We've moved the repo that holds trigger commits to a private repo since
there wasn't anything interesting there.

The path constructed in OpenAOSegmentFile() didn't take into account
"t_" semantic of filename. Ideally, the correct filename is passed to
function, so no need to construct the same.

Would be better if can move MakeAOSegmentFileName() inside
OpenAOSegmentFile(), as all callers call it except
truncate_ao_perFile(), which doesn't fit that model.

When ExecReScanBitmapHeapScan get executed, bitmap state (tbmiterator
and tbmres) gets freed in freeBitmapState. So the tbmres is NULL, and we
need to reinit bitmap state to start scan from the beginning and reset AO/AOCS
bitmap pages' flags(baos_gotpage, baos_lossy, baos_cindex and baos_ntuples).

Especially when ExecReScan happens on the bitmap append only scan and
not all the matched tuples in bitmap are consumed, for example, Bitmap
Heap Scan as inner plan of the Nest Loop Semi Join. If tbmres not get init,
and not read all tuples in last bitmap, BitmapAppendOnlyNext will assume the
current bitmap page still has data to return. but bitmap state already freed.

From the code, for Nest Loop Semi Join, when a match find, a new outer slot is
requested, and then `ExecReScanBitmapHeapScan` get called, `node->tbmres` and
`node->tbmiterator` set to NULL. `node->baos_gotpage` still keeps true.
When execute `BitmapAppendOnlyNext`, it skip create new `node->tbmres`.
And jump to access `tbmres->recheck`.
Reviewed-by: NJinbao Chen <jinchen@pivotal.io>
Reviewed-by: NAsim R P <pasim@vmware.com>

Commit 8190ed40 removed lockfile from
mainUtils, but did not remove a reference to its source directory in the
make clean/distclean target. As a result, because LOCKFILE_DIR is no
longer defined, the make clean/distclean target removes the
PYLIB_SRC_EXT directory.

Force to update checkpoint timeline id in control data after promotion and before pg_rewind. (#10402)

After promotion there is a checkpoint but not an immediate one, so the
checkpoint timeline id in pg_control data might not be updated in time when
running pg_rewind which depends on that to decide the necessity of incremental
recovery.  Let's run checkpoint after promotion in tests so that later
pg_rewind will not bypass the incremental recovery.

This should be able to fix some long-existing annoying flaky pg_rewind tests.
Reviewed-by: N(Jerome)Junfeng Yang <jeyang@pivotal.io>

--Also, add some links to other topics.

* docs - add GUC -write_to_gpfdist_timeout

Add GUC and add link to GUC in gpfdist reference

* docs - correct default value 600 --> 300. Fix xref.

Previously, CTimerUser didn't initialize timer, so the elapsed time provided by
Orca was not meaningful, sometimes confusing.

When traceflag T101012 is turned on, we can see the following trace message:

[OPT]: Memo (stage 0): [20 groups, 0 duplicate groups, 44 group expressions, 4 activated xforms]
[OPT]: stage 0 completed in 860087 msec,  plan with cost 1028.470667 was found
[OPT]: <Begin Xforms - stage 0>
......
[OPT]: <End Xforms - stage 0>
[OPT]: Search terminated at stage 1/1
[OPT]: Total Optimization Time: 67ms

As shown above, the stage 0 elapsed timer is much greater than the total
optimization time, which is obviously incorrect.

For GPDB FTS, if the primary, mirror replication keeps crash
continuously and attempt to crate replication connection too many times,
FTS should mark the mirror down. Otherwise, it may block other
processes.
If the WAL starts streaming, clear the attempt count to 0. This is because the blocked
transaction can only be released once the WAL in streaming state.

The solution for this is:

1. Use ` FTSReplicationStatus` which under `gp_replication.c`  to track current primary-mirror
replication status. This includes:
    - A continuous failure counter. The counter gets reset once the replication
    starts streaming, or replication restarted.
    - A record of the last disconnect timestamp which is refactored from
    `WalSnd` slot.
    The reason for moving this is: When FTS probe happens, the `WalSnd`
    slot may already get freed. And `WalSnd` slot is designed reusable.
    It's hacky to read value from a freed slot in shared memory.

