PostgreSQL 歷史版本列表 Page28

更新時間：2012-08-20
更新細節：

What's new in this version:

- Prevent access to external files/URLs via XML entity references 
- Prevent access to external files/URLs via contrib/xml2's xslt_process() 
- Prevent too-early recycling of btree index pages 
- Fix crash-safety bug with newly-created-or-reset sequences 
- Fix race condition in enum-type value comparisons 
- Fix txid_current() to report the correct epoch when not in hot standby 
- Prevent selection of unsuitable replication connections as the synchronous standby 
- Fix bug in startup of Hot Standby when a master transaction has many subtransactions 
- Ensure the backup_label file is fsync'd after pg_start_backup() 
- Fix timeout handling in walsender processes 
- Wake walsenders after each background flush by walwriter 
- Fix LISTEN/NOTIFY to cope better with I/O problems, such as out of disk space 
- Only allow autovacuum to be auto-canceled by a directly blocked process 
- Improve logging of autovacuum cancels 
- Fix log collector so that log_truncate_on_rotation works during the very first log rotation after server start 
- Fix WITH attached to a nested set operation (UNION/INTERSECT/EXCEPT) 
- Ensure that a whole-row reference to a subquery doesn't include any extra GROUP BY or ORDER BY columns 
- Fix dependencies generated during ALTER TABLE ... ADD CONSTRAINT USING INDEX 
- Fix REASSIGN OWNED to work on extensions 
- Disallow copying whole-row references in CHECK constraints and index definitions during CREATE TABLE 
- Fix memory leak in ARRAY(SELECT ...) subqueries 
- Fix planner to pass correct collation to operator selectivity estimators 
- Fix extraction of common prefixes from regular expressions 
- Fix bugs with parsing signed hh:mm and hh:mm:ss fields in interval constants 
- Fix pg_dump to better handle views containing partial GROUP BY lists 
- In PL/Perl, avoid setting UTF8 flag when in SQL_ASCII encoding 
- Use Postgres' encoding conversion functions, not Python's, when converting a Python Unicode string to the server encoding in PL/Python 
- Fix mapping of PostgreSQL encodings to Python encodings in PL/Python 
- Report errors properly in contrib/xml2's xslt_process() 
- Update time zone data files to tzdata release 2012e for DST law changes in Morocco and Tokelau

更新時間：2012-06-05
更新細節：

What's new in this version:

