The canonical config file is in src/backend/gpopt/.clang-format (instead
of under the non-existent src/backend/gporca), I've created one (instead
of two) symlink, for GPOPT headers. Care has been taken to repoint the
symlink to the canonical config under gpopt, instead of gpopt as it is
under HEAD.

This is spiritually a cherry-pick of commit 2f7dd76c.
(cherry picked from commit 2f7dd76c)

Add a stage called "check-format" that runs before the fan-out of
installcheck-small. While we're at it, also enforce that the full config
file is generated from the intent file. This should be fairly quick. On
my laptop, the `fmt chk` step takes 3 seconds. (On this backbranch, it
actually takes 1 second on my laptop).

Care has been taken to add back the matrix syntax in Travis CI config so
it's still valid. Also subtle is the explicit mention of the "test"
stage in the matrix so as not to lose it in the expansion, as this
backbranch effectively doesn't have a build matrix (every "matrix key"
has at most one value).

Enforcement in Concourse is forthcoming.

(cherry picked from commit 54273fdd)

This is intended for both local developer use and for CI.

This depends on GNU parallel. One-time install:

macOS: brew install parallel clang-format
Debian: apt install parallel clang-format-10

To format all ORCA / GPOPT code:

$ src/tools/fmt fmt

To check for formatting conformance:

$ src/tools/fmt chk

To modify the configuration, you'll need two steps:
1. Edit clang-format.intent.yml
2. Generate the expanded configuration file:

$ src/tools/fmt gen

This commit also adds a formatting README, To document some of the
rationale behind tooling choice. Also mention the new `README.format.md`
from both the style guide and ORCA's main README.

(cherry picked from commit 57b744c1)

Generated using clang-format-10

This is spiritually a cherry-pick of commit 16b48d24, but I have
to tweak things a bit by moving the .clang-format file from
src/backend/gporca to under src/backend/gpopt

(cherry picked from commit 16b48d24)

In a previous ORCA version (3.311) we added code to fall back gracefully
when a subquery select list contains a single outer ref that is not part
of an expression, such as in

select * from foo where a is null or a = (select foo.b from bar)

This commit adds a fix that allows us to handle such queries in ORCA
by adding a project in the translator that will echo the outer ref
from within the subquery, and using that projected value in the
select list of the subquery. This ensures that we use a NULL value for
the scalar subquery in the expression for the outer ref when the
subquery returns no rows.

Also note that this is still skipped for grouping cols in the target
list. This was done to avoid regression for certain queries, such as:

select *
from A
where not exists (select sum(C.i)
                  from C
                  where C.i = A.i
                  group by a.i);

ORCA is currently unable to decorrelate sub-queries that contain project
nodes, So, a `SELECT 1` in the subquery would also cause this
regression. In the above query, the parser adds `a.i` to the target list
of the subquery, that would get an echo projection (as described above),
and thus would prevent decorelation by ORCA. For this reason, we decided
to maintain existing behavior until ORCA is able to handle projections
in subqueries better.

Also add ICG tests.
Co-authored-by: NHans Zeller <hzeller@pivotal.io>
Co-authored-by: NShreedhar Hardikar <shardikar@pivotal.io>

The corresponding ORCA PR is https://github.com/greenplum-db/gporca/pull/605

We had several issues on 5x and 6x that shows the resource group wait queue is
somehow corrupted, this commit add some checks and PANIC at the earliest to
help debugging.

Co-authored-by: NXin Zhang <zhxin@vmware.com>
Co-authored-by: NBrent Doli <bdoil@vmware.com>

We hit interconnect hung issue many times in many cases, all have
the same pattern: the downstream interconnect motion senders keep
sending the tuples and they are blind to the fact that upstream
nodes have finished and quitted the execution earlier, the QD
then get enough tuples and wait all QEs to quit which cause a
deadlock.

Many nodes may quit execution earlier, eg, LIMIT, HashJoin, Nest
Loop, to resolve the hung issue, they need to stop the interconnect
stream explicitly by calling ExecSquelchNode(), however, we cannot
do that for rescan cases in which data might lose, eg, commit
2c011ce4. For rescan cases, we tried using QueryFinishPending to
stop the senders in commit 02213a73 and let senders check this
flag and quit, that commit has its own problem, firstly, QueryFini
shPending can only set by QD, it doesn't work for INSERT or UPDATE
cases, secondly, that commit only let the senders detect the flag
and quit the loop in a rude way (without sending the EOS to its
receiver), the receiver may still be stuck inreceiving tuples.

