Peter Eisentraut [Mon, 13 Feb 2017 21:50:29 +0000 (16:50 -0500)]
Change logical replication pg_hba.conf use
Logical replication no longer uses the "replication" keyword. It just
matches database entries in the normal way. The "replication" keyword
now only applies to physical replication.
Reviewed-by: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Simon Riggs [Wed, 22 Mar 2017 13:09:36 +0000 (13:09 +0000)]
Improve performance of replay of AccessExclusiveLocks
A hot standby replica keeps a list of Access Exclusive locks for a top
level transaction. These locks are released when the top level transaction
ends. Searching of this list is O(N^2), and each transaction had to pay the
price of searching this list for locks, even if it didn't take any AE
locks itself.
This patch optimizes this case by having the master server track which
transactions took AE locks, and passes that along to the standby server in
the commit/abort record. This allows the standby to only try to release
locks for transactions which actually took any, avoiding the majority of
the performance issue.
Refactor MyXactAccessedTempRel into MyXactFlags to allow minimal additional
cruft with this.
Analysis and initial patch by David Rowley
Author: David Rowley and Simon Riggs
Simon Riggs [Wed, 22 Mar 2017 07:05:12 +0000 (07:05 +0000)]
Teach xlogreader to follow timeline switches
Uses page-based mechanism to ensure we’re using the correct timeline.
Tests are included to exercise the functionality using a cold disk-level copy
of the master that's started up as a replica with slots intact, but the
intended use of the functionality is with later features.
Craig Ringer, reviewed by Simon Riggs and Andres Freund
Peter Eisentraut [Wed, 22 Mar 2017 02:09:40 +0000 (22:09 -0400)]
doc: Update tool sets documentation for modern FreeBSD
For several operating systems, we give handy package manager one-liners
to install all the requirements for building our documentation. All
current production FreeBSD releases have a friendly new package manager
a bit like apt/yum, so give a one line command here. Also, add a brief
note about gmake vs make in the doc subdirectory.
Author: Thomas Munro <thomas.munro@enterprisedb.com>
Andrew Dunstan [Tue, 21 Mar 2017 13:12:46 +0000 (09:12 -0400)]
Use CallerFInfoFunctionCall with btree_gist for numeric types
None of the existing types actually need to use this mechanism, but this
will allow support for enum types which will need it. A separate patch
will adjust the varlena types support for consistency.
Simon Riggs [Tue, 21 Mar 2017 14:04:49 +0000 (14:04 +0000)]
Add a pg_recvlogical wrapper to PostgresNode
Allows testing of logical decoding using SQL interface and/or pg_recvlogical
Most logical decoding tests are in contrib/test_decoding. This module
is for work that doesn't fit well there, like where server restarts
are required.
Robert Haas [Tue, 21 Mar 2017 13:48:04 +0000 (09:48 -0400)]
Don't scan partitioned tables.
Partitioned tables do not contain any data; only their unpartitioned
descendents need to be scanned. However, the partitioned tables still
need to be locked, even though they're not scanned. To make that
work, Append and MergeAppend relations now need to carry a list of
(unscanned) partitioned relations that must be locked, and InitPlan
must lock all partitioned result relations.
Aside from the obvious advantage of avoiding some work at execution
time, this has two other advantages. First, it may improve the
planner's decision-making in some cases since the empty relation
might throw things off. Second, it paves the way to getting rid of
the storage for partitioned tables altogether.
Teodor Sigaev [Tue, 21 Mar 2017 13:23:10 +0000 (16:23 +0300)]
Fix support for some operators (&<, &>, $<|, |&>) in box operator class
of SP-GiST.
Bug exists since initial commit of box opclass for SP-GiST,
so backpath to 9.6
Author: Nikita Glukhov with minor editorization of tests by me Reviewed-by: Kyotaro Horiguchi, Anastasia Lubennikova
https://commitfest.postgresql.org/13/981/
Andrew Dunstan [Tue, 21 Mar 2017 12:57:46 +0000 (08:57 -0400)]
Add a direct function call mechanism using the caller's context.
The current DirectFunctionCall functions use NULL as the flinfo in
initializing the FunctionCallInfoData for the call. That means the
called function has no fn_mcxt or fn_extra to work with, and attempting
to do so will result in an access violation. These functions instead use
the provided flinfo, which will usually be the caller's own flinfo. The
caller needs to ensure that it doesn't use the fn_extra in way that is
incompatible with the way the called function will use it. The called
function should not rely on anything else in the provided context, as it
will be relevant to the caller, not the callee.
