run out of shared memory when you try to assign an xid to a transaction.

Kevin Grittner

Flattening of subquery range tables during setrefs.c could lead to the
rangetable indexes in PlanRowMark nodes not matching up with the column
names previously assigned to the corresponding resjunk ctid (resp. tableoid
or wholerow) columns.  Typical symptom would be either a "cannot extract
system attribute from virtual tuple" error or an Assert failure.  This
wasn't a problem before 9.0 because we didn't support FOR UPDATE below the
top query level, and so the final flattening could never renumber an RTE
that was relevant to FOR UPDATE.  Fix by using a plan-tree-wide unique
number for each PlanRowMark to label the associated resjunk columns, so
that the number need not change during flattening.

Per report from David Johnston (though I'm darned if I can see how this got
past initial testing of the relevant code).  Back-patch to 9.0.

by Kevin Grittner

This follows my proposal of yesterday, namely that we try to recreate the
previous state of the extension exactly, instead of allowing CREATE
EXTENSION to run a SQL script that might create some entirely-incompatible
on-disk state.  In --binary-upgrade mode, pg_dump won't issue CREATE
EXTENSION at all, but instead uses a kluge function provided by
pg_upgrade_support to recreate the pg_extension row (and extension-level
pg_depend entries) without creating any member objects.  The member objects
are then restored in the same way as if they weren't members, in particular
using pg_upgrade's normal hacks to preserve OIDs that need to be preserved.
Then, for each member object, ALTER EXTENSION ADD is issued to recreate the
pg_depend entry that marks it as an extension member.

In passing, fix breakage in pg_upgrade's enum-type support: somebody didn't
fix it when the noise word VALUE got added to ALTER TYPE ADD.  Also,
rationalize parsetree representation of COMMENT ON DOMAIN and fix
get_object_address() to allow OBJECT_DOMAIN.

Add the views character_sets, collations, and
collation_character_set_applicability.

My original idea of doing extension member identification during
getDependencies() didn't work correctly: we have to mark member tables as
not-to-be-dumped rather earlier than that, else their subsidiary objects
like indexes get dumped anyway.  Rearrange code to mark them early enough.

This is an essential component of making the extension feature usable;
first because it's needed in the process of converting an existing
installation containing "loose" objects of an old contrib module into
the extension-based world, and second because we'll have to use it
in pg_dump --binary-upgrade, as per recent discussion.

Loosely based on part of Dimitri Fontaine's ALTER EXTENSION UPGRADE
patch.

also take the RW-conflict pool into account in the PredicateLockShmemSize()
estimate.

Specifying this option makes the server not wait for the
xlog to be archived, or emit a warning that it can't,
instead leaving the responsibility with the client.

This is useful when the log is being streamed using
the streaming protocol in parallel with the backup,
without having log archiving enabled.

Older versions of gcc tend to throw "variable might be clobbered by
`longjmp' or `vfork'" warnings whenever a variable is assigned in more than
one place and then used after the end of a PG_TRY block.  That's reasonably
easy to work around in execute_extension_script, and the overhead of
unconditionally saving/restoring the GUC variables seems unlikely to be a
serious concern.

Also clean up logic in ATExecValidateConstraint to make it easier to read
and less likely to provoke "variable might be used uninitialized in this
function" warnings.

This patch adds the server infrastructure to support extensions.
There is still one significant loose end, namely how to make it play nice
with pg_upgrade, so I am not yet committing the changes that would make
all the contrib modules depend on this feature.

In passing, fix a disturbingly large amount of breakage in
AlterObjectNamespace() and callers.

Dimitri Fontaine, reviewed by Anssi Kääriäinen,
Itagaki Takahiro, Tom Lane, and numerous others

This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch

new recovery.conf parameter recovery_target_name allows PITR to
specify named points as recovery targets.

Jaime Casanova, reviewed by Euler Taveira de Oliveira, plus minor edits

Status check functions only. Also, new recovery.conf parameter to
pause_at_recovery_target, default on.

