The tests in commit be5d11e2 contained a typo that caused the changes
in the Scenario "gpstart starts even if the standby host is unreachable"
to not properly cleanup after itself.  Though the test feature still
passes, this leaves a bug to be found later when more tests are added.

Append-optimized tables do not contain transaction information in
their tuples.  Therefore, pg_class.relfrozenxid must remain invalid.
This is being done correctly during table creation, however, when the
table was rewritten, the relfrozenxid was accidentally set.  Fix it
such that diff with upstream is minimised.  In particular, the function
"should_have_valid_relfozenxid" is removed.

The fixme comments that led me to this bug are also removed.

Reviewed by: Ashwin Agrawal

Postgresql libpq document:

> Note that when PQconnectStart or PQconnectStartParams returns a
> non-null pointer, you must call PQfinish when you are finished
> with it, in order to dispose of the structure and any associated
> memory blocks. **This must be done even if the connection attempt
> fails or is abandoned**.

However, cdbconn_disconnect() function did not call PQfinish when
CONNECTION_BAD, it can cause socket leaks (CLOSE_WAIT state).

It didn't log the error message before if pg_rewind fails, fix that to make
DBA/field/developer's life eaisier.

Before this:
```
20201022:15:19:10:011118 gprecoverseg:earth:adam-[INFO]:-Running pg_rewind on required mirrors
20201022:15:19:12:011118 gprecoverseg:earth:adam-[WARNING]:-Incremental recovery failed for dbid 2. You must use gprecoverseg -F to recover the segment.
20201022:15:19:12:011118 gprecoverseg:earth:adam-[INFO]:-Starting mirrors
20201022:15:19:12:011118 gprecoverseg:earth:adam-[INFO]:-era is 0406b847bf226356_201022151031
```

After this:
```
20201022:15:33:31:019577 gprecoverseg:earth:adam-[INFO]:-Running pg_rewind on required mirrors
20201022:15:33:31:019577 gprecoverseg:earth:adam-[WARNING]:-pg_rewind: fatal: could not find common ancestor of the source and target cluster's timelines
20201022:15:33:31:019577 gprecoverseg:earth:adam-[WARNING]:-Incremental recovery failed for dbid 2. You must use gprecoverseg -F to recover the segment.
20201022:15:33:31:019577 gprecoverseg:earth:adam-[INFO]:-Starting mirrors
20201022:15:33:31:019577 gprecoverseg:earth:adam-[INFO]:-era is 0406b847bf226356_201022151031
```

This conforms our code to the best practice that each polymorphic
function should have exactly one of "virtual", "override", and "final"
specifier. I made this change using the following invocation:

clang-tidy -checks '-*,modernize-use-override'

Once we've made this change, ideally this practice can be enforced in
CI. We can just run clang-tidy with a single "modernize-use-override"
check to start with. Or we can see if our compilers are helpful enough.
Fortunately Clang already issues warnings (turned into errors by
-Werror) when we have inconsistent use of "override", and GCC appears to
have something similar (-Wsuggest-override) in versions 9.2 and later.

Now that we are explicitly declaring copy-assignment operators and copy
constructors as deleted, we should also make them public -- private and
=delete don't make much sense in combination, and this results in the
best diagnostics in practice [1].

In the previous commit where private unimplemented special member
functions are changed to be declared as deleted, we left the new
declarations private. This follows up by moving those deleted functions
to the public section of their classes.

I made this change guided by tooling: even though it doesn't offer a
fix, clang-tidy is useful enough to emit diagnostics that look like the
following:

/home/pivotal/workspace/gpdb/src/backend/gporca/libgpopt/include/gpopt/base/CColRef.h:76:2: warning: deleted member function should be public [modernize-use-equals-delete]
        CColRef(const CColRef &) = delete;
        ^

The process involved of making this change is a tale of much sorrow,
blood and tears. Suffice it to say 20 different regular expressions were
involved, and I'm edging closer to a PTSD when looking at backslashes.

References:
[1] https://abseil.io/tips/143#summary

This commit replaces two pre-C++ 11 practices with their modern, more
intent-expressive equivalents: "disallowed" copy and assignments, and
pairs of empty braces for special member function (destructors, default
constructors, and etc) bodies.

"Disallowed" copy constructors / assignment
-------------------------------------------
Old: private, unimplemented copy constructors and copy-assignment
operators in classes. These are usually paired with a semi-descriptive
comment.

New: publicly declare them as "= delete".

