.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>SHOW/SET
|
|
<ul>
|
|
<li>Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
|
|
ANALYZE, and CLUSTER
|
|
</li><li>Add SET PATH for schemas?
|
|
<p> This is basically the same as SET search_path.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>Server-Side Languages
|
|
<ul>
|
|
<li>Fix PL/pgSQL RENAME to work on variables other than OLD/NEW
|
|
</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, plpython
|
|
</li><li>Add capability to create and call PROCEDURES
|
|
</li><li>Allow PL/pgSQL to handle %TYPE arrays, e.g. tab.col%TYPE[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?"></a>]
|
|
</li><li>Allow function argument names to be statements from PL/PgSQL
|
|
</li><li>Add MOVE to PL/pgSQL
|
|
</li><li>Add support for polymorphic arguments and return types to
|
|
languages other than PL/PgSQL
|
|
</li><li>Add support for OUT and INOUT parameters to languages other
|
|
than PL/PgSQL
|
|
</li><li>Add single-step debugging of PL/PgSQL functions
|
|
</li><li>Allow PL/PgSQL to support WITH HOLD cursors
|
|
</li></ul>
|
|
</li></ul>
|
|
<h1><a name="section_9">Clients</a></h1>
|
|
|
|
<ul>
|
|
<li>-<em>Have initdb set the input DateStyle (MDY or DMY) based on locale</em>
|
|
</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
|
|
<p> pg_ctl can not read the pid file because it isn't located in the
|
|
config directory but in the PGDATA directory. The solution is to
|
|
allow pg_ctl to read and understand postgresql.conf to find the
|
|
data_directory value.
|
|
</p>
|
|
</li><li>psql
|
|
<ul>
|
|
<li>Have psql show current values for a sequence
|
|
</li><li>Move psql backslash database information into the backend, use
|
|
mnemonic commands? [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?psql">psql</a>]
|
|
<p> This would allow non-psql clients to pull the same information out
|
|
of the database as psql.
|
|
</p>
|
|
</li><li>Fix psql's display of schema information (Neil)
|
|
</li><li>Allow psql \pset boolean variables to set to fixed values, rather
|
|
than toggle
|
|
</li><li>Consistently display privilege information for all objects in psql
|
|
</li><li>Improve psql's handling of multi-line statements
|
|
<p> Currently, while \e saves a single statement as one entry, interactive
|
|
statements are saved one line at a time. Ideally all statements
|
|
would be saved like \e does.
|
|
</p>
|
|
</li><li>Allow multi-line column values to align in the proper columns
|
|
<p> If the second output column value is 'a\nb', the 'b' should appear
|
|
in the second display column, rather than the first column as it
|
|
does now.
|
|
</p>
|
|
</li><li>Display IN, INOUT, and OUT parameters in \df+
|
|
<p> It probably requires psql to output newlines in the proper
|
|
column, which is already on the TODO list.
|
|
</p>
|
|
</li><li>Add auto-expanded mode so expanded output is used if the row
|
|
length is wider than the screen width.
|
|
<p> Consider using auto-expanded mode for backslash commands like \df+.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>pg_dump
|
|
<ul>
|
|
<li>%Have pg_dump use multi-statement transactions for INSERT dumps
|
|
</li><li>%Allow pg_dump to use multiple -t and -n switches [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?pg_dump">pg_dump</a>]
|
|
</li><li>%Add dumping of comments on index columns and composite type columns
|
|
</li><li>%Add full object name to the tag field. eg. for operators we need
|
|
'=(integer, integer)', instead of just '='.
|
|
</li><li>Add pg_dumpall custom format dumps?
|
|
</li><li>%Add CSV output format
|
|
</li><li>Update pg_dump and psql to use the new COPY libpq API (Christopher)
|
|
</li><li>Remove unnecessary function pointer abstractions in pg_dump source
|
|
code
|
|
</li><li>Allow selection of individual object(s) of all types, not just
|
|
tables
|
|
</li><li>In a selective dump, allow dumping of an object and all its
|
|
dependencies
|
|
</li><li>Add options like pg_restore -l and -L to pg_dump
|
|
</li><li>Stop dumping CASCADE on DROP TYPE commands in clean mode
|
|
</li><li>Allow pg_dump --clean to drop roles that own objects or have
|
|
privileges
|
|
</li><li>Add -f to pg_dumpall
|
|
</li></ul>
|
|
</li><li>ecpg
|
|
<ul>
|
|
<li>Docs
|
|
<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>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
|
|
</li><li>Implement SQLDA
|
|
</li><li>Fix nested C comments
|
|
</li><li>%sqlwarn[<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?6">6</a>] should be 'W' if the PRECISION or SCALE value specified
|
|
</li><li>Make SET CONNECTION thread-aware, non-standard?
