pageinspect: Use new pg_lsn datatype.

Michael Paquier, with slight comment changes by me
Corrections to replication slots code and documentation.

Andres Freund, per a report from Vik Faering
Bump catversion.

The previous patch should have entailed a catversion bump, but I
forgot.
Use a longer buffer in libpqrcv_startstreaming.

Because of the new SLOT clause in the START_REPLICATION command, it's
possible for the command to end up too long for the old maximum buffer
length.

Andres Freund
pg_dump et al: Add --if-exists option

This option makes pg_dump, pg_dumpall and pg_restore inject an IF EXISTS
clause to each DROP command they emit.  (In pg_dumpall, the clause is
not added to individual objects drops, but rather to the CREATE DATABASE
commands, as well as CREATE ROLE and CREATE TABLESPACE.)

This allows for a better user dump experience when using --clean in case
some objects do not already exist.  Per bug #7873 by Dave Rolsky.

Author: Pavel Stěhule
Reviewed-by: Jeevan Chalke, Álvaro Herrera, Josh Kupershmidt
Rename huge_tlb_pages to huge_pages, and improve docs.

Christian Kruse
Fix whitespace
Introduce logical decoding.

This feature, building on previous commits, allows the write-ahead log
stream to be decoded into a series of logical changes; that is,
inserts, updates, and deletes and the transactions which contain them.
It is capable of handling decoding even across changes to the schema
of the effected tables.  The output format is controlled by a
so-called "output plugin"; an example is included.  To make use of
this in a real replication system, the output plugin will need to be
modified to produce output in the format appropriate to that system,
and to perform filtering.

Currently, information can be extracted from the logical decoding
system only via SQL; future commits will add the ability to stream
changes via walsender.

Andres Freund, with review and other contributions from many other
people, including Álvaro Herrera, Abhijit Menon-Sen, Peter Gheogegan,
Kevin Grittner, Robert Haas, Heikki Linnakangas, Fujii Masao, Abhijit
Menon-Sen, Michael Paquier, Simon Riggs, Craig Ringer, and Steve
Singer.
Error out on send failure in walsender loop.

I changed the loop in 9.3 to use "goto send_failure" instead of "break" on
errors, but I missed this one case. It was a relatively harmless bug: if
the flush fails once it will most likely fail again as soon as we try to
flush the output again. But it's a bug nevertheless.

Report and fix by Andres Freund.
Minor corrections to logical decoding patch.
Allow VACUUM FULL/CLUSTER to bump freeze horizons even for pg_class.

pg_class is a special case for CLUSTER and VACUUM FULL, so although
commit 3cff1879f8d03cb729368722ca823a4bf74c0cac caused these
operations to advance relfrozenxid and relminmxid for all other
tables, it did not provide the same benefit for pg_class.  This
plugs that gap.

Andres Freund
Constructors for interval, timestamp, timestamptz

Author: Pavel Stěhule, editorialized somewhat by Álvaro Herrera
Reviewed-by: Tomáš Vondra, Marko Tiikkaja
With input from Fabrízio de Royes Mello, Jim Nasby
auto_explain: Add logging of trigger execution

Author: Kyotaro HORIGUCHI
Reviewed-by: Jaime Casanova
Provide a FORCE NULL option to COPY in CSV mode.

This forces an input field containing the quoted null string to be
returned as a NULL. Without this option, only unquoted null strings
behave this way. This helps where some CSV producers insist on quoting
every field, whether or not it is needed. The option takes a list of
fields, and only applies to those columns. There is an equivalent
column-level option added to file_fdw.

Ian Barwick, with some tweaking by Andrew Dunstan, reviewed by Payal
Singh.
Fix whitespace
Fix issues with pg_ctl

The new, small, free_readfile managed to have bug in it which could
cause it to try and free something it shouldn't, and fix the case
where it was being called with an invalid pointer leading to a
segfault.

Noted by Bruce, issues introduced and fixed by me.
Fix lastReplayedEndRecPtr calculation when starting from shutdown checkpoint.

When entering crash recovery followed by archive recovery, and the latest
checkpoint is a shutdown checkpoint, and there are no more WAL records to
replay before transitioning from crash to archive recovery, we would not
immediately allow read-only connections in hot standby mode even if we
could. That's because when starting from a shutdown checkpoint, we set
lastReplayedEndRecPtr incorrectly to the record before the checkpoint
record, instead of the checkpoint record itself. We don't run the redo
routine of the shutdown checkpoint record, but starting recovery from it
goes through the same motions, so it should be considered as replayed.

Reported by Kyotaro HORIGUCHI. All versions with hot standby are affected,
so backpatch to 9.0.
Do wal_level and hot standby checks when doing crash-then-archive recovery.

CheckRequiredParameterValues() should perform the checks if archive recovery
was requested, even if we are going to perform crash recovery first.

Reported by Kyotaro HORIGUCHI. Backpatch to 9.2, like the crash-then-archive
recovery mode.
Allocate fresh memory for post_opts/exec_path

Instead of having read_post_opts() depend on the memory allocated for
the config file (which is now getting free'd), pg_strdup() for
post_opts and exec_path (similar to how it's being done elsewhere).

Noted by Thom Brown.
pg_upgrade:  improve C comment about what old/new oids match