Fun fact: we had 13 spellings in comments on disallowed copy
constructors:

01. disable copy ctor
02. hidden copy ctor
03. inaccessible copy ctor
04. no copy ctor
05. no default copy ctor
06. private copy ctor
07. private no copy ctor
08. disabled copy constructor
09. no copy constructor
10. private copy constructor
11. copy c'tor - not defined
12. no copy c'tor
13. private copy c'tor

This commit removes all of them, because the new code ("~T() = delete")
already clearly expresses the intent of disallowing copy and assignment.

To keep the history clear, this commit leaves the declaration of
"prohibited" functions private. A forthcoming commit will wholesale
change them to public.

Defaulted special member functions
----------------------------------
Old:
struct A {
  A() {}
  ~A();
};
A::~A() {}

New:
struct A {
  A() = default;
  ~A();
};
A::~A() = default;

Replacing empty braces with defaulting not only makes them more clear,
they also enable more opportunities in compiler optimizations, as e.g.
some defaulted functions might be recognized as trivial.

Most of this commit is produced by running clang-tidy with an invocation
like the following (plus some CMake and shell tricks):

clang-tidy-12 -header-filter 'gpdbcost|gpopt|gpos|naucrates' -checks '-*,modernize-use-equals-delete,modernize-use-equals-default'

The tool uses a slightly conservative heuristic to detect a large
portion of the two outdated patterns above and rewrite them into using
"= delete" and "= default". Making the "= delete" functions public, is
sadly a FIXME item, so we'll have to do it by hand (in a forthcoming
commit).

The current setup in CMake (and Makefile's too, but that's an even
harder problem) leads to equivalent-but-not-identical header include
paths (-I) for the same directory, e.g. -Ilibgpopt/include vs
-Ilibgpdbcost/../libgpopt/include .

This confuses Clang-based tooling into identifying multiple paths for
the same header -- the difference being the extra sibling directory
followed by dot-dot, or "niece" directory followed by two levels of
dot-dot, and so forth -- as different headers. That, in turn, undermines
the conflict resolution and edit deduplication features in Clang's
refactoring engine, leading to duplicate edits when applying FixIt's.

This commit applies some fairly simple fixes to spell the sibling
directories in a way that generates consistent include paths, so that
Clang tooling are more functional. The Makefile's are left unchanged as
that is a lot more difficult to make "right". One can argue that we
_might_ want to instead transform the intermediate representation of
Clang's "replacement" YAML files, but that's left for another day.

During the development of a forthcoming commit that replaces private
unimplemented special member functions with explicitly deleted ones, we
got a surprising improvement of compiler diagnostics: Clang started to
see a lot of unused private fields that are masked by the fact that
there were unimplemented functions in the class. This makes sense
because the ostensibly unused field _could be_ used by a method whose
definition compiler hasn't seen in the current translation unit -- it
also suggests that the compiler would be better equipped at detecting
this if we had used whole-program analysis.

A sample of the errors looks like the following:

In file included from CMiniDumper.cpp:14:
In file included from ../../../../../../src/backend/gporca/libgpos/include/gpos/error/CErrorContext.h:17:
../../../../../../src/backend/gporca/libgpos/include/gpos/error/CMiniDumper.h:32:15: error: private field 'm_mp' is not used [-Werror,-Wunused-private-field]
        CMemoryPool *m_mp;
                     ^
1 error generated.

There are 12 such warnings, and this commit fixes them all. Note that
code mortality is a chain reaction: oftentimes, a variable (including
parameter) is only live because it's passed to another variable. While I
was at it, I also performed chained removal of variables and parameters
that became dead after removing the dead fields.

We have a bunch of classes with private fields that are used only in
debug builds, some of them are probably opportunities for complete
removal. This is exposed by an upcoming commit that enforces the use of
"=delete" and "=default" throughout the codebase.

I've attempted to solve this by adding the GPOS_ASSERTS_ONLY attribute,
but GCC doesn't like that, throwing errors like the following:

In file included from ../src/backend/gporca/libgpos/include/gpos/common/clibwrapper.h:22,
                 from ../src/backend/gporca/libgpos/include/gpos/error/CMessage.h:21,
                 from ../src/backend/gporca/libgpos/include/gpos/error/CMessageTable.h:14,
                 from ../src/backend/gporca/libgpos/include/gpos/error/CMessageRepository.h:14,
                 from ../src/backend/gporca/libgpos/src/_api.cpp:15:
../src/backend/gporca/libgpos/include/gpos/attributes.h:15:43: error: ‘unused’ attribute ignored [-Werror=attributes]
   15 | #define GPOS_UNUSED __attribute__((unused))
      |                                           ^
../src/backend/gporca/libgpos/include/gpos/attributes.h:21:27: note: in expansion of macro ‘GPOS_UNUSED’
   21 | #define GPOS_ASSERTS_ONLY GPOS_UNUSED
      |                           ^~~~~~~~~~~
../src/backend/gporca/libgpos/include/gpos/memory/CAutoMemoryPool.h:56:31: note: in expansion of macro ‘GPOS_ASSERTS_ONLY’
   56 |  ELeakCheck m_leak_check_type GPOS_ASSERTS_ONLY;
      |                               ^~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

So we're back to the good ol' #ifdef GPOS_DEBUG.

