diff --git a/doc/src/sgml/release-9.0.sgml b/doc/src/sgml/release-9.0.sgml index 8777a2c904..e5002c1341 100644 --- a/doc/src/sgml/release-9.0.sgml +++ b/doc/src/sgml/release-9.0.sgml @@ -1,4 +1,4 @@ - + Release 9.0 @@ -8,10 +8,6 @@ 2010-??-?? - - Overview @@ -32,123 +28,78 @@ recovery_connections -> hot_standby + - Allow continuous archive standby systems to accept read-only queries + Built-in, binary, log-based replication. This advance consists of two features: + Hot Standby allows continuous archive standby database servers to accept read-only + queries, and Streaming Replication allows continuous archive (WAL) files + to be streamed over a network port to a standby database server. - Allow continuous archive (WAL) files to be streamed to a - standby system + Easier database object permissions management. GRANT/REVOKE + IN SCHEMA supports mass permissions changes, and + the ALTER + DEFAULT PRIVILEGES command controls privileges + of all newly-created objects. Large object permissions now + support GRANT/REVOKE as well. - Add the ability to make mass permission changes per - schema using the new GRANT/REVOKE - IN SCHEMA clause + Broadly enhanced stored procedure support. + The DO statement permits + ad-hoc or anonymous code blocks. Functions can now be called using named + parameters. PL/pgSQL is now installed by default, and PL/Perl and PL/Python + have been enhanced in several ways. - Add the ability to control large object permissions with - GRANT/REVOKE + Triggers now support two new features, + SQL-compliant per-column triggers, and + conditional trigger execution. - Implement anonymous functions using the DO statement + Deferrable + unique constraints, now permit mass updates to unique keys. - Allow function calls to supply parameter names and match them to named - parameters in the function definition (Pavel Stehule) + Exclusion constraints let database designers define uniqueness + based on complex criteria, including for non-scalar data such + as time periods, ranges and arrays. - Install server-side language PL/pgSQL by default + The LISTEN/NOTIFY + feature has been overhauled to make it into + a high-performance event queuing system. It now stores + events in a memory-based queue, and it now allows delivery + of a string payload to listeners with each event. - Major PL/Perl enhancements - - - - - - Allow SQL-compliant per-column triggers - - - - - - Add deferrable - unique constraints - - - - - - Have LISTEN/NOTIFY store events - in a memory queue, rather than a system table - - - - - - Allow NOTIFY - to pass an optional string to listeners - - - - - - Change VACUUM FULL to rewrite the entire table and - indexes, rather than moving around single rows to compact space - - - - - - Add prefix support for the full text search synonym dictionary - - - - - - Use red-black trees for GIN index creation - - - - - - Add get_bit() - and set_bit() functions for bit - strings, mirroring those for bytea - - - - - - Add the ability for clients to set an application - name, which is displayed in - pg_stat_activity + As part of our decade-long effort to eliminate the pain of VACUUM, + VACUUM FULL is not substantially faster by + rewriting the entire table and + indexes, rather than moving around single rows to compact space. @@ -164,7 +115,7 @@ recovery_connections -> hot_standby Add /contrib/pg_upgrade - to support in-place upgrades + to support in-place upgrades from 8.3 or 8.4 to 9.0. @@ -208,7 +159,7 @@ recovery_connections -> hot_standby Remove server variable regex_flavor, which was defaulted to advanced - (e.g. Perl-regex compatible) for many years (Tom Lane) + (e.g. Perl-regex compatible) for many years. (Tom Lane) @@ -307,9 +258,23 @@ recovery_connections -> hot_standby - Administrators still can rename such columns manually. Expression - index names are also not renamed. WHY ARE EXPRESSION INDEXES - SIGNIFICANT? + Administrators still can rename such columns manually. This change + will require an update of the JDBC driver and possibly other drivers + so that unique indexes are correctly recognized. + + + + + + No longer change function input variable names via + REPLACE FUNCTION(Pavel Stehule). + + + + In order to support names parameter calls, it is + no longer possible to change the aliases for input variables + in the function declaration in place. You now have to DROP + and recreate the function. @@ -333,7 +298,8 @@ recovery_connections -> hot_standby linkend="plpgsql-var-subst">plpgsql.variable_conflict, or by the per-function option #variable_conflict. The former behavior was to bind to variable names over - column names. + column names, but not consistently. Stored procedures + with naming conflicts will probably need to be refactored. @@ -357,7 +323,7 @@ recovery_connections -> hot_standby - Variables can be double-quoted to avoid this restriction. + Variables can be double-quoted to avoid this restriction. @@ -372,9 +338,17 @@ recovery_connections -> hot_standby