We shouldn't set successor[whatever] to an offset number that is less
than FirstOffsetNumber or more than maxoff. We already avoided that
for redirects, but not for CTID links. Allowing bad offset numbers
into the successor[] array causes core dumps.
We shouldn't use HeapTupleHeaderIsHotUpdated() because it checks
stuff other than the status of the infomask2 bit HEAP_HOT_UPDATED.
We only care about the status of that bit, not the other stuff
that HeapTupleHeaderIsHotUpdated() checks. This mistake can cause
verify_heapam() to report corruption when none is present.
The first hunk of this patch was written by me. The other two were
written by Andres Freund. This could probably do with more review
before commit, but I'd like to try to get the buildfarm green again
sooner rather than later.
Discussion: http://postgr.es/m/20230322204552.s6cv3ybqkklhhybb@awork3.anarazel.de
Prior to this commit, we only consider each tuple or line pointer
on the page in isolation, but now we can do some validation of a line
pointer against its successor. For example, a redirect line pointer
shouldn't point to another redirect line pointer, and if a tuple
is HOT-updated, the result should be a heap-only tuple.
Himanshu Upadhyaya and Robert Haas, reviewed by Aleksander Alekseev,
Andres Freund, and Peter Geoghegan.
64bit xids can't represent xids before epoch 0 (see also be504a3e97). When
FullTransactionIdFromXidAndCtx() was passed such an xid, it'd create a 64bit
xid far into the future. Noticed while adding assertions in the course of
investigating be504a3e97, as amcheck's test create such xids.
To fix the issue, just return FirstNormalFullTransactionId in this case. A
freshly initdb'd cluster already has a newer horizon. The most minimal version
of this would make the messages for some detected corruptions differently
inaccurate. To make those cases accurate, switch
FullTransactionIdFromXidAndCtx() to use the 32bit modulo difference between
xid and nextxid to compute the 64bit xid, yielding sensible "in the future" /
"in the past" answers.
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20230108002923.cyoser3ttmt63bfn@awork3.anarazel.de
Backpatch: 14-, where heapam verification was introduced
The initialization order in update_cached_xid_range() was wrong, calling
FullTransactionIdFromXidAndCtx() before setting
->next_xid. FullTransactionIdFromXidAndCtx() uses ->next_xid.
In most situations this will not cause visible issues, because the next call
to update_cached_xid_range() will use a less wrong ->next_xid. It's rare that
xids advance fast enough for this to be a problem.
Found while adding more asserts to the 64bit xid infrastructure.
Reviewed-by: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://postgr.es/m/20230108002923.cyoser3ttmt63bfn@awork3.anarazel.de
Backpatch: 14-, where heapam verification was introduced
Per discussion, the existing routine name able to initialize a SRF
function with materialize mode is unpopular, so rename it. Equally, the
flags of this function are renamed, as of:
- SRF_SINGLE_USE_EXPECTED -> MAT_SRF_USE_EXPECTED_DESC
- SRF_SINGLE_BLESS -> MAT_SRF_BLESS
The previous function and flags introduced in 9e98583 are kept around
for compatibility purposes, so as any extension code already compiled
with v15 continues to work as-is. The declarations introduced here for
compatibility will be removed from HEAD in a follow-up commit.
The new names have been suggested by Andres Freund and Melanie
Plageman.
Discussion: https://postgr.es/m/20221013194820.ciktb2sbbpw7cljm@awork3.anarazel.de
Backpatch-through: 15
Remove the Trap and TrapMacro macros, which were nearly unused
and confusingly had the opposite condition polarity from the
otherwise-functionally-equivalent Assert macros.
Having done that, it's very hard to justify carrying the errorType
argument of ExceptionalCondition, so drop that too, and just
let it assume everything's an Assert. This saves about 64K
of code space as of current HEAD.
