About

PostgreSQL is an object-relational database management system (ORDBMS) based on POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer Science Department. POSTGRES pioneered many concepts that only became available in some commercial database systems much later.

PostgreSQL is an open-source descendant of this original Berkeley code. It supports SQL92 and SQL99 and offers many modern features:
complex queries
foreign keys
triggers
views
transactional integrity
multiversion concurrency control

Additionally, PostgreSQL can be extended by the user in many ways, for example by adding new
data types
functions
operators
aggregate functions
index methods
procedural languages

And because of the liberal license, PostgreSQL can be used, modified, and distributed by everyone free of charge for any purpose, be it private, commercial, or academic.

This release contains a variety of fixes from 8.3.0.
E.1.1. Migration to Version 8.3.1

A dump/restore is not required for those running 8.3.X. However, you might need to REINDEX indexes on textual columns after updating, if you are affected by the Windows locale issue described below.
E.1.2. Changes


Fix character string comparison for Windows locales that consider different character combinations as equal (Tom)

This fix applies only on Windows and only when using UTF-8 database encoding. The same fix was made for all other cases over two years ago, but Windows with UTF-8 uses a separate code path that was not updated. If you are using a locale that considers some non-identical strings as equal, you may need to REINDEX to fix existing indexes on textual columns.

Repair corner-case bugs in VACUUM FULL (Tom)

A potential deadlock between concurrent VACUUM FULL operations on different system catalogs was introduced in 8.2. This has now been corrected. 8.3 made this worse because the deadlock could occur within a critical code section, making it a PANIC rather than just ERROR condition.

Also, a VACUUM FULL that failed partway through vacuuming a system catalog could result in cache corruption in concurrent database sessions.

Another VACUUM FULL bug introduced in 8.3 could result in a crash or out-of-memory report when dealing with pages containing no live tuples.

Fix misbehavior of foreign key checks involving character or bit columns (Tom)

If the referencing column were of a different but compatible type (for instance varchar), the constraint was enforced incorrectly.

Avoid needless deadlock failures in no-op foreign-key checks (Stephan Szabo, Tom)

Fix possible core dump when re-planning a prepared query (Tom)

This bug affected only protocol-level prepare operations, not SQL PREPARE, and so tended to be seen only with JDBC, DBI, and other client-side drivers that use prepared statements heavily.

Fix possible failure when re-planning a query that calls an SPI-using function (Tom)

Fix failure in row-wise comparisons involving columns of different datatypes (Tom)

Fix longstanding LISTEN/NOTIFY race condition (Tom)

In rare cases a session that had just executed a LISTEN might not get a notification, even though one would be expected because the concurrent transaction executing NOTIFY was observed to commit later.

A side effect of the fix is that a transaction that has executed a not-yet-committed LISTEN command will not see any row in pg_listener for the LISTEN, should it choose to look; formerly it would have. This behavior was never documented one way or the other, but it is possible that some applications depend on the old behavior.

Disallow LISTEN and UNLISTEN within a prepared transaction (Tom)

This was formerly allowed but trying to do it had various unpleasant consequences, notably that the originating backend could not exit as long as an UNLISTEN remained uncommitted.

Disallow dropping a temporary table within a prepared transaction (Heikki)

This was correctly disallowed by 8.1, but the check was inadvertently broken in 8.2 and 8.3.

Fix rare crash when an error occurs during a query using a hash index (Heikki)

Fix incorrect comparison of tsquery values (Teodor)

Fix incorrect behavior of LIKE with non-ASCII characters in single-byte encodings (Rolf Jentsch)

Disable xmlvalidate (Tom)

This function should have been removed before 8.3 release, but was inadvertently left in the source code. It poses a small security risk since unprivileged users could use it to read the first few characters of any file accessible to the server.

Fix memory leaks in certain usages of set-returning functions (Neil)

Make encode(bytea, 'escape') convert all high-bit-set byte values into \nnn octal escape sequences (Tom)

This is necessary to avoid encoding problems when the database encoding is multi-byte. This change could pose compatibility issues for applications that are expecting specific results from encode.

Fix input of datetime values for February 29 in years BC (Tom)

The former coding was mistaken about which years were leap years.

Fix "unrecognized node type" error in some variants of ALTER OWNER (Tom)

Avoid tablespace permissions errors in CREATE TABLE LIKE INCLUDING INDEXES (Tom)

Ensure pg_stat_activity.waiting flag is cleared when a lock wait is aborted (Tom)

Fix handling of process permissions on Windows Vista (Dave, Magnus)

In particular, this fix allows starting the server as the Administrator user.

