< This would be beneficial when there are few distinct values.
> This would be beneficial when there are few distinct values. This is
> already used by GROUP BY.
946d946
< * Allow DISTINCT to use hashing like GROUP BY
<
390d388
<
453c451
< removed or have its heap and index files truncated. One
> be removed or have its heap and index files truncated. One
< * Use a phantom command counter for nested subtransactions to reduce
< per-tuple overhead
< cmin/cmax pair and is stored in local memory.
> cmin/cmax pair and is stored in local memory. Another idea is to
> store both cmin and cmax only in local memory.
< 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.
> 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.
> o Allow COPY on a newly-created table to skip WAL logging
450a452,456
> On crash recovery, the table involved in the COPY would
> 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.
> * Use UTF8 encoding for NLS messages so all server encodings can
> read them properly
< o %Add support for Unicode
<
< To fix this, the data needs to be converted to/from UTF16/UTF8
< so the Win32 wcscoll() can be used, and perhaps other functions
< like towupper(). However, UTF8 already works with normal
< locales but provides no ordering or character set classes.
< could only see committed rows from another transaction. However,
> could only see rows from another completed transaction. However,
981c981
< proper visibility of the row, for example, for cursors.
> proper visibility of the row's cmin, for example, for cursors.
* Merge xmin/xmax/cmin/cmax back into three header fields
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 committed rows from another 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, for example, for cursors.
One possible solution is to create a phantom cid which represents a
cmin/cmax pair and is stored in local memory.
< * Maintain a map of recently-expired rows
<
< This allows vacuum to target specific pages for possible free space
< without requiring a sequential scan.
<
Update entry:
> 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.
>
> 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.
> o Issue a warning if a change-on-restart-only postgresql.conf value
> is modified and the server config files are reloaded
> o Mark change-on-restart-only values in postgresql.conf
205a209
> o Fix SELECT '0.01 years'::interval, '0.01 months'::interval
>
> Currently, while \e saves a single query as one entry, interactive
> queries are saved one line at a time. Ideally all queries
> whould be saved like \e does.
>
> o Allow multi-line column values to align in the proper columns
>
> 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.
< in PL/PgSQL is to use EXECUTE.
> 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.
< inheritance, and allow it to work for UPDATE and DELETE queries
> inheritance, allow it to work for UPDATE and DELETE queries, and allow
> it to be used for all queries with little performance impact
< * Allow constraint_elimination to be automatically performed
<
< This requires additional code to reduce the performance loss caused by
< constraint elimination.
< * -Allow limits on per-db/role connections
43d41
< * -Prevent dropping user that still owns objects, or auto-drop the objects
49d46
< * -Add the client IP address and port to pg_stat_activity
< * -Add session start time and last statement time to pg_stat_activity
< * -Add a function that returns the start time of the postmaster
230d224
< o -Allow MIN()/MAX() on arrays
< o -Modify array literal representation to handle array index lower bound
< of other than one
253d244
< * -Add function to return compressed length of TOAST data values
< * -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.
<
< * -Have views on temporary tables exist in the temporary namespace
< * -Allow temporary views on non-temporary tables
329d311
< * -Add BETWEEN SYMMETRIC/ASYMMETRIC
< * -Add E'' escape string marker so eventually ordinary strings can treat
< backslashes literally, for portability
<
< * -Allow additional tables to be specified in DELETE for joins
<
< UPDATE already allows this (UPDATE...FROM) but we need similar
< functionality in DELETE. It's been agreed that the keyword should
< be USING, to avoid anything as confusing as DELETE FROM a FROM b.
<
341d313
< * -Allow REINDEX to rebuild all database indexes
< * -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.
<
426d391
< o -Allow FOR UPDATE queries to do NOWAIT locks
473d437
< o -Allow COPY to understand \x as a hex byte
< o -Allow COPY to optionally include column headings in the first line
< o -Allow COPY FROM ... CSV to interpret newlines and carriage
< returns in data
525d485
< o -Have SHOW ALL show descriptions for server-side variables
< o -Allow PL/PgSQL's RAISE function to take expressions
<
< Currently only constants are supported.