|
|
</li><li>Allow multidimensional arrays
|
|
</li><li>Add internationalized message strings
|
|
</li></ul>
|
|
</li></ul>
|
|
<p>libpq
|
|
</p>
|
|
<ul>
|
|
<li>Add a function to support Parse/DescribeStatement capability
|
|
</li><li>Add PQescapeIdentifier()
|
|
</li><li>Prevent PQfnumber() from lowercasing unquoted the column name
|
|
<p> PQfnumber() should never have been doing lowercasing, but
|
|
historically it has so we need a way to prevent it
|
|
</p>
|
|
</li><li>Allow statement results to be automatically batched to the client
|
|
<p> Currently, all statement results are transferred to the libpq
|
|
client before libpq makes the results available to the
|
|
application. This feature would allow the application to make
|
|
use of the first result rows while the rest are transferred, or
|
|
held on the server waiting for them to be requested by libpq.
|
|
One complexity is that a statement like SELECT 1/col could error
|
|
out mid-way through the result set.
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_10">Referential Integrity</a></h1>
|
|
|
|
<ul>
|
|
<li>Add MATCH PARTIAL referential integrity
|
|
</li><li>Add deferred trigger queue file
|
|
<p> Right now all deferred trigger information is stored in backend
|
|
memory. This could exhaust memory for very large trigger queues.
|
|
This item involves dumping large queues into files.
|
|
</p>
|
|
</li><li>Change foreign key constraint for array -> element to mean element
|
|
in array?
|
|
</li><li>Allow DEFERRABLE UNIQUE constraints?
|
|
</li><li>Allow triggers to be disabled in only the current session.
|
|
<p> This is currently possible by starting a multi-statement transaction,
|
|
modifying the system tables, performing the desired SQL, restoring the
|
|
system tables, and committing the transaction. ALTER TABLE ...
|
|
TRIGGER requires a table lock so it is not ideal for this usage.
|
|
</p>
|
|
</li><li>With disabled triggers, allow pg_dump to use ALTER TABLE ADD FOREIGN KEY
|
|
<p> If the dump is known to be valid, allow foreign keys to be added
|
|
without revalidating the data.
|
|
</p>
|
|
</li><li>Allow statement-level triggers to access modified rows
|
|
</li><li>Support triggers on columns (Greg Sabino Mullane)
|
|
</li><li>Enforce referential integrity for system tables
|
|
</li><li>Allow AFTER triggers on system tables
|
|
<p> System tables are modified in many places in the backend without going
|
|
through the executor and therefore not causing triggers to fire. To
|
|
complete this item, the functions that modify system tables will have
|
|
to fire triggers.
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_11">Dependency Checking</a></h1>
|
|
|
|
<ul>
|
|
<li>Flush cached query plans when the dependent objects change,
|
|
when the cardinality of parameters changes dramatically, or
|
|
when new ANALYZE statistics are available
|
|
<p> A more complex solution would be to save multiple plans for different
|
|
cardinality and use the appropriate plan based on the EXECUTE values.
|
|
</p>
|
|
</li><li>Track dependencies in function bodies and recompile/invalidate
|
|
<p> This is particularly important for references to temporary tables
|
|
in PL/PgSQL because PL/PgSQL caches query plans. The only workaround
|
|
in PL/PgSQL is to use EXECUTE. One complexity is that a function
|
|
might itself drop and recreate dependent tables, causing it to
|
|
invalidate its own query plan.