- Fix incorrect password transformation in contrib/pgcrypto's DES crypt() function (Solar Designer) If a password string contained the byte value 0x80, the remainder of the password was ignored, causing the password to be much weaker than it appeared. With this fix, the rest of the string is properly included in the DES hash. Any stored password values that are affected by this bug will thus no longer match, so the stored values may need to be updated. 
- Ignore SECURITY DEFINER and SET attributes for a procedural language's call handler Applying such attributes to a call handler could crash the server. 
- Make contrib/citext's upgrade script fix collations of citext arrays and domains over citext Release 9.1.2 provided a fix for collations of citext columns and indexes in databases upgraded or reloaded from pre-9.1 installations, but that fix was incomplete: it neglected to handle arrays and domains over citext. This release extends the module's upgrade script to handle these cases. As before, if you have already run the upgrade script, you'll need to run the collation update commands by hand instead. See the 9.1.2 release notes for more information about doing this.
- Allow numeric timezone offsets in timestamp input to be up to 16 hours away from UTC Some historical time zones have offsets larger than 15 hours, the previous limit. This could result in dumped data values being rejected during reload.
- Fix timestamp conversion to cope when the given time is exactly the last DST transition time for the current timezone This oversight has been there a long time, but was not noticed previously because most DST-using zones are presumed to have an indefinite sequence of future DST transitions.
- Fix text to name and char to name casts to perform string truncation correctly in multibyte encodings 
- Fix memory copying bug in to_tsquery() 
- Ensure txid_current() reports the correct epoch when executed in hot standby 
- Fix planner's handling of outer PlaceHolderVars within subqueries This bug concerns sub-SELECTs that reference variables coming from the nullable side of an outer join of the surrounding query. In 9.1, queries affected by this bug would fail with "ERROR: Upper-level PlaceHolderVar found where not expected". But in 9.0 and 8.4, you'd silently get possibly-wrong answers, since the value transmitted into the subquery wouldn't go to null when it should.
- Fix planning of UNION ALL subqueries with output columns that are not simple variables Planning of such cases got noticeably worse in 9.1 as a result of a misguided fix for "MergeAppend child's targetlist doesn't match MergeAppend" errors. Revert that fix and do it another way.
- Fix slow session startup when pg_attribute is very large If pg_attribute exceeds one-fourth of shared_buffers, cache rebuilding code that is sometimes needed during session start would trigger the synchronized-scan logic, causing it to take many times longer than normal. The problem was particularly acute if many new sessions were starting at once.
- Ensure sequential scans check for query cancel reasonably often A scan encountering many consecutive pages that contain no live tuples would not respond to interrupts meanwhile.
- Ensure the Windows implementation of PGSemaphoreLock() clears ImmediateInterruptOK before returning This oversight meant that a query-cancel interrupt received later in the same query could be accepted at an unsafe time, with unpredictable but not good consequences.
- Show whole-row variables safely when printing views or rules Corner cases involving ambiguous names (that is, the name could be either a table or column name of the query) were printed in an ambiguous way, risking that the view or rule would be interpreted differently after dump and reload. Avoid the ambiguous case by attaching a no-op cast.
- Fix COPY FROM to properly handle null marker strings that correspond to invalid encoding A null marker string such as E'\0' should work, and did work in the past, but the case got broken in 8.4.
- Fix EXPLAIN VERBOSE for writable CTEs containing RETURNING clauses 
- Fix PREPARE TRANSACTION to work correctly in the presence of advisory locks Historically, PREPARE TRANSACTION has simply ignored any session-level advisory locks the session holds, but this case was accidentally broken in 9.1.
- Fix truncation of unlogged tables 
- Ignore missing schemas during non-interactive assignments of search_path This re-aligns 9.1's behavior with that of older branches. Previously 9.1 would throw an error for nonexistent schemas mentioned in search_path settings obtained from places such as ALTER DATABASE SET.
- Fix bugs with temporary or transient tables used in extension scripts This includes cases such as a rewriting ALTER TABLE within an extension update script, since that uses a transient table behind the scenes.
- Ensure autovacuum worker processes perform stack depth checking properly Previously, infinite recursion in a function invoked by auto-ANALYZE could crash worker processes.
- Fix logging collector to not lose log coherency under high load The collector previously could fail to reassemble large messages if it got too busy.
- Fix logging collector to ensure it will restart file rotation after receiving SIGHUP 
- Fix "too many LWLocks taken" failure in GiST indexes 
- Fix WAL replay logic for GIN indexes to not fail if the index was subsequently dropped 
- Correctly detect SSI conflicts of prepared transactions after a crash 
- Avoid synchronous replication delay when committing a transaction that only modified temporary tables In such a case the transaction's commit record need not be flushed to standby servers, but some of the code didn't know that and waited for it to happen anyway.
- Fix error handling in pg_basebackup 
- Fix walsender to not go into a busy loop if connection is terminated 
- Fix memory leak in PL/pgSQL's RETURN NEXT command 
- Fix PL/pgSQL's GET DIAGNOSTICS command when the target is the function's first variable 
- Ensure that PL/Perl package-qualifies the _TD variable This bug caused trigger invocations to fail when they are nested within a function invocation that changes the current package.
- Fix PL/Python functions returning composite types to accept a string for their result value This case was accidentally broken by the 9.1 additions to allow a composite result value to be supplied in other formats, such as dictionaries.
- Fix potential access off the end of memory in psql's expanded display (x) mode 
- Fix several performance problems in pg_dump when the database contains many objects pg_dump could get very slow if the database contained many schemas, or if many objects are in dependency loops, or if there are many owned sequences.
- Fix memory and file descriptor leaks in pg_restore when reading a directory-format archive 
- Fix pg_upgrade for the case that a database stored in a non-default tablespace contains a table in the cluster's default tablespace 
- In ecpg, fix rare memory leaks and possible overwrite of one byte after the sqlca_t structure 
- Fix contrib/dblink's dblink_exec() to not leak temporary database connections upon error 
- Fix contrib/dblink to report the correct connection name in error messages 
- Fix contrib/vacuumlo to use multiple transactions when dropping many large objects This change avoids exceeding max_locks_per_transaction when many objects need to be dropped. The behavior can be adjusted with the new -l (limit) option.
- Update time zone data files to tzdata release 2012c for DST law changes in Antarctica, Armenia, Chile, Cuba, Falkland Islands, Gaza, Haiti, Hebron, Morocco, Syria, and Tokelau Islands; also historical corrections for Canada.