<
< o -Change PL/PgSQL to use palloc() instead of malloc()
545d499
< o -Allow PL/pgSQL EXECUTE query_var INTO record_var;
550d503
< o -Pass arrays natively instead of as text between plperl and postgres
598d550
< o -Add dumping and restoring of LOB comments
638d589
< * -Implement shared row locks and use them in RI triggers
642d592
< * -Allow triggers to be disabled
< * -Add two-phase commit
<
<
< * -Prevent inherited tables from expanding temporary subtables of other
< sessions
< * -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.
<
< * -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.
<
< * -Fix incorrect rtree results due to wrong assumptions about "over"
< operator semantics
782d694
< o -Add concurrency to GIST
813d724
< * -Allow multiple blocks to be written to WAL with one write()
< * -Consider use of open/fcntl(O_DIRECT) to minimize OS caching,
< for WAL writes
<
< O_DIRECT doesn't have the same media write guarantees as fsync, so it
< is in addition to the fsync method, not in place of it.
<
< * -Cache last known per-tuple offsets to speed long tuple access
< * -Allow the size of the buffer cache used by temporary objects to be
< specified as a GUC variable
<
< Larger local buffer cache sizes requires more efficient handling of
< local cache lookups.
<
< * -Improve the background writer
<
< Allow the background writer to more efficiently write dirty buffers
< from the end of the LRU cache and use a clock sweep algorithm to
< write other dirty buffers to reduced checkpoint I/O
<
897d788
< * -Add a warning when the free space map is too small
917d807
< o -Move into the backend code
< * -Make locking of shared data structures more fine-grained
<
< This requires that more locks be acquired but this would reduce lock
< contention, improving concurrency.
<
< * -Improve SMP performance on i386 machines
<
< i386-based SMP machines can generate excessive context switching
< caused by lock failure in high concurrency situations. This may be
< caused by CPU cache line invalidation inefficiencies.
<
979d857
< o -Add ability to turn off full page writes
< * -Eliminate WAL logging for CREATE TABLE AS when not doing WAL archiving
< * -Change WAL to use 32-bit CRC, for performance reasons
<
< * -Use CHECK constraints to influence optimizer decisions
<
< CHECK constraints contain information about the distribution of values
< within the table. This is also useful for implementing subtables where
< a tables content is distributed across several subtables.
<
1045d913
< * -ANALYZE should record a pg_statistic entry for an all-NULL column
1099d966
< * -Remove kerberos4 from source tree
1103d969
< * -Make src/port/snprintf.c thread-safe
1118d983
< * -Add C code on Unix to copy directories for use in creating new databases
1133d997
< o -Improve dlerror() reporting string
< Currently SIGTERM of a backend can lead to lock table corruption.
> 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.
< o Allow postgresql.conf values to be set so they can not be changed
< by the user
166c167,171
< * %Remove Money type, add money formatting for decimal type
> * Improve the MONEY data type
>
> Change the MONEY data type to use DECIMAL internally, with special
> locale-aware output formatting.
>
225c230
< o %Allow MIN()/MAX() on arrays
> o -Allow MIN()/MAX() on arrays
228c233
< o Modify array literal representation to handle array index lower bound
> o -Modify array literal representation to handle array index lower bound
235a241
> o Auto-delete large objects when referencing row is deleted
< Currently large objects entries do not have owners. Permissions can
< only be set at the pg_largeobject table level.
> /contrib/lo offers this functionality.
240d244
< o Auto-delete large objects when referencing row is deleted
< * %Have views on temporary tables exist in the temporary namespace
< * Allow temporary views on non-temporary tables
< * %Allow RULE recompilation
> * -Have views on temporary tables exist in the temporary namespace
> * -Allow temporary views on non-temporary tables
> * Allow VIEW/RULE recompilation when the underlying tables change
340a345,347
>
> This is like DELETE CASCADE, but truncates.
>
381c388
< * Make row-wise comparisons work per SQL spec
> * %Make row-wise comparisons work per SQL spec
< o Currently the system uses the operating system COPY command to
< create a new database. Add ON COMMIT capability to CREATE TABLE AS
< SELECT
> o Add ON COMMIT capability to CREATE TABLE AS ... SELECT
427c432
< o %Add ALTER DOMAIN TYPE
> o Add ALTER DOMAIN to modify the underlying data type
< o %Disallow dropping of an inherited constraint
< o -Allow objects to be moved to different schemas
> o Add missing object types for ALTER ... SET SCHEMA
< o %Prevent child tables from altering constraints like CHECK that were
< inherited from the parent table
> o %Disallow dropping of an inherited constraint
> o %Prevent child tables from altering or dropping constraints
> like CHECK that were inherited from the parent table
< o Handle references to temporary tables that are created, destroyed,
< then recreated during a session, and EXECUTE is not used
<
< This requires the cached PL/PgSQL byte code to be invalidated when
< an object referenced in the function is changed.