2. When handling each probe query, `GetMirrorStatus` will check the current
mirror status and the failure count from walsender's application ` FTSReplicationStatus`.
If the count exceeds the limit, the retry test will ignore the last replication
disconnect time since it gets refreshed when new walsender starts. (Since
in the current case, the walsender keeps restart.)

3. On FTS bgworker. If mirror down and retry set to false, mark the mirror
down.

A `gp_fts_replication_attempt_count` GUC is added. When the replication failure count
exceed this GUC, ignore the last replication disconnect time when checking for mirror
probe retry.

The life cycle of a ` FTSReplicationStatus`:
1. It gets created when first enable replication during the replication
start phase. Each replication's sender should have a unique
`application_name`, which also used to specify the replication priority
in multi-mirror env. So ` FTSReplicationStatus` uses the `application_name` mark
itself.

2. The ` FTSReplicationStatus` for replication will exist until FTS detects
failure and stop the replication between primary and mirror. Then
` FTSReplicationStatus` for that `application_name` will be dropped.

Now the `FTSReplicationStatus` is used only for GPDB primary-mirror replication.

Previously, there are some code executed in QEs that will check
the value of the GUC gp_enable_global_deadlock_detector. The
historical reason is that:
  Before we have GDD, UPDATE|DELETE operations cannot be
  concurrently executed, and we do not meet the EvalPlanQual
  issue and concurrent split update issue. After we have GDD,
  we meet such issues and add code to resolve them, and we
  add the code `if (gp_enable_global_deadlock_detector)` at
  the very first. It is just like habitual thinking.

In fact, we do not rely on it in QEs and I tried to remove this
in the context: https://github.com/greenplum-db/gpdb/pull/9992#pullrequestreview-402364938.
I tried to add an assert there but could not handle utility mode
as Heikki's comments. To continue that idea, we can just remove
the check of gp_enable_global_deadlock_detector. This brings two
benefits:
  1. Some users only change this GUC on master. By removing the usage
     in QEs, it is safe now to make the GUC master only.
  2. We can bring back the skills to only restart master node's postmaster
     to enable GDD, this save a lot of time in pipeline. This commit
     also do this for the isolation2 test cases: lockmodes and gdd/.

The Github issue https://github.com/greenplum-db/gpdb/issues/10030  is gone after this commit.

1. `localAllocated` is not set to 0 when resetting the memory context, which
makes the statistics data incorrect. 
2. Size is an unsigned integer, and `MEMORY_ACCOUNT_UPDATE_ALLOCATED`
uses the opposite value for subtraction. Since they have the same bit width
and the same bit results. We'd avoid using it in this way.
3. Fix memory accounting when setting a new parent. The accounting
parent must be one of the ancestors of the child. Re-setting the parent
might break the rule, see below:

If we set the new parent to the sibling or the ancestor of the old parent,
all children's accounting parent may have to change, because
the old accountingParent may not be the ancestor of the children's AllocSet.
We must have a loop to find it. For example:

root <- A <- B <- H <- C <- D
               \
                 <-E
root <- A <- B <- H
               \
                 <-E <- C <- D

We want to change the parent of C to E, and both C and D have the B
to be the accountingParent. After we set the new parent of C to E,
the accountingParent has to update. But if the new parent of C is B,
it still satisfies the above rule. So, we don't have to update the accountingParent.

The issue 1 is fixed in PR(https://github.com/greenplum-db/gpdb/pull/10106).
Reviewed-by: NNing Yu <nyu@pivotal.io>

For below example:
```
CREATE TABLE mytable2 (
    key character varying(20) NOT NULL,
    key_value character varying(50)
) DISTRIBUTED BY (key);

CREATE VIEW aaa AS
SELECT
    CASE mytable2.key_value
        WHEN IS NOT DISTINCT FROM 'NULL'::text THEN 'now'::text::date
        ELSE to_date(mytable2.key_value::text, 'YYYYMM'::text)
        END AS t
    FROM mytable2;

```

mytable2.key_value will cast to type date. For clause `(ARG1) IS NOT
DISTINCT FROM (ARG2)`, this leads ARG1 to become a RelabelType node and
contains CaseTestExpr node in RelabelType->arg.

