Correct off-by-one when reading from pipe

In pg_basebackup.c:reached_end_position(), we're reading from an
internal pipe with our own background process but we're possibly
reading more bytes than will actually fit into our buffer due to
an off-by-one error.  As we're reading from an internal pipe
there's no real risk here, but it's good form to not depend on
such convenient arrangements.

Bug spotted by the Coverity scanner.

Back-patch to 9.2 where this showed up.
vacuumlo: Use a cursor to limit client-side memory usage.

This prevents the client from gobbling up too much memory when the
number of large objects to be removed is very large.

Andrew Dunstan, reviewed by Josh Kupershmidt
Regression tests for LOCK TABLE.

Robins Tharakan, reviewed by Szymon Guz, substantially revised by me.
Assert that syscache lookups don't happen outside transactions.

Andres Freund
Tab completion for \lo_import

Josh Kupershmidt
Check get_tle_by_resno() result before deref

When creating a sort to support a group by, we need to look up the
target entry in the target list by the resno using get_tle_by_resno().
This particular code-path didn't check the result prior to attempting
to dereference it, while all other callers did.  While I can't see a
way for this usage of get_tle_by_resno() to fail (you can't ask for
a column to be sorted on which isn't included in the group by), it's
probably best to check that we didn't end up with a NULL somehow
anyway than risk the segfault.

I'm willing to back-patch this if others feel it's necessary, but my
guess is new features are what might tickle this rather than anything
existing.

Missing check spotted by the Coverity scanner.
Fix PQconninfoParse error message handling

The returned error message already includes a newline, but the callers
were adding their own when printing it out.
Allow background workers to be started dynamically.

There is a new API, RegisterDynamicBackgroundWorker, which allows
an ordinary user backend to register a new background writer during
normal running.  This means that it's no longer necessary for all
background workers to be registered during processing of
shared_preload_libraries, although the option of registering workers
at that time remains available.

When a background worker exits and will not be restarted, the
slot previously used by that background worker is automatically
released and becomes available for reuse.  Slots used by background
workers that are configured for automatic restart can't (yet) be
released without shutting down the system.

This commit adds a new source file, bgworker.c, and moves some
of the existing control logic for background workers there.
Previously, there was little enough logic that it made sense to
keep everything in postmaster.c, but not any more.

This commit also makes the worker_spi contrib module into an
extension and adds a new function, worker_spi_launch, which can
be used to demonstrate the new facility.
Add support for REFRESH MATERIALIZED VIEW CONCURRENTLY.

This allows reads to continue without any blocking while a REFRESH
runs.  The new data appears atomically as part of transaction
commit.

Review questioned the Assert that a matview was not a system
relation.  This will be addressed separately.

Reviewed by Hitoshi Harada, Robert Haas, Andres Freund.
Merged after review with security patch f3ab5d4.
Add --progress option to show progress report

Patch contributed by Fabien COELHO, reviewed by KONDO Mitsumasa.
Comment on why planagg.c punts "MIN(x ORDER BY y)".
Implement the FILTER clause for aggregate function calls.

This is SQL-standard with a few extensions, namely support for
subqueries and outer references in clause expressions.

catversion bump due to change in Aggref and WindowFunc.

David Fetter, reviewed by Dean Rasheed.
Fix systable_recheck_tuple() for MVCC scan snapshots.

Since this function assumed non-MVCC snapshots, it broke when commit
568d4138c646cd7cd8a837ac244ef2caf27c6bb8 switched its one caller from
SnapshotNow scans to MVCC-snapshot scans.

Reviewed by Robert Haas, Tom Lane and Andres Freund.
Use correct parameter name for view_option_value

The documentation for ALTER VIEW had a minor copy-and-paste error in
defining the parameters.  Noticed when reviewing the WITH CHECK OPTION
patch.

Backpatch to 9.2 where this was first introduced.
Fix typo in previous pgbench --progress patch.
Fix end-of-loop optimization in pglz_find_match() function.

After the recent pglz optimization patch, the next/prev pointers in the
hash table are never NULL, INVALID_ENTRY_PTR is used to represent invalid
entries instead. The end-of-loop check in pglz_find_match() function didn't
get the memo. The result was the same from a correctness point of view, but
because the NULL-check would never fail, the tiny optimization turned into
a pessimization.

Reported by Stephen Frost, using Coverity scanner.
Fix assert failure at end of recovery, broken by XLogInsert scaling patch.

Initialization of the first XLOG buffer at end-of-recovery was broken for
the case that the last read WAL record ended at a page boundary. Instead of
trying to copy the last full xlog page to the buffer cache in that case,
just set shared state so that the next page is initialized when the first
WAL record after startup is inserted. (that's what we did in earlier
version, too)

To make the shared state required for that case less surprising, replace the
XLogCtl->curridx variable, which was the index of the latest initialized
buffer, with an XLogRecPtr of how far the buffers have been initialized.
That also allows us to get rid of the XLogRecEndPtrToBufIdx macro.

While we're at it, make a similar change for XLogCtl->Write.curridx, getting
rid of that variable and calculating the next buffer to write from
XLogCtl->LogwrtResult instead.
Fix variable names mentioned in comment to match the code.

Also, in another comment, explain why holding an insertion slot is a
critical section.

Per review by Amit Kapila.
Fix a few problems in barrier.h.

On HPPA, implement pg_memory_barrier() as pg_compiler_barrier(), which
should be correct since this arch doesn't do memory access reordering,
and is anyway better than the completely-nonfunctional-on-this-arch
dummy_spinlock code.  (But note this patch only fixes things for gcc,
not for builds with HP's compiler.)

Also, fix incorrect default definition of pg_memory_barrier as a macro
requiring an argument.

Also, fix incorrect spelling of "#elif" as "#else if" in icc code path
(spotted by pgindent).

This doesn't come close to fixing all of the functional and stylistic
deficiencies in barrier.h, but at least it un-breaks my personal build.
Now that we're actually using barriers in the code, this file is going
to need some serious attention.
doc: Remove tab from SGML file