Update time zone data files to tzdata release 2008a (in particular, recent Chile changes); adjust timezone abbreviation VET (Venezuela) to mean UTC-4:30, not UTC-4:00 (Tom)

Fix ecpg problems with arrays (Michael)

Fix pg_ctl to correctly extract the postmaster's port number from command-line options (Itagaki Takahiro, Tom)

Previously, pg_ctl start -w could try to contact the postmaster on the wrong port, leading to bogus reports of startup failure.

Use -fwrapv to defend against possible misoptimization in recent gcc versions (Tom)

This is known to be necessary when building PostgreSQL with gcc 4.3 or later.

Enable building contrib/uuid-ossp with MSVC (Hiroshi Saito)

Protect against indirect security threats caused by index functions changing session-local state (Gurjeet Singh, Tom)

This change prevents allegedly-immutable index functions from possibly subverting a superuser's session (CVE-2009-4136).

Reject SSL certificates containing an embedded null byte in the common name (CN) field (Magnus)

This prevents unintended matching of a certificate to a server or client name during SSL validation (CVE-2009-4034).

Fix hash index corruption (Tom)

The 8.4 change that made hash indexes keep entries sorted by hash value failed to update the bucket splitting and compaction routines to preserve the ordering. So application of either of those operations could lead to permanent corruption of an index, in the sense that searches might fail to find entries that are present. To deal with this, it is recommended to REINDEX any hash indexes you may have after installing this update.

Fix possible crash during backend-startup-time cache initialization (Tom)

Avoid crash on empty thesaurus dictionary (Tom)

Prevent signals from interrupting VACUUM at unsafe times (Alvaro)

This fix prevents a PANIC if a VACUUM FULL is cancelled after it's already committed its tuple movements, as well as transient errors if a plain VACUUM is interrupted after having truncated the table.

Fix possible crash due to integer overflow in hash table size calculation (Tom)

This could occur with extremely large planner estimates for the size of a hashjoin's result.

Fix crash if a DROP is attempted on an internally-dependent object (Tom)

Fix very rare crash in inet/cidr comparisons (Chris Mikkelson)

Ensure that shared tuple-level locks held by prepared transactions are not ignored (Heikki)

Fix premature drop of temporary files used for a cursor that is accessed within a subtransaction (Heikki)

Fix memory leak in syslogger process when rotating to a new CSV logfile (Tom)

Fix memory leak in postmaster when re-parsing pg_hba.conf (Tom)

Fix Windows permission-downgrade logic (Jesse Morris)

This fixes some cases where the database failed to start on Windows, often with misleading error messages such as "could not locate matching postgres executable".

Make FOR UPDATE/SHARE in the primary query not propagate into WITH queries (Tom)

For example, in
WITH w AS (SELECT * FROM foo) SELECT * FROM w, bar ... FOR UPDATE

the FOR UPDATE will now affect bar but not foo. This is more useful and consistent than the original 8.4 behavior, which tried to propagate FOR UPDATE into the WITH query but always failed due to assorted implementation restrictions. It also follows the design rule that WITH queries are executed as if independent of the main query.

Fix bug with a WITH RECURSIVE query immediately inside another one (Tom)

Fix concurrency bug in hash indexes (Tom)

Concurrent insertions could cause index scans to transiently report wrong results.

Fix incorrect logic for GiST index page splits, when the split depends on a non-first column of the index (Paul Ramsey)

Fix wrong search results for a multi-column GIN index with fastupdate enabled (Teodor)

Fix bugs in WAL entry creation for GIN indexes (Tom)

These bugs were masked when full_page_writes was on, but with it off a WAL replay failure was certain if a crash occurred before the next checkpoint.

Don't error out if recycling or removing an old WAL file fails at the end of checkpoint (Heikki)

It's better to treat the problem as non-fatal and allow the checkpoint to complete. Future checkpoints will retry the removal. Such problems are not expected in normal operation, but have been seen to be caused by misdesigned Windows anti-virus and backup software.

Ensure WAL files aren't repeatedly archived on Windows (Heikki)

This is another symptom that could happen if some other process interfered with deletion of a no-longer-needed file.

Fix PAM password processing to be more robust (Tom)

The previous code is known to fail with the combination of the Linux pam_krb5 PAM module with Microsoft Active Directory as the domain controller. It might have problems elsewhere too, since it was making unjustified assumptions about what arguments the PAM stack would pass to it.

Raise the maximum authentication token (Kerberos ticket) size in GSSAPI and SSPI authentication methods (Ian Turner)

While the old 2000-byte limit was more than enough for Unix Kerberos implementations, tickets issued by Windows Domain Controllers can be much larger.

Ensure that domain constraints are enforced in constructs like ARRAY[...]::domain, where the domain is over an array type (Heikki)

Fix foreign-key logic for some cases involving composite-type columns as foreign keys (Tom)

Ensure that a cursor's snapshot is not modified after it is created (Alvaro)

This could lead to a cursor delivering wrong results if later operations in the same transaction modify the data the cursor is supposed to return.

