Functions using SQL and PL/pgSQL will plan and execute arbitrary SQL
inside a running query. The first time we initialize a plan for an SQL
block, the memory accounting system creates a new memory account for
each Executor/Node.  In the case that we are executing a cached plan,
(i.e.  plancache.c) the memory accounts will have already been assigned
in a previous execution of the plan.

As a result, when explain_memory_verbosity is set to 'detail', it is not
clear what memory account corresponds to which executor. Instead, move
the memoryAccountId into PlanState/QueryDesc, which will insure that
every time we initialize an executor, it will be assigned a unique
memoryAccountId.
Co-authored-by: NMelanie Plageman <mplageman@pivotal.io>

The FIXME was added to GPDB in commit f86622d9, which backported the
local cache of resource owners attached to LOCALLOCK. I think the comment
was added, because in the upstream commit that added the cache, the
upstream didn't thave the check guarding the pfree() yet. It was added
later in upstream, too, in commit 7e6e3bdd3c, and that had already been
backported to GPDB. So it's alright, the guard on the pfree is a good thing
to have, and there's nothing further to do here.

We had changed this in GPDB, to print less parens. That's fine and dandy,
but it hardly seems worth it to carry a diff vs upstream for this. Which
format is better, is a matter of taste. The extra parens make some
expressions more clear, but OTOH, it's unnecessarily verbose for simple
expressions. Let's follow the upstream on this.

These changes were made to GPDB back in 2006, as part of backporting
to EXPLAIN-related patches from PostgreSQL 8.2. But I didn't see any
explanation for this particular change in output in that commit message.

It's nice to match upstream, to make merging easier. However, this won't
make much difference to that: almost all EXPLAIN plans in regression
tests are different from upstream anyway, because GPDB needs Motion nodes
for most queries. But every little helps.

I don't understand what all this was about, but people have compiled GPDB
successfully after the merge commit, where this was commented out, so
apparently it's not needed.

They were all treated the same, with the SeqScan code being duplicated
for AppendOnlyScans and AOCSScans. That is a merge hazard: if some code
is changed for SeqScans, we would have to remember to manually update
the other copies. Small differences in the code had already crept up,
although given that everything worked, I guess it had no effect. Or
only had a small effect on the computed costs.

To avoid the duplication, use SeqScan for all of them. Also get rid of
TableScan as a separate node type, and have ORCA translator also create
SeqScans.

The executor for SeqScan node can handle heap, AO and AOCS tables, because
we're not actually using the upstream SeqScan code for it. We're using the
GPDB code in nodeTableScan.c, and a TableScanState, rather than
SeqScanState, as the executor node. That's how it worked before this patch
already, what this patch changes is that we now use SeqScan *before* the
executor phase, instead of SeqScan/AppendOnlyScan/AOCSScan/TableScan.

To avoid having to change all the expected outputs for tests that use
EXPLAIN, add code to still print the SeqScan as "Seq Scan", "Table Scan",
"Append-only Scan" or "Append-only Columnar Scan", depending on whether
the plan was generated by ORCA, and what kind of a table it is.

As noted in the FIXME, having two copies of the function is bad. It's easy
to avoid the duplication, if we just put it in xlogdesc.c, so that it's
available to xlog_desc() in client programs, too.

Fixes compiler warning on unused variable which was left over in the
9.3 merge.
Reviewed-by: NHeikki Linnakangas <hlinnakangas@pivotal.io>

Clang 3.3 correctly complains that a variable of type enum
MultiXactStatus cannot hold a value of -1, which makes sense.  Change
the declared type of the variable to int instead, and apply casting as
necessary to avoid the warning.

Per notice from Andres Freund

Merge with PostgreSQL, up to the point where the REL9_3_STABLE branch was
created, and 9.4 development started on the PostgreSQL master branch. That
is almost up to 9.3beta2.

