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 e37a84b95f..7f1546e9c4 100644 --- a/doc/src/FAQ/TODO.html +++ b/doc/src/FAQ/TODO.html @@ -8,7 +8,7 @@

PostgreSQL TODO List

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 +

Add "include file" functionality in postgresql.conf +
Allow postgresql.conf values to be set so they can not be changed + by the user +
Allow commenting of variables in postgresql.conf to restore them + to defaults +
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. +
+

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. +
+
- 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. +
  +
- Allow WAL replay of CREATE TABLESPACE to work when the directory + structure on the recovery computer is different from the original +
- Allow per-tablespace quotas +
+

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 +

Monitoring

+ +

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. +
+
Add ability to monitor the use of temporary sort files +
-Add session start time and last statement time to pg_stat_activity +
Allow server logs to be remotely read using SQL commands +
-Add a function that returns the start time of the postmaster

Data Types

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
  - Improve vacuum of large objects, like /contrib/vacuumlo (?) +
  - Improve vacuum of large objects, like /contrib/vacuumlo?
  - Add security checking for large objects
    Currently large objects entries do not have owners. Permissions can only be set at the pg_largeobject table level. @@ -240,7 +214,42 @@ first.
-
Multi-Language Support
+
Functions
+ +
- 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. +
  +
+
Multi-Language Support
- Add NCHAR (as distinguished from ordinary varchar), @@ -254,11 +263,11 @@ first.
  Right now only one encoding is allowed per database.
- Support multiple simultaneous character sets, per SQL92 -
- Improve UTF8 combined character handling (?) +
- Improve UTF8 combined character handling?
- Add octet_length_server() and octet_length_client()
- Make octet_length_client() the same as octet_length()?
-
Views / Rules
+
Views / Rules
- 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
-
Indexes
- -
- 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) -
-
Commands
+
Commands
- -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 +
  - 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 +
  +
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

Clients

Add a libpq function to support Parse/DescribeStatement capability -
Prevent libpq's PQfnumber() from lowercasing the column name (?) +
Prevent libpq's PQfnumber() from lowercasing the column name?
Allow libpq to access SQLSTATE so pg_ctl can test for connection failure
This would be used for checking if the server is up.
@@ -577,7 +526,7 @@ first.
Document differences between ecpg and the SQL standard and information about the Informix-compatibility module.
-
Solve cardinality > 1 for input descriptors / variables (?) +
Solve cardinality > 1 for input descriptors / variables?
Add a semantic check level, e.g. check if a table really exists
fix handling of DB attributes that are arrays
Use backend PREPARE/EXECUTE facility for ecpg where possible @@ -589,7 +538,7 @@ first.
Add internationalized message strings

Referential Integrity

Add MATCH PARTIAL referential integrity @@ -601,8 +550,8 @@ first.
-Implement shared row locks and use them in RI triggers
Enforce referential integrity for system tables
Change foreign key constraint for array -> element to mean element - in array (?) -
Allow DEFERRABLE UNIQUE constraints (?) + in array? +
Allow DEFERRABLE UNIQUE constraints?
Allow triggers to be disabled [trigger]
Currently the only way to disable triggers is to modify the system tables. @@ -624,13 +573,13 @@ first. to fire triggers.

Dependency Checking

Flush cached query plans when the dependent objects change
Track dependencies in function bodies and recompile/invalidate

Exotic Features

Add SQL99 WITH clause to SELECT @@ -658,9 +607,81 @@ first.
Allow nested schemas

PERFORMANCE

Indexes

Fsync

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 +
- 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 +
+

Fsync

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

Cache

Cache Usage

Allow free-behind capability for large sequential scans, perhaps using @@ -725,7 +746,7 @@ first. at the start of the table.

Vacuum

Improve speed with indexes @@ -758,7 +779,7 @@ first.
Do VACUUM FULL if table is nearly empty?

Locking

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)

Startup Time

Startup Time Improvements

Experiment with multi-threaded backend [thread] @@ -796,7 +817,7 @@ first. existing backends is one of the difficulties with a backend approach.

Write-Ahead Log

Eliminate need to write full pages to WAL before page modification [wal] @@ -806,7 +827,7 @@ first. eliminated from point-in-time archive files.
Reduce WAL traffic so only modified values are written rather than - entire rows (?) + entire rows?
Turn off full page writes if fsync is disabled
If fsync is off, there is no purpose in writing full pages to WAL
@@ -831,7 +852,7 @@ first.
Eliminate WAL logging for CREATE TABLE AS when not doing WAL archiving
-Change WAL to use 32-bit CRC, for performance reasons

Optimizer / Executor

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?

Miscellaneous

Miscellaneous Performance

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

Source Code

Add use of 'const' for variables in source tree @@ -948,7 +969,7 @@ first.

Developers who have claimed items are:

Alvaro is Alvaro Herrera <alvherre@dcc.uchile.cl>
Andrew is Andrew Dunstan <andrew@dunslane.net> -- cgit v1.2.1