Discussion: https://postgr.es/m/3928703.1665345117@sss.pgh.pa.us
The generated resource files aren't exactly the same ones as the old
buildsystems generate. Previously "InternalName" and "OriginalFileName" were
mostly wrong / not set (despite being required), but that was hard to fix in
at least the make build. Additionally, the meson build falls back to a
"auto-generated" description when not set, and doesn't set it in a few cases -
unlikely that anybody looks at these descriptions in detail.
Author: Andres Freund <andres@anarazel.de>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Make sure that function declarations use names that exactly match the
corresponding names from function definitions in contrib code.
Like other recent commits that cleaned up function parameter names, this
commit was written with help from clang-tidy.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WznJt9CMM9KJTMjJh_zbL5hD9oX44qdJ4aqZtjFi-zA3Tg@mail.gmail.com
Autoconf is showing its age, fewer and fewer contributors know how to wrangle
it. Recursive make has a lot of hard to resolve dependency issues and slow
incremental rebuilds. Our home-grown MSVC build system is hard to maintain for
developers not using Windows and runs tests serially. While these and other
issues could individually be addressed with incremental improvements, together
they seem best addressed by moving to a more modern build system.
After evaluating different build system choices, we chose to use meson, to a
good degree based on the adoption by other open source projects.
We decided that it's more realistic to commit a relatively early version of
the new build system and mature it in tree.
This commit adds an initial version of a meson based build system. It supports
building postgres on at least AIX, FreeBSD, Linux, macOS, NetBSD, OpenBSD,
Solaris and Windows (however only gcc is supported on aix, solaris). For
Windows/MSVC postgres can now be built with ninja (faster, particularly for
incremental builds) and msbuild (supporting the visual studio GUI, but
building slower).
Several aspects (e.g. Windows rc file generation, PGXS compatibility, LLVM
bitcode generation, documentation adjustments) are done in subsequent commits
requiring further review. Other aspects (e.g. not installing test-only
extensions) are not yet addressed.
When building on Windows with msbuild, builds are slower when using a visual
studio version older than 2019, because those versions do not support
MultiToolTask, required by meson for intra-target parallelism.
The plan is to remove the MSVC specific build system in src/tools/msvc soon
after reaching feature parity. However, we're not planning to remove the
autoconf/make build system in the near future. Likely we're going to keep at
least the parts required for PGXS to keep working around until all supported
versions build with meson.
Some initial help for postgres developers is at
https://wiki.postgresql.org/wiki/Meson
With contributions from Thomas Munro, John Naylor, Stone Tickle and others.
Author: Andres Freund <andres@anarazel.de>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Author: Peter Eisentraut <peter@eisentraut.org>
Reviewed-By: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/20211012083721.hvixq4pnh2pixr3j@alap3.anarazel.de
guc.c has grown to be one of our largest .c files, making it
a bottleneck for compilation. It's also acquired a bunch of
knowledge that'd be better kept elsewhere, because of our not
very good habit of putting variable-specific check hooks here.
Hence, split it up along these lines:
* guc.c itself retains just the core GUC housekeeping mechanisms.
* New file guc_funcs.c contains the SET/SHOW interfaces and some
SQL-accessible functions for GUC manipulation.
* New file guc_tables.c contains the data arrays that define the
built-in GUC variables, along with some already-exported constant
tables.
* GUC check/assign/show hook functions are moved to the variable's
home module, whenever that's clearly identifiable. A few hard-
to-classify hooks ended up in commands/variable.c, which was
already a home for miscellaneous GUC hook functions.
To avoid cluttering a lot more header files with #include "guc.h",
I also invented a new header file utils/guc_hooks.h and put all
the GUC hook functions' declarations there, regardless of their
originating module. That allowed removal of #include "guc.h"
from some existing headers. The fallout from that (hopefully
all caught here) demonstrates clearly why such inclusions are
best minimized: there are a lot of files that, for example,
were getting array.h at two or more levels of remove, despite
not having any connection at all to GUCs in themselves.