Notable upstream changes, from a GPDB point of view:

* LATERAL support. Mostly works in GPDB now, although performance might not
  be very good. LATERAL subqueries, except for degenerate cases that can be
  made non-LATERAL during optimization, typically use nested loop joins.
  Unless the data distribution is the same on both sides of the join, GPDB
  needs to add Motion nodes, and cannot push down the outer query parameter
  to the inner side through the motion. That is the same problem we have
  with SubPlans and nested loop joins in general, but it happens frequently
  with LATERAL. Also, there are a couple of cases, covered by the upstream
  regression tests, where the planner currently throws an error. They have
  been disabled and marked with GPDB_93_MERGE_FIXME comments, and will need
  to be investigated later. Also, no ORCA support for LATERAL yet.

* Materialized views. They have not been made to work in GPDB yet. CREATE
  MATERIALIZED VIEW works, but REFRESH MATERIALIZED VIEW does not. The
  'matviews' test has been temporarily disabled, until that's fixed. There
  is a GPDB_93_MERGE_FIXME comment about this too.

* Support for background worker processes. Nothing special was done about
  them in the merge, but we could now make use of them for all the various
  GPDB-specific background processes, like the FTS prober and gpmon
  processes.

* Support for writable foreign tables was introduced. I believe foreign
  tables now have all the same functionality, at a high level, as external
  tables, so we could start merging the two concepts. But this merge commit
  doesn't do anything about that yet, external tables and foreign tables
  are still two entirely different beasts.

* A lot of expected output churn, thanks to a few upstream changes. We no
  longer print a NOTICE on implicitly created indexes and sequences (commit
  d7c73484), and the rules on when table aliases are printed were changed
  (commit 11e13185).

* Caught up to a bunch of features that we had already backported from 9.3:
  data page checksums, numeric datatype speedups, COPY FROM/TO PROGRAM, and
  pg_upgrade as whole.

A couple of other noteworthy changes:

* contrib/xlogdump utility is removed, in favor of the upstream
  contrib/pg_xlogdump utility.

* Removed "idle session timeout" hook. The current implementation was badly
  broken by upstream refactoring of timeout handling (commit f34c68f0).
  We'll probably need to re-introduce it in some form, but it will look
  quite different, to make it fit more nicely with the new timeout APIs.
Co-authored-by: NAshwin Agrawal <aagrawal@pivotal.io>
Co-authored-by: NAsim R P <apraveen@pivotal.io>
Co-authored-by: NDavid Kimura <dkimura@pivotal.io>
Co-authored-by: NEkta Khanna <ekhanna@pivotal.io>
Co-authored-by: NHeikki Linnakangas <hlinnakangas@pivotal.io>
Co-authored-by: NJacob Champion <pchampion@pivotal.io>
Co-authored-by: NJinbao Chen <jinchen@pivotal.io>
Co-authored-by: NKalen Krempely <kkrempely@pivotal.io>
Co-authored-by: NPaul Guo <paulguo@gmail.com>
Co-authored-by: NRichard Guo <guofenglinux@gmail.com>
Co-authored-by: NShaoqi Bai <sbai@pivotal.io>

```
$ wget http://ftp.jaist.ac.jp/pub/apache/apr/${APR}.tar.gz
--2018-09-21 07:16:24--  http://ftp.jaist.ac.jp/pub/apache/apr/apr-1.6.3.tar.gz
Resolving ftp.jaist.ac.jp (ftp.jaist.ac.jp)... 150.65.7.130, 2001:df0:2ed:feed::feed
Connecting to ftp.jaist.ac.jp (ftp.jaist.ac.jp)|150.65.7.130|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2018-09-21 07:16:25 ERROR 404: Not Found.
```

It happens if the copy command errors out before assigning
dispatcherState. Initialize the dispatcherState as NULL to fix it,
palloc0() to avoid future new member issues.

