## E.167. Release 8.2.23

### Release Date

2011-12-05

This release contains a variety of fixes from 8.2.22. For information about new features in the 8.2 major release, see Section E.190, “Release 8.2”.

This is expected to be the last PostgreSQL release in the 8.2.X series. Users are encouraged to update to a newer release branch soon.

### E.167.1. Migration to Version 8.2.23

A dump/restore is not required for those running 8.2.X.

However, a longstanding error was discovered in the definition of the `information_schema.referential_constraints` view. If you rely on correct results from that view, you should replace its definition as explained in the first changelog item below.

Also, if you are upgrading from a version earlier than 8.2.14, see Section E.176, “Release 8.2.14”.

### E.167.2. Changes

- Fix bugs in `information_schema.referential_constraints` view (Tom Lane)

  This view was being insufficiently careful about matching the foreign-key constraint to the depended-on primary or unique key constraint. That could result in failure to show a foreign key constraint at all, or showing it multiple times, or claiming that it depends on a different constraint than the one it really does.

  Since the view definition is installed by initdb, merely upgrading will not fix the problem. If you need to fix this in an existing installation, you can (as a superuser) drop the `information_schema` schema then re-create it by sourcing ``SHAREDIR`/information_schema.sql`. (Run `pg_config --sharedir` if you're uncertain where `SHAREDIR` is.) This must be repeated in each database to be fixed.

- Fix TOAST-related data corruption during `CREATE TABLE dest AS SELECT * FROM src` or `INSERT INTO dest SELECT * FROM src` (Tom Lane)

  If a table has been modified by `ALTER TABLE ADD COLUMN`, attempts to copy its data verbatim to another table could produce corrupt results in certain corner cases. The problem can only manifest in this precise form in 8.4 and later, but we patched earlier versions as well in case there are other code paths that could trigger the same bug.

- Fix race condition during toast table access from stale syscache entries (Tom Lane)

  The typical symptom was transient errors like “missing chunk number 0 for toast value NNNNN in pg_toast_2619”, where the cited toast table would always belong to a system catalog.

- Improve locale support in `money` type's input and output (Tom Lane)

  Aside from not supporting all standard `lc_monetary` formatting options, the input and output functions were inconsistent, meaning there were locales in which dumped `money` values could not be re-read.

- Don't let `transform_null_equals` affect `CASE foo WHEN NULL ...` constructs (Heikki Linnakangas)

  `transform_null_equals` is only supposed to affect `foo = NULL` expressions written directly by the user, not equality checks generated internally by this form of `CASE`.

- Change foreign-key trigger creation order to better support self-referential foreign keys (Tom Lane)

  For a cascading foreign key that references its own table, a row update will fire both the `ON UPDATE` trigger and the `CHECK` trigger as one event. The `ON UPDATE` trigger must execute first, else the `CHECK` will check a non-final state of the row and possibly throw an inappropriate error. However, the firing order of these triggers is determined by their names, which generally sort in creation order since the triggers have auto-generated names following the convention “RI_ConstraintTrigger_NNNN”. A proper fix would require modifying that convention, which we will do in 9.2, but it seems risky to change it in existing releases. So this patch just changes the creation order of the triggers. Users encountering this type of error should drop and re-create the foreign key constraint to get its triggers into the right order.

- Preserve blank lines within commands in psql's command history (Robert Haas)

  The former behavior could cause problems if an empty line was removed from within a string literal, for example.

- Use the preferred version of xsubpp to build PL/Perl, not necessarily the operating system's main copy (David Wheeler and Alex Hunsaker)

- Honor query cancel interrupts promptly in `pgstatindex()` (Robert Haas)

- Ensure VPATH builds properly install all server header files (Peter Eisentraut)

- Shorten file names reported in verbose error messages (Peter Eisentraut)

  Regular builds have always reported just the name of the C file containing the error message call, but VPATH builds formerly reported an absolute path name.

- Fix interpretation of Windows timezone names for Central America (Tom Lane)

  Map “Central America Standard Time” to `CST6`, not `CST6CDT`, because DST is generally not observed anywhere in Central America.

- Update time zone data files to tzdata release 2011n for DST law changes in Brazil, Cuba, Fiji, Palestine, Russia, and Samoa; also historical corrections for Alaska and British East Africa.