Andrew Dunstan [Mon, 20 Mar 2017 20:40:45 +0000 (16:40 -0400)]
Add IF NOT EXISTS for CREATE SERVER and CREATE USER MAPPING
There is still some inconsistency with the error messages surrounding
foreign servers. Some use the word "foreign" and some don't. My
inclination is to remove all such uses of "foreign" on the basis that
the CREATE/ALTER/DROP SERVER commands don't use the word. However, that
is left for another day. In this patch I have kept to the existing usage
in the affected commands, which omits "foreign".
Anastasia Lubennikova, reviewed by Arthur Zakirov and Ashtosh Bapat.
Andrew Dunstan [Mon, 20 Mar 2017 20:01:45 +0000 (16:01 -0400)]
Use a consistent error message style for user mappings.
User mappings are essentially anonymous, so messages referring to "user
mapping foo on server bar" are wrong, and inconsistent with other error
messages referring to user mappings. To be consistent with existing use,
use "user mapping for foo on server bar" instead.
I dropped the noise word "user" from the original suggestion to be
consistent with other uses.
Bump WAL version. The original patch to make hash indexes write-ahead
logged probably should have done this, and the single page vacuuming
patch probably should have done it again, but better late than never.
Tom Lane [Mon, 20 Mar 2017 16:51:45 +0000 (12:51 -0400)]
Add missed "make clean" logic in src/interfaces/libpq/Makefile.
Commit 818fd4a67 missed cleaning up the symlinks it added for various .c
files imported from src/port and src/common. Neatnik-ishly make the
file lists in the "clean" target look exactly like the earlier lists of
what to symlink in.
Tom Lane [Mon, 20 Mar 2017 16:30:08 +0000 (12:30 -0400)]
Improve regression test coverage for TID scanning.
TidScan plan nodes were not systematically tested before. These additions
raise the LOC coverage number for the basic regression tests from 52% to
92% in nodeTidscan.c, and from 60% to 93% in tidpath.c.
Teodor Sigaev [Mon, 20 Mar 2017 15:48:46 +0000 (18:48 +0300)]
Revert unintentional change in increasing usage count during pin of buffers,
this makes buffer access strategy have no effect.
Change was a part of commit 48354581a49c30f5757c203415aa8412d85b0f70 during 9.6
release cycle, so backpath to 9.6
Reported-by: Jim Nasby
Author: Alexander Korotkov Reviewed-by: Jim Nasby, Andres Freund
https://commitfest.postgresql.org/13/1029/
Stephen Frost [Sun, 19 Mar 2017 20:56:14 +0000 (16:56 -0400)]
pg_dump: Skip COLLATION-related regression tests
Not every platform supports non-default collations, as pointed out by
the buildfarm, so skip collation-related regression tests in pg_dump
when they aren't supported.
Tom Lane [Sat, 18 Mar 2017 21:49:06 +0000 (17:49 -0400)]
Fix REFRESH MATERIALIZED VIEW to report activity to the stats collector.
The non-concurrent code path for REFRESH MATERIALIZED VIEW failed to
report its updates to the stats collector. This is bad since it means
auto-analyze doesn't know there's any work to be done. Adjust it to
report the refresh as a table truncate followed by insertion of an
appropriate number of rows.
Since a matview could contain more than INT_MAX rows, change the
signature of pgstat_count_heap_insert() to accept an int64 rowcount.
(The accumulator it's adding into is already int64, but existing
callers could not insert more than a small number of rows at once,
so the argument had been declared just "int n".)
This is surely a bug fix, but changing pgstat_count_heap_insert()'s API
seems too risky for the back branches. Given the lack of previous
complaints, I'm not sure it's a big enough problem to justify a kluge
solution that would avoid that. So, no back-patch, at least for now.
Peter Eisentraut [Sat, 18 Mar 2017 18:17:28 +0000 (14:17 -0400)]
doc: Tweak reference page header style
Change the header style of references pages in HTML and PDF output to be
more like the old style under DSSSL. In particular, the page should
start with a header containing the command name, instead of just "Name".
