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)

As part of moving away from Hungarian notation in the GPORCA codebase,
the integration points between GPORCA and GPDB in the translator have
been renamed to the new convention used in GPORCA. The libraries
currently updated to the new notation in GPORCA are Naucrates and GPOS.
The new naming convention is a custom version of common C++ naming
conventions. The style guide for this convention can be found in the
GPORCA repository.

Also bump ORCA version to 2.69.0
Co-authored-by: NShreedhar Hardikar <shardikar@pivotal.io>
Co-authored-by: NMelanie Plageman <mplageman@pivotal.io>
Co-authored-by: NEkta Khanna <ekhanna@pivotal.io>
Co-authored-by: NAbhijit Subramanya <asubramanya@pivotal.io>
Co-authored-by: NSambitesh Dash <sdash@pivotal.io&gt;&lt;Paste>
Co-authored-by: NDhanashree Kashid <dkashid@pivotal.io>
Co-authored-by: NOmer Arap <oarap@pivotal.io>

After 8.3 merge, gpdb has new polymorphic types, ANYENUM and ANYNONARRAY.

This fix adds support for ANYENUM and ANYNONARRAY in Translator.

As per postgreSQL, when a function has polymorphic arguments and results;
in the function call they must have the same actual type.
For example, a function declared as `f(ANYARRAY) returns ANYENUM`
will only accept arrays of enum types.

We already have this resolution logic implemented in
`resolve_polymorphic_argtypes()`.

Refactor the code in `PdrgpmdidResolvePolymorphicTypes()` to use
`resolve_polymorphic_argtypes()` to deduce the correct data type for
function argument and return type, based on function call.
Signed-off-by: NBhuvnesh Chaudhary <bchaudhary@pivotal.io>
Signed-off-by: NOmer Arap <oarap@pivotal.io>

syscache.h was previously included from parse_oper.h, but I removed that
in commit 8d77fb99. Turns out that gpdbwrappers.c was relying on that
indirect include.

* Add 'const' to arguments of some functions. While we're at it, remove the
duplicate extern declaration of FaultInjector_InjectFaultIfSet from
gpdbdefs.h.

* pstrdup() constants passed to makeString(). I think the lack of copy
was harmless, but makeString() explicitly says that the caller should make
a copy, and all other callers seem to obey that, so better safe than sorry.

ORCA uses its own metadata cache to store information about relations,
operators etc. Currently, we always reset the cache when planning a query,
unless the optimizer_release_mdcache GUC is turned off, which is slow.

To make it safe to turn optimizer_release_mdcache off, use the catalog
cache invalidation mechanism to still reset the cache when there are
changes to the catalogs that affect the metadata cache.

The ORCA-facing interface of this is the same as in the previous attempt:
A function that returns true/false indicating whether there has been any
catalog changes whatsoever since last call.

This reverts commit 6c31a3b4. Per
discussion, we will implement the same functionality in a simpler way.

Added a generation-based Metadata Versioning mechanism
which will be used by ORCA to cache and invalidate catalog
data in its Metadata Cache.
Versioning is disabled by default at this point, until the
Metadata Cache eviction policy is completed.