This commit revert the QueryFinishPending method firstly.

To resolve the hung issue, we move TeardownInterconnect to the
ahead of cdbdisp_checkDispatchResult so it guarantees to stop
the interconnect stream before waiting and checking the status
of QEs.

For UDPIFC, TeardownInterconnect() remove the ic entries, any
packets for this interconnect context will be treated as 'past'
packets and be acked with STOP flag.

For TCP, TeardownInterconnect() close all connection with its
children, the children will treat any readable data in the
connection as a STOP message include the closure operation.

this commit backport from master ec1d9a70

Commit 889ba39e fixed the query string truncation in dispatcher to
make it locale-aware.  This patch refactors that change so as to avoid
accessing a string beyond its length.

Reviewed by: Heikki, Ning Yu and Polina Bungina

(cherry picked from commit abf6b330)

Execution of a long enough query containing multi-byte characters can cause incorrect truncation of the query string. Incorrect truncation implies an occasional cut of a multi-byte character and (with log_min_duration_statement set to 0 ) subsequent write of an invalid symbol to segment logs. Such broken character present in logs produces problems when trying to fetch logs info from gp_toolkit.__gp_log_segment_ext  table - queries fail with the following error: «ERROR: invalid byte sequence for encoding…».
This is caused by buildGpQueryString function in `cdbdisp_query.c`, which prepares query text for dispatch to QE. It does not take into account character length when truncation is necessary (text is longer than QUERY_STRING_TRUNCATE_SIZE).

(cherry picked from commit f31600e9)

When client_encoding is dispatch to QE, error messages generated in QEs were
converted to client_encoding, but QD assumed that they were in server encoding,
it will leads to corruption.

This is fixed in 6X in a6c9b4, but this skips the gpcopy changes since 5X
doesn't support syntax 'COPY...ENCODING'.

Fix issue: https://github.com/greenplum-db/gpdb/issues/10815

Function `RelationGetIndexList()` does not filter out invalid indexes.
That responsiblity is left to the caller (e.g. `get_relation_info()`).
Issue is that Orca was not checking index validity.

This commit also introduces an optimization to Orca that is already used
in Planner whereby we first check relhasindex before checking pg_index.

(cherry picked from commit b011c351)

This bug was found in a production environment where vacuum on
gp_persistent_relation was concurrently running with a backend
performing end-of-xact filesystem operations.  And the GUC
debug_persistent_print was enabled.

The *_ReadTuple() function was called on a persistent TID after the
corresponding tuple was deleted with frozen transaction ID.  The
concurrent vacuum recycled the tuple and it led to a SIGSEGV when the
backend tried to access values from the tuple.

Fix it by avoiding the debug log message in case when the persistent
tuple is freed (transitioning to FREE state).  All other state
transitions are logged.

In absence of concurrent vacuum, things worked just fine because the
*_ReadTuple() interface reads tuples from persistent tables directly
using TID.

GPDB does not support FK, but keep FK grammar in DDL, since it
reduce DB migration manual workload from others.
Hence, we do not need FK check for truncate command, rid of it.

Using exit() requires stdlib.h, which is not included.  Use return
instead.  Also add return type for main().
Reviewed-by: NHeikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: NThomas Munro <thomas.munro@enterprisedb.com>
(cherry picked from commit 1c0cf52b)
(cherry picked from commit 6d3c99bb)

This file will be used to record commits to be ignored by default by
git-blame (user still has to opt in). This is intended to include
large (generally automated) reformatting or renaming commits.

(cherry picked from commit b19e6abb)

When the standby is unreachable and the user proceeds with startup,
gpstart fails to start when temporary or transaction files have been
moved to a non-default filespace.

