Make the streaming replication protocol messages architecture-independent.

We used to send structs wrapped in CopyData messages, which works as long as
the client and server agree on things like endianess, timestamp format and
alignment. That's good enough for running a standby server, which has to run
on the same platform anyway, but it's useful for tools like pg_receivexlog
to work across platforms.

This breaks protocol compatibility of streaming replication, but we never
promised that to be compatible across versions, anyway.
In pg_upgrade docs, mention using base backup as part of rsync for
logical replication upgrades.

Backpatch to 9.2.
Don't try to use a unopened relation

Commit 4c9d0901 mistakenly introduced a call to
TransferPredicateLocksToHeapRelation() on an index relation that had
been closed a few lines above.  Moving up an index_open() call that's
below is enough to fix the problem.

Discovered by me while testing an unrelated patch.
Add URLs to document why DLLIMPORT is needed on Windows.

Per email from Craig Ringer
Fix missing inclusions.

Some platforms require including <netinet/in.h> and/or <arpa/inet.h> to
use htonl() and ntohl().  Per build failure locally.
Teach pg_basebackup and pg_receivexlog to reply to server keepalives.

Without this, the connection will be killed after timeout if
wal_sender_timeout is set in the server.

Original patch by Amit Kapila, modified by me to fit recent changes in the
code.
Don't trash input list structure in does_not_exist_skipping().

The trigger and rule cases need to split up the input name list, but
they mustn't corrupt the passed-in data structure, since it could be part
of a cached utility-statement parsetree.  Per bug #7641.
Rename ResolveNew() to ReplaceVarsFromTargetList(), and tweak its API.

This function currently lacks the option to throw error if the provided
targetlist doesn't have any matching entry for a Var to be replaced.
Two of the four existing call sites would be better off with an error,
as would the usage in the pending auto-updatable-views patch, so it seems
past time to extend the API to support that.  To do so, replace the "event"
parameter (historically of type CmdType, though it was declared plain int)
with a special-purpose enum type.

It's unclear whether this function might be called by third-party code.
Since many C compilers wouldn't warn about a call site continuing to use
the old calling convention, rename the function to forcibly break any
such code that hasn't been updated.  The old name was none too well chosen
anyhow.
Fix WaitLatch() to return promptly when the requested timeout expires.

If the sleep is interrupted by a signal, we must recompute the remaining
time to wait; otherwise, a steady stream of non-wait-terminating interrupts
could delay return from WaitLatch indefinitely.  This has been shown to be
a problem for the autovacuum launcher, and there may well be other places
now or in the future with similar issues.  So we'd better make the function
robust, even though this'll add at least one gettimeofday call per wait.

Back-patch to 9.2.  We might eventually need to fix 9.1 as well, but the
code is quite different there, and the usage of WaitLatch in 9.1 is so
limited that it's not clearly important to do so.

Reported and diagnosed by Jeff Janes, though I rewrote his patch rather
heavily.
XSLT stylesheet: Add slash to directory name

Some versions of the XSLT stylesheets don't handle the missing slash
correctly (they concatenate directory and file name without the slash).
This might never have worked correctly.
Remove leftover LWLockRelease() call

This code was refactored in d5497b95 but an extra LWLockRelease call was
left behind.

Per report from Erik Rijkers
Check for stack overflow in transformSetOperationTree().

Since transformSetOperationTree() recurses, it can be driven to stack
overflow with enough UNION/INTERSECT/EXCEPT clauses in a query.  Add a
check to ensure it fails cleanly instead of crashing.  Per report from
Matthew Gerber (though it's not clear whether this is the only thing
going wrong for him).

Historical note: I think the reasoning behind not putting a check here in
the beginning was that the check in transformExpr() ought to be sufficient
to guard the whole parser.  However, because transformSetOperationTree()
recurses all the way to the bottom of the set-operation tree before doing
any analysis of the statement's expressions, that check doesn't save it.
doc: "only relevant" -> "relevant only"

Karl O. Pinc
Silence "expression result unused" warnings in AssertVariableIsOfTypeMacro

At least clang 3.1 generates those warnings. Prepend (void) to avoid them,
like we have in AssertMacro.
Use correct text domain for translating errcontext() messages.

errcontext() is typically used in an error context callback function, not
within an ereport() invocation like e.g errmsg and errdetail are. That means
that the message domain that the TEXTDOMAIN magic in ereport() determines
is not the right one for the errcontext() calls. The message domain needs to
be determined by the C file containing the errcontext() call, not the file
containing the ereport() call.