5X has no such problem.

```
(gdb) c
Continuing.
Detaching after fork from child process 25843.

Program received signal SIGSEGV, Segmentation fault.
0x0000000000aa04dd in getCdbCopyPrimaryGang (c=0x23d4150) at cdbcopy.c:44
44              return (Gang *)linitial(c->dispatcherState->allocatedGangs);
(gdb) bt
\#0  0x0000000000aa04dd in getCdbCopyPrimaryGang (c=0x23d4150) at cdbcopy.c:44
\#1  0x0000000000aa12d8 in cdbCopyEndAndFetchRejectNum (c=0x23d4150, total_rows_completed=0x0, abort_msg=0xd0c8f8 "aborting COPY in QE due to error in QD") at cdbcopy.c:642
\#...
(gdb) p c->dispatcherState
$1 = (struct CdbDispatcherState *) 0x100000000
```

In aligned format, there is an end-of-line marker at the end of each line,
and its position depends on the longest line. If the width changes, all
lines need to be adjusted for the moved end-of-line-marker.

While testing this, we found out that 'atmsort' had been doing bad things
to the YAML output before:

    -- Check Explain YAML output
    EXPLAIN (FORMAT YAML) SELECT * from boxes LEFT JOIN apples ON apples.id = boxes.apple_id LEFT JOIN box_locations ON box_locations.id = boxes.location_id;
    QUERY PLAN
    ___________
    {
      'id' => 1,
      'short' => '- Plan:                                                  +'
    }
    GP_IGNORE:(1 row)

In other worse, we were not comparing the output at all, except for that one
line that says "Plan:". The access plan for one of the queries had changed,
from a Left Join to a Right Join, and we still had the old plan memorized
in expected output, but the test was passing because atmsort hid the issue.
This commit fixes the expected output for the new plan.

When creating an ORCA plan for "INSERT ... (<col list>) VALUES (<values>)"
statement, the ORCA translator performed NULL checks for any columns not
listed in the column list. Nothing wrong with that per se, but we needed
to keep the error messages in sync, or we'd get regression test failures
caused by different messages. To simplify that, remove the check from
ORCA translator, and rely on the execution time check.

We bumped into this while working on the 9.3 merge, because 9.3 added
DETAIL to the error message in executor:

postgres=# create table notnulls (a text NOT NULL, b text NOT NULL);
CREATE TABLE
postgres=# insert into notnulls (a) values ('x');
ERROR:  null value in column "b" violates not-null constraint
postgres=# insert into notnulls (a,b) values ('x', NULL);
ERROR:  null value in column "b" violates not-null constraint  (seg2 127.0.0.1:40002 pid=26547)
DETAIL:  Failing row contains (x, null).

Doing this now will avoid that inconsistency in the merge.

One little difference with this is that EXPLAIN on an insert like above
now works, and you only get the error when you try to execute it. Before,
with ORCA, even EXPLAIN would throw the error.

gpfdist --sslclean option is a platform related patch for Solaris system.
gpfdist delays cleaning ssl buffer for some seconds which is configured
by sslclean option.
GPDB6 doesn't support Solaris now. We don't think that solution has
benefit for other platforms, so we remove --sslclean option.

Have Verified this patch manually and the default test cases cover this change.

* Unify all error report to ereport in cdbutil.c:getCdbComponentInfo.

* Change the message to lower case which is the usual PostgreSQL
style for error messages.

Reviewed by Paul and heikki, ideas brought by heikki

* Fix pg_stat_activity show wrong session id after session reset bug

Currently if a session is reset because of some error such as OOM,
after call CheckForResetSession, gp_session_id will bump to a new one,
but sess_id in pg_stat_activity remains unchanged and show the wrong number.
This commit changes sess_id in pg_stat_activity, once a session is reset.

* Refactor test using gp_execute_on_server to trigger session reset

Revert following commits related to ORCA version 3.0.0

b1f543f3.

b0359e69.

a341621d.

Signed-off-by: NDhanashree Kashid <dkashid@pivotal.io>

Via https://github.com/greenplum-db/gporca/pull/400, ORCA will optimize
DML queries by enforcing a gather on segment instead of master, whenever
possible.