Fix CREATE TABLE to properly merge default expressions coming from different inheritance parent tables (Tom)

This used to work but was broken in 8.4.

Re-enable collection of access statistics for sequences (Akira Kurosawa)

This used to work but was broken in 8.3.

Fix processing of ownership dependencies during CREATE OR REPLACE FUNCTION (Tom)

Fix incorrect handling of WHERE x=x conditions (Tom)

In some cases these could get ignored as redundant, but they aren't — they're equivalent to x IS NOT NULL.

Fix incorrect plan construction when using hash aggregation to implement DISTINCT for textually identical volatile expressions (Tom)

Fix Assert failure for a volatile SELECT DISTINCT ON expression (Tom)

Fix ts_stat() to not fail on an empty tsvector value (Tom)

Make text search parser accept underscores in XML attributes (Peter)

Fix encoding handling in xml binary input (Heikki)

If the XML header doesn't specify an encoding, we now assume UTF-8 by default; the previous handling was inconsistent.

Fix bug with calling plperl from plperlu or vice versa (Tom)

An error exit from the inner function could result in crashes due to failure to re-select the correct Perl interpreter for the outer function.

Fix session-lifespan memory leak when a PL/Perl function is redefined (Tom)

Ensure that Perl arrays are properly converted to PostgreSQL arrays when returned by a set-returning PL/Perl function (Andrew Dunstan, Abhijit Menon-Sen)

This worked correctly already for non-set-returning functions.

Fix rare crash in exception processing in PL/Python (Peter)

Fix ecpg problem with comments in DECLARE CURSOR statements (Michael)

Fix ecpg to not treat recently-added keywords as reserved words (Tom)

This affected the keywords CALLED, CATALOG, DEFINER, ENUM, FOLLOWING, INVOKER, OPTIONS, PARTITION, PRECEDING, RANGE, SECURITY, SERVER, UNBOUNDED, and WRAPPER.

Re-allow regular expression special characters in psql's \df function name parameter (Tom)

In contrib/pg_standby, disable triggering failover with a signal on Windows (Fujii Masao)

This never did anything useful, because Windows doesn't have Unix-style signals, but recent changes made it actually crash.

Put FREEZE and VERBOSE options in the right order in the VACUUM command that contrib/vacuumdb produces (Heikki)

Fix possible leak of connections when contrib/dblink encounters an error (Tatsuhito Kasahara)

Ensure psql's flex module is compiled with the correct system header definitions (Tom)

This fixes build failures on platforms where --enable-largefile causes incompatible changes in the generated code.

Make the postmaster ignore any application_name parameter in connection request packets, to improve compatibility with future libpq versions (Tom)

Update the timezone abbreviation files to match current reality (Joachim Wieland)

This includes adding IDT to the default timezone abbreviation set.

Update time zone data files to tzdata release 2009s for DST law changes in Antarctica, Argentina, Bangladesh, Fiji, Novokuznetsk, Pakistan, Palestine, Samoa, Syria; also historical corrections for Hong Kong.

Add new configuration parameter ssl_renegotiation_limit to control how often we do session key renegotiation for an SSL connection (Magnus)

This can be set to zero to disable renegotiation completely, which may be required if a broken SSL library is used. In particular, some vendors are shipping stopgap patches for CVE-2009-3555 that cause renegotiation attempts to fail.

Fix possible deadlock during backend startup (Tom)

Fix possible crashes due to not handling errors during relcache reload cleanly (Tom)

Fix possible crash due to use of dangling pointer to a cached plan (Tatsuo)

Fix possible crash due to overenthusiastic invalidation of cached plan for ROLLBACK (Tom)

Fix possible crashes when trying to recover from a failure in subtransaction start (Tom)

Fix server memory leak associated with use of savepoints and a client encoding different from server's encoding (Tom)

Fix incorrect WAL data emitted during end-of-recovery cleanup of a GIST index page split (Yoichi Hirai)

This would result in index corruption, or even more likely an error during WAL replay, if we were unlucky enough to crash during end-of-recovery cleanup after having completed an incomplete GIST insertion.

Fix bug in WAL redo cleanup method for GIN indexes (Heikki)

Fix incorrect comparison of scan key in GIN index search (Teodor)

Make substring() for bit types treat any negative length as meaning "all the rest of the string" (Tom)

The previous coding treated only -1 that way, and would produce an invalid result value for other negative values, possibly leading to a crash (CVE-2010-0442).