So when dumping the view, it'll dump extra `CASE_TEST_EXPR` as below
```
select pg_get_viewdef('notdisview3',false);
                               pg_get_viewdef
-----------------------------------------------------------------------------
  SELECT                                                                    +
         CASE mytable2.key_value                                            +
             WHEN (CASE_TEST_EXPR) IS NOT DISTINCT FROM 'NULL'::text THEN ('now'::text)::date+
             ELSE to_date((mytable2.key_value)::text, 'YYYYMM'::text)       +
         END AS t                                                           +
    FROM mytable2;
(1 row)
```

I dig into commit a453004e, if left-hand argument for `IS NOT DISTINCT
FROM` contains any `CaseTestExpr` node, the left-hand arg should be omitted.
`CaseTestExpr` is a placeholder for CASE expression.
Reviewed-by: NPaul Guo <paulguo@gmail.com>

It could be called in utility mode, however we should avoid calling into
FtsNotifyProber() for such case. Ideally we could do that if we access the
master node and postgres is no in single mode, but it seems that we do not that
need.

Here is the stack of the issue I encountered.

0  0x0000003397e32625 in raise () from /lib64/libc.so.6
1  0x0000003397e33e05 in abort () from /lib64/libc.so.6
2  0x0000000000b39844 in ExceptionalCondition (conditionName=0xeebac0 "!(Gp_role == GP_ROLE_DISPATCH)", errorType=0xeebaaf "FailedAssertion",
    fileName=0xeeba67 "cdbfts.c", lineNumber=101) at assert.c:66
3  0x0000000000bffb1e in FtsNotifyProber () at cdbfts.c:101
4  0x0000000000c389a4 in cdbcomponent_getCdbComponents () at cdbutil.c:714
5  0x0000000000c26e3a in gp_pgdatabase__ (fcinfo=0x7ffd7b009c10) at cdbpgdatabase.c:74
6  0x000000000076dbd6 in ExecMakeTableFunctionResult (funcexpr=0x3230fc0, econtext=0x3230988, argContext=0x3232b68, expectedDesc=0x3231df8, randomAccess=0 '\000',
	    operatorMemKB=32768) at execQual.c:2275
......
18 0x00000000009afeb2 in exec_simple_query (query_string=0x316ce20 "select * from gp_pgdatabase") at postgres.c:1778
Reviewed-by: NHubert Zhang <hzhang@pivotal.io>

If the directory of tablespace does not exist, we should got a
error on commit transaction. But error on commit transaction will
cause a panic. So the directory of tablespace should be checked
so that we can avoid panic.

* Doc updates to cover packaging changes/additions for versions 7/6

* Removing nav link to non-default steps

* Add missing chown examples; add note about symbolic link update in upgrade procedure

* Typo fix

Skip foreign table when gpexpand

This commit introduce some compile warnings, so revert it first.

This reverts commit b1b99c43.

Most of the code that uses fault injector is in the preprocess block.
But the function gpdb::InjectFaultInOptTasks() isn't guarded by
the macro FAULT_INJECTOR.

This PR enables the developer to disable fault injector manually in
pg_config_manual.h.
See issue: https://github.com/greenplum-db/gpdb/issues/10341

These NOTICEs:

    Connected as user 'heikki' to database 'postgres', port '5432', gpdb version '7.0'
    -------------------------------------------------------------------
    Batch size: 4
    Performing test 'duplicate'
    NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column(s) named 'segid' as the Greenplum Database data distribution key for this table.
    HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
    NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column(s) named 'segid' as the Greenplum Database data distribution key for this table.
    HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
    ...
    NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column(s) named 'segid' as the Greenplum Database data distribution key for this table.
    HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
    Total runtime for test 'duplicate': 0:00:06.83

    SUMMARY REPORT: PASSED
    ===================================================================
    Completed 1 test(s) on database 'postgres' at 2020-06-25 11:49:19 with elapsed time 0:00:06
    Found no catalog issue

They're useless chatter. Add explicit DISTRIBUTED BY to the CREATE TABLE AS
commands to silence them.
Reviewed-by: NAshwin Agrawal <aashwin@vmware.com>