Previous to this commit, ORCA always picked the first segment to gather
on while translating the DXL-GatherMotion node to GPDB motion node.

This commit uses GPDB's hash function to select the segment to gather
on, in a round-robin fashion starting with a random segment index. This
will ensure that concurrent DML queries issued via a same session, will
be gathered on different segments to distribute the workload.
Signed-off-by: NDhanashree Kashid <dkashid@pivotal.io>

When ON, ORCA will optimize DML queries by enforcing a non-master gather
whenever possible. When off, a gather on master will be enforced
instead.

Default value will be ON.

Also add new tests to ensure sane behavior when this optimization is
turned on and fix the existing tests.
Signed-off-by: NSambitesh Dash <sdash@pivotal.io>
Signed-off-by: NDhanashree Kashid <dkashid@pivotal.io>

Previously we were running all tests for all operating systems. This
commit reduces the running tests down to *only* ICW for both planner and
ORCA running *only* on Ubuntu. This reduces the chance that a flakey
test causes a false-negative run of the PR pipeline. Less tests to run
should also improve the speed of the pipeline, giving us faster
feedback, while giving us most of the confidence we need.  Exhaustive
testing will be done downstream after a PR has been merged.
Co-authored-by: NTaylor Vesely <tvesely@pivotal.io>

9.1 added a new, more compact "short" format to the numeric datatype.
This format wasn't handled by the ao_upgrade test in isolation2, so it
failed -- but the pipeline was still green because I forgot to add the
new test to the schedule in 54895f54.

To fix the issue, add a new helper which will force any Numeric back to
the legacy long format, and call that from convertNumericToGPDB4() in
the ao_upgrade test. And add the test to the schedule, so we don't have
to do this again.
Co-authored-by: NKalen Krempely <kkrempely@pivotal.io>

This fixes several small bugs:

- Schema-qualify the functions in all queries.

- Quote database and tablespace names correctly in the dispatched
  queries.

- In the variants that take OID, also dispatch the OID rather than the
  resolved name. This avoids having to deal with quoting schema and table
  names in the query, and seems like the right thing to do anyway.

- Dispatch pg_table_size() pg_indexes_size() variants. These were added
  in PostgreSQL 9.0, but we missed modifying them in the merge, the same
  way that we have modified all the other variants.

Also, refactor the internal function used to dispatch the pg_*_size()
calls to use CdbDispatchCommand directly, instead of using SPI and the
gp_dist_random('gp_id') trick. Seems more straightforward, although I
believe that trick should've worked, too.

Add tests. We didn't have any bespoken tests for these functions, although
we used some of the variants in other tests.
Reviewed-by: NDaniel Gustafsson <dgustafsson@pivotal.io>

Printing the value was added in GPDB, back in 2007. The commit message of
that change (in the historical pre-open-sourcing git repository) said:

    Merge forward from Release-3_0_0-branch. Update comment block.
    Tidy numeric_to_pos_int8_trunc.

That wasn't not very helpful...

Arguably, printing the value can be useful, but if so, we should submit
this change to upstream. I don't think it's worth the trouble, though, so
I suggest that we just revert this to the way it is in the upstream. The
reason I'm doing this now is that this caused merge conflicts in the 9.3
merge, that we're working on right now. We could probably fix the conflict
in a way that keeps the extra message, but it's simpler to just drop it.

Commit c1690010 removed most of these, but missed these few in GPDB-
specific executor node. These are no longer needed, just like all the ones
that were removed in commit c1690010.

Reviewed and ideas brought by heikki

The test was added in commit 3672f912, but I forgot to add it to the
schedule. Oops.