There is some very minor code beautification here, such as
renaming a couple of inconsistently-named hook functions
and improving some comments. But mostly this just moves
code from point A to point B and deals with the ensuing
needs for #include adjustments and exporting a few functions
that previously weren't exported.
Patch by me, per a suggestion from Andres Freund; thanks also
to Michael Paquier for the idea to invent guc_funcs.c.
Discussion: https://postgr.es/m/587607.1662836699@sss.pgh.pa.us
This replaces all MemSet() calls with struct initialization where that
is easily and obviously possible. (For example, some cases have to
worry about padding bits, so I left those.)
(The same could be done with appropriate memset() calls, but this
patch is part of an effort to phase out MemSet(), so it doesn't touch
memset() calls.)
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://www.postgresql.org/message-id/9847b13c-b785-f4e2-75c3-12ec77a3b05c@enterprisedb.com
The macro is being applied to a TOAST pointer, not a varlena header.
Therefore the use of VARATT_IS_COMPRESSED() is wrong. We can check
VARATT_EXTERNAL_IS_COMPRESSED(), but then we don't need the length
check that follows.
Report and fix by Kyotaro Horiguchi.
Discussion: http://postgr.es/m/20220517.162719.1671558681467343711.horikyota.ntt@gmail.com
Since a117cebd6, some older gcc versions issue "variable may be used
uninitialized in this function" complaints for brin_summarize_range.
Silence that using the same coding pattern as in bt_index_check_internal;
arguably, a117cebd6 had too narrow a view of which compilers might give
trouble.
Nathan Bossart and Tom Lane. Back-patch as the previous commit was.
Discussion: https://postgr.es/m/20220601163537.GA2331988@nathanxps13
When a feature enumerates relations and runs functions associated with
all found relations, the feature's user shall not need to trust every
user having permission to create objects. BRIN-specific functionality
in autovacuum neglected to account for this, as did pg_amcheck and
CLUSTER. An attacker having permission to create non-temp objects in at
least one schema could execute arbitrary SQL functions under the
identity of the bootstrap superuser. CREATE INDEX (not a
relation-enumerating operation) and REINDEX protected themselves too
late. This change extends to the non-enumerating amcheck interface.
Back-patch to v10 (all supported versions).
Sergey Shinderuk, reviewed (in earlier versions) by Alexander Lakhin.
Reported by Alexander Lakhin.
Security: CVE-2022-1552
This makes the code more consistent with SpGiST, GiST and GIN, that
already use this style, and the idea is to make easier the introduction
of more sanity checks for each of these AM-specific macros. BRIN uses a
different set of macros to get a page's type and flags, so it has no
need for something similar.
Author: Matthias van de Meent
Discussion: https://postgr.es/m/CAEze2WjE3+tGO9Fs9+iZMU+z6mMZKo54W1Zt98WKqbEUHbHOBg@mail.gmail.com
The previous method for doing that was to write zeroes into a
predetermined set of page locations. However, there's a roughly
1-in-64K chance that the existing checksum will match by chance,
and yesterday several buildfarm animals started to reproducibly
see that, resulting in test failures because no checksum mismatch
was reported.
Since the checksum includes the page LSN, test success depends on
the length of the installation's WAL history, which is affected by
(at least) the initial catalog contents, the set of locales installed
on the system, and the length of the pathname of the test directory.
Sooner or later we were going to hit a chance match, and today is
that day.
Harden these tests by specifically inverting the checksum field and
leaving all else alone, thereby guaranteeing that the checksum is
incorrect.
In passing, fix places that were using seek() to set up for syswrite(),
a combination that the Perl docs very explicitly warn against. We've
probably escaped problems because no regular buffered I/O is done on
these filehandles; but if it ever breaks, we wouldn't deserve or get
much sympathy.
Although we've only seen problems in HEAD, now that we recognize the
environmental dependencies it seems like it might be just a matter
of time until someone manages to hit this in back-branch testing.
Hence, back-patch to v11 where we started doing this kind of test.
