Reader gangs use local snapshot to access catalog, as a result, it will
not synchronize with the sharedSnapshot from write gang which will
lead to inconsistent visibility of catalog table on idle reader gang.
Considering the case:

select * from t, t t1; -- create a reader gang.
begin;
create role r1;
set role r1;  -- set command will also dispatched to idle reader gang

When set role command dispatched to idle reader gang, reader gang
cannot see the new tuple t1 in catalog table pg_auth.
To fix this issue, we should drop the idle reader gangs after each
utility statement which may modify the catalog table.
Reviewed-by: NZhenghua Lyu <zlv@pivotal.io>

General and segmentGeneral locus imply that if the corresponding slice
is executed in many different segments should provide the same result
data set. Thus, in some cases, General and segmentGeneral can be
treated like broadcast.

But what if the segmentGeneral and general locus path contain volatile
functions? volatile functions, by definition, do not guarantee results
of different invokes. So for such cases, they lose the property and
cannot be treated as *general. Previously, Greenplum planner
does not handle these cases correctly. Limit general or segmentgeneral
path also has such issue.

The fix idea of this commit is: when we find the pattern (a general or
segmentGeneral locus paths contain volatile functions), we create a
motion path above it to turn its locus to singleQE and then create a
projection path. Then the core job becomes how we choose the places to
check:

  1. For a single base rel, we should only check its restriction, this is
     the at bottom of planner, this is at the function set_rel_pathlist
  2. When creating a join path, if the join locus is general or segmentGeneral,
     check its joinqual to see if it contains volatile functions
  3. When handling subquery, we will invoke set_subquery_pathlist function,
     at the end of this function, check the targetlist and havingQual
  4. When creating limit path, the check and change algorithm should also be used
  5. Correctly handle make_subplan

OrderBy clause and Group Clause should be included in targetlist and handled
by the above Step 3.

Also this commit fixes DMLs on replicated table. Update & Delete Statement on
a replicated table is special. These statements have to be dispatched to each
segment to execute. So if they contain volatile functions in their targetList
or where clause, we should reject such statements:

  1. For targetList, we check it at the function create_motion_path_for_upddel
  2. For where clause, they will be handled in the query planner and if we
     find the pattern and want to fix it, do another check if we are updating
     or deleting replicated table, if so reject the statement.
  3. Upsert case is handled in transform stage.

Because the variable rel is only used in if (SRF_IS_FIRSTCALL()) branch,
we should move it's declaration into this branch (suggested by Hubert Zhang).

The approach of using a connection string is fragile in the event of an
update to pygresql or missing values, as demonstrated by errors after
update of pygresql in f5758021

Instead, we'll use a named value as arguments to pgdb.connect(),
following the example of dbconn.py
Authored-by: NTyler Ramer <tramer@vmware.com>

Notably we want the shared snapshot dumping information when encountering the
"snapshot collision" error, which was seen on real scenario and it is hard to
debug.

We've seen such a case on a stable release but it is hard to debug via the
message only, so let's provide more details in the error message.

Issue #10069 noted some problems with the linux documentation.

Updating this documentation to be more accurate and direct configuration
steps to the appropriate documentation.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

Previously, `cdbpath_dedup_fixup` is the only function that
will invoke `pathnode_walk_node`. And it was removed by the
commit 9628a332.

So in this commit we remove these unused functions.

Remove the set `gp_fts_probe_retries to 1` which may cause FTS probe failed.
This was first added to reduce the test time, but set a lower retry
value may cause the test failed to probe FTS update segment
configuration. Since reduce the `gp_fts_replication_attempt_count` also
save the test time, so skip alter ``gp_fts_probe_retries`.

Also find an assertion may not match when mark mirror down happens before
walsender exit, which will free the replication status before walsender
exit and try to record disconnect info. Which lead the segment crash
and starts recover.

We used to use the option --with-libuv to enable ic-proxy, it is not
staightforward to understand the purpose of that option, though.  So we
renamed it to --enable-ic-proxy, and the default setting is changed to
"disable".

Suggested by Kris Macoskey <kmacoskey@pivotal.io>

Only in proxy mode, of course.  Currently the ic-proxy mode shares most
of the backend logic with ic-tcp mode, so instead of copying the code we
actually embed the ic-proxy specific logic in ic_tcp.c .

It is for the ic-proxy mode.

The interconnect proxy mode, a.k.a. ic-proxy, is a new interconnect
mode, all the backends communicate via a proxy bgworker, all the
backends on the same segment share the same proxy bgworker, so every two
segments only need one network connection between them, which reduces
the network flows as well the ports.