Simon Riggs, reviewed by Fujii Masao

If the standby was streaming when trigger file arrives, check also in the
archive for additional WAL files. This is a corner case since it is
unlikely that we would trigger a failover while the master is still
available and sending data to standby, while at the same time running in
archive mode and also while the streaming standby has fallen behind archive.
Someone would eventually be unlucky; we must plug all gaps however small.

Fujii Masao

FK constraints that are marked NOT VALID may later be VALIDATED, which uses an
ShareUpdateExclusiveLock on constraint table and RowShareLock on referenced
table. Significantly reduces lock strength and duration when adding FKs.
New state visible from psql.

Simon Riggs, with reviews from Marko Tiikkaja and Robert Haas

about uninitialized field you get on some compilers.

Waiting for relation locks can lead to starvation - it pins down an
autovacuum worker for as long as the lock is held.  But if we're doing
an anti-wraparound vacuum, then we still wait; maintenance can no longer
be put off.

To assist with troubleshooting, if log_autovacuum_min_duration >= 0,
we log whenever an autovacuum or autoanalyze is skipped for this reason.

Per a gripe by Josh Berkus, and ensuing discussion.

I thought we didn't need that, but then I remembered that it added a new
SLRU subdirectory, pg_serial. While we're at it, document what pg_serial is.

Until now, our Serializable mode has in fact been what's called Snapshot
Isolation, which allows some anomalies that could not occur in any
serialized ordering of the transactions. This patch fixes that using a
method called Serializable Snapshot Isolation, based on research papers by
Michael J. Cahill (see README-SSI for full references). In Serializable
Snapshot Isolation, transactions run like they do in Snapshot Isolation,
but a predicate lock manager observes the reads and writes performed and
aborts transactions if it detects that an anomaly might occur. This method
produces some false positives, ie. it sometimes aborts transactions even
though there is no anomaly.

To track reads we implement predicate locking, see storage/lmgr/predicate.c.
Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared
memory is finite, so when a transaction takes many tuple-level locks on a
page, the locks are promoted to a single page-level lock, and further to a
single relation level lock if necessary. To lock key values with no matching
tuple, a sequential scan always takes a relation-level lock, and an index
scan acquires a page-level lock that covers the search key, whether or not
there are any matching keys at the moment.

A predicate lock doesn't conflict with any regular locks or with another
predicate locks in the normal sense. They're only used by the predicate lock
manager to detect the danger of anomalies. Only serializable transactions
participate in predicate locking, so there should be no extra overhead for
for other transactions.

Predicate locks can't be released at commit, but must be remembered until
all the transactions that overlapped with it have completed. That means that
we need to remember an unbounded amount of predicate locks, so we apply a
lossy but conservative method of tracking locks for committed transactions.
If we run short of shared memory, we overflow to a new "pg_serial" SLRU
pool.

We don't currently allow Serializable transactions in Hot Standby mode.
That would be hard, because even read-only transactions can cause anomalies
that wouldn't otherwise occur.

Serializable isolation mode now means the new fully serializable level.
Repeatable Read gives you the old Snapshot Isolation level that we have
always had.

Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and
Anssi Kääriäinen

We forgot to adjust it when we changed relistemp to relpersistence.

They are extracted from COPY API patch.

suggested by Noah Misch

String are converted to UTF8 on the way into perl and to the
database encoding on the way back. This avoids a number of
observed anomalies, and ensures Perl a consistent view of the
world.

Some minor code cleanups are also accomplished.

Alex Hunsaker, reviewed by Andy Colson.

using an itemized list.

done for a few other macros in that file, for other reasons.  I also
remove pgindent/README mention of the file.

If the foreign table's rowtype is being used as the type of a column in
another table, we can't just up and change its data type.  This was
already checked for composite types and ordinary tables, but we
previously failed to enforce it for foreign tables.

longjump.

Make sure it's clear that the prohibition on adding a column with a default
when the rowtype is used elsewhere is intentional, and be a bit more
explicit about the other cases where we perform this check.