Fix integer-to-bit-string conversions to handle the first fractional byte correctly when the output bit width is wider than the given integer by something other than a multiple of 8 bits (Tom)

Fix some cases of pathologically slow regular expression matching (Tom)

Fix bug occurring when trying to inline a SQL function that returns a set of a composite type that contains dropped columns (Tom)

Fix bug with trying to update a field of an element of a composite-type array column (Tom)

Avoid failure when EXPLAIN has to print a FieldStore or assignment ArrayRef expression (Tom)

These cases can arise now that EXPLAIN VERBOSE tries to print plan node target lists.

Avoid an unnecessary coercion failure in some cases where an undecorated literal string appears in a subquery within UNION/INTERSECT/EXCEPT (Tom)

This fixes a regression for some cases that worked before 8.4.

Avoid undesirable rowtype compatibility check failures in some cases where a whole-row Var has a rowtype that contains dropped columns (Tom)

Fix the STOP WAL LOCATION entry in backup history files to report the next WAL segment's name when the end location is exactly at a segment boundary (Itagaki Takahiro)

Always pass the catalog ID to an option validator function specified in CREATE FOREIGN DATA WRAPPER (Martin Pihlak)

Fix some more cases of temporary-file leakage (Heikki)

This corrects a problem introduced in the previous minor release. One case that failed is when a plpgsql function returning set is called within another function's exception handler.

Add support for doing FULL JOIN ON FALSE (Tom)

This prevents a regression from pre-8.4 releases for some queries that can now be simplified to a constant-false join condition.

Improve constraint exclusion processing of boolean-variable cases, in particular make it possible to exclude a partition that has a "bool_column = false" constraint (Tom)

Prevent treating an INOUT cast as representing binary compatibility (Heikki)

Include column name in the message when warning about inability to grant or revoke column-level privileges (Stephen Frost)

This is more useful than before and helps to prevent confusion when a REVOKE generates multiple messages, which formerly appeared to be duplicates.

When reading pg_hba.conf and related files, do not treat @something as a file inclusion request if the @ appears inside quote marks; also, never treat @ by itself as a file inclusion request (Tom)

This prevents erratic behavior if a role or database name starts with @. If you need to include a file whose path name contains spaces, you can still do so, but you must write @"/path to/file" rather than putting the quotes around the whole construct.

Prevent infinite loop on some platforms if a directory is named as an inclusion target in pg_hba.conf and related files (Tom)

Fix possible infinite loop if SSL_read or SSL_write fails without setting errno (Tom)

This is reportedly possible with some Windows versions of openssl.

Disallow GSSAPI authentication on local connections, since it requires a hostname to function correctly (Magnus)

Protect ecpg against applications freeing strings unexpectedly (Michael)

Make ecpg report the proper SQLSTATE if the connection disappears (Michael)

Fix translation of cell contents in psql \d output (Heikki)

Fix psql's numericlocale option to not format strings it shouldn't in latex and troff output formats (Heikki)

Fix a small per-query memory leak in psql (Tom)

Make psql return the correct exit status (3) when ON_ERROR_STOP and --single-transaction are both specified and an error occurs during the implied COMMIT (Bruce)

Fix pg_dump's output of permissions for foreign servers (Heikki)

Fix possible crash in parallel pg_restore due to out-of-range dependency IDs (Tom)

Fix plpgsql failure in one case where a composite column is set to NULL (Tom)

Fix possible failure when calling PL/Perl functions from PL/PerlU or vice versa (Tim Bunce)

Add volatile markings in PL/Python to avoid possible compiler-specific misbehavior (Zdenek Kotala)

Ensure PL/Tcl initializes the Tcl interpreter fully (Tom)

The only known symptom of this oversight is that the Tcl clock command misbehaves if using Tcl 8.5 or later.

Prevent ExecutorEnd from being run on portals created within a failed transaction or subtransaction (Tom)

This is known to cause issues when using contrib/auto_explain.

Prevent crash in contrib/dblink when too many key columns are specified to a dblink_build_sql_* function (Rushabh Lathia, Joe Conway)

Allow zero-dimensional arrays in contrib/ltree operations (Tom)

This case was formerly rejected as an error, but it's more convenient to treat it the same as a zero-element array. In particular this avoids unnecessary failures when an ltree operation is applied to the result of ARRAY(SELECT ...) and the sub-select returns no rows.

Fix assorted crashes in contrib/xml2 caused by sloppy memory management (Tom)

Make building of contrib/xml2 more robust on Windows (Andrew)

Fix race condition in Windows signal handling (Radu Ilie)

One known symptom of this bug is that rows in pg_listener could be dropped under heavy load.

Make the configure script report failure if the C compiler does not provide a working 64-bit integer datatype (Tom)

This case has been broken for some time, and no longer seems worth supporting, so just reject it at configure time instead.

Update time zone data files to tzdata release 2010e for DST law changes in Bangladesh, Chile, Fiji, Mexico, Paraguay, Samoa.