To determine when the standby is unreachable fetch_tli was reworked to
raise a StandbyUnreachable exception. And the standby is not started if
it is unreachable.
Co-authored-by: NBhuvnesh Chaudhary <bchaudhary@vmware.com>

Add a failing behave test to ensure that gpstart prompts and continues
successfully if the standby host is unreachable. The subsequent commit
will fix the test case.
Co-authored-by: NKalen Krempely <kkrempely@vmware.com>

This approach special cases gp_segment_id enough to include the column
as a distributed column constraint. It also updates direct dispatch info
to be aware of gp_segment_id which represents the raw value of the
segment where the data resides. This is different than other columns
which hash the datum value to decide where the data resides.

After this change the following DDL shows Gather Motion from 2 segments
on a 3 segment demo cluster.

```
CREATE TABLE t(a int, b int) DISTRIBUTED BY (a);
EXPLAIN SELECT gp_segment_id, * FROM t WHERE gp_segment_id=1 or gp_segment_id=2;
                                  QUERY PLAN
-------------------------------------------------------------------------------
 Gather Motion 2:1  (slice1; segments: 2)  (cost=0.00..431.00 rows=1 width=12)
   ->  Seq Scan on t  (cost=0.00..431.00 rows=1 width=12)
         Filter: ((gp_segment_id = 1) OR (gp_segment_id = 2))
 Optimizer: Pivotal Optimizer (GPORCA)
(4 rows)

```

(cherry picked from commit 10e2b2d9)

* Bump ORCA version to 3.110.0

This reverts commit 5bab25f7.

The following test_movetransfiles.py tinc tests are failing from the
cs_walrep_1 job:
test_standby_is_configured
test_transfiles_are_moved
test_tempfiles_are_moved

gpfilespace --showtransfilespace and --showtempfilespace return with a
non-zero exit code.

This reverts commit 05071344.

When the standby is unreachable and the user proceeds with startup,
gpstart fails to start when temporary or transaction files have been
moved to a non-default filespace.

To determine when the standby is unreachable fetch_tli was reworked to
raise a StandbyUnreachable exception. And the standby is not started if
it is unreachable.
Co-authored-by: NBhuvnesh Chaudhary <bchaudhary@vmware.com>

Add a failing behave test to ensure that gpstart prompts and continues
successfully if the standby host is unreachable. The subsequent commit
will fix the test case.
Co-authored-by: NKalen Krempely <kkrempely@vmware.com>

commit 4f5a2c23 breaks the unittest cdbtm_test

* Add test cases for correlated subqueries with outer joins

We found several problems with outer references in outer joins and
related areas, especially when using optimizer_join_order = exhaustive2.

Adding some tests. Please note that due to some remaining problems in
both ORCA and planner, the tests contain some FIXMEs.

* Bump ORCA version to 3.109.0

Resource group used to access resGroupSlot in SessionState without
lock. This is correct when session only access resGroupSlot by itself.
But as we introduced runaway feature, we need to traverse the current
session array to find the top consumer session when redzone is reached.
This requires:
1. runaway detector should hold shared resgroup lock to avoid resGroupSlot
is detached from a session concurrently when redzone is reached.
2. normal session should hold exclusive lock when modifying resGroupSlot
in SessionState.
Reviewed-by: NNing Yu <nyu@pivotal.io>

(cherry picked from commit a4cb06b4)

When calculating safeChunksThreshold of runaway in resource group,
we used to divide by 100 to get the number of safe chunks. This may
lead to small chunk numbers to be rounded to zero. Fix it by storing
safeChunksThreshold100(100 times bigger than the real safe chunk) and
do the computation on the fly.
Reviewed-by: NNing Yu <nyu@pivotal.io>
(cherry picked from commit 757184f9)

This variable was used mixing with atomic api functions and direct access.
This is not wrong usually in real scenario but is not a good implementation
since 1) that depends on compiler and H/W to ensure the correctness of direct
access. 2) code is not graceful.