更新時間：2012-06-05
更新細節：

What's new in this version:

- Fix incorrect password transformation in contrib/pgcrypto's DES crypt() function (Solar Designer) If a password string contained the byte value 0x80, the remainder of the password was ignored, causing the password to be much weaker than it appeared. With this fix, the rest of the string is properly included in the DES hash. Any stored password values that are affected by this bug will thus no longer match, so the stored values may need to be updated. 
- Ignore SECURITY DEFINER and SET attributes for a procedural language's call handler Applying such attributes to a call handler could crash the server. 
- Make contrib/citext's upgrade script fix collations of citext arrays and domains over citext Release 9.1.2 provided a fix for collations of citext columns and indexes in databases upgraded or reloaded from pre-9.1 installations, but that fix was incomplete: it neglected to handle arrays and domains over citext. This release extends the module's upgrade script to handle these cases. As before, if you have already run the upgrade script, you'll need to run the collation update commands by hand instead. See the 9.1.2 release notes for more information about doing this.
- Allow numeric timezone offsets in timestamp input to be up to 16 hours away from UTC Some historical time zones have offsets larger than 15 hours, the previous limit. This could result in dumped data values being rejected during reload.
- Fix timestamp conversion to cope when the given time is exactly the last DST transition time for the current timezone This oversight has been there a long time, but was not noticed previously because most DST-using zones are presumed to have an indefinite sequence of future DST transitions.
- Fix text to name and char to name casts to perform string truncation correctly in multibyte encodings 
- Fix memory copying bug in to_tsquery() 
- Ensure txid_current() reports the correct epoch when executed in hot standby 
- Fix planner's handling of outer PlaceHolderVars within subqueries This bug concerns sub-SELECTs that reference variables coming from the nullable side of an outer join of the surrounding query. In 9.1, queries affected by this bug would fail with "ERROR: Upper-level PlaceHolderVar found where not expected". But in 9.0 and 8.4, you'd silently get possibly-wrong answers, since the value transmitted into the subquery wouldn't go to null when it should.
- Fix planning of UNION ALL subqueries with output columns that are not simple variables Planning of such cases got noticeably worse in 9.1 as a result of a misguided fix for "MergeAppend child's targetlist doesn't match MergeAppend" errors. Revert that fix and do it another way.
- Fix slow session startup when pg_attribute is very large If pg_attribute exceeds one-fourth of shared_buffers, cache rebuilding code that is sometimes needed during session start would trigger the synchronized-scan logic, causing it to take many times longer than normal. The problem was particularly acute if many new sessions were starting at once.
- Ensure sequential scans check for query cancel reasonably often A scan encountering many consecutive pages that contain no live tuples would not respond to interrupts meanwhile.
- Ensure the Windows implementation of PGSemaphoreLock() clears ImmediateInterruptOK before returning This oversight meant that a query-cancel interrupt received later in the same query could be accepted at an unsafe time, with unpredictable but not good consequences.
- Show whole-row variables safely when printing views or rules Corner cases involving ambiguous names (that is, the name could be either a table or column name of the query) were printed in an ambiguous way, risking that the view or rule would be interpreted differently after dump and reload. Avoid the ambiguous case by attaching a no-op cast.