To enable the proxy mode we need to first configure the guc
gp_interconnect_proxy_addresses, for example:

    gpconfig \
      -c gp_interconnect_proxy_addresses \
      -v "'1:-1:10.0.0.1:2000,2:0:10.0.0.2:2001,3:1:10.0.0.3:2002'" \
      --skipvalidation

Then restart to take effect.

It is a preparation for the ic-proxy mode, we need this information to
distinguish a primary segment with its mirror.

Local fork at gpMgmt/bin/ext/yaml was removed by 8d6c3059. Unpack
it from gpMgmt/bin/pythonSrc/ext just like pygresql.

Pull out the implementation for binary heap into its own templated h
file.

Prior to this commit, merging two histograms was not commutative.
Meaning histogram1->Union(histogram2) could result in a row estimate of
1500 rows, but histogram2->Union(histogram1) could result in a row
estimate of 600 rows.

Now, MakeBucketMerged has been renamed to SplitAndMergeBuckets. This
function, which calculates the statistics for the merged bucket, now
consistently return the same histogram buckets regardless of the order
of input. This in turn, makes MakeUnionHistogramNormalize and
MakeUnionAllHistogramNormalize commutative.

Once we have successfully split the buckets and merged them as
necessary, we may have generated up to 3X the number of buckets that
were originally present. Thus we cap the number of buckets to be either
the max size of the two incoming buckets, or, 100 buckets.

CombineBuckets will then reduce the size of the histogram by combining
consecutive buckets that have similar information. It does this by using
a combination of two ratios: freq/ndv and freq/bucket_width. These two
ratios were decided based off the following examples:

Assuming that we calculate row counts for selections like the following:
- For a predicate col = const: rows * freq / NDVs
- For a predicate col < const: rows * (sum of full or fractional frequencies)

Example 1 (rows = 100), freq/width, ndvs/width and ndvs/freq are all the same:
  ```
  Bucket 1: [0, 4)   freq .2  NDVs 2  width 4  freq/width = .05 ndv/width = .5 freq/ndv = .1
  Bucket 2: [4, 12)  freq .4  NDVs 4  width 8  freq/width = .05 ndv/width = .5 freq/ndv = .1
  Combined: [0, 12)  freq .6  NDVs 6  width 12
  ```

This should give the same estimates for various predicates, with separate or combined buckets:
```
pred          separate buckets         combined bucket   result
-------       ---------------------    ---------------   -----------
col = 3  ==>  100 * .2 / 2           = 100 * .6 / 6    = 10 rows
col = 5  ==>  100 * .4 / 4           = 100 * .6 / 6    = 10 rows
col < 6  ==>  100 * (.2 + .25 * .4)  = 100 * .5 * .6   = 30 rows
```

Example 2 (rows = 100), freq and ndvs are the same, but width is different:
```
Bucket 1: [0, 4)   freq .4  NDVs 4  width 4  freq/width = .1 ndv/width = 1 freq/ndv = .1
Bucket 2: [4, 12)  freq .4  NDVs 4  width 8  freq/width = .05 ndv/width = .5 freq/ndv = .1
Combined: [0, 12)  freq .8  NDVs 8  width 12
```

This will give different estimates with the combined bucket, but only for non-equal preds:
```
pred          separate buckets         combined bucket   results
-------       ---------------------    ---------------   --------------
col = 3  ==>  100 * .4 / 4           = 100 * .8 / 8    = 10 rows
col = 5  ==>  100 * .4 / 4           = 100 * .8 / 8    = 10 rows
col < 6  ==>  100 * (.4 + .25 * .4) != 100 * .5 * .8     50 vs. 40 rows
```

Example 3 (rows = 100), now NDVs / freq is different:
```
Bucket 1: [0, 4)   freq .2  NDVs 4  width 4  freq/width = .05 ndv/width = 1 freq/ndv = .05
Bucket 2: [4, 12)  freq .4  NDVs 4  width 8  freq/width = .05 ndv/width = .5 freq/ndv = .1
Combined: [0, 12)  freq .6  NDVs 8  width 12
```

This will give different estimates with the combined bucket, but only for equal preds:
```
pred          separate buckets         combined bucket   results
-------       ---------------------    ---------------   ---------------
col = 3  ==>  100 * .2 / 4          != 100 * .6 / 8      5 vs. 7.5 rows
col = 5  ==>  100 * .4 / 4          != 100 * .8 / 8      10 vs. 7.5 rows
col < 6  ==>  100 * (.2 + .25 * .4)  = 100 * .5 * .6   = 30 rows
```

This commit also adds an attribute to the statsconfig for MaxStatsBuckets
and changes the scaling method when creating singleton buckets.

