From 8ea398513ef287bc25ac08dc7a4d92fb68dc668d Mon Sep 17 00:00:00 2001
From: Bruce Momjian
Date: Mon, 4 Jul 2005 17:00:32 +0000
Subject: Restructure TODO sections.
---
doc/src/FAQ/TODO.html | 471 ++++++++++++++++++++++++++------------------------
1 file changed, 246 insertions(+), 225 deletions(-)
(limited to 'doc/src')
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 @@
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
-Last updated: Mon Jul 4 08:32:37 EDT 2005
+Last updated: Mon Jul 4 13:00:23 EDT 2005
The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html.
@@ -27,94 +27,27 @@ first.
Remove behavior of postmaster -o after making postmaster/postgres
flags unique
Allow limits on per-db/role connections
- Allow server log information to be output as INSERT statements
- This would allow server log information to be easily loaded into
- a database for analysis.
-
- Prevent dropping user that still owns objects, or auto-drop the objects
Allow pooled connections to list all prepared queries
This would allow an application inheriting a pooled connection to know
the queries prepared in the current session.
Allow major upgrades without dump/reload, perhaps using pg_upgrade
[pg_upgrade]
- Allow GRANT/REVOKE permissions to be applied to all schema objects with one
- command
- The proposed syntax is:
-
GRANT SELECT ON ALL TABLES IN public TO phpuser;
- GRANT SELECT ON NEW TABLES IN public TO phpuser;
-
- Allow GRANT/REVOKE permissions to be inherited by objects based on
- schema permissions
Check for unreferenced table files created by transactions that were
in-progress when the server terminated abruptly
- Allow reporting of which objects are in which tablespaces
- 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.
-
- 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
- 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.
-
- Add a GUC variable to control the tablespace for temporary objects and
- sort files
- It could start with a random tablespace from a supplied list and cycle
- through the list.
-
- Add ability to monitor the use of temporary sort files
- Allow WAL replay of CREATE TABLESPACE to work when the directory
- structure on the recovery computer is different from the original
- Add "include file" functionality in postgresql.conf
- -Add session start time and last statement time to pg_stat_activity
- Allow server logs to be remotely read using SQL commands
- Allow pg_hba.conf settings to be controlled via SQL
- 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.
-
Allow administrators to safely terminate individual sessions either
via an SQL function or SIGTERM
Currently SIGTERM of a backend can lead to lock table corruption.
- Un-comment all variables in postgresql.conf
- 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.
-
- Allow point-in-time recovery to archive partially filled write-ahead
- logs [pitr]
- 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.
-
- Automatically force archiving of partially-filled WAL files when
- pg_stop_backup() is called or the server is stopped
- Doing this will allow administrators to know more easily when the
- archive contins all the files needed for point-in-time recovery.
-
- Create dump tool for write-ahead logs for use in determining
- transaction id for point-in-time recovery
+ Prevent dropping user that still owns objects, or auto-drop the objects
Set proper permissions on non-system schemas during db creation
Currently all schemas are owned by the super-user because they are
copied from the template1 database.
- Add a function that returns the 'uptime' of the postmaster
- Allow a warm standby system to also allow read-only queries [pitr]
- This is useful for checking PITR recovery.
-
- Allow the PITR process to be debugged and data examined
-Add the client IP address and port to pg_stat_activity
+ 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
Improve replication solutions
- Load balancing
@@ -124,14 +57,87 @@ first.
- Allow replication over unreliable or non-persistent links
- 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
- Allow postgresql.conf values to be set so they can not be changed by
- the user
- Allow per-tablespace quotas
+ Configuration files
+
+ Tablespaces
+
+ - 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
+
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.
+
+ - Allow reporting of which objects are in which tablespaces
+
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.
+
+
+
+ Point-in-time Recovery (PITR)
+
+ - Allow point-in-time recovery to archive partially filled
+ write-ahead logs [pitr]
+
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.
+
+ - Automatically force archiving of partially-filled WAL files when
+ pg_stop_backup() is called or the server is stopped
+
Doing this will allow administrators to know more easily when
+ the archive contins all the files needed for point-in-time
+ recovery.
