mirror of https://github.com/postgres/postgres
Peter Eisentraut
17 years ago
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<!-- $PostgreSQL: pgsql/doc/src/sgml/release-8.5.sgml,v 1.1 2009/08/17 22:14:44 petere Exp $ --> |
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<sect1 id="release-8.5"> |
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<title>Release 8.5alpha1</title> |
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<sect2> |
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<title>Overview</title> |
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<para> |
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PostgreSQL alpha releases are snapshots of development code. They |
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are intended to preview and test upcoming features and to provide |
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the possibility for early feedback. They should not be used in |
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production installations or active development projects. While the |
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PostgreSQL code is continuously subject to a number of automated |
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and manual tests, alpha releases might have serious bugs. Also |
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features may be changed incompatibly or removed at any time during |
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the development cycle. |
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</para> |
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<para> |
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The development cycle of a PostgreSQL major release alternates |
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between periods of development and periods of integration work, |
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called commit fests, normally one month each. Alpha releases are |
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planned to be produced at the end of every commit fest, thus every |
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two months. Since the first commit fest starts within a month from |
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the beginning of development altogether, early alpha releases are |
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not indicative of the likely feature set of the final release. |
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</para> |
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<para> |
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The release notes below highlight user visible changes and new |
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features. There are normally numerous bug fixes and performance |
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improvements in every new snapshot of PostgreSQL, and it would be |
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too bulky to attempt to list them all. Note that many bug fixes are |
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also backported to stable releases of PostgreSQL, and you should be |
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using those if you are looking for bug-fix-only upgrades for your |
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current installations. |
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</para> |
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</sect2> |
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<sect2> |
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<title>Migration</title> |
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<para> |
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To upgrade from any release to an alpha release or from an alpha |
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release to any other release will most likely require a |
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dump/restore upgrade procedure. It may happen that this is not |
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necessary in particular cases, but that is not verified beforehand. |
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(The server will warn you in any case when a dump/restore is |
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necessary if you attempt to use it with an old data directory.) |
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Note, however, that the dump/restore upgrade procedure is expected |
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to work for alpha releases, and problems in this area should be |
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reported. |
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</para> |
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</sect2> |
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<sect2> |
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<title>Changes</title> |
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<sect3> |
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<title>SQL Features</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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DROP COLUMN and DROP CONSTRAINT now support an IF EXISTS clause so |
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that users can avoid fatal errors when running repeatable scripts. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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UNIQUE constraints can now be DEFERRABLE. This is primarily useful |
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for incremental updates of numerical keys, e.g. "ID = ID + |
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1" |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Allows parentheses around the query expression that follows a WITH |
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clause. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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INFORMATION_SCHEMA, a catalog of standard views of database |
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objects, has been updated to the SQL:2008 ANSI/ISO standard. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Changes character_octet_length to more sensible values in |
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INFORMATION_SCHEMA. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Allow * as parameter for FORCE QUOTE for COPY CSV, so that all |
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columns will be quoted. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Performance</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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EXPLAIN allows output of plans in XML or JSON format for automated |
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processing of explain plans by analysis or visualization tools. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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EXPLAIN now supports the use of generic options in EXPLAIN ( option |
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value, ... ) format, which permits the creation of additional |
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EXPLAIN options. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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ALTER TABLE ... ALTER COLUMN ... SET STATISTICS DISTINCT allows |
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users to manually tweak the number of distinct values estimated for |
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a column, to fix cases where ANALYZE estimates are incorrect. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Makes GEQO's planning deterministic by having it start from a |
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predictable random number seed each time. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Rewrite GEQO's gimme_tree function so that it always finds a legal |
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join sequence. Previously, it could have failed to produce a plan |
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in some cases. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Tweak TOAST code so that columns marked with MAIN storage strategy |
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are not forced out-of-line unless that is necessary to make the row |
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fit on a page. Previously, they were forced out-of-line if needed |
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to get the row down to the default target size (1/4th page). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Simplify the forms foo <> true and foo <> false to foo |
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= false and foo = true during query optimization. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Avoid per-send() system calls to manage SIGPIPE in libpq, if the |
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platform provides either sockopt(SO_NOSIGPIPE) or the MSG_NOSIGNAL |
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flag to send(). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Reserve the shared memory region during backend startup on Windows, |
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so that memory allocated by starting third party DLLs doesn't end |
