Includes removal of changetrackingdump contrib module.

To avoid being confused by a user-created function called "sum".

Fixes github issue #4185.

It wasn't very useful. The semaphore code is inherited from upstream, and
not likely to break any time soon. If you need this information during
debugging, use a debugger.

* Remove PXF regression tests from master pipeline
* Change regression_pxf test file name
* Incorporate feedback
* Update pxf_tarball location

Author: Chris Hajas <chajas@pivotal.io>
Author: Karen Huddleston <khuddleston@pivotal.io>

This reverts commit a0fcfc37.

This commit brings in ORCA changes that ensure that a Materialize node is not
added under a Filter when its child contains outer references.  Otherwise, the
subplan is not rescanned (because it is under a Material), producing wrong
results. A rescan is necessary for it evaluates the subplan for each of the
outer referenced values.

For example:

```
SELECT * FROM A,B WHERE EXISTS (
  SELECT * FROM E WHERE E.j = A.j and B.i NOT IN (
    SELECT E.i FROM E WHERE E.i != 10));
```

For the above query ORCA produces a plan with two nested subplans:

```
Result
  Filter: (SubPlan 2)
  ->  Gather Motion 3:1
        ->  Nested Loop
              Join Filter: true
              ->  Broadcast Motion 3:3
                    ->  Table Scan on a
              ->  Table Scan on b
  SubPlan 2
    ->  Result
          Filter: public.c.j = $0
          ->  Materialize
                ->  Result
                      Filter: (SubPlan 1)
                      ->  Materialize
                            ->  Gather Motion 3:1
                                  ->  Table Scan on c
                      SubPlan 1
                        ->  Materialize
                              ->  Gather Motion 3:1
                                    ->  Table Scan on c
                                          Filter: i <> 10
```

The Materialize node (on top of Filter with Subplan 1) has cdb_strict = true.
The cdb_strict semantics dictate that when the Materialize is rescanned,
instead of destroying its tuplestore, it resets the accessor pointer to the
beginning and the subtree is NOT rescanned.
So the entries from the first scan are returned for all future calls; i.e. the
results depend on the first row output by the cross join. This causes wrong and
non-deterministic results.

Also, this commit reinstates this test in qp_correlated_query.sql. It also
fixes another wrong result caused by the same issue. Note that the changes in
rangefuncs_optimizer.out are because ORCA now no longer falls back for those
queries. Instead it produces a plan which is executed on master (instead of the
segments as was done by planner) which changes the error messages.

Also bump ORCA version to 2.53.8.
Signed-off-by: NEkta Khanna <ekhanna@pivotal.io>

gpstart did a cluster-wide check of heap_checksum settings and refused
to start the cluster if this setting was inconsistent. This meant a
round of ssh'ing across the cluster which was causing OOM errors with
large clusters.

This commit moves the heap_checksum validation to gpsegstart.py, and
changes the logic so that only those segments which have the same
heap_checksum setting as master are started.

Author: Nadeem Ghani <nghani@pivotal.io>
Author: Shoaib Lari <slari@pivotal.io>

This reverts commit c4062620.

- In the script used for creating user "gpadmin", instead of using a
nonstandard group named "supergroup" that doesn't seem to be used
anywhere, do the more standard practice of creating a group "gpadmin" that matches
the username.
Signed-off-by: NLarry Hamel <lhamel@pivotal.io>

* docs: updates to create function attribute execute on

* docs: review comment updates for CREATE FUNCTION

Some of our OS container images have been updated to have conan 1.0.0.
This new version changes the conan install command a bit.

* docs - type SET DEFAULT ENCODING

* edits requested by david

* add gp-specific clauses to summary of greenplum features page

It didn't handle relation forks correctly, and counted the main fork's size
three times.

Now that we use the upstream implementation for window functions, the
'gp_enable_sequential_window_plans' and 'gp_idf_deduplicate' GUCs are no
longer.

HASHJOIN_IS_OUTER already existed in nodeHashJoin.c; but was added again
by commit 321c0529.
This commit removes the redundant copy of the same.

This is to avoid collision of the nonsegwalrep binary.

Long ago, we thought we might need to support multiple mirrors. But we
don't, and don't forsee it coming soon. Simplify the code to only ever
have one mirror, but still allow for the possibility of no mirrors

Author: Shoaib Lari <slari@pivotal.io>
Author: C.J. Jameson <cjameson@pivotal.io>

The gpArray use of GpDB and Segment classes was confusing. This change renames
GpDB to Segment and Segment to SegmentPair to clarify usage. Its a big diff, but
a simple, repeating change.

Author: Shoaib Lari <slari@pivotal.io>
Author: Marbin Tan <mtan@pivotal.io>
Author: C.J. Jameson <cjameson@pivotal.io>

* Have a separate docker file for gpadmin user

* Add indent package for centos6

The temporary file hack to deal with pygresql output oddities didn't
ensure that those files were always removed. Instead of a named file we
don't need, just use a TemporaryFile that will go away as soon as we
release it.

Added a FIXME to revisit this once we upgrade pygresql.

pg_proc_gp.h is generated from pg_proc.sql, but a few recent commits
updated only pg_proc_gp.h, not pg_proc.sql. As a result, if you ran the
perl script, the gp_replication_error() function vanished, and the obsolete
PT verification functions reappeared. Update pg_proc_gp.h, so that
pg_proc_gp.h is reproduced by the perl script again.

Instead of assuming that casts are always binary coercible (and hence that we
could get away with just dropping them), translate casts in ORCA plans into
either a RelabelType or a FuncExpr.
Signed-off-by: NSambitesh Dash <sdash@pivotal.io>

PR for 5X_STABLE
Will be ported to MAIN

* docs: change GUC default: optimizer_join_arity_for_associativity_commutativity=18

* docs: GUC removed ZSTD (zstandard)  from gp_default_storage_options (added by mistake)

The correct order is as follows:
1. modify ~/.bash_profile
2. ssh to localhost
3. make create-demo-cluster

See https://github.com/greenplum-db/gpdb/issues/3704 for more detail

There is a long-standing race condition in BackoffSweeper() which
triggers an error and then triggers another assertion failure for
not reset sweeperInProgress to false.

This commit doesn't resolve the race condition fundamentally with
lock or other implementation, because the whole backoff mechanism
did not ask for accurate control, so skipping some sweeps should
be fine so far. We also downgrade the log level to DEBUG because
a restart of sweeper backend is unnecessary.