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_12">Exotic Features</a></h1>
|
|
|
|
<ul>
|
|
<li>Add SQL99 WITH clause to SELECT
|
|
</li><li>Add SQL99 WITH RECURSIVE to SELECT
|
|
</li><li>Add pre-parsing phase that converts non-ISO syntax to supported
|
|
syntax
|
|
<p> This could allow SQL written for other databases to run without
|
|
modification.
|
|
</p>
|
|
</li><li>Allow plug-in modules to emulate features from other databases
|
|
</li><li>SQL*Net listener that makes PostgreSQL appear as an Oracle database
|
|
to clients
|
|
</li><li>Allow statements across databases or servers with transaction
|
|
semantics
|
|
<p> This can be done using dblink and two-phase commit.
|
|
</p>
|
|
</li><li>Add the features of packages
|
|
<ul>
|
|
<li>Make private objects accessible only to objects in the same schema
|
|
</li><li>Allow current_schema.objname to access current schema objects
|
|
</li><li>Add session variables
|
|
</li><li>Allow nested schemas
|
|
</li></ul>
|
|
</li></ul>
|
|
<h1><a name="section_13">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>Allow SELECT ... FOR UPDATE on inherited tables
|
|
</li><li>Add UNIQUE capability to non-btree indexes
|
|
</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>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>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>Allow constraint_exclusion to work for UNIONs like it does for
|
|
inheritance, allow it to work for UPDATE and DELETE statements, and allow
|
|
it to be used for all statements with little performance impact
|
|
</li><li>Allow CREATE INDEX to take an additional parameter for use with
|
|
special index types
|
|
</li><li>Consider compressing indexes by storing key values duplicated in
|
|
several rows as a single index entry
|
|
<p> This is difficult because it requires datatype-specific knowledge.
|
|
</p>
|
|
</li><li>GIST
|
|
<ul>
|
|
<li>Add more GIST index support for geometric data types
|
|
</li><li>Allow GIST indexes to create certain complex index types, like
|
|
digital trees (see Aoki)
|
|
</li></ul>
|
|
</li><li>Hash
|
|
<ul>
|
|
<li>Pack hash index buckets onto disk pages more efficiently
|
|
<p> Currently 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>Add WAL logging for crash recovery
|
|
</li><li>Allow multi-column hash indexes
|
|
</li></ul>
|
|
</li></ul>
|
|
<h1><a name="section_14">Fsync</a></h1>
|
|
|
|
<ul>
|
|
<li>Improve commit_delay handling to reduce fsync()
|
|
</li><li>Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options
|
|
<p> Ideally this requires a separate test program that can be run
|
|
at initdb time or optionally later. Consider O_SYNC when
|
|
O_DIRECT exists.
|
|
</p>
|
|
</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_15">Cache Usage</a></h1>
|
|
|
|
<ul>
|
|
<li>Allow free-behind capability for large sequential scans, perhaps using
|
|
posix_fadvise()
|
|
<p> Posix_fadvise() can control both sequential/random file caching and
|
|
free-behind behavior, but it is unclear how the setting affects other
|
|
backends that also have the file open, and the feature is not supported
|
|
on all operating systems.
|
|
</p>
|
|
</li><li>Speed up COUNT(*)
|
|
<p> We could use a fixed row count and a +/- count to follow MVCC
|
|
visibility rules, or a single cached value could be used and
|
|
invalidated if anyone modifies the table. Another idea is to
|
|
get a count directly from a unique index, but for this to be
|
|
faster than a sequential scan it must avoid access to the heap
|
|
to obtain tuple visibility information.
|
|
</p>
|
|
</li><li>Add estimated_count(*) to return an estimate of COUNT(*)
|
|
<p> This would use the planner ANALYZE statistics to return an estimated
|
|
count.
|
|
</p>
|
|
</li><li>Allow data to be pulled directly from indexes
|
|
<p> Currently indexes do not have enough tuple visibility information
|
|
to allow data to be pulled from the index without also accessing
|
|
the heap. One way to allow this is to set a bit on index tuples
|
|
to indicate if a tuple is currently visible to all transactions
|
|
when the first valid heap lookup happens. This bit would have to
|
|
be cleared when a heap tuple is expired.