* docs - correct pljava JAVA_HOME, LD_LIBRARY_PATH settings

* restoring typo fix after resolving conflict

When building a Sort node to represent the ordering that is preserved
by a Motion node, in make_motion(), the call to make_sort_from_pathkeys()
would sometimes fail with "could not find pathkey item to sort". This
happened when the ordering was over a UNION ALL operation. When building
Motion nodes for MergeAppend subpaths, the path keys that represented the
ordering referred to the items in the append rel's target list, not the
subpaths. In create_merge_append_plan(), where we do a similar thing for
each subpath, we correctly passed the 'relids' argument to
prepare_sort_from_pathkeys(), so that prepare_sort_from_pathkeys() can
match the target list entries of the append relation with the entries of
the subpaths. But when creating the Motion nodes for each subpath, we
were passing NULL as 'relids' (via make_sort_from_pathkeys()).

At a high level, the fix is straightforward: we need to pass the correct
'relids' argument to prepare_sort_from_pathkeys(), in
cdbpathtoplan_create_motion_plan(). However, the current code structure
makes that not so straightforward, so this required some refactoring of
the make_motion() and related functions:

Previously, make_motion() and make_sorted_union_motion() would take a path
key list as argument, to represent the ordering, and it called
make_sort_from_pathkeys() to extract the sort columns, operators etc.
After this patch, those functions take arrays of sort columns, operators,
etc. directly as arguments, and the caller is expected to do the call to
make_sort_from_pathkeys() to get them, or build them through some other
means. In cdbpathtoplan_create_motion_plan(), call
prepare_sort_from_pathkeys() directly, rather than the
make_sort_from_pathkeys() wrapper, so that we can pass the 'relids'
argument. Because prepare_sort_from_pathkeys() is marked as 'static', move
cdbpathtoplan_create_motion_plan() from cdbpathtoplan.c to createplan.c,
so that it can call it.

Add test case. It's a slightly reduced version of a query that we already
had in 'olap_group' test, but seems better to be explicit. Revert the
change in expected output of 'olap_group', made in commit 28087f4e,
which memorized the error in the expected output.

Fixes https://github.com/greenplum-db/gpdb/issues/5695.
Reviewed-by: NPengzhou Tang <ptang@pivotal.io>
Reviewed-by: NMelanie Plageman <mplageman@pivotal.io>

OUT parameters make calling the function much less awkward, as you don't
need to specify the output columns in every invocation. Also, change the
datatype of a few columns to pg_node_tree, so that you can use pg_get_expr()
to pretty-print them.

I'm doing this to hide the trivial differences in the internal string
representation of expressions. This came up in the 9.3 merge, which added
a new field to FuncExpr again, which would cause the test to fail. Using
pg_get_expr() to print the fields in human-readable format, which is not
sensitive to small changes like that, will avoid that problem.

s/GDPB/GPDB/

One of the queries in the olap_window_seq suite was non-deterministic as
it was ordering around a column which had duplicate values. Switch to the
_ord version of the table and use the sequence column which yields
deterministic results.
Reviewed-by: NVenkatesh Raghavan <vraghavan@pivotal.io>

This commit adds the tests corresponding to the below change introduced in PQO.
In case of Insert on Randomly distributed relations, a random / redistribute
motion must exists to ensure randomness of the data inserted, else there will
be skew on 1 segment.

Consider the below scenario:
Scenario 1:
```
CREATE TABLE t1_random (a int) DISTRIBUTED RANDOMLY;
INSERT INTO t1_random VALUES (1), (2);
SET optimizer_print_plan=on;

EXPLAIN INSERT INTO t1_random VALUES (1), (2);
Physical plan:
+--CPhysicalDML (Insert, "t1_random"), Source Columns: ["column1" (0)], Action: ("ColRef_0001" (1))   rows:2   width:4  rebinds:1   cost:0.020884   origin: [Grp:1, GrpExpr:2]
   +--CPhysicalComputeScalar
      |--CPhysicalMotionRandom  ==> Random Motion Inserted (2)
      |  +--CPhysicalConstTableGet Columns: ["column1" (0)] Values: [(1); (2)] ==> Delivers Universal Spec (1)
      +--CScalarProjectList
         +--CScalarProjectElement "ColRef_0001" (1)
            +--CScalarConst (1)
",
                                       QUERY PLAN
----------------------------------------------------------------------------------------
 Insert  (cost=0.00..0.02 rows=1 width=4)
   ->  Result  (cost=0.00..0.00 rows=1 width=8)
         ->  Result  (cost=0.00..0.00 rows=1 width=4) ==> Random Motion Converted to a Result Node with Hash Filter to avoid duplicates (4)
               ->  Values Scan on "Values"  (cost=0.00..0.00 rows=1 width=4) ==> Delivers Universal Spec (3)
 Optimizer: PQO version 2.70.0
```