+
+ - Create dump tool for write-ahead logs for use in determining
+ transaction id for point-in-time recovery
+
- Allow a warm standby system to also allow read-only queries
+ [pitr]
+
This is useful for checking PITR recovery.
+
+ - Allow the PITR process to be debugged and data examined
+
+
+
+
+
-
+
- Remove Money type, add money formatting for decimal type
@@ -148,24 +154,10 @@ first.
inaccurate, in one sense.
- - Add function to return compressed length of TOAST data values
-
- Allow INET subnet tests using non-constants to be indexed
-
- Add transaction_timestamp(), statement_timestamp(), clock_timestamp()
- functionality
-
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.
-
- - Have sequence dependency track use of DEFAULT sequences,
- seqname.nextval (?)
-
- Disallow changing default expression of a SERIAL column (?)
+
- Have sequence dependency track use of DEFAULT sequences,
+ seqname.nextval?
+
- Disallow changing default expression of a SERIAL column?
- Allow infinite dates just like infinite timestamps
-
- Have initdb set DateStyle based on locale?
-
- Add pg_get_acldef(), pg_get_typedefault(), and pg_get_attrdef()
-
- Allow to_char() to print localized month names
-
- Allow functions to have a schema search path specified at creation time
-
- Allow substring/replace() to get/set bit values
- Add a GUC variable to allow output of interval values in ISO8601 format
- Fix data types where equality comparison isn't intuitive, e.g. box
- Merge hardwired timezone names with the TZ database; allow either kind
@@ -185,24 +177,6 @@ first.
- Allow INET + INT4 to increment the host part of the address, or
throw an error on overflow
- Add 'tid != tid ' operator for use in corruption recovery
-
- Prevent to_char() on interval from returning meaningless values
-
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.
-
- - Allow to_char() on interval values to accumulate the highest unit
- requested
-
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.
-
-
- - to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
-
- to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
-
- to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
-
- to_char(INTERVAL '3 years 5 months','MM') => 41
-
- Add ISO INTERVAL handling
- Add support for day-time syntax, INTERVAL '1 2:03:04' DAY TO SECOND
@@ -229,7 +203,7 @@ first.
- BINARY DATA
-
+
+
+
+ - Add function to return compressed length of TOAST data values
+
- Allow INET subnet tests using non-constants to be indexed
+
- Add transaction_timestamp(), statement_timestamp(), clock_timestamp()
+ functionality
+
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.
+
+ - Add pg_get_acldef(), pg_get_typedefault(), and pg_get_attrdef()
+
- Allow to_char() to print localized month names
+
- Allow functions to have a schema search path specified at creation time
+
- Allow substring/replace() to get/set bit values
+
- Allow to_char() on interval values to accumulate the highest unit
+ requested
+
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.
+
+
+ - to_char(INTERVAL '1 hour 5 minutes', 'MI') => 65
+
- to_char(INTERVAL '43 hours 20 minutes', 'MI' ) => 2600
+
- to_char(INTERVAL '43 hours 20 minutes', 'WK:DD:HR:MI') => 0:1:19:20
+
- to_char(INTERVAL '3 years 5 months','MM') => 41
+
+ - Prevent to_char() on interval from returning meaningless values
+
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.
+
+
+
-
+
- Automatically create rules on views so they are updateable, per SQL99
@@ -271,90 +280,16 @@ first.
- Allow temporary views on non-temporary tables
- Allow RULE recompilation
-
-
-
- - Allow inherited tables to inherit index, UNIQUE constraint, and primary
- key, foreign key
-
- UNIQUE INDEX on base column not honored on INSERTs/UPDATEs from
- inherited table: INSERT INTO inherit_table (unique_index_col) VALUES
- (dup) should fail
-
The main difficulty with this item is the problem of creating an index
- that can span more than one table.
-
- - Add UNIQUE capability to non-btree indexes
-
- Add more gist index support for geometric data types
-
- -Use indexes for MIN() and MAX()
-
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.
-
- - -Use index to restrict rows returned by multi-key index when used with
- non-consecutive keys to reduce heap accesses
-
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.
-
- - Prevent index uniqueness checks when UPDATE does not modify the column
-
Uniqueness (index) checks are done when updating a column even if the
- column is not modified by the UPDATE.