- Fix COPY FROM to properly handle null marker strings that correspond to invalid encoding A null marker string such as E'\0' should work, and did work in the past, but the case got broken in 8.4.
- Fix EXPLAIN VERBOSE for writable CTEs containing RETURNING clauses 
- Fix PREPARE TRANSACTION to work correctly in the presence of advisory locks Historically, PREPARE TRANSACTION has simply ignored any session-level advisory locks the session holds, but this case was accidentally broken in 9.1.
- Fix truncation of unlogged tables 
- Ignore missing schemas during non-interactive assignments of search_path This re-aligns 9.1's behavior with that of older branches. Previously 9.1 would throw an error for nonexistent schemas mentioned in search_path settings obtained from places such as ALTER DATABASE SET.
- Fix bugs with temporary or transient tables used in extension scripts This includes cases such as a rewriting ALTER TABLE within an extension update script, since that uses a transient table behind the scenes.
- Ensure autovacuum worker processes perform stack depth checking properly Previously, infinite recursion in a function invoked by auto-ANALYZE could crash worker processes.
- Fix logging collector to not lose log coherency under high load The collector previously could fail to reassemble large messages if it got too busy.
- Fix logging collector to ensure it will restart file rotation after receiving SIGHUP 
- Fix "too many LWLocks taken" failure in GiST indexes 
- Fix WAL replay logic for GIN indexes to not fail if the index was subsequently dropped 
- Correctly detect SSI conflicts of prepared transactions after a crash 
- Avoid synchronous replication delay when committing a transaction that only modified temporary tables In such a case the transaction's commit record need not be flushed to standby servers, but some of the code didn't know that and waited for it to happen anyway.
- Fix error handling in pg_basebackup 
- Fix walsender to not go into a busy loop if connection is terminated 
- Fix memory leak in PL/pgSQL's RETURN NEXT command 
- Fix PL/pgSQL's GET DIAGNOSTICS command when the target is the function's first variable 
- Ensure that PL/Perl package-qualifies the _TD variable This bug caused trigger invocations to fail when they are nested within a function invocation that changes the current package.
- Fix PL/Python functions returning composite types to accept a string for their result value This case was accidentally broken by the 9.1 additions to allow a composite result value to be supplied in other formats, such as dictionaries.
- Fix potential access off the end of memory in psql's expanded display (x) mode 
- Fix several performance problems in pg_dump when the database contains many objects pg_dump could get very slow if the database contained many schemas, or if many objects are in dependency loops, or if there are many owned sequences.
- Fix memory and file descriptor leaks in pg_restore when reading a directory-format archive 
- Fix pg_upgrade for the case that a database stored in a non-default tablespace contains a table in the cluster's default tablespace 
- In ecpg, fix rare memory leaks and possible overwrite of one byte after the sqlca_t structure 
- Fix contrib/dblink's dblink_exec() to not leak temporary database connections upon error 
- Fix contrib/dblink to report the correct connection name in error messages 
- Fix contrib/vacuumlo to use multiple transactions when dropping many large objects This change avoids exceeding max_locks_per_transaction when many objects need to be dropped. The behavior can be adjusted with the new -l (limit) option.
- Update time zone data files to tzdata release 2012c for DST law changes in Antarctica, Armenia, Chile, Cuba, Falkland Islands, Gaza, Haiti, Hebron, Morocco, Syria, and Tokelau Islands; also historical corrections for Canada.