When an Insert is requested on t1_random from a Universal Source, Optimization
framework does add a Random Motion / CPhysicalMotionRandom (See (2) above) to
redistribute the data. However, since CPhysicalConstTableGet / Values Scan
delivers Universal Spec, it is converted to a Result Node with hash filter to
avoid duplicates in DXL to Planned Statement (See (4) above). Now, since there
is no redistribute motion to spray the data randomly on the segments, due to
the result node with hash filters, data from only one segment is allowed to
propagate further, which is inserted by the DML node. This results in all the
data being inserted on to 1 segment only.

Scenario 2:
```
CREATE TABLE t1_random (a int) DISTRIBUTED RANDOMLY;
CREATE TABLE t2_random (a int) DISTRIBUTED RANDOMLY;
EXPLAIN INSERT INTO t1_random SELECT * FROM t1_random;
Physical plan:
+--CPhysicalDML (Insert, "t1_random"), Source Columns: ["a" (0)], Action: ("ColRef_0008" (8))   rows:1   width:34  rebinds:1   cost:431.010436   origin: [Grp:1, GrpExpr:2]
   +--CPhysicalComputeScalar   rows:1   width:1  rebinds:1   cost:431.000011   origin: [Grp:5, GrpExpr:1]
      |--CPhysicalTableScan "t2_random" ("t2_random")   rows:1   width:34  rebinds:1   cost:431.000006   origin: [Grp:0, GrpExpr:1]
      +--CScalarProjectList   origin: [Grp:4, GrpExpr:0]
         +--CScalarProjectElement "ColRef_0008" (8)   origin: [Grp:3, GrpExpr:0]
            +--CScalarConst (1)   origin: [Grp:2, GrpExpr:0]
",
                                        QUERY PLAN
------------------------------------------------------------------------------------------
 Insert  (cost=0.00..431.01 rows=1 width=4)
   ->  Result  (cost=0.00..431.00 rows=1 width=8)
         ->  Table Scan on t1_random  (cost=0.00..431.00 rows=1 width=4)
 Optimizer: PQO version 2.70.0
```

When an Insert is request on t1_random (randomly distributed table) from
another randomly distributed table, optimization framework does not add a
redistribute motion because CPhysicalDML requested Random Spec and the source
t2_random delivers random distribution spec matching / satisfying the requested
spec.

So, in summary, there are 2 causes for skewness in the data inserted into randomly distributed table.
Scenario 1: Where the Random Motion is converted into a Result Node to Hash Filters
Scneario 2: Where the requested and derived spec matches.

This patch fixes the issue by ensuring that if an insert is performed on a
randomly distributed table, there must exists a random motion which has been
enforced by a true motion.  This is achived in 2 steps:
1. CPhysicalDML / Insert on Randomly Distributed table must request a Strict Random Spec
2. Append Enforcer for Random Spec must track if the motion node enforced has
a universal child, if it has, then update the bool flag to false else true

Characteristic of Strict Random Spec:
1. Strict Random Spec matches / satisfies Strict Random Spec Only
2. Random Spec enforced by a true motion matches / satisfies Strict Random Spec.