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up conflicting with it. Hopefully this solves the long-time issue |
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with "could not reattach to shared memory" errors on |
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Win32. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Administration and Monitoring</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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Add the ability to include the SQLSTATE error code of any error |
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messages in the PostgreSQL activity log with the new |
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log_line_prefix placeholder %e. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Show the exact value being complained of in |
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unique-constraint-violation error messages, including unique-index |
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build failures. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Security</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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New has_sequence_privilege() functions allow you to check sequence |
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privileges for a given ROLE. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Built-In Functions</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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The to_char() formatting functions now supports EEEE (scientific |
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notation). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Use floor() not rint() when reducing precision of fractional |
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seconds in timestamp_trunc, timestamptz_trunc, and interval_trunc() |
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for the float-datetime case. This improves accuracy of time |
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calculations. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Fix ancient bug in handling of to_char() modifier 'TH', when used |
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with HH. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Datatypes</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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New hex-string input and output format options for type BYTEA. Hex |
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output format is enabled by default, which is an INCOMPATIBLE |
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CHANGE. See the new bytea_output parameter if you need to restore |
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compatibility. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Adds prefix support for text search synonym dictionary, allowing |
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creation of synonyms on partial matches. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Server Tools</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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pg_dump/pg_restore --clean now drops large objects. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Modifies parallel pg_restore ordering logic to avoid a potential |
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O(N^2) slowdown for some complex databases. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>psql</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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Have \d show child tables that inherit from the specified parent |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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psql now shows the index methods in \di |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Procedural Languages</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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PL/pgSQL functions using RETURNS QUERY or RECORD types no longer |
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always need to be rebuilt after adding or dropping a column for the |
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related tables. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Improves error context reporting in PL/Python, for easier |
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debugging. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Greatly expands the regression testing for PL/Python. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Additional Supplied Modules</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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pgbench is now multi-threaded, allowing it to use multiple CPU's |
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for its client connections, and to do more realistic workload |
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testing. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Added the ability to retrieve asynchronous notifications using |
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dblink, via the addition of the function dblink_get_notify(). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Added matchorig, matchsynonyms, and keepsynonyms options to |
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contrib/dict_xsyn. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Development</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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Functions which conflict with C++ reserved words have been renamed, |
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making backend header files now safe to use with C++ libraries. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Add man pages for SPI functions. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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ECPG now includes a STRING datatype for Informix compatibility |
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mode. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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<sect3> |
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<title>Source code, build options</title> |
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<itemizedlist> |
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<listitem> |
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<para> |
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Upgrade to Autoconf 2.63 (not relevant to users of distribution |
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tarballs). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Minimum version of Flex is now 2.5.31, to support reentrant |
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scanners (not relevant to users of distribution tarballs). |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Documentation build rules have been improved. The generated |
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documentation files are now shipped "loose", not in |
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sub-tarballs. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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New toolchain to generate man pages. From now on, the man pages |
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will be current in every release. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Code-coverage testing support now extends to the entire source |
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tree, not only src/backend/. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Reserve the shared memory region during backend startup on Windows, |
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so that memory allocated by starting third party DLLs doesn't end |
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up conflicting with it. Hopefully this solves the long-time issue |
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with "could not reattach to shared memory" errors on |
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Win32. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Make the core scanner re-entrant, along with additional fixes that |
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will let it be used directly by PL/pgSQL. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Fix backend startup to not depend on the flat-file copy of |
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pg_database. This is a first step towards eliminating the flat |
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files altogether. |
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</para> |
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</listitem> |
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<listitem> |
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<para> |
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Add s_lock support for SuperH architecture (not well tested). |
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</para> |
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</listitem> |
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</itemizedlist> |
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</sect3> |
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</sect2> |
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</sect1> |
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