更新時間：2012-06-04
更新細節：

更新時間：2012-06-04
更新細節：

更新時間：2012-06-04
更新細節：

更新時間：2012-02-28
更新細節：

What's new in this version:

Changes:
* Require execute permission on the trigger function for CREATE TRIGGER 
- This missing check could allow another user to execute a trigger function with forged input data, by installing it on a table he owns. This is only of significance for trigger functions marked SECURITY DEFINER, since otherwise trigger functions run as the table owner anyway. 
* Remove arbitrary limitation on length of common name in SSL certificates 
- Both libpq and the server truncated the common name extracted from an SSL certificate at 32 bytes. Normally this would cause nothing worse than an unexpected verification failure, but there are some rather-implausible scenarios in which it might allow one certificate holder to impersonate another. The victim would have to have a common name exactly 32 bytes long, and the attacker would have to persuade a trusted CA to issue a certificate in which the common name has that string as a prefix. Impersonating a server would also require some additional exploit to redirect client connections. 
* Convert newlines to spaces in names written in pg_dump comments 
- pg_dump was incautious about sanitizing object names that are emitted within SQL comments in its output script. A name containing a newline would at least render the script syntactically incorrect. Maliciously crafted object names could present a SQL injection risk when the script is reloaded. 
* Fix btree index corruption from insertions concurrent with vacuuming 
- An index page split caused by an insertion could sometimes cause a concurrently-running VACUUM to miss removing index entries that it should remove. After the corresponding table rows are removed, the dangling index entries would cause errors (such as "could not read block N in file ...") or worse, silently wrong query results after unrelated rows are re-inserted at the now-free table locations. This bug has been present since release 8.2, but occurs so infrequently that it was not diagnosed until now. If you have reason to suspect that it has happened in your database, reindexing the affected index will fix things.
* Fix transient zeroing of shared buffers during WAL replay 
- The replay logic would sometimes zero and refill a shared buffer, so that the contents were transiently invalid. In hot standby mode this can result in a query that's executing in parallel seeing garbage data. Various symptoms could result from that, but the most common one seems to be "invalid memory alloc request size".
* Fix handling of data-modifying WITH subplans in READ COMMITTED rechecking 
- A WITH clause containing INSERT/UPDATE/DELETE would crash if the parent UPDATE or DELETE command needed to be re-evaluated at one or more rows due to concurrent updates in READ COMMITTED mode.
* Fix corner case in SSI transaction cleanup 
- When finishing up a read-write serializable transaction, a crash could occur if all remaining active serializable transactions are read-only.
* Fix postmaster to attempt restart after a hot-standby crash 
- A logic error caused the postmaster to terminate, rather than attempt to restart the cluster, if any backend process crashed while operating in hot standby mode.
* Fix CLUSTER/VACUUM FULL handling of toast values owned by recently-updated rows 
- This oversight could lead to "duplicate key value violates unique constraint" errors being reported against the toast table's index during one of these commands.
* Update per-column permissions, not only per-table permissions, when changing table owner 
- Failure to do this meant that any previously granted column permissions were still shown as having been granted by the old owner. This meant that neither the new owner nor a superuser could revoke the now-untraceable-to-table-owner permissions.
* Support foreign data wrappers and foreign servers in REASSIGN OWNED 
- This command failed with "unexpected classid" errors if it needed to change the ownership of any such objects.
* Allow non-existent values for some settings in ALTER USER/DATABASE SET 
- Allow default_text_search_config, default_tablespace, and temp_tablespaces to be set to names that are not known. This is because they might be known in another database where the setting is intended to be used, or for the tablespace cases because the tablespace might not be created yet. The same issue was previously recognized for search_path, and these settings now act like that one.
* Fix "unsupported node type" error caused by COLLATE in an INSERT expression 
* Avoid crashing when we have problems deleting table files post-commit 
- Dropping a table should lead to deleting the underlying disk files only after the transaction commits. In event of failure then (for instance, because of wrong file permissions) the code is supposed to just emit a warning message and go on, since it's too late to abort the transaction. This logic got broken as of release 8.4, causing such situations to result in a PANIC and an unrestartable database.
* Recover from errors occurring during WAL replay of DROP TABLESPACE 
- Replay will attempt to remove the tablespace's directories, but there are various reasons why this might fail (for example, incorrect ownership or permissions on those directories). Formerly the replay code would panic, rendering the database unrestartable without manual intervention. It seems better to log the problem and continue, since the only consequence of failure to remove the directories is some wasted disk space.
* Fix race condition in logging AccessExclusiveLocks for hot standby 
- Sometimes a lock would be logged as being held by "transaction zero". This is at least known to produce assertion failures on slave servers, and might be the cause of more serious problems.
* Track the OID counter correctly during WAL replay, even when it wraps around 