Stephen Frost [Sat, 18 Mar 2017 17:18:24 +0000 (13:18 -0400)]
Improve pg_dump regression tests and code coverage
These improvements bring the lines-of-code coverage of pg_dump.c up to
87.7% (at least using LCOV 1.12, 1.11 seems to differ slightly). Nearly
every function is covered, three of the four which aren't are only
called when talking to older PG instances.
There is more which can, and should, be done here to improve the
coverage but it's past time to see what the buildfarm thinks of this.
What has been added:
- Coverage for many more command-line options
- Use command_fails_like instead of command_exit_is
- Operator classes, operator families
- Text search configuration, templates, parsers, dictionaries
- FDWs, servers, foreign tables
- Materialized views
- Improved Publications / Subscriptions test (though this needs work,
see PG10 open items and tests marked with XXX in 002_pg_dump.pl)
- Unlogged tables
- Partitioned tables
- Additional ACL testing for various object types
There is room for improvement, specifically:
- Various type-based option (alignment, storage, etc)
- Composite type collation
- Extra Procedural language functions (inline, validator)
- Different function options (SRF, Transform, config, security definer,
cost, leakproof)
- OpClass options (default, storage, order by, recheck)
- OpFamily options (order by, recheck)
- Aggregate functions (combinefunc, serialfunc, deserialfunc, etc)
- Text Search parser 'headline'
- Text Search template 'init'
- FDW options (handler, validator, options)
- Server options (type, version, options)
- User mapping options
- Default ACLs for sequences, types
- Security labels
- View circular dependencies (last function that needs coverage)
- Toast table autovacuum options
- Replica identity options
- Independent indexes (plus marking them as clustered on)
- Deferrable / initially deferred constraints
- Independent domain constraints
There's bits of extension pg_dump'ing also not covered, but those will
need to go into test_pg_dump (such as having a filter for config
tables).
Last, but not least, this approximately halves the number of tests run
with 'ok()' by removing the ok()-based checking of if all runs are
covered by each test. Instead, 002_pg_dump.pl will just exit out in
such a case (with a message in the log file). In general, when adding
tests, cover all runs unless there is a very good reason not to (such as
adding a 'catch-all' case). With these changes, the resulting output
and number of "tests" run is actually reduced.
Robert Haas [Sat, 18 Mar 2017 11:43:01 +0000 (07:43 -0400)]
Create and use wait events for read, write, and fsync operations.
Previous commits, notably 53be0b1add7064ca5db3cd884302dfc3268d884e and 6f3bd98ebfc008cbd676da777bb0b2376c4c4bfa, made it possible to see from
pg_stat_activity when a backend was stuck waiting for another backend,
but it's also fairly common for a backend to be stuck waiting for an
I/O. Add wait events for those operations, too.
Rushabh Lathia, with further hacking by me. Reviewed and tested by
Michael Paquier, Amit Kapila, Rajkumar Raghuwanshi, and Rahila Syed.
Tom Lane [Fri, 17 Mar 2017 18:58:06 +0000 (14:58 -0400)]
Fix WaitEventSetWait() to handle write-ready waits properly on Windows.
Windows apparently will not detect socket write-ready events unless a
preceding send attempt returned WSAEWOULDBLOCK. In many usage patterns
that's satisfied by the caller of WaitEvenSetWait(), but not always.
Apply the same solution that we already had in pgwin32_select(), namely to
perform a dummy WSASend() call with len=0. This will return WSAEWOULDBLOCK
if there's no buffer space (even though it could legitimately do nothing
and report success, which makes me a bit nervous about this solution;
but since it's been working fine in libpq, let's roll with it).
In passing, improve the comments about this in pgwin32_select(), and remove
duplicated code there.
Back-patch to 9.6 where WaitEventSetWait() was introduced. We might need
to back-patch something similar into predecessor code. But given the lack
of complaints so far, it's not clear that the case ever gets exercised
in the back branches, so I'm not going to expend effort on it right now.
This should resolve recurring failures on buildfarm member bowerbird,
which has been failing since 1e8a85009 went in.
Diagnosis and patch by Petr Jelinek, cosmetic adjustments by me.
Andrew Gierth [Fri, 17 Mar 2017 14:35:54 +0000 (14:35 +0000)]
Repair test for vacuum reltuples fix.