<
< o Add table function support to pltcl, plperl, plpython?
< o Allow PL/pgSQL to name columns by ordinal position, e.g. rec.(3)
> o Add table function support to pltcl, plpython
549a548
> o Allow function argument names to be queries from PL/PgSQL
< o Pass arrays natively instead of as text between plperl and postgres
< o Add support for polymorphic arguments and return types to plperl
> o -Pass arrays natively instead of as text between plperl and postgres
> o Add support for polymorphic arguments and return types to
> languages other than PL/PgSQL
> o Add support for OUT and INOUT parameters to languages other
> than PL/PgSQL
< * Allow libpq to access SQLSTATE so pg_ctl can test for connection failure
<
< This would be used for checking if the server is up.
<
565c563
< * Have initdb set DateStyle based on locale?
> * Have initdb set the input DateStyle (MDY or DMY) based on locale?
567d564
< * Add a schema option to createlang
< o Add pg_dumpall custom format dumps.
<
< This is probably best done by combining pg_dump and pg_dumpall
< into a single binary.
<
> o Add pg_dumpall custom format dumps?
612c605,606
< o Remove unnecessary abstractions in pg_dump source code
> o Remove unnecessary function pointer abstractions in pg_dump source
> code
< * %Remove CREATE CONSTRAINT TRIGGER
<
< This was used in older releases to dump referential integrity
< constraints.
<
682a672,675
> 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.
>
748c741
< * Fetch heap pages matching index entries in sequential order
> * -Fetch heap pages matching index entries in sequential order
797c790
< Currently no only one hash bucket can be stored on a page. Ideally
> Currently only one hash bucket can be stored on a page. Ideally
806a800,802
> o Add WAL logging for crash recovery
> o Allow multi-column hash indexes
>
812a809,812
>
> Ideally this requires a separate test program that can be run
> at initdb time or optionally later.
>
867c867
< * Improve the background writer
> * -Improve the background writer
< For large table adjustements during vacuum, it is faster to reindex
< rather than update the index.
> For large table adjustements during VACUUM FULL, it is faster to
> reindex rather than update the index.
< * Reduce lock time by moving tuples with read lock, then write
< lock and truncate table
> * Reduce lock time during VACUUM FULL by moving tuples with read lock,
> then write lock and truncate table
919c919,920
< o %Suggest VACUUM FULL if a table is nearly empty
> o %Issue log message to suggest VACUUM FULL if a table is nearly
> empty?
995d995
< * Add WAL index reliability improvement to non-btree indexes
1045c1045
< * ANALYZE should record a pg_statistic entry for an all-NULL column
> * -ANALYZE should record a pg_statistic entry for an all-NULL column
1047a1048,1051
> * Allow constraint_elimination to be automatically performed
>
> This requires additional code to reduce the performance loss caused by
> constraint elimination.
1090c1094
< * Remove memory/file descriptor freeing before ereport(ERROR)
> * %Remove memory/file descriptor freeing before ereport(ERROR)
< * Promote debug_query_string into a server-side function current_query()
< * Allow the identifier length to be increased via a configure option
> * %Promote debug_query_string into a server-side function current_query()
> * %Allow the identifier length to be increased via a configure option
1113d1116
< * Fix cross-compiling of time zone database via 'zic'
1130c1133
< o Improve dlerror() reporting string
> o -Improve dlerror() reporting string
1132c1135
< o Add support for Unicode
> o %Add support for Unicode
< Currently, if a variable is commented out, it keeps the
< previous uncommented value until a server restarted.
> Currently, if a variable is commented out, it keeps the
> previous uncommented value until a server restarted.
> Logically, a reload should set the same values as a
> server restart.
< * Allow triggers to be disabled [trigger]
> * -Allow triggers to be disabled [trigger]
> * Allow triggers to be disabled in only the current session.
< Currently the only way to disable triggers is to modify the system
< tables.
> 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 idea for this usage.
< inheritance
< * Allow enable_constraint_exclusion to work for UPDATE and DELETE queries
> inheritance, and allow it to work for UPDATE and DELETE queries
Bruce Momjian