This is the first of a pair of manual changes. In the immediately
following commit I'll remove the remaining (unconditionally) unused
private fields.

Seems resource group run_tests task didn't configure with Python
before and seems image doesn't have PYTHON, as changing the configure
default failed the job. Hence, explicitely adding --without-python to
retain old functionality with changed default.

This allows us to reduce code duplication of workload SQL scripts

Reviewed-by: NPaul Guo <guopa@vmware.com>

Many tests in GPDB depend on plpython, hence enabling it by default is
helpful, instead of required to specify everytime. Given python is
needed on developer system for GPDB Management Scripts so its not
adding any new dependency.

Discussion:
https://groups.google.com/a/greenplum.org/g/gpdb-dev/c/laqc2YXxCWU/m/fS6ojeDIAQAJReviewed-by: NPaul Guo <guopa@vmware.com>

gpcloud has dependency on libxml. gpcloud enabled by default and
libxml disabled by default in configure, creates a weird pattern where
at least one option needs to be specified for configure to pass, just
./configure never passes for Greenplum.

ICG and isolation2 tests just pass without it so seems a better route
to disable gpcloud. Alternatively, can enable libxml by default but
seems conflicts with upstream and seems unnecessary dependency to add
for routine development.

Discussion:
https://groups.google.com/a/greenplum.org/g/gpdb-dev/c/laqc2YXxCWU/m/fS6ojeDIAQAJReviewed-by: NPaul Guo <guopa@vmware.com>

Postgres 991f3e5a introduce new error
message fields, but cdbdisp_get_PQerror() did not extract these newly
added message field. These fields client cannot see from libpq.

This fixes https://github.com/greenplum-db/gpdb/issues/7934.
Co-authored-by: NAshwin Agrawal <aashwin@vmware.com>
Reviewed-by: NHeikki Linnakangas <hlinnaka@iki.fi>

Currently, if a host is unreachable when gpstart is run, it will not report this
and will instead fail with an error that is both inaccurate and unhelpful to the
user, such as claiming that checksums are invalid for segments on a given host
when it simply can't reach that host to verify the checksums.

This commit adds a check to verify that all hosts are reachable before beginning
the startup process and, if one or more hosts are not reachable, marks segments
on those hosts down (in gparray, not in the cluster) so gpstart won't try to run
any checks against unreachable hosts and so that the cluster can still be started
in this state so long as there are otherwise enough valid segments to start it.

Commit 4f85fde8 refactored the infrastructure for interrupt processing,
simplified signal handlers and it had no more need to perform
StartTransactionCommand()...CommitTransactionCommand() call inside any
signal handler.

So the AmIInSIGUSR1Handler() should not happen at all, remove it.

To allow experimentation of various Postgres recovery features, we
must handle distributed commit WAL records similarly to commit and
commit prepared WAL records. This will allow the standby master
segment to utilize the recovery features. The mirror segments already
get handled since they use the regular commit and commit prepared WAL
records.

With this change, the standby master segment will be able to properly
output a value for a pg_last_xact_replay_timestamp() call (while in
hot standby), have delayed WAL replay, and use PITR/archive recovery
settings such as recovery_target_time and recovery_target_xid.

In function DropResourceGroup(), group->lockedForDrop is set
to true by calling ResGroupCheckForDrop, however, it can only
be set to false inside dropResgroupCallback. This callback is
registered at the ending of function DropResourceGroup. If an
error occured between them, group->lockedForDrop would be true
forever.

Fix it by putting the register process ahead of the lock call.
To prevent Assert(group->nRunning* > 0) if ResGroupCheckForDrop
throws an error, return directly if group->lockedForDrop did
not change.

See:

```
gpconfig -c gp_resource_manager -v group
gpstop -r -a

psql
# CREATE RESOURCE GROUP resg_test WITH (
                CPU_RATE_LIMIT=20,
                MEMORY_LIMIT=20,
                CONCURRENCY=50,
                MEMORY_SHARED_QUOTA=80,
                MEMORY_SPILL_RATIO=20,
                MEMORY_AUDITOR=vmtracker
        );
# CREATE USER user_test PASSWORD '123456' RESOURCE GROUP resg_test;
# DROP RESOURCE GROUP resg_test;

psql -U user_test
> \d -- hang
```

Use GPHOME directly. There is no need for GPSEARCH.

