E.42.1. Migration to version 7.4.9

A dump/restore is not required for those running 7.4.X. However, if you are upgrading from a version earlier than 7.4.8, see the release notes for 7.4.8.

E.42.2. Changes

• Fix error that allowed VACUUM to remove ctid chains too soon, and add more checking in code that follows ctid links

  This fixes a long-standing problem that could cause crashes in very rare circumstances.

• Fix CHAR() to properly pad spaces to the specified length when using a multiple-byte character set (Yoshiyuki Asaba)

  In prior releases, the padding of CHAR() was incorrect because it only padded to the specified number of bytes without considering how many characters were stored.

• Fix the sense of the test for read-only transaction in COPY

  The code formerly prohibited COPY TO, where it should prohibit COPY FROM.

• Fix planning problem with outer-join ON clauses that reference only the inner-side relation

• Further fixes for x FULL JOIN y ON true corner cases

• Make array_in and array_recv more paranoid about validating their OID parameter

• Fix missing rows in queries like UPDATE a=... WHERE a... with GiST index on column a

• Improve robustness of datetime parsing

• Improve checking for partially-written WAL pages

• Improve robustness of signal handling when SSL is enabled

• Don't try to open more than max_files_per_process files during postmaster startup

• Various memory leakage fixes

• Various portability improvements

• Fix PL/PgSQL to handle var := var correctly when the variable is of pass-by-reference type

• Update contrib/tsearch2 to use current Snowball code