Discussion: https://postgr.es/m/3192026.1648185780@sss.pgh.pa.us
The Config and Cwd modules were no longer used, but remained imported,
in a number of tests. Remove to keep the imports to the actually used
modules.
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/A5A074CD-3198-492B-BE5E-7961EFC3733F@yesql.se
9e98583 introduced a helper to centralize building their needed state
(tuplestore, tuple descriptors, etc.), checking for any errors. This
commit updates all places of contrib/ that can be switched to use
SetSingleFuncCall() as a drop-in replacement, resulting in the removal
of a lot of boilerplate code in all the modules updated by this commit.
Per analysis, some places remain as they are:
- pg_logdir_ls() in adminpack/ uses historically TYPEFUNC_RECORD as
return type, and I suspect that changing it may cause issues at run-time
with some of its past versions, down to 1.0.
- dblink/ uses a wrapper function doing exactly the work of
SetSingleFuncCall(). Here the switch should be possible, but rather
invasive so it does not seem the extra backpatch maintenance cost.
- tablefunc/, similarly, uses multiple helper functions with portions of
SetSingleFuncCall() spread across the code paths of this module.
Author: Melanie Plageman
Discussion: https://postgr.es/m/CAAKRu_bvDPJoL9mH6eYwvBpPtTGQwbDzfJbCM-OjkSZDu5yTPg@mail.gmail.com
Slow hosts may avoid load-induced, spurious failures by setting
environment variable PG_TEST_TIMEOUT_DEFAULT to some number of seconds
greater than 180. Developers may see faster failures by setting that
environment variable to some lesser number of seconds. In tests, write
$PostgreSQL::Test::Utils::timeout_default wherever the convention has
been to write 180. This change raises the default for some briefer
timeouts. Back-patch to v10 (all supported versions).
Discussion: https://postgr.es/m/20220218052842.GA3627003@rfd.leadboat.com
Rather than doing manual book keeping to plan the number of tests to run
in each TAP suite, conclude each run with done_testing() summing up the
the number of tests that ran. This removes the need for maintaning and
updating the plan count at the expense of an accurate count of remaining
during the test suite runtime.
This patch has been discussed a number of times, often in the context of
other patches which updates tests, so a larger number of discussions can
be found in the archives.
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/DD399313-3D56-4666-8079-88949DAC870F@yesql.se
Some pre-2017 Test::More versions need perfect $Test::Builder::Level
maintenance to find the variable. Buildfarm member snapper reported an
overall failure that the file intended to hide via the TODO construct.
That trouble was reachable in v11 and v10. For later branches, this
serves as defense in depth. Back-patch to v10 (all supported versions).
Discussion: https://postgr.es/m/20220202055556.GB2745933@rfd.leadboat.com
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
Expand the checks of toasted attributes to complain if the rawsize is
overlarge. For compressed attributes, also complain if compression
appears to have expanded the attribute or if the compression method is
invalid.
Mark Dilger, reviewed by Justin Pryzby, Alexander Alekseev, Heikki
Linnakangas, Greg Stark, and me.
Discussion: http://postgr.es/m/8E42250D-586A-4A27-B317-8B062C3816A8@enterprisedb.com
Commits fdd965d07 and 3cd9c3b92 tested CREATE INDEX CONCURRENTLY by
launching two separate pgbench runs concurrently. This was needed so
that only a single client thread would run CREATE INDEX CONCURRENTLY,
avoiding deadlock between two CICs. However, there's a better way,
which is to use an advisory lock to prevent concurrent CICs. That's
better in part because the test code is shorter and more readable, but
mostly because it automatically scales things to launch an appropriate
number of CICs relative to the number of INSERT transactions.
As committed, typically half to three-quarters of the CIC transactions
were pointless because the INSERT transactions had already stopped.
In passing, remove background_pgbench, which was added to support
these tests and isn't needed anymore. We can always put it back
if we find a use for it later.