This enables demo_cluster.sh to handle symlinks which is useful when
GPDB is installed using RPMs and a demo cluster is desired.

The parameters were incorrectly passed while gprecoverseg was invoked
causing gprecoverseg to fail.

Co-authored-by: Bhuvnesh Chaudhary<bchaudhary@vmware.com>

https://github.com/greenplum-db/gpdb/issues/8558

Upstream's pg_regress supports starting a temporary instance and running
tests against it with `--temp-instance`, but Greenplum's could not.

This commit is working around it from the make file.
Signed-off-by: NAdam Lee <adlee@vmware.com>

Client package test on windows and the related binary was removed
by commit c2574cc4 and 8bb057ac, but there's still one usage in
rename_rc_artifacts task. Remove it also to fix release candidate
job.

The result of NULL not in an unempty set is false. The result of
NULL not in an empty set is true. But if an unempty set has
partitioned locus. This set will be divided into several subsets.
Some subsets may be empty. Because NULL not in empty set equals
true. There will be some tuples that shouldn't exist in the result
set.

The patch disable the partitioned locus of inner table by removing
the join clause from the redistribution_clauses.
Co-authored-by: NHubert Zhang <hubertzhang@apache.org>
Co-authored-by: NRichard Guo <riguo@pivotal.io>

The buildGpQueryString() function should use palloc() instead of palloc0()
to allocate the buffer for holding the serialized query string, thus
avoiding the unnecessary cost of setting all bytes in buffer to zero.
Reviewed-by: NHeikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: NAshwin Agrawal <aashwin@vmware.com>

Test partition1 creates table hhh_r1 also and that test runs with test
partition in parallel with schedule file greenplum_schedule, and this
could cause below test failure. Fixing this by renaming the table name.

@@ -523,9 +523,7 @@
 partition aa start (date '2007-01-01') end (date '2008-01-01')
       every (interval '0 days')
 );
-ERROR:  EVERY parameter too small
-LINE 5:       every (interval '0 days')
-                     ^
+ERROR:  relation "hhh_r1" already exists
 create table foo_p (i int) distributed by(i)
 partition by range(i)
 (start (1) end (20) every(0));
Reviewed-by: NAsim R P <pasim@vmware.com>

Reviewed-by: NAshwin Agrawal <aashwin@vmware.com>

Reviewed-by: NPaul Guo <pguo@pivotal.io>

Reviewed-by: NPaul Guo <pguo@pivotal.io>

plpython3u extension can already exist hence put it under
{start_ignore end_ignore} block.

Given we have simpler mechanism to have all test helpers as part of
setup test, no more need to have parsing "include:" syntax in sql
isolation framework. One less thing to depend in python.

Given now setup test runs internally once, having all helper functions
in one place with it seems better. Avoids per test overhead to parse
and run these helper include files.

This eliminates need to remember running setup for some tests which
depend on it. Plus, all the prerequisite functions can be combined in
setup and run once. Irrespective of way tests are triggered like via
schedule file or singleton, setup will be run and create the required
functions once automatically.

Sometime in history Insist() error reporting function wrapper was
added in gpdb. It was miss used in some occasions inplace of simple
assert like in heap_insert(), Insist(RelationIsHeap(relation)); This
should just be assert as adds per tuple cost in production.

Plus, the interface never emitted proper error message for non-assert
enabled builds. Hence, best to remove this interface and remove
confusion.

Should be using Assert(), elog() or ereport() which covers for all the
usecases present.

Discussion:
https://groups.google.com/a/greenplum.org/g/gpdb-dev/c/BH1IXU6vnEw/m/56vxCQsMBAAJReviewed-by: NHeikki Linnakangas <linnakangash@vmware.com>

All the instances of Insist() seem appropriate to be replaced with
just Assert(). This batch finally removes all usage of Insist() and
will help to get rid of it from GPDB.
Reviewed-by: NHeikki Linnakangas <linnakangash@vmware.com>

These instances seem worth to use elog(ERROR) instead of Insist() and
just Assert didn't seem appropriate for these.
Reviewed-by: NHeikki Linnakangas <linnakangash@vmware.com>

This would prevent us from creating alternatives that most likely would
be invalid, as the physical plan cannot contain a subquery. This check
occurs earlier than the previous commit and reduces the overall work if
we're going to generate an invalid plan.