CPhysicalDML always has a CPhysicalComputeScalar node below it which projects
the additional column indicating if it's an Insert. The request for Strict
Motion is not propagated down the CPhysicalComputeScalar node,
CPhysicalComputeScalar requests Random Spec from its child instead. This is to
mandate the existence of a true random motion either by the childs of CPhysicalDML
node or it should be inserted between CPhysicalDML and CPhysicalComputeScalar.
If there is any motion in the same group holding CPhysicalComputeScalar,
it should also request Random Spec from its childs.

Plans after the fix
Scenario 1:
```
EXPLAIN INSERT INTO t1_random VALUES (1), (2);
Physical plan:
+--CPhysicalDML (Insert, "t1_random"), Source Columns: ["column1" (0)], Action: ("ColRef_0001" (1))   rows:2   width:4  rebinds:1   cost:0.020884   origin: [Grp:1, GrpExpr:2]
   +--CPhysicalMotionRandom   rows:2   width:1  rebinds:1   cost:0.000051   origin: [Grp:5, GrpExpr:2] ==> Strict Random Motion Enforcing true randomness
      +--CPhysicalComputeScalar   rows:2   width:1  rebinds:1   cost:0.000034   origin: [Grp:5, GrpExpr:1]
         |--CPhysicalMotionRandom   rows:2   width:4  rebinds:1   cost:0.000029   origin: [Grp:0, GrpExpr:2]
         |  +--CPhysicalConstTableGet Columns: ["column1" (0)] Values: [(1); (2)]   rows:2   width:4  rebinds:1   cost:0.000008   origin: [Grp:0, GrpExpr:1]
         +--CScalarProjectList   origin: [Grp:4, GrpExpr:0]
            +--CScalarProjectElement "ColRef_0001" (1)   origin: [Grp:3, GrpExpr:0]
               +--CScalarConst (1)   origin: [Grp:2, GrpExpr:0]
",
                                       QUERY PLAN
----------------------------------------------------------------------------------------
 Insert  (cost=0.00..0.02 rows=1 width=4)
   ->  Redistribute Motion 3:3  (slice1; segments: 3)  (cost=0.00..0.00 rows=1 width=8) ==> Strict Random Motion Enforcing true randomness
         ->  Result  (cost=0.00..0.00 rows=1 width=8)
               ->  Result  (cost=0.00..0.00 rows=1 width=4)
                     ->  Values Scan on "Values"  (cost=0.00..0.00 rows=1 width=4)
 Optimizer: PQO version 2

```

Scenario 2:
```
EXPLAIN INSERT INTO t1_random SELECT * FROM t1_random;
Physical plan:
+--CPhysicalDML (Insert, "t1_random"), Source Columns: ["a" (0)], Action: ("ColRef_0008" (8))   rows:2   width:34  rebinds:1   cost:431.020873   origin: [Grp:1, GrpExpr:2]
   +--CPhysicalMotionRandom   rows:2   width:1  rebinds:1   cost:431.000039   origin: [Grp:5, GrpExpr:2] ==> Strict Random Motion Enforcing True Randomness
      +--CPhysicalComputeScalar   rows:2   width:1  rebinds:1   cost:431.000023   origin: [Grp:5, GrpExpr:1]
         |--CPhysicalTableScan "t1_random" ("t1_random")   rows:2   width:34  rebinds:1   cost:431.000012   origin: [Grp:0, GrpExpr:1]
         +--CScalarProjectList   origin: [Grp:4, GrpExpr:0]
            +--CScalarProjectElement "ColRef_0008" (8)   origin: [Grp:3, GrpExpr:0]
               +--CScalarConst (1)   origin: [Grp:2, GrpExpr:0]
",
                                        QUERY PLAN
------------------------------------------------------------------------------------------
 Insert  (cost=0.00..431.02 rows=1 width=4)
   ->  Redistribute Motion 3:3  (slice1; segments: 3)  (cost=0.00..431.00 rows=1 width=8) ==> Strict Random Motion Enforcing true randomness
         ->  Result  (cost=0.00..431.00 rows=1 width=8)
               ->  Table Scan on t1_random  (cost=0.00..431.00 rows=1 width=4)
 Optimizer: PQO version 2.70.0
(5 rows)
```