MergeHistogramMapsforDisjPreds

This commit refactors MakeStatsFilter to use
MakeHistHashMapConjOrDisjFilter instead of individually calling
MakeHistHashMapConj and MakeHistHashMapDisj.

This commit also modifies MergeHistogramMapsForDisjPreds to avoid copy
and creating unnecessary histogram buckets.

Commit 21a2cb27b38117cce90c4ff06d8d447842c5acf1, added in PR #10361,
updated yaml and changed yaml.load to yaml.safe_load in gpload.

gppkg uses yaml as well, but references were not updated - this commit
resolves that discrepancy.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

Fixes https://github.com/greenplum-db/gpdb/issues/10437

Previously, the PdrgpcrsAddEquivClass function would modify the input
colref set. This does not appear intentional, as this same reference may
be accessed in other places. This caused Orca to fall back to planner in
some cases during translation with "Attribute number 0 not found in
project list".
Co-authored-by: Nmubo.fy <mubo.fy@alibaba-inc.com>
Co-authored-by: NChris Hajas <chajas@pivotal.io>
Co-authored-by: NHans Zeller <hzeller@vmware.com>

The entry in aocsseg table might be compacted and waiting for drop, so we
should use 'state' to filter the unused entry.

- CMakeLists.txt moved to gpMgmt/bin/pythonSrc/PyGreSQL
- Unpack source code from gpMgmt/bin/pythonSrc/ext/PyGreSQL-*.tar.gz
- Add declaration to force dllexport on init_pg
- Remove the pygresql level folder. All files are moved up.

column 'vpinfo' in pg_aoseg.pg_aocsseg_xxx record the 'eof' of each attribute
in the AOCS table. Add a new check 'aoseg_table' in gpcheckcat, it checks the
number of attributes in 'vpinfo' is the same as the number of attributes in
'pg_attribute'. This check is performed in parallel and independently on each
segment, and it checks aoseg table and pg_attribute in different transaction,
so it should be run 'offline' to avoid false alarm.

Travis will consume some of the output if make -s install is used
instead of separate make and make install steps.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

Yaml was imported but unused in several locations.
gpMgmt/test/behave/mgmt_utils/steps/mgmt_utils.py had numerous unused
or duplicated imports.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

It seems this yaml class is dead code. Removing it for this reason.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

The version of PyYAML vendored in gpMgmt/bin/ext is old, unmaintained,
and does not support python3. Actually, it does not even contain a
`__version__` attribute, so it is not possible to know the version.

We need to unvendor YAML and get to a library version that supports
python3 - for this reason, we are updating to the latest PyYAML
available.

Also update yaml.load to use yaml.safe_load instead.
Co-authored-by: NTyler Ramer <tramer@vmware.com>
Co-authored-by: NJamie McAtamney <jmcatamney@vmware.com>

* docs - gphdfs2pxf migration pxf supports avro compression

* missing plural

When alter table add a column to AOCS table, the storage setting (compresstype,
compresslevel and blocksize) of the new column can be specified in the ENCODING
clause; it inherits the setting from the table if ENCODING is not specified; it
will use the value from GUC 'gp_default_storage_options' when the table dosen't
have the compression configuration.

When there is a big lag between primary and mirror replay, gp_replica_check
will fail if the checkpoint is not replayed in about 60 seconds. Extend the
timeout to 600 seconds to reduce the chance of flaky.

Currently, replicated tables are not allowed to inherit a parent
table. But ALTER TABLE .. INHERIT can pass around the restriction.

On the other hand, a replicated table is allowed to be inherited
by a hash distributed table. It makes things much complicated.
When the parent table is declared as a replicated table inherited by
a hash distributed table, its data on the parent is replicated
but the data on the child is hash distributed. When running
`select * from parent;`, the generated plan is:
```
gpadmin=# explain select * from parent;
                                 QUERY PLAN
-----------------------------------------------------------------------------
 Gather Motion 3:1  (slice1; segments: 3)  (cost=0.00..4.42 rows=14 width=6)
   ->  Append  (cost=0.00..4.14 rows=5 width=6)
         ->  Result  (cost=0.00..1.20 rows=4 width=7)
               One-Time Filter: (gp_execution_segment() = 1)
               ->  Seq Scan on parent  (cost=0.00..1.10 rows=4 width=7)
         ->  Seq Scan on child  (cost=0.00..3.04 rows=2 width=4)
 Optimizer: Postgres query optimizer
(7 rows)
```
It's not particularly useful for the parent table to be replicated.
So, we disallow the replicated table to be inherited.
Reported-by: NHeikki Linnakangas <hlinnakangas@pivotal.io>
Reviewed-by: NHubert Zhang <hzhang@pivotal.io>

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.