- Previously the OID counter would remain stuck at a high value until the system exited replay mode. The practical consequences of that are usually nil, but there are scenarios wherein a standby server that's been promoted to master might take a long time to advance the OID counter to a reasonable value once values are needed.
* Prevent emitting misleading "consistent recovery state reached" log message at the beginning of crash recovery 
* Fix initial value of pg_stat_replication.replay_location 
- Previously, the value shown would be wrong until at least one WAL record had been replayed.
* Fix regular expression back-references with * attached 
- Rather than enforcing an exact string match, the code would effectively accept any string that satisfies the pattern sub-expression referenced by the back-reference symbol.
- A similar problem still afflicts back-references that are embedded in a larger quantified expression, rather than being the immediate subject of the quantifier. This will be addressed in a future PostgreSQL release.
* Fix recently-introduced memory leak in processing of inet/cidr values 
- A patch in the December 2011 releases of PostgreSQL caused memory leakage in these operations, which could be significant in scenarios such as building a btree index on such a column.
* Fix planner's ability to push down index-expression restrictions through UNION ALL 
- This type of optimization was inadvertently disabled by a fix for another problem in 9.1.2.
* Fix planning of WITH clauses referenced in UPDATE/DELETE on an inherited table 
- This bug led to "could not find plan for CTE" failures.
* Fix GIN cost estimation to handle column IN (...) index conditions 
- This oversight would usually lead to crashes if such a condition could be used with a GIN index.
* Prevent assertion failure when exiting a session with an open, failed transaction 
- This bug has no impact on normal builds with asserts not enabled.
* Fix dangling pointer after CREATE TABLE AS/SELECT INTO in a SQL-language function 
- In most cases this only led to an assertion failure in assert-enabled builds, but worse consequences seem possible.
* Avoid double close of file handle in syslogger on Windows 
- Ordinarily this error was invisible, but it would cause an exception when running on a debug version of Windows.
* Fix I/O-conversion-related memory leaks in plpgsql 
- Certain operations would leak memory until the end of the current function.
* Work around bug in perl's SvPVutf8() function 
- This function crashes when handed a typeglob or certain read-only objects such as $^V. Make plperl avoid passing those to it.
* In pg_dump, don't dump contents of an extension's configuration tables if the extension itself is not being dumped 
* Improve pg_dump's handling of inherited table columns 
- pg_dump mishandled situations where a child column has a different default expression than its parent column. If the default is textually identical to the parent's default, but not actually the same (for instance, because of schema search path differences) it would not be recognized as different, so that after dump and restore the child would be allowed to inherit the parent's default. Child columns that are NOT NULL where their parent is not could also be restored subtly incorrectly.
* Fix pg_restore's direct-to-database mode for INSERT-style table data 
- Direct-to-database restores from archive files made with --inserts or --column-inserts options fail when using pg_restore from a release dated September or December 2011, as a result of an oversight in a fix for another problem. The archive file itself is not at fault, and text-mode output is okay.
* Teach pg_upgrade to handle renaming of plpython's shared library 
- Upgrading a pre-9.1 database that included plpython would fail because of this oversight.
* Allow pg_upgrade to process tables containing regclass columns 
- Since pg_upgrade now takes care to preserve pg_class OIDs, there was no longer any reason for this restriction.
* Make libpq ignore ENOTDIR errors when looking for an SSL client certificate file 
- This allows SSL connections to be established, though without a certificate, even when the user's home directory is set to something like /dev/null.
* Fix some more field alignment issues in ecpg's SQLDA area 
* Allow AT option in ecpg DEALLOCATE statements 
- The infrastructure to support this has been there for awhile, but through an oversight there was still an error check rejecting the case.
* Do not use the variable name when defining a varchar structure in ecpg 
* Fix contrib/auto_explain's JSON output mode to produce valid JSON 
- The output used brackets at the top level, when it should have used braces.
* Fix error in contrib/intarray's int[] & int[] operator 
- If the smallest integer the two input arrays have in common is 1, and there are smaller values in either array, then 1 would be incorrectly omitted from the result.
* Fix error detection in contrib/pgcrypto's encrypt_iv() and decrypt_iv() 
- These functions failed to report certain types of invalid-input errors, and would instead return random garbage values for incorrect input.
* Fix one-byte buffer overrun in contrib/test_parser 
- The code would try to read one more byte than it should, which would crash in corner cases. Since contrib/test_parser is only example code, this is not a security issue in itself, but bad example code is still bad.
* Use __sync_lock_test_and_set() for spinlocks on ARM, if available 
- This function replaces our previous use of the SWPB instruction, which is deprecated and not available on ARMv6 and later. Reports suggest that the old code doesn't fail in an obvious way on recent ARM boards, but simply doesn't interlock concurrent accesses, leading to bizarre failures in multiprocess operation.
* Use -fexcess-precision=standard option when building with gcc versions that accept it 
- This prevents assorted scenarios wherein recent versions of gcc will produce creative results.
* Allow use of threaded Python on FreeBSD 
- Our configure script previously believed that this combination wouldn't work; but FreeBSD fixed the problem, so remove that error check.
* Allow MinGW builds to use standardly-named OpenSSL libraries

