* Need to set relFileNode field correctly in MirroredAppendOnlyOpen, along
  with the File descriptor itself. Otherwise the relfilenode is set
  incorrectly in WAL records.

* Pretend that filespace location is always "tblspc_dummy_<tablespace oid>".
  The filespace/tablespace stuff is quite broken ATM, but hopefully this
  at least avoids some crashing.

The fault injection points used in the test didn't exist anymore. Add a new
injection point in RecordTransactionCommit(), just before writing the commit
WAL record, and use that in the test.

Remove a bunch of fault injection IDs that are no longer used. (They are
still referenced in some TINC tests, but the injection points don't exist
anymore, so those tests will need to be rewritten if we want to keep them.)

It was done in the later startup passes, which were removed. Add the call
to where it is in the upstream.

Fix compiler warning about unused variable in the passing.

* Revert almost all the changes in smgr.c / md.c, to not go through
  the Mirrored* APIs.

* Remove mmxlog stuff. Use upstream "pending relation deletion" code
  instead.

* Get rid of multiple startup passes. Now it's just a single pass like
  in the upstream.

* Revert the way database drop/create are handled to the way it is in
  upstream. Doesn't use PT anymore, but accesses file system directly,
  and WAL-logs a single CREATE/DROP DATABASE WAL record.

* Get rid of MirroredLock

* Remove a few tests that were specific to persistent tables.

* Plus a lot of little removals and reverts to upstream code.

With file replication code removed, wal replication is only HA system for
Greenplum now. Ideally wished to remove the config option as its no more a
choice but keeping for now as all code checking for same needs to be modified
anyways at some point.

This just removes already decoupled code for filerep, lot more fts code needs to
be cleaned-up for filerep removal.

Another tricky removal but got through.

User of fault injector should set the fault at desired like master, primary or
mirror. Doesn't seem underneath fault injector code to be so heavy in checking
for right role.

This was little painful one to entangle, but seems done now. Though if any
shake-up happens shoudl be primary suspect.

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