Concurrent auto-analyze could be holding a snapshot, affecting the
removal of deleted row versions. Remove the deletion to avoid this
happening. Per buildfarm.
In passing, make the test independent of assumptions of physical row
order, just out of sheer paranoia.
Robert Haas [Fri, 17 Mar 2017 13:46:58 +0000 (09:46 -0400)]
Rename "pg_clog" directory to "pg_xact".
Names containing the letters "log" sometimes confuse users into
believing that only non-critical data is present. It is hoped
this renaming will discourage ill-considered removals of transaction
status data.
Add TAP tests for password-based authentication methods.
Tests all combinations of users with MD5, plaintext and SCRAM verifiers
stored in pg_authid, with plain 'password', 'md5' and 'scram'
authentication methods.
Fix and simplify check for whether we're running as Windows service.
If the process token contains SECURITY_SERVICE_RID, but it has been
disabled by the SE_GROUP_USE_FOR_DENY_ONLY attribute, win32_is_service()
would incorrectly report that we're running as a service. That situation
arises, e.g. if postmaster is launched with a restricted security token,
with the "Log in as Service" privilege explicitly removed.
Replace the broken code with CheckProcessTokenMembership(), which does
this correctly. Also replace similar code in win32_is_admin(), even
though it got this right, for simplicity and consistency.
Per bug #13755, reported by Breen Hagan. Back-patch to all supported
versions. Patch by Takayuki Tsunakawa, reviewed by Michael Paquier.
Andrew Gierth [Thu, 16 Mar 2017 22:28:03 +0000 (22:28 +0000)]
Avoid having vacuum set reltuples to 0 on non-empty relations in the
presence of page pins, which leads to serious estimation errors in the
planner. This particularly affects small heavily-accessed tables,
especially where locking (e.g. from FK constraints) forces frequent
vacuums for mxid cleanup.
Fix by keeping separate track of pages whose live tuples were actually
counted vs. pages that were only scanned for freezing purposes. Thus,
reltuples can only be set to 0 if all pages of the relation were
actually counted.
Backpatch to all supported versions.
Per bug #14057 from Nicolas Baccelli, analyzed by me.
Robert Haas [Thu, 16 Mar 2017 19:05:02 +0000 (15:05 -0400)]
Add pg_ls_logdir() and pg_ls_waldir() functions.
These functions are intended to be used by monitoring tools, and,
unlike pg_ls_dir(), access to them can be granted to non-superusers,
so that those monitoring tools can observe the principle of least
privilege.
Dave Page, revised by me, and also reviewed a bit by Thomas Munro.
Robert Haas [Thu, 16 Mar 2017 17:34:59 +0000 (13:34 -0400)]
postgres_fdw: Push down FULL JOINs with restriction clauses.
The previous deparsing logic wasn't smart enough to produce subqueries
when deparsing; make it smart enough to do that. However, we only do
it that way when necessary, because it generates more complicated SQL
which will be harder for any humans reading the queries to understand.
Stephen Frost [Thu, 16 Mar 2017 04:13:37 +0000 (00:13 -0400)]
Be more careful about signed vs. unsigned char
The buildfarm has reminded me that not all systems consider char to be
signed and we need to be explicit. Adjust the various bits of mac8.c
for what we intend, mostly using casts to unsigned char as suggested by
Tom, and adjust the tests for valid input accordingly. Explicitly make
the hexlookup table signed as it's useful to use -1 there to indicate an
invalid value.
Stephen Frost [Thu, 16 Mar 2017 03:23:28 +0000 (23:23 -0400)]
Clean up overly paranoid checks in mac8.c
Andres' compiler points out, quite correctly, that there's no need for
some of the overly paranoid checks which were put into mac8.c. Remove
those, as they're useless, add some comments and make a few other minor
improvements- reduce the size of hexlookup by making it a char array
instead of an int array, and pass in the ptr location directly instead
of making hex2_to_uchar re-calculate the location based off the offset
every time.
Andres Freund [Thu, 16 Mar 2017 02:03:29 +0000 (19:03 -0700)]
Specify bindir in pg_isolation_regress_installcheck.
It appears dcae5faccab64776376d3 forgot to add it to
pg_isolation_regress_installcheck, while it was added to
pg_regress_installcheck. It seems to so far have escaped notice,
because buildfarm animals requiring it, didn't actually use
pg_isolation_regress_installcheck anywhere - that changed with 60f826c5e6244, triggering failures on narwhal and frogmouth.