Mirror registration passes through several steps at the moment:
1. CREATE_QE_ARRAY (QE_MIRROR_ARRAY is ordered by content)
2. ARRAY_REORDER (QE_MIRROR_ARRAY is ordered by port)
3. CREATE_ARRAY_SORTED_ON_CONTENT_ID (form QE_MIRROR_ARRAY_SORTED_ON_CONTENT_ID
   on a base of QE_MIRROR_ARRAY)
4. REGISTER_MIRRORS (walk through QE_MIRROR_ARRAY, register mirrors with
   pg_catalog.gp_add_segment_mirror on master's gp_segment_configuration
   and update QE_MIRROR_ARRAY with returned dbids)
5. CREATE_SEGMENT (walk through QE_MIRROR_ARRAY_SORTED_ON_CONTENT_ID with old
   dbids and create mirrors on segment hosts with pg_basebackup)
The problem is in a step 4 - we update the wrong array (QE_MIRROR_ARRAY instead
of QE_MIRROR_ARRAY_SORTED_ON_CONTENT_ID). Because of that we get inconsistency
between mirror dbids on gp_segment_configuration and internal.auto.conf files.
This can cause inoperable cluster state in some situations when we promote a
failed primary from a mirror with wrong dbids (FTS can't solve this issue).

Also fixed column indexes in array used for segment arrray ordering.
It was not done after commit https://github.com/greenplum-db/gpdb/commit/03c7d557720c5a78af1e2574ac385d10a0797f5e
which prepend array with new hostname column.
Co-authored-by: NVasiliy Ivanov <ivi@arenadata.io>

* docs - update pxf migration info and greenplum upgrade info

* post upgrade init not always required

* use procedure step name for xref

* forgot about this page - xref to pxf dita landing page

* fix some links

* xref to PXF packaging README on greenplum oss docs landing page

* redirect install topic to pxf README for oss docs

* pxf oss subnav includes only migration/upgrade topics

* next greenplum minor releases will include embedded pxf

* migrate topic - call pxf directly

* update upgrade subnav title

* use underscore in filename

Currently, GPDB5 is built with --enable-rpath (default configure
option). For plperl, it's Makefile specifies an absolute path to the
location of "$(perl -MConfig -e 'print $Config{archlibexp}')/CORE"
(e.g., /usr/lib64/perl5/CORE on RHEL7). This directory is not on the
default search path for the runtime linker. Without the proper RUNPATH
entry, libperl.so cannot be found when postgres tries to load the plperl
extension.

Without setting correct RUNPATH for plperl.so, will see a error like
followin:
ERROR:  could not load library
"/usr/local/greenplum-db-devel/lib/postgresql/plperl.so": libperl.so:
cannot open shared object file: No such file or directory
Authored-by: NShaoqi Bai <bshaoqi@vmware.com>
(cherry picked from commit a3eeadd5a575820ebc9a401c96b252355f183bb1)

[#173046174]
Authored-by: NBradford D. Boyle <bradfordb@vmware.com>
(cherry picked from commit 28bcd4447551b3b9790e23d7865dbf403f79ef36)

Authored-by: NShaoqi Bai <sbai@pivotal.io>
(cherry picked from commit 6b71cd2e0085170139fd1c645696e6e2b8895058)

Authored-by: NTingfang Bao <baotingfang@gmail.com>
(cherry picked from commit ae9bcdda4252524401fe6d1b4752355aa66e18ea)

When upgrading from GPDB5 to GPDB6, gpupgrade will need to be able to call
binaries from both major versions. Relying on LD_LIBRARY_PATH is not an option
because this can cause binaries to load libraries from the wrong version.
Instead, we need the libraries to have RPATH/RUNPATH set correctly. Since the
built binaries may be relocated we need to use a relative path.

This commit disables the rpath configure option (which would result in an
absolute path) and use LDFLAGS to use `$ORIGIN`.

For most ELF files a RUNPATH of `$ORIGIN/../lib` is correct. For pygresql
python module and the quicklz_compressor extension, the RUNPATH needs to be
adjusted accordingly. The LDFLAGS for those artifacts can be modified with
different environment variables PYGRESQL_LDFLAGS and QUICKLZ_LDFLAGS.

We always use `--enable-new-dtags` to set RUNPATH. On CentOS 6, with new dtags,
both DT_RPATH and DT_RUNPATH are set and DT_RPATH will be ignored.