Note: If Insert is performed on a Randomly Distributed Table from a Hash
Distributed Table (childs), an additional redistribute motion is not enforced
between CPhysicalDML and CPhysicalComputeScalar as there already exists a true
random motion due to mismatch of random vs hash distributed spec.
```
pivotal=# explain insert into t1_random select * from t1_hash;
LOG:  statement: explain insert into t1_random select * from t1_hash;
LOG:  2018-08-20 13:31:01:135438 PDT,THD000,TRACE,"
Physical plan:
+--CPhysicalDML (Insert, "t1_random"), Source Columns: ["a" (0)], Action: ("ColRef_0008" (8))   rows:100   width:34  rebinds:1   cost:432.043222   origin: [Grp:1, GrpExpr:2]
   +--CPhysicalComputeScalar   rows:100   width:1  rebinds:1   cost:431.001555   origin: [Grp:5, GrpExpr:1]
      |--CPhysicalMotionRandom   rows:100   width:34  rebinds:1   cost:431.001289   origin: [Grp:0, GrpExpr:2]
      |  +--CPhysicalTableScan "t1_hash" ("t1_hash")   rows:100   width:34  rebinds:1   cost:431.000623   origin: [Grp:0, GrpExpr:1]
      +--CScalarProjectList   origin: [Grp:4, GrpExpr:0]
         +--CScalarProjectElement "ColRef_0008" (8)   origin: [Grp:3, GrpExpr:0]
            +--CScalarConst (1)   origin: [Grp:2, GrpExpr:0]
",
                                           QUERY PLAN
-------------------------------------------------------------------------------------------------
 Insert  (cost=0.00..432.04 rows=34 width=4)
   ->  Result  (cost=0.00..431.00 rows=34 width=8)
         ->  Redistribute Motion 3:3  (slice1; segments: 3)  (cost=0.00..431.00 rows=34 width=4)
               ->  Table Scan on t1_hash  (cost=0.00..431.00 rows=34 width=4)
 Optimizer: PQO version 2.70.0
(5 rows)

Time: 69.309 ms
```

PostgreSQL 9.3 introduces a -q option, for "quiet" mode. But in GPDB, we
have been using it to mean "create non-unique indexes instead of unique,
primary key, indexes". To avoid the clash once we merge with 9.3, rename
the GPDB option to --use-unique-keys.

It was left broken by the 9.2 merge. Need to use getopt_long() now, as in
upstream, and we were passing wrong variable to snprintf(). Both of these
were causing compiler warnings, and the latter was causing a segfault.

We don't seem to have any tests for pgbench. I think we'll get some from
upstream later on, and pgbench isn't super-critical anyway, so I didn't
address that at this moment.

* docs - update when pg_class.relfrozenxid is 0 (zero)

* docs - update relfrozenxid info. Update - XID values start at 3 (0, 1, 2 are special IDs).

I think this is more clear. Now that we the error position is displayed
with the error, we don't need to work so hard to deparse the value and the
partition type. The error position makes that clear.

This came up during the 9.3 merge. Passing InvalidOid to
deparse_context_for() will no longer work in 9.3, so we'd need to change
this somehow in the 9.3 merge, anyway.

Looking at the test, it seems pretty uninteresting. It basically tests that
there is call to IsStandbyMode() in appendonly_redo(), and that the
switch-case statement works. I don't think we need bespoken tests for those
things.

This came up while working on the 9.3 merge. 9.3 moves all the *_desc()
functions to separate files, so after that, only the appendonly_redo()
function would remain in cdbappendonlystorage.c. It would make sense to
move it into cdbappendonlyxlog.c, but we couldn't do that, because this
mock test got in the way. We could fix that in the merge, but I'm opening
a separate PR of this removal, to give more visibility to the decision.

Several instances of s/funciton/function/