Changing to all use atomic api functions.
Reviewed-by: NGeorgios Kokolatos <gkokolatos@pivotal.io>
(cherry picked from commit f59307f5)

Earlier, we always deducted FREEABLE_BATCHFILE_METADATA inside
closeSpillFile() regardless of whether the spill file was already
suspended. This deduction, is already performed inside
suspendSpillFiles(). This double accounting leads to
hashtable->mem_for_metadata becoming negative and we get:

FailedAssertion("!(hashtable->mem_for_metadata > 0)", File: "execHHashagg.c", Line: 2019)
Co-authored-by: NSoumyadeep Chakraborty <sochakraborty@pivotal.io>

This commit fixes the following assertion failure message reported in:
(#9902) https://github.com/greenplum-db/gpdb/issues/9902

FailedAssertion("!(hashtable->nbuckets > spill_set->num_spill_files)", File: "execHHashagg.c", Line: 1355)

hashtable->nbuckets can actually end up being equal to
spill_set->num_spill_files, which causes the failure. This is because:

hashtable->nbuckets is set with HashAggTableSizes->nbuckets, which can
end up being equal to: gp_hashagg_default_nbatches. Refer:
nbuckets = Max(nbuckets, gp_hashagg_default_nbatches);

Also, spill_set->num_spill_files is set with
HashAggTableSizes->nbatches, which is further set to
gp_hashagg_default_nbatches.

Thus, these two entities can be equal.
Co-authored-by: NSoumyadeep Chakraborty <sochakraborty@pivotal.io>
(cherry picked from commit 067bb350)

Raise a meaningful error message for this case.
GPDB doesn't support alter type on primary key and unique
constraint column. Because it requires to drop - recreate logic.
The drop currently only performs on master which lead error when
recreating index (since recreate index will dispatch to segments and
there still an old constraint index exists).

This fixes the issue https://github.com/greenplum-db/gpdb/issues/10561.
Reviewed-by: NHubert Zhang <hzhang@pivotal.io>
(cherry picked from commit 32446a32)

Previous commit ab74e1c6, c7befb1d did not completely solve its race
condition, it did not test for last iteration of the while/for loop.
This could result in failed assertion in the following loop. The patch
moves the judgement to the ending of the for loop, it is safe, because
the first iteration will never trigger: Assert(activeWeight > 0.0).

Also, the other one race condition can trigger this assertion
Assert(gl->numFollowersActive > 0). Consider this situation:

    Backend A, B belong to the same statement.

    Timestamp1: backend A's leader is A, backend B's leader is B.

    Timestamp2: backend A's numFollowersActive remains zero due to timeout.

    Timestamp3: Sweeper calculates leader B's numFollowersActive to 1.

    Timestamp4: backend B changes it's leader to A even if A is inactive.

We stop sweeping for this race condition just like commit ab74e1c6 did.

Both Assert(activeWeight > 0.0) and Assert(gl->numFollowersActive > 0)
are removed.

(cherry picked from commit b1c19196)

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.

(cherry picked from commit ab74e1c6)

shmNumGxacts and shmGxactArray are accessed under the protection of
shmControlLock, this commit add some defensive code and PANIC at the earliest
when the shared memory is corrupted.

* Fix dblink's libpq issue

When using dblink to connect to a postgres database, it reports the
following error:
unsupported frontend protocol 28675.0: server supports 2.0 to 3.0

Even if dblink.so is dynamic linked to libpq.so which is compiled
with the option -DFRONTEND, but when it's loaded in gpdb and run,
it will use the backend libpq which is compiled together with
postgres program and reports the error. So we define FRONTEND
before defining libpq-fe.h.

* dblink can't be built on Mac

Commit 445fc7cc hardened some parts of analyzedb. However, it missed a
couple of cases.

1) When the statement to get the modcount from the pg_aoseg table failed
due to a dropped table, the transaction was also terminated. This caused
further modcount queries to fail and while those tables were analyzed,
it would error and not properly record the mod count. Therefore, we now
restart the transaction when it errors.

2) If the table is dropped and then recreated while analyzedb is running
(or some other mechanism that results in the table being successfully
analyzed, but the pg_aoseg table did not exist during the initial
check), the logic to update the modcount may fail. Now, we skip the
update for the table if this occurs. In this case, the modcount would
not be recorded and the next analyzedb run will consider the table
modified (or dirty) and re-analyze it, which is the desired behavior.

Note: This isn't as hardened as gpdb master/6X due to improvements in
newer versions of pygresql, so there does exist a window where dropped
tables still cause analyzedb to fail.