Back-patch to v12; older pgbench versions lack the
conditional-execution features needed for this method.
Tom Lane and Andrey Borodin
Discussion: https://postgr.es/m/139687.1635277318@sss.pgh.pa.us
The five modules in our TAP test framework all had names in the top
level namespace. This is unwise because, even though we're not
exporting them to CPAN, the names can leak, for example if they are
exported by the RPM build process. We therefore move the modules to the
PostgreSQL::Test namespace. In the process PostgresNode is renamed to
Cluster, and TestLib is renamed to Utils. PostgresVersion becomes simply
PostgreSQL::Version, to avoid possible confusion about what it's the
version of.
Discussion: https://postgr.es/m/aede93a4-7d92-ef26-398f-5094944c2504@dunslane.net
Reviewed by Erik Rijkers and Michael Paquier
The purpose of commit 8a54e12a38 was to
fix this, and it sufficed when the PREPARE TRANSACTION completed before
the CIC looked for lock conflicts. Otherwise, things still broke. As
before, in a cluster having used CIC while having enabled prepared
transactions, queries that use the resulting index can silently fail to
find rows. It may be necessary to reindex to recover from past
occurrences; REINDEX CONCURRENTLY suffices. Fix this for future index
builds by making CIC wait for arbitrarily-recent prepared transactions
and for ordinary transactions that may yet PREPARE TRANSACTION. As part
of that, have PREPARE TRANSACTION transfer locks to its dummy PGPROC
before it calls ProcArrayClearTransaction(). Back-patch to 9.6 (all
supported versions).
Andrey Borodin, reviewed (in earlier versions) by Andres Freund.
Discussion: https://postgr.es/m/01824242-AA92-4FE9-9BA7-AEBAFFEA3D0C@yandex-team.ru
CIC and REINDEX CONCURRENTLY assume backends see their catalog changes
no later than each backend's next transaction start. That failed to
hold when a backend absorbed a relevant invalidation in the middle of
running RelationBuildDesc() on the CIC index. Queries that use the
resulting index can silently fail to find rows. Fix this for future
index builds by making RelationBuildDesc() loop until it finishes
without accepting a relevant invalidation. It may be necessary to
reindex to recover from past occurrences; REINDEX CONCURRENTLY suffices.
Back-patch to 9.6 (all supported versions).
Noah Misch and Andrey Borodin, reviewed (in earlier versions) by Andres
Freund.
Discussion: https://postgr.es/m/20210730022548.GA1940096@gust.leadboat.com
Incrementing the level of the call stack reported is useful for
debugging purposes as it allows to control which part of the test is
exactly failing, especially if a test is structured with subroutines
that call routines from Test::More.
This adds more incrementations of $Test::Builder::Level where debugging
gets improved (for example it does not make sense for some paths like
pg_rewind where long subroutines are used).
A note is added to src/test/perl/README about that, based on a
suggestion from Andrew Dunstan and a wording coming from both of us.
Usage of Test::Builder::Level has spread in 12, so a backpatch down to
this version is done.
Reviewed-by: Andrew Dunstan, Peter Eisentraut, Daniel Gustafsson
Discussion: https://postgr.es/m/YV1CCFwgM1RV1LeS@paquier.xyz
Backpatch-through: 12
Have verify_heapam.c treat unlogged relations as if they were simply
empty when in Hot Standby mode. This brings it in line with
verify_nbtree.c, which has handled unlogged relations in the same way
since bugfix commit 6754fe65a4. This was an oversight in commit
866e24d47d, which extended contrib/amcheck to check heap relations.
In passing, lower the verbosity used when reporting that a relation has
been skipped like this, from NOTICE to DEBUG1. This is appropriate
because the skipping behavior is only an implementation detail, needed
to work around the fact that unlogged tables don't have smgr-level
storage for their main fork when in Hot Standby mode.