|
|
</p>
|
|
<p> Another idea is to maintain a bitmap of heap pages where all rows
|
|
are visible to all backends, and allow index lookups to reference
|
|
that bitmap to avoid heap lookups, perhaps the same bitmap we might
|
|
add someday to determine which heap pages need vacuuming. Frequently
|
|
accessed bitmaps would have to be stored in shared memory. One 8k
|
|
page of bitmaps could track 512MB of heap pages.
|
|
</p>
|
|
</li><li>Consider automatic caching of statements at various levels:
|
|
<ul>
|
|
<li>Parsed query tree
|
|
</li><li>Query execute plan
|
|
</li><li>Query results
|
|
</li></ul>
|
|
</li><li>Allow sequential scans to take advantage of other concurrent
|
|
sequential scans, also called "Synchronised Scanning"
|
|
<p> One possible implementation is to start sequential scans from the lowest
|
|
numbered buffer in the shared cache, and when reaching the end wrap
|
|
around to the beginning, rather than always starting sequential scans
|
|
at the start of the table.
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_16">Vacuum</a></h1>
|
|
|
|
<ul>
|
|
<li>Improve speed with indexes
|
|
<p> For large table adjustments during VACUUM FULL, it is faster to
|
|
reindex rather than update the index.
|
|
</p>
|
|
</li><li>Reduce lock time during VACUUM FULL by moving tuples with read lock,
|
|
then write lock and truncate table
|
|
<p> Moved tuples are invisible to other backends so they don't require a
|
|
write lock. However, the read lock promotion to write lock could lead
|
|
to deadlock situations.
|
|
</p>
|
|
</li><li>Auto-fill the free space map by scanning the buffer cache or by
|
|
checking pages written by the background writer
|
|
</li><li>Create a bitmap of pages that need vacuuming
|
|
<p> Instead of sequentially scanning the entire table, have the background
|
|
writer or some other process record pages that have expired rows, then
|
|
VACUUM can look at just those pages rather than the entire table. In
|
|
the event of a system crash, the bitmap would probably be invalidated.
|
|
One complexity is that index entries still have to be vacuumed, and
|
|
doing this without an index scan (by using the heap values to find the
|
|
index entry) might be slow and unreliable, especially for user-defined
|
|
index functions.
|
|
</p>
|
|
</li><li>%Add system view to show free space map contents
|
|
</li><li>Auto-vacuum
|
|
<ul>
|
|
<li>Use free-space map information to guide refilling
|
|
</li><li>%Issue log message to suggest VACUUM FULL if a table is nearly
|
|
empty?
|
|
</li><li>Improve xid wraparound detection by recording per-table rather
|
|
than per-database
|
|
</li><li>Consider logging activity either to the logs or a system view
|
|
</li></ul>
|
|
</li></ul>
|
|
<h1><a name="section_17">Locking</a></h1>
|
|
|
|
<ul>
|
|
<li>Fix priority ordering of read and write light-weight locks (Neil)
|
|
</li></ul>
|
|
<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>]
|
|
<p> 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,
|
|
Solaris) might benefit from threading. Also explore the idea of
|
|
a single session using multiple threads to execute a statement faster.
|
|
</p>
|
|
</li><li>Add connection pooling
|
|
<p> It is unclear if this should be done inside the backend code or done
|
|
by something external like pgpool. The passing of file descriptors to
|
|
existing backends is one of the difficulties with a backend approach.
|
|
</p>
|
|
</li></ul>
|
|
<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>]
|
|
<p> 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.
|
|
</p>
|
|
<ul>
|
|
<li>When off, write CRC to WAL and check file system blocks
|
|
on recovery
|
|
<p> If CRC check fails during recovery, remember the page in case
|
|
a later CRC for that page properly matches.
|
|
</p>
|
|
</li><li>Write full pages during file system write and not when
|
|
the page is modified in the buffer cache
|
|
<p> This allows most full page writes to happen in the background
|
|
writer. It might cause problems for applying WAL on recovery
|
|
into a partially-written page, but later the full page will be
|
|
replaced from WAL.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>Allow WAL traffic to be streamed to another server for stand-by
|
|
replication
|
|
</li><li>Reduce WAL traffic so only modified values are written rather than
|
|
entire rows?