更新時間：2012-02-28
更新細節：

What's new in this version:

Changes:
* Require execute permission on the trigger function for CREATE TRIGGER 
- This missing check could allow another user to execute a trigger function with forged input data, by installing it on a table he owns. This is only of significance for trigger functions marked SECURITY DEFINER, since otherwise trigger functions run as the table owner anyway. 
* Remove arbitrary limitation on length of common name in SSL certificates 
- Both libpq and the server truncated the common name extracted from an SSL certificate at 32 bytes. Normally this would cause nothing worse than an unexpected verification failure, but there are some rather-implausible scenarios in which it might allow one certificate holder to impersonate another. The victim would have to have a common name exactly 32 bytes long, and the attacker would have to persuade a trusted CA to issue a certificate in which the common name has that string as a prefix. Impersonating a server would also require some additional exploit to redirect client connections. 
* Convert newlines to spaces in names written in pg_dump comments 
- pg_dump was incautious about sanitizing object names that are emitted within SQL comments in its output script. A name containing a newline would at least render the script syntactically incorrect. Maliciously crafted object names could present a SQL injection risk when the script is reloaded. 
* Fix btree index corruption from insertions concurrent with vacuuming 
- An index page split caused by an insertion could sometimes cause a concurrently-running VACUUM to miss removing index entries that it should remove. After the corresponding table rows are removed, the dangling index entries would cause errors (such as "could not read block N in file ...") or worse, silently wrong query results after unrelated rows are re-inserted at the now-free table locations. This bug has been present since release 8.2, but occurs so infrequently that it was not diagnosed until now. If you have reason to suspect that it has happened in your database, reindexing the affected index will fix things.
* Fix transient zeroing of shared buffers during WAL replay 
- The replay logic would sometimes zero and refill a shared buffer, so that the contents were transiently invalid. In hot standby mode this can result in a query that's executing in parallel seeing garbage data. Various symptoms could result from that, but the most common one seems to be "invalid memory alloc request size".
* Fix handling of data-modifying WITH subplans in READ COMMITTED rechecking 
- A WITH clause containing INSERT/UPDATE/DELETE would crash if the parent UPDATE or DELETE command needed to be re-evaluated at one or more rows due to concurrent updates in READ COMMITTED mode.
* Fix corner case in SSI transaction cleanup 
- When finishing up a read-write serializable transaction, a crash could occur if all remaining active serializable transactions are read-only.
* Fix postmaster to attempt restart after a hot-standby crash 
- A logic error caused the postmaster to terminate, rather than attempt to restart the cluster, if any backend process crashed while operating in hot standby mode.
* Fix CLUSTER/VACUUM FULL handling of toast values owned by recently-updated rows 
- This oversight could lead to "duplicate key value violates unique constraint" errors being reported against the toast table's index during one of these commands.
* Update per-column permissions, not only per-table permissions, when changing table owner 
- Failure to do this meant that any previously granted column permissions were still shown as having been granted by the old owner. This meant that neither the new owner nor a superuser could revoke the now-untraceable-to-table-owner permissions.
* Support foreign data wrappers and foreign servers in REASSIGN OWNED 
- This command failed with "unexpected classid" errors if it needed to change the ownership of any such objects.
* Allow non-existent values for some settings in ALTER USER/DATABASE SET 
- Allow default_text_search_config, default_tablespace, and temp_tablespaces to be set to names that are not known. This is because they might be known in another database where the setting is intended to be used, or for the tablespace cases because the tablespace might not be created yet. The same issue was previously recognized for search_path, and these settings now act like that one.
* Fix "unsupported node type" error caused by COLLATE in an INSERT expression 
* Avoid crashing when we have problems deleting table files post-commit 
- Dropping a table should lead to deleting the underlying disk files only after the transaction commits. In event of failure then (for instance, because of wrong file permissions) the code is supposed to just emit a warning message and go on, since it's too late to abort the transaction. This logic got broken as of release 8.4, causing such situations to result in a PANIC and an unrestartable database.
* Recover from errors occurring during WAL replay of DROP TABLESPACE 
- Replay will attempt to remove the tablespace's directories, but there are various reasons why this might fail (for example, incorrect ownership or permissions on those directories). Formerly the replay code would panic, rendering the database unrestartable without manual intervention. It seems better to log the problem and continue, since the only consequence of failure to remove the directories is some wasted disk space.
* Fix race condition in logging AccessExclusiveLocks for hot standby 
- Sometimes a lock would be logged as being held by "transaction zero". This is at least known to produce assertion failures on slave servers, and might be the cause of more serious problems.
* Track the OID counter correctly during WAL replay, even when it wraps around 
- Previously the OID counter would remain stuck at a high value until the system exited replay mode. The practical consequences of that are usually nil, but there are scenarios wherein a standby server that's been promoted to master might take a long time to advance the OID counter to a reasonable value once values are needed.
