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