[#171588878]
Co-authored-by: NBradford D. Boyle <bboyle@pivotal.io>
Co-authored-by: NXin Zhang <xzhang@pivotal.io>
(cherry picked from commit 2eec06b39abe8cb5370e949056f26997b9d02572)

Following the [Greenplum Server RPM Packaging Specification][0], we need
to update greenplum_path.sh file, and ensure many environment variables
set correct.

There are a few basic requirments for Greenplum Path Layer:

* greenplum-path.sh shall be installed to `${installation
  prefix}/greenplum-db-[package-version]/greenplum_path.sh`
* ${GPHOME} is set by given parameter, by default it should point to
  `%{installation prefix}/greenplum-db-devel`
* `${LD_LIBRARY_PATH}` shall be safely set to avoid a trailing colon
  (which will cause the linker to search the current directory when
  resolving shared objects)
* `${PYTHONPATH}` shall be set to `${GPHOME}/lib/python`
* `${PATH}` shall be set to `${GPHOME}/bin:${PATH}`
* If the file `${GPHOME}/etc/openssl.cnf` exists then `${OPENSSL_CONF}`
  shall be set to `${GPHOME}/etc/openssl.cnf`
* The greenplum_path.sh file shall pass [ShellCheck][1]

[0]: https://github.com/greenplum-db/greenplum-database-release/blob/master/Greenplum-Server-RPM-Packaging-Specification.md#detailed-package-behavior
[1]: https://github.com/koalaman/shellcheckAuthored-by: NTingfang Bao <bbao@pivotal.io>
(cherry picked from commit 5150237ac884227383f9f4f94e2383450756e7da)

The previous commit updated 'orafce' module to new upstream version.
This commit fixes it so that it works with GPDB. We carried many of these
diffs against the old version too, but some are new with the new orafce
version.

Old differences, put back in this commit:

- In the 'finish no data found' NOTICEs, GPDB strips trailing spaces

- GPDB doesn't allow SQL_ASCII as database encoding. Use 'iso-8859-1' in
  the 'nlssort' test instead.

- Don't install dbms_alert. It doesn't work in GPDB.

- GPDB doesn't have 'tts_tableOid' field in TupleTableSlot

New differences:

- Use init_file to suppress extra NOTICEs about distribution keys and such
  that GPDB prints. (Previously, we had changed the expected outputs to
  include the NOTICEs, but this seems nicer.)

- GPDB has built-in DECODE() support, so don't install the orafce decode()
  compatibility functions. The DECODE() is transformed to a CASE-WHEN
  construct, so fix all the regression tests that had 'decode' as the
  result column name now into 'case' instead. A few tests are now erroring
  out because of missing casts between text and other datatypes, but that's
  expected / accepted because the GPDB implementation of DECODE() is
  different.

This replaces the sources in the tree verbatim with upstream version
3.13.4. It does not work with GPDB as it is, but I wanted to have the GPDB
changes in separate commit. The next commit will fix it so that it works
again.

The reason to update it now is that we are working with mergign PostgreSQL
v12 into GPDB, and the old 3.7 version we had in the repository will not
work with PostgreSQL v12. This version should work with both PostgreSQL
9.6 where we are at the moment, and with v12.

Commit 4ab87e24f61b9aff26738cdb154673e03cd772a8 replaced too many usages
of "with self.lock as l" with "with self.lock"

This commit corrects the missing "with self.lock as l" problems to
ensure the unit tests pass
Authored-by: NTyler Ramer <tramer@vmware.com>

aggregate_leaf_partition_MCVs() and aggregate_leaf_partition_histograms()
functions did catalog lookups to count how many leaf partitions a root
table has. Why? Because the caller passes two arrays as inputs, with an
entry for each partition, and the functions need to know how large the
input arrays are. That's overly complicated, of course: the caller can
simply pass the size of the arrays as an argument. That's much more robust
too, I think the current code would crash and burn if the partition
hierarchy was modified concurrently. I'm not sure if that's a live bug, or
if we're holding locks that prevent that, but let's keep things simple in
any case.

This removes the last callers of rel_get_leaf_children_relids() function,
so remove that altogether.
Reviewed-by: NAbhijit Subramanya <asubramanya@pivotal.io>
Reviewed-by: NHans Zeller <hzeller@vmware.com>

*Problem:
getDnsCachedAddress() always returns empty string if the hostname only
has IPv6 addresses

*Root cause:
Array hostinfo[] is redeclared in code section for IPv6, so the real
lookup result never returns.