Fix by turning errcontext() into a macro that passes the TEXTDOMAIN to use
for the errcontext message. "errcontext" was used in a few places as a
variable or struct field name, I had to rename those out of the way, now
that errcontext is a macro.

We've had this problem all along, but this isn't doesn't seem worth
backporting. It's a fairly minor issue, and turning errcontext from a
function to a macro requires at least a recompile of any external code that
calls errcontext().
Oops, have to rename local variables called 'errcontext' in contrib, too.

As pointed out by Alvaro.
Use a stamp file for the XSLT HTML doc build

This way it works more like the DSSSL build, and dependencies are
tracked better by make.

Also copy the CSS stylesheet to the html directory.  This was forgotten
when the output directory was changed.
Fix multiple problems in WAL replay.

Most of the replay functions for WAL record types that modify more than
one page failed to ensure that those pages were locked correctly to ensure
that concurrent queries could not see inconsistent page states.  This is
a hangover from coding decisions made long before Hot Standby was added,
when it was hardly necessary to acquire buffer locks during WAL replay
at all, let alone hold them for carefully-chosen periods.

The key problem was that RestoreBkpBlocks was written to hold lock on each
page restored from a full-page image for only as long as it took to update
that page.  This was guaranteed to break any WAL replay function in which
there was any update-ordering constraint between pages, because even if the
nominal order of the pages is the right one, any mixture of full-page and
non-full-page updates in the same record would result in out-of-order
updates.  Moreover, it wouldn't work for situations where there's a
requirement to maintain lock on one page while updating another.  Failure
to honor an update ordering constraint in this way is thought to be the
cause of bug #7648 from Daniel Farina: what seems to have happened there
is that a btree page being split was rewritten from a full-page image
before the new right sibling page was written, and because lock on the
original page was not maintained it was possible for hot standby queries to
try to traverse the page's right-link to the not-yet-existing sibling page.

To fix, get rid of RestoreBkpBlocks as such, and instead create a new
function RestoreBackupBlock that restores just one full-page image at a
time.  This function can be invoked by WAL replay functions at the points
where they would otherwise perform non-full-page updates; in this way, the
physical order of page updates remains the same no matter which pages are
replaced by full-page images.  We can then further adjust the logic in
individual replay functions if it is necessary to hold buffer locks
for overlapping periods.  A side benefit is that we can simplify the
handling of concurrency conflict resolution by moving that code into the
record-type-specfic functions; there's no more need to contort the code
layout to keep conflict resolution in front of the RestoreBkpBlocks call.

In connection with that, standardize on zero-based numbering rather than
one-based numbering for referencing the full-page images.  In HEAD, I
removed the macros XLR_BKP_BLOCK_1 through XLR_BKP_BLOCK_4.  They are
still there in the header files in previous branches, but are no longer
used by the code.

In addition, fix some other bugs identified in the course of making these
changes:

spgRedoAddNode could fail to update the parent downlink at all, if the
parent tuple is in the same page as either the old or new split tuple and
we're not doing a full-page image: it would get fooled by the LSN having
been advanced already.  This would result in permanent index corruption,
not just transient failure of concurrent queries.

Also, ginHeapTupleFastInsert's "merge lists" case failed to mark the old
tail page as a candidate for a full-page image; in the worst case this
could result in torn-page corruption.

heap_xlog_freeze() was inconsistent about using a cleanup lock or plain
exclusive lock: it did the former in the normal path but the latter for a
full-page image.  A plain exclusive lock seems sufficient, so change to
that.

Also, remove gistRedoPageDeleteRecord(), which has been dead code since
VACUUM FULL was rewritten.

Back-patch to 9.0, where hot standby was introduced.  Note however that 9.0
had a significantly different WAL-logging scheme for GIST index updates,
and it doesn't appear possible to make that scheme safe for concurrent hot
standby queries, because it can leave inconsistent states in the index even
between WAL records.  Given the lack of complaints from the field, we won't
work too hard on fixing that branch.
doc: Add link to CREATE TABLE AS on CREATE TABLE reference page

Karl O. Pinc
Clarify docs on hot standby lock release

Andres Freund and Simon Riggs