Affected unlogged relations should be considered "trivially verified",
not skipped over. They are verified in the same sense that a totally
empty relation can be verified. This behavior seems least surprising
overall, since unlogged relations on a replica will initially be empty
if and when the replica is promoted and Hot Standby ends.
Author: Mark Dilger <mark.dilger@enterprisedb.com>
Reviewed-By: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-Wzk_pukOFY7JmdiFLsrz+Pd3V8OwgC1TH2Vd5BH5ZgK4bA@mail.gmail.com
Backpatch: 14-, where heapam verification was introduced.
Sequences were left out of the list of relation kinds that
verify_heapam knew how to check, though it is fairly trivial to allow
them. Doing that, and while at it, updating pg_amcheck to include
sequences in relations matched by table and relation patterns.
Author: Mark Dilger <mark.dilger@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/81ad4757-92c1-4aa3-7bee-f609544837e3%40enterprisedb.com
There is only one constructor now for PostgresNode, with the idiomatic
name 'new'. The method is not exported by the class, and must be called
as "PostgresNode->new('name',[args])". All the TAP tests that use
PostgresNode are modified accordingly. Third party scripts will need
adjusting, which is a fairly mechanical process (I just used a sed
script).
The idea behind this patch is to design out bugs like the one fixed
by commit 9d523119f. Previously, once one did RelationOpenSmgr(rel),
it was considered okay to access rel->rd_smgr directly for some
not-very-clear interval. But since that pointer will be cleared by
relcache flushes, we had bugs arising from overreliance on a previous
RelationOpenSmgr call still being effective.
Now, very little code except that in rel.h and relcache.c should ever
touch the rd_smgr field directly. The normal coding rule is to use
RelationGetSmgr(rel) and not expect the result to be valid for longer
than one smgr function call. There are a couple of places where using
the function every single time seemed like overkill, but they are now
annotated with large warning comments.
Amul Sul, after an idea of mine.
Discussion: https://postgr.es/m/CANiYTQsU7yMFpQYnv=BrcRVqK_3U3mtAzAsJCaqtzsDHfsUbdQ@mail.gmail.com
Most error messages about a relkind that was not supported or
appropriate for the command was of the pattern
"relation \"%s\" is not a table, foreign table, or materialized view"
This style can become verbose and tedious to maintain. Moreover, it's
not very helpful: If I'm trying to create a comment on a TOAST table,
which is not supported, then the information that I could have created
a comment on a materialized view is pointless.
Instead, write the primary error message shorter and saying more
directly that what was attempted is not possible. Then, in the detail
message, explain that the operation is not supported for the relkind
the object was. To simplify that, add a new function
errdetail_relkind_not_supported() that does this.
In passing, make use of RELKIND_HAS_STORAGE() where appropriate,
instead of listing out the relkinds individually.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://www.postgresql.org/message-id/flat/dc35a398-37d0-75ce-07ea-1dd71d98f8ec@2ndquadrant.com
Code comments were claiming that verify_heapam() was checking
privileges on the relation it was operating on, but it didn't actually
do that. Perhaps earlier versions of the patch did that, but now the
access is regulated by privileges on the function. Remove the wrong
comments.
Also "make reformat-dat-files".
The only change worthy of note is that pgindent messed up the formatting
of launcher.c's struct LogicalRepWorkerId, which led me to notice that
that struct wasn't used at all anymore, so I just took it out.
This isn't strictly necessary, but in theory it might matter if in the
future the width of the nbtree special area changes -- its total size
might not be an even number of MAXALIGN() quantums, even with padding.
PageInit() MAXALIGN()s all special area offsets, but amcheck uses the
offset to perform initial basic validation of line pointers, so we don't
rely on the offset from the page header.
The real reason to do this is to set a good example for new code that
adds amcheck coverage for other index AMs.
Reported-By: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Discussion: https://postgr.es/m/CALj2ACUMqTR9nErh99FbOBmzCXE9=gXNqhBiwYOhejJJS1LXqQ@mail.gmail.com