|
|
</li><li>Allow the pg_xlog directory location to be specified during initdb
|
|
with a symlink back to the /data location
|
|
</li><li>Allow WAL information to recover corrupted pg_controldata
|
|
</li><li>Find a way to reduce rotational delay when repeatedly writing
|
|
last WAL page
|
|
<p> 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.
|
|
</p>
|
|
</li><li>Allow buffered WAL writes and fsync
|
|
<p> Instead of guaranteeing recovery of all committed transactions, this
|
|
would provide improved performance by delaying WAL writes and fsync
|
|
so an abrupt operating system restart might lose a few seconds of
|
|
committed transactions but still be consistent. We could perhaps
|
|
remove the 'fsync' parameter (which results in an an inconsistent
|
|
database) in favor of this capability.
|
|
</p>
|
|
</li><li>Allow control over which tables are WAL-logged
|
|
<p> Allow tables to bypass WAL writes and just fsync() dirty pages on
|
|
commit. To do this, only a single writer can modify the table, and
|
|
writes must happen only on new pages. Readers can continue accessing
|
|
the table. This would affect COPY, and perhaps INSERT/UPDATE too.
|
|
Another option is to avoid transaction logging entirely and truncate
|
|
or drop the table on crash recovery. These should be implemented
|
|
using ALTER TABLE, e.g. ALTER TABLE PERSISTENCE [ DROP | TRUNCATE |
|
|
STABLE | DEFAULT ]. Tables using non-default logging should not use
|
|
referential integrity with default-logging tables, and tables using
|
|
stable logging probably can not have indexes. [<a href="http://momjian.postgresql.org/cgi-bin/pgtodo?wallog">wallog</a>]
|
|
</p>
|
|
</li></ul>
|
|
<h1><a name="section_20">Optimizer / Executor</a></h1>
|
|
|
|
<ul>
|
|
<li>Improve selectivity functions for geometric operators
|
|
</li><li>Allow ORDER BY ... LIMIT # to select high/low value without sort or
|
|
index using a sequential scan for highest/lowest values
|
|
<p> Right now, if no index exists, ORDER BY ... LIMIT # requires we sort
|
|
all values to return the high/low value. Instead The idea is to do a
|
|
sequential scan to find the high/low value, thus avoiding the sort.
|
|
MIN/MAX already does this, but not for LIMIT > 1.
|
|
</p>
|
|
</li><li>Precompile SQL functions to avoid overhead
|
|
</li><li>Create utility to compute accurate random_page_cost value
|
|
</li><li>Improve ability to display optimizer analysis using OPTIMIZER_DEBUG
|
|
</li><li>Have EXPLAIN ANALYZE highlight poor optimizer estimates
|
|
</li><li>Consider using hash buckets to do DISTINCT, rather than sorting
|
|
<p> This would be beneficial when there are few distinct values. This is
|
|
already used by GROUP BY.
|
|
</p>
|
|
</li><li>Log statements where the optimizer row estimates were dramatically
|
|
different from the number of rows actually found?
|
|
</li></ul>
|
|
<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?
|
|
<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.
|
|
</p>
|
|
</li><li>Consider mmap()'ing files into a backend?
|
|
<p> Doing I/O to large tables would consume a lot of address space or
|
|
require frequent mapping/unmapping. Extending the file also causes
|
|
mapping problems that might require mapping only individual pages,
|
|
leading to thousands of mappings. Another problem is that there is no
|
|
way to _prevent_ I/O to disk from the dirty shared buffers so changes
|
|
could hit disk before WAL is written.
|
|
</p>
|
|
</li><li>Add a script to ask system configuration questions and tune postgresql.conf
|
|
</li><li>Merge xmin/xmax/cmin/cmax back into three header fields
|
|
<p> Before subtransactions, there used to be only three fields needed to
|
|
store these four values. This was possible because only the current
|
|
transaction looks at the cmin/cmax values. If the current transaction
|
|
created and expired the row the fields stored where xmin (same as
|
|
xmax), cmin, cmax, and if the transaction was expiring a row from a
|
|
another transaction, the fields stored were xmin (cmin was not
|
|
needed), xmax, and cmax. Such a system worked because a transaction
|
|
could only see rows from another completed transaction. However,
|
|
subtransactions can see rows from outer transactions, and once the
|
|
subtransaction completes, the outer transaction continues, requiring
|
|
the storage of all four fields. With subtransactions, an outer
|
|
transaction can create a row, a subtransaction expire it, and when the
|
|
subtransaction completes, the outer transaction still has to have
|
|
proper visibility of the row's cmin, for example, for cursors.