-
- - Fetch heap pages matching index entries in sequential order
-
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.
-
- - -Allow non-bitmap indexes to be combined by creating bitmaps in memory
-
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.
-
- - Allow the creation of on-disk bitmap indexes which can be quickly
- combined with other bitmap indexes
-
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.
-
- - Allow use of indexes to search for NULLs
-
One solution is to create a partial index on an IS NULL expression.
-
- - -Add concurrency to GIST
-
- Pack hash index buckets onto disk pages more efficiently
-
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.
-
- - Consider sorting hash buckets so entries can be found using a binary
- search, rather than a linear scan
-
- In hash indexes, consider storing the hash value with or instead
- of the key itself
-
- Allow accurate statistics to be collected on indexes with more than
- one column or expression indexes, perhaps using per-index statistics
-
- Add fillfactor to control reserved free space during index creation
-
- Allow the creation of indexes with mixed ascending/descending specifiers
-
- -Fix incorrect rtree results due to wrong assumptions about "over"
- operator semantics
-
- Allow GIST indexes to create certain complex index types, like digital
- trees (see Aoki)
-
-
+
- -Add BETWEEN SYMMETRIC/ASYMMETRIC
- Change LIMIT/OFFSET and FETCH/MOVE to use int8
- Allow CREATE TABLE AS to determine column lengths for complex
expressions like SELECT col1 || col2
-
- Allow UPDATE to handle complex aggregates [update] (?)
-
- Allow backslash handling in quoted strings to be disabled for portability
-
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.
-
+ - Allow UPDATE to handle complex aggregates [update]?
+
- -Add E'' escape string marker so eventually ordinary strings can treat
+ backslashes literally, for portability
- Allow an alias to be provided for the target table in UPDATE/DELETE
This is not SQL-spec but many DBMSs allow it.
@@ -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.
+ - Have initdb set DateStyle based on locale?
- Add CORRESPONDING BY to UNION/INTERSECT/EXCEPT
- -Allow REINDEX to rebuild all database indexes
- Add ROLLUP, CUBE, GROUPING SETS options to GROUP BY
@@ -394,7 +330,7 @@ first.
Currently the system uses the operating system COPY command to create
a new database.
- - Add C code to copy directories for use in creating new databases
+
- Add C code on Unix to copy directories for use in creating new databases
- Have pg_ctl look at PGHOST in case it is a socket directory?
- 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.
-
- Allow column-level GRANT/REVOKE privileges
- Add a GUC variable to warn about non-standard SQL usage in queries
- Add MERGE command that does UPDATE/DELETE, or on failure, INSERT (rules,
triggers?)
@@ -412,7 +347,7 @@ first.
creation
- Add COMMENT ON for all cluster global objects (roles, databases
and tablespaces)
-
- Add an option to automatically use savepoints for each statement in a
+
- -Add an option to automatically use savepoints for each statement in a
multi-statement transaction.
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.
- -Allow COPY to understand \x as a hex byte
-
- Have COPY return the number of rows loaded/unloaded (?)
+
- Have COPY return the number of rows loaded/unloaded?
- -Allow COPY to optionally include column headings in the first line
- -Allow COPY FROM ... CSV to interpret newlines and carriage
returns in data
+ - GRANT/REVOKE
+
+ - Allow column-level privileges
+
+
- CURSOR
- Allow UPDATE/DELETE WHERE CURRENT OF cursor
@@ -484,7 +433,7 @@ first.
and no FOR UPDATE lock.
- Prevent DROP TABLE from dropping a row referenced by its own open
- cursor (?)
+ cursor?
- Allow pooled connections to list all open WITH HOLD cursors
Because WITH HOLD cursors exist outside transactions, this allows
them to be listed so they can be closed.
@@ -505,7 +454,7 @@ first.
- -Have SHOW ALL show descriptions for server-side variables
- Add SET PERFORMANCE_TIPS option to suggest INDEX, VACUUM, VACUUM
ANALYZE, and CLUSTER
-
- Add SET PATH for schemas (?)
+
- Add SET PATH for schemas?
This is basically the same as SET search_path.
@@ -524,7 +473,7 @@ first.