Server - Continuous Archiving - + Continuous Archiving and Binary Replication + + PostgreSQL's native standby capability has been expanded both to + support read-only queries on standby slaves and to greatly reduce + the lag between master and standby servers. For many users, this + will be a useful and low-administration form of replication, either + for high availability or for horizontal scalability. + + + Allow continuous archive standby systems to accept read-only queries @@ -396,6 +370,7 @@ recovery_connections -> hot_standby + This feature is called Streaming Replication. Previously WAL files could be sent to standby systems only as 16 megabytes files; this allows master changes to be sent to the standby with very little delay. There are new postgresql.conf @@ -421,6 +396,12 @@ recovery_connections -> hot_standby Performance + + + Version 9.0 also contains several performance and optimizer enhancements to + improve specific uses of PostgreSQL and remedy certain poor-performing cases. + + @@ -454,17 +435,6 @@ recovery_connections -> hot_standby Optimizer - - - Allow IS NOT NULL restrictions to use indexes (Tom Lane) - - - - This is particularly useful for finding - MAX()/MIN() values in indexes that also - contain NULLs. - - @@ -474,7 +444,21 @@ recovery_connections -> hot_standby Outer joins where the inner side is unique and not referenced in - the query are unnecessary and are therefore now removed. + the query are unnecessary and are therefore now removed. This will + accelerate many automatically generated queries, such as those created + by object-relational mappers. + + + + + + Allow IS NOT NULL restrictions to use indexes (Tom Lane) + + + + This is particularly useful for finding + MAX()/MIN() values in indexes that also + contain NULLs. @@ -567,7 +551,9 @@ recovery_connections -> hot_standby This allows user-override of the number or percentage of distinct values for a column and optionally its child tables. This value - is normally computed by ANALYZE. + is normally computed by ANALYZE. Database administrators + can use this feature to fix some poor statistics, especially on + tables with millions or billions of rows. @@ -900,8 +886,10 @@ recovery_connections -> hot_standby - It currently supports tables, views, sequences, and functions, and - also has per-schema control. + This greatly simplifies the assignment of object priveleges in + a complex database application. Defaults currently support tables + views, sequences, and functions. Defaults may be assigned on a + per-schema basis or database-wide. @@ -995,8 +983,17 @@ recovery_connections -> hot_standby TABLE CONSTRAINT ... EXCLUDE clause. While uniqueness checks could be specified using this syntax, the real value of this feature is in using complex - operators that do not have built-in constraints. + operators that do not have built-in constraints. + + + The primary use of exclusion constraints is to allow defining + non-overlapping uniqueness, such as for time periods, arrays + or ranges of values. This supports data integrity at the + table level for calendaring, time-management, and scientific + applications. + + @@ -1026,6 +1023,13 @@ recovery_connections -> hot_standby linkend="SQL-GRANT">GRANT/REVOKE IN SCHEMA clause (Petr Jelinek) + + + This simplifies the assignment of object permissions + and makes it easier to utilize database roles for application + data security. + + @@ -1055,7 +1059,9 @@ recovery_connections -> hot_standby - This greatly improves performance for these operations. + LISTEN/NOTIFY may now be used as a full-featured, high-performance + event queue system for PostgreSQL, with transactional support + and guaranteed delivery. @@ -1114,6 +1120,18 @@ recovery_connections -> hot_standby <link linkend="SQL-EXPLAIN"><command>EXPLAIN</></link> + + + Allow EXPLAIN output in XML, JSON, + and YAML formats (Robert Haas, Greg Sabino Mullane) + + + + The new output formats will support the development of new tools + for analysis of EXPLAIN output. + + + Add new EXPLAIN (BUFFERS) to report query buffer @@ -1121,6 +1139,7 @@ recovery_connections -> hot_standby + This allows better query profiling for individual queries. log_*_stats log output, e.g. log_statement_stats, no longer shows this information. @@ -1134,13 +1153,6 @@ recovery_connections -> hot_standby - - - Allow EXPLAIN output in XML, JSON, - and YAML formats (Robert Haas, Greg Sabino Mullane) - - - Allow EXPLAIN options to be specified inside parentheses @@ -1169,8 +1181,11 @@ recovery_connections -> hot_standby - The previous method was usually slower and caused index bloat. + The previous method was usually slower and caused index bloat. + Note that the new method may use more disk space during VACUUM + FULL. + @@ -1228,9 +1243,10 @@ recovery_connections -> hot_standby - Red-black trees are self-balanced so allow for faster index - creation. + Red-black trees are self-balanced. This means much faster + GIN index creation. +