|
|
</p>
|
|
<p> One possible solution is to create a phantom cid which represents a
|
|
cmin/cmax pair and is stored in local memory. Another idea is to
|
|
store both cmin and cmax only in local memory.
|
|
</p>
|
|
</li><li>Research storing disk pages with no alignment/padding
|
|
</li></ul>
|
|
<h1><a name="section_22">Source Code</a></h1>
|
|
|
|
<ul>
|
|
<li>Add use of 'const' for variables in source tree
|
|
</li><li>Rename some /contrib modules from pg* to pg_*
|
|
</li><li>Move some things from /contrib into main tree
|
|
</li><li>Move some /contrib modules out to their own project sites
|
|
</li><li>%Remove warnings created by -Wcast-align
|
|
</li><li>Move platform-specific ps status display info from ps_status.c to ports
|
|
</li><li>Add optional CRC checksum to heap and index pages
|
|
</li><li>Improve documentation to build only interfaces (Marc)
|
|
</li><li>Remove or relicense modules that are not under the BSD license, if possible
|
|
</li><li>%Remove memory/file descriptor freeing before ereport(ERROR)
|
|
</li><li>Acquire lock on a relation before building a relcache entry for it
|
|
</li><li>%Promote debug_query_string into a server-side function current_query()
|
|
</li><li>%Allow the identifier length to be increased via a configure option
|
|
</li><li>Allow cross-compiling by generating the zic database on the target system
|
|
</li><li>Improve NLS maintenace of libpgport messages linked onto applications
|
|
</li><li>Allow ecpg to work with MSVC and BCC
|
|
</li><li>Add xpath_array() to /contrib/xml2 to return results as an array
|
|
</li><li>Allow building in directories containing spaces
|
|
<p> This is probably not possible because 'gmake' and other compiler tools
|
|
do not fully support quoting of paths with spaces.
|
|
</p>
|
|
</li><li>-<em>Allow installing to directories containing spaces</em>
|
|
<p> This is possible if proper quoting is added to the makefiles for the
|
|
install targets. Because PostgreSQL supports relocatable installs, it
|
|
is already possible to install into a directory that doesn't contain
|
|
spaces and then copy the install to a directory with spaces.
|
|
</p>
|
|
</li><li>Fix sgmltools so PDFs can be generated with bookmarks
|
|
</li><li>%Clean up compiler warnings (especially with gcc version 4)
|
|
</li><li>Use UTF8 encoding for NLS messages so all server encodings can
|
|
read them properly
|
|
</li><li>Update Bonjour to work with newer cross-platform SDK
|
|
</li><li>-<em>Remove BeOS and QNX-specific code</em>
|
|
</li><li>Win32
|
|
<ul>
|
|
<li>Remove configure.in check for link failure when cause is found
|
|
</li><li>Remove readdir() errno patch when runtime/mingwex/dirent.c rev
|
|
1.4 is released
|
|
</li><li>Remove psql newline patch when we find out why mingw outputs an
|
|
extra newline
|
|
</li><li>Allow psql to use readline once non-US code pages work with
|
|
backslashes
|
|
</li><li>Re-enable timezone output on log_line_prefix '%t' when a
|
|
shorter timezone string is available
|
|
</li><li>Fix problem with shared memory on the Win32 Terminal Server
|
|
</li><li>Improve signal handling,
|
|
<a href="http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php">http://archives.postgresql.org/pgsql-patches/2005-06/msg00027.php</a>
|
|
</li><li>Add long file support for binary pg_dump output
|
|
<p> While Win32 supports 64-bit files, the MinGW API does not,
|
|
meaning we have to build an fseeko replacement on top of the
|
|
Win32 API, and we have to make sure MinGW handles it. Another
|
|
option is to wait for the MinGW project to fix it, or use the
|
|
code from the LibGW32C project as a guide.