- Allow function parameters to be passed by name,
get_employee_salary(emp_id => 12345, tax_year => 2001)
- Add Oracle-style packages
-
- Add table function support to pltcl, plperl, plpython (?)
+
- Add table function support to pltcl, plperl, plpython?
- Allow PL/pgSQL to name columns by ordinal position, e.g. rec.(3)
- -Allow PL/pgSQL EXECUTE query_var INTO record_var;
- Add capability to create and call PROCEDURES
@@ -534,11 +483,11 @@ first.
- Add support for polymorphic arguments and return types to plperl
-
+
-
+
-
+
- Flush cached query plans when the dependent objects change
- Track dependencies in function bodies and recompile/invalidate
-
+
- Add SQL99 WITH clause to SELECT
@@ -658,9 +607,81 @@ first.
- Allow nested schemas
-
+
-
+
+ - Allow inherited tables to inherit index, UNIQUE constraint, and primary
+ key, foreign key
+
- UNIQUE INDEX on base column not honored on INSERTs/UPDATEs from
+ inherited table: INSERT INTO inherit_table (unique_index_col) VALUES
+ (dup) should fail
+
The main difficulty with this item is the problem of creating an index
+ that can span more than one table.
+
+ - Add UNIQUE capability to non-btree indexes
+
- Add more GIST index support for geometric data types
+
- -Use indexes for MIN() and MAX()
+
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.
+
+ - -Use index to restrict rows returned by multi-key index when used with
+ non-consecutive keys to reduce heap accesses
+
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.
+
+ - Prevent index uniqueness checks when UPDATE does not modify the column
+
Uniqueness (index) checks are done when updating a column even if the
+ column is not modified by the UPDATE.
+
+ - Fetch heap pages matching index entries in sequential order
+
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.
+
+ - -Allow non-bitmap indexes to be combined by creating bitmaps in memory
+
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.
+
+ - Allow the creation of on-disk bitmap indexes which can be quickly
+ combined with other bitmap indexes
+
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.
+
+ - Allow use of indexes to search for NULLs
+
One solution is to create a partial index on an IS NULL expression.
+
+ - -Add concurrency to GIST
+
- Allow accurate statistics to be collected on indexes with more than
+ one column or expression indexes, perhaps using per-index statistics
+
- Add fillfactor to control reserved free space during index creation
+
- Allow the creation of indexes with mixed ascending/descending specifiers
+
- -Fix incorrect rtree results due to wrong assumptions about "over"
+ operator semantics
+
- Allow GIST indexes to create certain complex index types, like digital
+ trees (see Aoki)
+
- Hash
+
+
+
- Improve commit_delay handling to reduce fsync()
@@ -669,7 +690,7 @@ first.
- Add an option to sync() before fsync()'ing checkpoint files
- Add program to test if fsync has a delay compared to non-fsync
-
+
- Allow free-behind capability for large sequential scans, perhaps using
@@ -725,7 +746,7 @@ first.
at the start of the table.
-
+
- Improve speed with indexes
@@ -758,7 +779,7 @@ first.
- Do VACUUM FULL if table is nearly empty?
-
+
- Make locking of shared data structures more fine-grained
@@ -780,7 +801,7 @@ first.
- Research use of sched_yield() for spinlock acquisition failure
- Fix priority ordering of read and write light-weight locks (Neil)
-
+
- Experiment with multi-threaded backend [thread]
@@ -796,7 +817,7 @@ first.
existing backends is one of the difficulties with a backend approach.
-
+
-
+
- Add missing optimizer selectivities for date, r-tree, etc
@@ -856,16 +877,16 @@ first.
- ANALYZE should record a pg_statistic entry for an all-NULL column
- 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?
-
+
- Do async I/O for faster random read-ahead of data
Async I/O allows multiple I/O requests to be sent to the disk with
results coming back asynchronously.
- - Use mmap() rather than SYSV shared memory or to write WAL files (?)
+
- Use mmap() rather than SYSV shared memory or to write WAL files?
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.
- Use a phantom command counter for nested subtransactions to reduce
per-tuple overhead
-
+
- Add use of 'const' for variables in source tree
@@ -948,7 +969,7 @@ first.
-
+