I've decided to not, for now at least, backpatch this, because the
relevant invocations look quite different in the back branches. Seems
quite possible that we'll want to backport 60f826c5e6244 as a whole if
it proves stable.
Tom Lane [Wed, 15 Mar 2017 17:26:26 +0000 (13:26 -0400)]
Rewrite async-connection loop in libpqwalreceiver.c, once again.
The original coding in commit 1e8a85009 didn't use PQconnectPoll per
spec, and while the rewrite in e434ad39a is closer, it still doesn't
guarantee to wait until the socket is read-ready or write-ready (as
appropriate) before calling PQconnectPoll. It's not clear whether
that omission is causing the continuing failures on buildfarm member
bowerbird; but given the lack of other explanations meeting the
available facts, let's tighten that up and see what happens.
An independent issue in the same loop was that it had a race condition
whereby it could clear the process's latch without having serviced an
interrupt request, causing failure to respond to a cancel while waiting
for connection (the very problem 1e8a85009 was meant to fix).
Stephen Frost [Wed, 15 Mar 2017 15:16:25 +0000 (11:16 -0400)]
Add support for EUI-64 MAC addresses as macaddr8
This adds in support for EUI-64 MAC addresses by adding a new data type
called 'macaddr8' (using our usual convention of indicating the number
of bytes stored).
This was largely a copy-and-paste from the macaddr data type, with
appropriate adjustments for having 8 bytes instead of 6 and adding
support for converting a provided EUI-48 (6 byte format) to the EUI-64
format. Conversion from EUI-48 to EUI-64 inserts FFFE as the 4th and
5th bytes but does not perform the IPv6 modified EUI-64 action of
flipping the 7th bit, but we add a function to perform that specific
action for the user as it may be commonly done by users who wish to
calculate their IPv6 address based on their network prefix and 48-bit
MAC address.
Author: Haribabu Kommi, with a good bit of rework of macaddr8_in by me.
Reviewed by: Vitaly Burovoy, Kuntal Ghosh
Peter Eisentraut [Wed, 15 Mar 2017 03:12:18 +0000 (23:12 -0400)]
doc: Fix TOC generation for refentries
The XSLT stylesheets by default don't show refentries inside sections in
table of contents, which for our documentation leads to some regressions
compared to the DSSSL output. For example, in the SPI chapter, which is
mostly refentries, you don't get any usable table of contents. Tweak
things so it's mostly back to what it was before.
Robert Haas [Tue, 14 Mar 2017 22:20:17 +0000 (18:20 -0400)]
Some preliminary refactoring towards partitionwise join.
Partitionwise join proposes add a concept of child join relations,
which will have the same relationship with join relations as "other
member" relations do with base relations. These relations will need
some but not all of the handling that we currently have for join
relations, and some but not all of the handling that we currently have
for appendrels, since they are a mix of the two. Refactor a little
bit so that the necessary bits of logic are exposed as separate
functions.
Ashutosh Bapat, reviewed and tested by Rajkumar Raghuwanshi and
by me.
Andres Freund [Tue, 14 Mar 2017 22:56:17 +0000 (15:56 -0700)]
Improve isolation tests infrastructure.
Previously if a directory had both isolationtester and plain
regression tests, they couldn't be run in parallel, because they'd
access the same files/directories. That, so far, only affected
contrib/test_decoding.
Rather than fix that locally in contrib/test_decoding, improve
pg_regress_isolation_[install]check to use separate resources from
plain regression tests.
That requires a minor change in pg_regress, namely that the
--outputdir is created if not already existing, that seems like good
idea anyway.
Use the improved helpers even where previously not used.
Author: Tom Lane and Andres Freund
Discussion: https://postgr.es/m/20170311194831.vm5ikpczq52c2drg@alap3.anarazel.de
Peter Eisentraut [Tue, 14 Mar 2017 21:13:56 +0000 (17:13 -0400)]
Add option to control snapshot export to CREATE_REPLICATION_SLOT
We used to export snapshots unconditionally in CREATE_REPLICATION_SLOT
in the replication protocol, but several upcoming patches want more
control over what happens.
Suppress snapshot export in pg_recvlogical, which neither needs nor can
use the exported snapshot. Since snapshot exporting can fail this
improves reliability.