|
|
</p>
|
|
</li></ul>
|
|
</li><li>Wire Protocol Changes
|
|
<ul>
|
|
<li>Allow dynamic character set handling
|
|
</li><li>Add decoded type, length, precision
|
|
</li><li>Use compression?
|
|
</li><li>Update clients to use data types, typmod, <a href="http://schema.table.column">schema.table.column</a>/ names
|
|
of result sets using new statement protocol
|
|
</li></ul>
|
|
</li></ul>
|
|
<hr/>
|
|
|
|
<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>>
|
|
</li><li>Bruce is Bruce Momjian <<a href="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a>> of Software Research Assoc.
|
|
</li><li>Christopher is Christopher Kings-Lynne <<a href="mailto:chriskl@familyhealth.com.au">chriskl@familyhealth.com.au</a>> of
|
|
Family Health Network
|
|
</li><li>D'Arcy is D'Arcy J.M. Cain <<a href="mailto:darcy@druid.net">darcy@druid.net</a>> of The Cain Gang Ltd.
|
|
</li><li>Fabien is Fabien Coelho <<a href="mailto:coelho@cri.ensmp.fr">coelho@cri.ensmp.fr</a>>
|
|
</li><li>Gavin is Gavin Sherry <<a href="mailto:swm@linuxworld.com.au">swm@linuxworld.com.au</a>> of Alcove Systems Engineering
|
|
</li><li>Greg is Greg Sabino Mullane <<a href="mailto:greg@turnstep.com">greg@turnstep.com</a>>
|
|
</li><li>Jan is Jan Wieck <<a href="mailto:JanWieck@Yahoo.com">JanWieck@Yahoo.com</a>> of Afilias, Inc.
|
|
</li><li>Joe is Joe Conway <<a href="mailto:mail@joeconway.com">mail@joeconway.com</a>>
|
|
</li><li>Karel is Karel Zak <<a href="mailto:zakkr@zf.jcu.cz">zakkr@zf.jcu.cz</a>>
|
|
</li><li>Magnus is Magnus Hagander <<a href="mailto:mha@sollentuna.net">mha@sollentuna.net</a>>
|
|
</li><li>Marc is Marc Fournier <<a href="mailto:scrappy@hub.org">scrappy@hub.org</a>> of PostgreSQL, Inc.
|
|
</li><li>Matthew T. O'Connor <<a href="mailto:matthew@zeut.net">matthew@zeut.net</a>>
|
|
</li><li>Michael is Michael Meskes <<a href="mailto:meskes@postgresql.org">meskes@postgresql.org</a>> of Credativ
|
|
</li><li>Neil is Neil Conway <<a href="mailto:neilc@samurai.com">neilc@samurai.com</a>>
|
|
</li><li>Oleg is Oleg Bartunov <<a href="mailto:oleg@sai.msu.su">oleg@sai.msu.su</a>>
|
|
</li><li>Peter is Peter Eisentraut <<a href="mailto:peter_e@gmx.net">peter_e@gmx.net</a>>
|
|
</li><li>Philip is Philip Warner <<a href="mailto:pjw@rhyme.com.au">pjw@rhyme.com.au</a>> of Albatross Consulting Pty. Ltd.
|
|
</li><li>Rod is Rod Taylor <<a href="mailto:pg@rbt.ca">pg@rbt.ca</a>>
|
|
</li><li>Simon is Simon Riggs <<a href="mailto:simon@2ndquadrant.com">simon@2ndquadrant.com</a>>
|
|
</li><li>Stephan is Stephan Szabo <<a href="mailto:sszabo@megazone23.bigpanda.com">sszabo@megazone23.bigpanda.com</a>>
|
|
</li><li>Tatsuo is Tatsuo Ishii <<a href="mailto:t-ishii@sra.co.jp">t-ishii@sra.co.jp</a>> of Software Research Assoc.
|
|
</li><li>Teodor is Teodor Sigaev <<a href="mailto:teodor@sigaev.ru">teodor@sigaev.ru</a>>
|
|
</li><li>Tom is Tom Lane <<a href="mailto:tgl@sss.pgh.pa.us">tgl@sss.pgh.pa.us</a>> of Red Hat
|
|
</li></ul>
|
|
</li></ul></li></ul>
|
|
</body>
|
|
</html>
|