* Prevent emitting misleading "consistent recovery state reached" log message at the beginning of crash recovery 
* Fix initial value of pg_stat_replication.replay_location 
- Previously, the value shown would be wrong until at least one WAL record had been replayed.
* Fix regular expression back-references with * attached 
- Rather than enforcing an exact string match, the code would effectively accept any string that satisfies the pattern sub-expression referenced by the back-reference symbol.
- A similar problem still afflicts back-references that are embedded in a larger quantified expression, rather than being the immediate subject of the quantifier. This will be addressed in a future PostgreSQL release.
* Fix recently-introduced memory leak in processing of inet/cidr values 
- A patch in the December 2011 releases of PostgreSQL caused memory leakage in these operations, which could be significant in scenarios such as building a btree index on such a column.
* Fix planner's ability to push down index-expression restrictions through UNION ALL 
- This type of optimization was inadvertently disabled by a fix for another problem in 9.1.2.
* Fix planning of WITH clauses referenced in UPDATE/DELETE on an inherited table 
- This bug led to "could not find plan for CTE" failures.
* Fix GIN cost estimation to handle column IN (...) index conditions 
- This oversight would usually lead to crashes if such a condition could be used with a GIN index.
* Prevent assertion failure when exiting a session with an open, failed transaction 
- This bug has no impact on normal builds with asserts not enabled.
* Fix dangling pointer after CREATE TABLE AS/SELECT INTO in a SQL-language function 
- In most cases this only led to an assertion failure in assert-enabled builds, but worse consequences seem possible.
* Avoid double close of file handle in syslogger on Windows 
- Ordinarily this error was invisible, but it would cause an exception when running on a debug version of Windows.
* Fix I/O-conversion-related memory leaks in plpgsql 
- Certain operations would leak memory until the end of the current function.
* Work around bug in perl's SvPVutf8() function 
- This function crashes when handed a typeglob or certain read-only objects such as $^V. Make plperl avoid passing those to it.
* In pg_dump, don't dump contents of an extension's configuration tables if the extension itself is not being dumped 
* Improve pg_dump's handling of inherited table columns 
- pg_dump mishandled situations where a child column has a different default expression than its parent column. If the default is textually identical to the parent's default, but not actually the same (for instance, because of schema search path differences) it would not be recognized as different, so that after dump and restore the child would be allowed to inherit the parent's default. Child columns that are NOT NULL where their parent is not could also be restored subtly incorrectly.
* Fix pg_restore's direct-to-database mode for INSERT-style table data 
- Direct-to-database restores from archive files made with --inserts or --column-inserts options fail when using pg_restore from a release dated September or December 2011, as a result of an oversight in a fix for another problem. The archive file itself is not at fault, and text-mode output is okay.
* Teach pg_upgrade to handle renaming of plpython's shared library 
- Upgrading a pre-9.1 database that included plpython would fail because of this oversight.
* Allow pg_upgrade to process tables containing regclass columns 
- Since pg_upgrade now takes care to preserve pg_class OIDs, there was no longer any reason for this restriction.
* Make libpq ignore ENOTDIR errors when looking for an SSL client certificate file 
- This allows SSL connections to be established, though without a certificate, even when the user's home directory is set to something like /dev/null.
* Fix some more field alignment issues in ecpg's SQLDA area 
* Allow AT option in ecpg DEALLOCATE statements 
- The infrastructure to support this has been there for awhile, but through an oversight there was still an error check rejecting the case.
* Do not use the variable name when defining a varchar structure in ecpg 
* Fix contrib/auto_explain's JSON output mode to produce valid JSON 
- The output used brackets at the top level, when it should have used braces.
* Fix error in contrib/intarray's int[] & int[] operator 
- If the smallest integer the two input arrays have in common is 1, and there are smaller values in either array, then 1 would be incorrectly omitted from the result.
* Fix error detection in contrib/pgcrypto's encrypt_iv() and decrypt_iv() 
- These functions failed to report certain types of invalid-input errors, and would instead return random garbage values for incorrect input.
* Fix one-byte buffer overrun in contrib/test_parser 
- The code would try to read one more byte than it should, which would crash in corner cases. Since contrib/test_parser is only example code, this is not a security issue in itself, but bad example code is still bad.
* Use __sync_lock_test_and_set() for spinlocks on ARM, if available 
- This function replaces our previous use of the SWPB instruction, which is deprecated and not available on ARMv6 and later. Reports suggest that the old code doesn't fail in an obvious way on recent ARM boards, but simply doesn't interlock concurrent accesses, leading to bizarre failures in multiprocess operation.
* Use -fexcess-precision=standard option when building with gcc versions that accept it 
- This prevents assorted scenarios wherein recent versions of gcc will produce creative results.
* Allow use of threaded Python on FreeBSD 
- Our configure script previously believed that this combination wouldn't work; but FreeBSD fixed the problem, so remove that error check.
* Allow MinGW builds to use standardly-named OpenSSL libraries

更新時間：2012-02-27
更新細節：

更新時間：2012-02-27
更新細節：