This also paves the way for allowing the creation of replication slots
on standbys, which cannot export snapshots because they cannot allocate
new XIDs.
Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Andres Freund [Tue, 14 Mar 2017 20:07:38 +0000 (13:07 -0700)]
amcheck: Harden tests against concurrent autovacuums.
The previous coding of the test was vulnerable against autovacuum
triggering work on one of the tables in check_btree.sql.
For the purpose of the test it's entirely sufficient to check for
locks taken by the current process, so add an appropriate restriction.
While touching the test, expand it to also check for locks on the
underlying relations, rather than just the indexes.
Reported-By: Tom Lane
Discussion: https://postgr.es/m/30354.1489434301@sss.pgh.pa.us
Robert Haas [Tue, 14 Mar 2017 18:33:14 +0000 (14:33 -0400)]
Fix regression in parallel planning against inheritance tables.
Commit 51ee6f3160d2e1515ed6197594bda67eb99dc2cc accidentally changed
the behavior around inheritance hierarchies; before, we always
considered parallel paths even for very small inheritance children,
because otherwise an inheritance hierarchy with even one small child
wouldn't be eligible for parallelism. That exception was inadverently
removed; put it back.
In passing, also adjust the degree-of-parallelism comptuation for
index-only scans not to consider the number of heap pages fetched.
Otherwise, we'll avoid parallel index-only scans on tables that are
mostly all-visible, which isn't especially logical.
Robert Haas and Amit Kapila, per a report from Ashutosh Sharma.
Robert Haas [Tue, 14 Mar 2017 17:27:02 +0000 (13:27 -0400)]
hash: Add write-ahead logging support.
The warning about hash indexes not being write-ahead logged and their
use being discouraged has been removed. "snapshot too old" is now
supported for tables with hash indexes. Most importantly, barring
bugs, hash indexes will now be crash-safe and usable on standbys.
This commit doesn't yet add WAL consistency checking for hash
indexes, as we now have for other index types; a separate patch has
been submitted to cure that lack.
Amit Kapila, reviewed and slightly modified by me. The larger patch
series of which this is a part has been reviewed and tested by Álvaro
Herrera, Ashutosh Sharma, Mark Kirkwood, Jeff Janes, and Jesper
Pedersen.
Tom Lane [Tue, 14 Mar 2017 16:47:46 +0000 (12:47 -0400)]
Make logging about multixact wraparound protection less chatty.
The original messaging design, introduced in commit 068cfadf9, seems too
chatty now that some time has elapsed since the bug fix; most installations
will be in good shape and don't really need a reminder about this on every
postmaster start.
Hence, arrange to suppress the "wraparound protections are now enabled"
message during startup (specifically, during the TrimMultiXact() call).
The message will still appear if protection becomes effective at some
later point.
Robert Haas [Tue, 14 Mar 2017 15:51:11 +0000 (11:51 -0400)]
Fix failure to mark init buffers as BM_PERMANENT.
This could result in corruption of the init fork of an unlogged index
if the ambuildempty routine for that index used shared buffers to
create the init fork, which was true for brin, gin, gist, and hash
indexes.
Patch by me, based on an earlier patch by Michael Paquier, who also
reviewed this one. This also incorporates an idea from Artur
Zakirov.
Robert Haas [Tue, 14 Mar 2017 11:28:35 +0000 (07:28 -0400)]
Remove some bogus logic from create_gather_merge_plan.
This logic was adapated from create_merge_append_plan, but the two
cases aren't really analogous, because create_merge_append_plan is not
projection-capable and must therefore have a tlist identical to that
of the underlying paths. Overwriting the tlist of Gather Merge with
whatever the underlying plan happens to produce is no good at all.
Patch by me, reviewed by Rushabh Lathia, who also reported the issue
and made an initial attempt at a fix.
Alvaro Herrera [Mon, 13 Mar 2017 21:54:35 +0000 (18:54 -0300)]
Silence unused variable compiler warning
Fallout from fcec6caafa2: mark a variable in
set_tablefunc_size_estimates as used for asserts only.
Also, the planner_rte_fetch() call is pointless with assertions
disabled, so enclose it in a USE_ASSERT_CHECKING #ifdef; fix the same
problem in set_subquery_size_estimates().
First problem noted by David Rowley, whose compiler is noisier than mine
in this regard.