*How to reproduce:
You can reproduce this issue even you don't have pure IPv6 environment
1. Assign a IPv6 address for your default net device
   sudo ip -6 addr add 2401::1234/128 dev ${netdev}
2. Add the address to /etc/hosts with a dummy hostname, for example
   2401::1234/128	ipv6host
3. Create external table using the dummy hostname
   create external table test_ext_ipv6(a int) location('gpfdist://ipv6host:8080/data_file') format 'csv';
4. Launch gpfdist
5. Run test SQL
   select * from test_ext_ipv6
   Then an error will be reported with an empty address in url:
   ERROR:  connection with gpfdist failed for "gpfdist://ipv6host:8080/data_file", effective url: "http://:8080/data_file"
Co-authored-by: NPeifeng Qiu <pqiu@pivotal.io>

[Lockfile](https://pypi.org/project/lockfile/) has not been maintained
since around 2015. Further, the functionality it provided seems poor - a
review of the code indicated that it used the presence of the PID file
itself as the lock - in Unix, using a file's existence followed by a
creation is not atomic, so a lock could be prone to race conditions.

The lockfile package also did not clean up after itself - a process
which was destroyed unexpectedly would not clear the created locks, so
some faulty logic was added to mainUtils.py, which checked to see if a
process with the same PID as the lockfile's creator was running. This
is obviously failure prone, as a new process might be assigned the same
PID as the old lockfile's owner, without actually being the same process.

(Of note, the SIG_DFL argument to os.kill() is not a signal at all, but
rather of type signal.handler. It appears that the python cast this
handler to the int 0, which, according to man 2 kill, leads to no signal
being sent, but existance and permission checks are still performed. So
it is a happy accident that this code worked at all)

This commit removes lockfile from the codebase entirely.

It also adds a "PIDLockFile" class which provides an atomic-guarenteed
lock via the mkdir and rmdir commands on Unix - thus, it is not safely
portable to Windows, but this should not be an issue as only Unix-based
utilities use the "simple_main()" function.

PIDLockFile provides API compatible classes to replace most of the
functionality from lockfile.PidLockFile, but does remove any timeout
logic as it was not used in any meaningful sense - a hard-coded timeout
of 1 second was used, but an immediate result of if the lock is held is
sufficient.

PIDLockFile also includes appropriate __enter__, __exit__, and __del__
attributes, so that, should we extend this class in the future, with
syntax is functional, and __del__ calls release, so a process reaped
unexpectedly should still clean its own locks as part of the garbage
collection process.
Authored-by: NTyler Ramer <tramer@pivotal.io>

If the directory of tablespace does not exist, we should got a
error on commit transaction. But error on commit transaction will
cause a panic. So the directory of tablespace should be checked
so that we can avoid panic.

* Only apply transformGroupedWindows() with ORCA.

The Postgres planner doesn't need it. Move the code to do it, so that it's
only used before passing a tree to ORCA. This doesn't change anything with
ORCA, but with the Postgres planner, it has some benefits:

* Some cases before this patch do not give correct results and now they run
  correctly (e.g. case `regress/olap_window_seq`)
* Fixes github issue #10143.

* Make transformGroupedWindows walk the entire tree

The transformGroupedWindows function now recursively transforms any
Query node in the tree that has both window functions and groupby or
aggregates.

Also fixed a pre-existing bug where we put a subquery in the target
list of such a Query node into the upper query, Q'. This meant that
any outer references to the scope of Q' no longer had the correct
varattno. The fix is to place the subquery into the target list of
the lower query, Q'' instead, which has the same range table as the
original query Q. Therefore, the varattnos to outer references to the
scope of Q (now Q'') don't need to be updated. Note that varlevelsup to
scopes above Q still need to be adjusted, since we inserted a new
scope Q'. (See comments in code for explanations of Q, Q', Q'').
Co-authored-by: NHeikki Linnakangas <hlinnakangas@pivotal.io>
Co-authored-by: NHans Zeller <hzeller@vmware.com>
Co-authored-by: NAbhijit Subramanya <asubramanya@pivotal.io>