## E.175. Release 8.4.4

Release date: 2010-05-17

This release contains a variety of fixes from 8.4.3. For information about new features in the 8.4 major release, see Section E.179.

### E.175.1. Migration to Version 8.4.4

A dump/restore is not required for those running 8.4.X. However, if you are upgrading from a version earlier than 8.4.2, see Section E.177.

### E.175.2. Changes

- Enforce restrictions in `plperl` using an opmask applied to the whole interpreter, instead of using `Safe.pm` (Tim Bunce, Andrew Dunstan)

  Recent developments have convinced us that `Safe.pm` is too insecure to rely on for making `plperl` trustable. This change removes use of `Safe.pm` altogether, in favor of using a separate interpreter with an opcode mask that is always applied. Pleasant side effects of the change include that it is now possible to use Perl's `strict` pragma in a natural way in `plperl`, and that Perl's `$a` and `$b` variables work as expected in sort routines, and that function compilation is significantly faster. (CVE-2010-1169)

- Prevent PL/Tcl from executing untrustworthy code from `pltcl_modules` (Tom)

  PL/Tcl's feature for autoloading Tcl code from a database table could be exploited for trojan-horse attacks, because there was no restriction on who could create or insert into that table. This change disables the feature unless `pltcl_modules` is owned by a superuser. (However, the permissions on the table are not checked, so installations that really need a less-than-secure modules table can still grant suitable privileges to trusted non-superusers.) Also, prevent loading code into the unrestricted “normal” Tcl interpreter unless we are really going to execute a `pltclu` function. (CVE-2010-1170)

- Fix data corruption during WAL replay of `ALTER ... SET TABLESPACE` (Tom)

  When `archive_mode` is on, `ALTER ... SET TABLESPACE` generates a WAL record whose replay logic was incorrect. It could write the data to the wrong place, leading to possibly-unrecoverable data corruption. Data corruption would be observed on standby slaves, and could occur on the master as well if a database crash and recovery occurred after committing the `ALTER` and before the next checkpoint.

- Fix possible crash if a cache reset message is received during rebuild of a relcache entry (Heikki)

  This error was introduced in 8.4.3 while fixing a related failure.

- Apply per-function GUC settings while running the language validator for the function (Itagaki Takahiro)

  This avoids failures if the function's code is invalid without the setting; an example is that SQL functions may not parse if the `search_path` is not correct.

- Do constraint exclusion for inherited `UPDATE` and `DELETE` target tables when `constraint_exclusion` = `partition` (Tom)

  Due to an oversight, this setting previously only caused constraint exclusion to be checked in `SELECT` commands.

- Do not allow an unprivileged user to reset superuser-only parameter settings (Alvaro)

  Previously, if an unprivileged user ran `ALTER USER ... RESET ALL` for himself, or `ALTER DATABASE ... RESET ALL` for a database he owns, this would remove all special parameter settings for the user or database, even ones that are only supposed to be changeable by a superuser. Now, the `ALTER` will only remove the parameters that the user has permission to change.

- Avoid possible crash during backend shutdown if shutdown occurs when a `CONTEXT` addition would be made to log entries (Tom)

  In some cases the context-printing function would fail because the current transaction had already been rolled back when it came time to print a log message.

- Fix erroneous handling of `%r` parameter in `recovery_end_command` (Heikki)

  The value always came out zero.

- Ensure the archiver process responds to changes in `archive_command` as soon as possible (Tom)

- Fix PL/pgSQL's `CASE` statement to not fail when the case expression is a query that returns no rows (Tom)

- Update PL/Perl's `ppport.h` for modern Perl versions (Andrew)

- Fix assorted memory leaks in PL/Python (Andreas Freund, Tom)

- Handle empty-string connect parameters properly in ecpg (Michael)

- Prevent infinite recursion in psql when expanding a variable that refers to itself (Tom)

- Fix psql's `\copy` to not add spaces around a dot within `\copy (select ...)` (Tom)

  Addition of spaces around the decimal point in a numeric literal would result in a syntax error.

- Avoid formatting failure in psql when running in a locale context that doesn't match the `client_encoding` (Tom)

- Fix unnecessary “GIN indexes do not support whole-index scans” errors for unsatisfiable queries using `contrib/intarray` operators (Tom)

- Ensure that `contrib/pgstattuple` functions respond to cancel interrupts promptly (Tatsuhito Kasahara)

- Make server startup deal properly with the case that `shmget()` returns `EINVAL` for an existing shared memory segment (Tom)

  This behavior has been observed on BSD-derived kernels including macOS. It resulted in an entirely-misleading startup failure complaining that the shared memory request size was too large.

- Avoid possible crashes in syslogger process on Windows (Heikki)

- Deal more robustly with incomplete time zone information in the Windows registry (Magnus)

- Update the set of known Windows time zone names (Magnus)

- Update time zone data files to tzdata release 2010j for DST law changes in Argentina, Australian Antarctic, Bangladesh, Mexico, Morocco, Pakistan, Palestine, Russia, Syria, Tunisia; also historical corrections for Taiwan.

  Also, add `PKST` (Pakistan Summer Time) to the default set of timezone abbreviations.