Various performance improvements to Row instanciation
- avoid passing processors if they are all None
- improve processor logic in cython
- improve tuplegetter using slices when contiguous indexes are used

Some timing follow.

In particular [base_]row_new_proc that tests using processors has
a 25% improvement compared to before in cython.
Looking at the [b]row_new_proc_none that test a list of processors
all None, this has 50% improvement in cython when passing the none list,
but in this patch it would usually be disabled by passing None, so the
performance gain is actually 90%, since it would run the case
[base_]row_new.

Tuplegetter is a bit faster in the single item get and when getting
sequential indexes (like indexes 1,2,3,4) at the cost of a bit
longer creation time in python, cython is mostly the same.

Current times
                    | python      | cython      | cy / py     |
base_row_new        | 0.639817400 | 0.118265500 | 0.184842582 |
row_new             | 0.680355100 | 0.129714600 | 0.190657202 |
base_row_new_proc   | 3.076538900 | 1.488428600 | 0.483799701 |
row_new_proc        | 3.119700100 | 1.532197500 | 0.491136151 |
brow_new_proc_none  | 1.917702300 | 0.475511500 | 0.247958977 |
row_new_proc_none   | 1.956253300 | 0.497803100 | 0.254467609 |

tuplegetter_one     | 0.152512600 | 0.148523900 | 0.973846751 |
tuplegetter_many    | 0.184394100 | 0.184511500 | 1.000636680 |
tuplegetter_seq     | 0.154832800 | 0.156270100 | 1.009282917 |
tuplegetter_new_one | 0.523730000 | 0.343402200 | 0.655685563 |
tuplegetter_new_many| 0.738924400 | 0.420961400 | 0.569694816 |
tuplegetter_new_seq | 1.062036900 | 0.495462000 | 0.466520514 |

Parent commit times
                    | python      | cython      | cy / py     |
base_row_new        | 0.643890800 | 0.113548300 | 0.176347138 |
row_new             | 0.674885900 | 0.124391800 | 0.184315304 |
base_row_new_proc   | 3.072020400 | 2.017367000 | 0.656690626 |
row_new_proc        | 3.109943400 | 2.048359400 | 0.658648450 |
brow_new_proc_none  | 1.967133700 | 1.006326000 | 0.511569702 |
row_new_proc_none   | 1.960814900 | 1.025217800 | 0.522852922 |

tuplegetter_one     | 0.197359900 | 0.205999000 | 1.043773330 |
tuplegetter_many    | 0.196575900 | 0.194888500 | 0.991416038 |
tuplegetter_seq     | 0.192723900 | 0.205635000 | 1.066992729 |
tuplegetter_new_one | 0.534644500 | 0.414311700 | 0.774929322 |
tuplegetter_new_many| 0.479376500 | 0.417448100 | 0.870814694 |
tuplegetter_new_seq | 0.481580200 | 0.412697900 | 0.856966088 |

Change-Id: I2ca1f49dca2beff625c283f1363c29c8ccc0c3f7

Improved :class:`_engine.Row` implementation to optimize
``__getattr__`` performance.
The serialization of a :class:`_engine.Row` to pickle has changed with
this change. Pickle saved by older SQLAlchemy versions can still be loaded,
but new pickle saved by this version cannot be loaded by older ones.

Fixes: #9678
Closes: #9668
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/9668
Pull-request-sha: 86b8ccd1959dbd91b1208f7a648a91f217e1f866

Change-Id: Ia85c26a59e1a57ba2bf0d65578c6168f82a559f2

A small optimization to the Cython implementation of :class:`.ResultProxy`
using a cdef for a particular int value to avoid Python overhead. Pull
request courtesy Matus Valo.

Fixes: #9343
Closes: #9344
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/9344
Pull-request-sha: fc6a97debe45497ef502f3861611b021a5885b63

Change-Id: I231d4fb292decfe9bccdf54f2851ce6f69d5d6c7

All modules in sqlalchemy.engine are strictly
typed with the exception of cursor, default, and
reflection.  cursor and default pass with non-strict
typing, reflection is waiting on the multi-reflection
refactor.

Behavioral changes:

* create_connect_args() methods return a tuple of list,
  dict, rather than a list of list, dict
* removed allow_chars parameter from
  pyodbc connector ._get_server_version_info()
  method
* the parameter list passed to do_executemany is now
  a list in all cases. previously, this was being run
  through dialect.execute_sequence_format, which
  defaults to tuple and was only intended for individual
  tuple params.
* broke up dialect.dbapi into dialect.import_dbapi
  class method and dialect.dbapi module object.  added
  a deprecation path for legacy dialects.  it's not
  really feasible to type a single attr as a classmethod
  vs. module type.  The "type_compiler" attribute also
  has this problem with greater ability to work around,
  left that one for now.
* lots of constants changing to be Enum, so that we can
  type them.  for fixed tuple-position constants in
  cursor.py / compiler.py (which are used to avoid the
  speed overhead of namedtuple), using Literal[value]
  which seems to work well
* some tightening up in Row regarding __getitem__, which
  we can do since we are on full 2.0 style result use
* altered the set_connection_execution_options and
  set_engine_execution_options event flows so that the
  dictionary of options may be mutated within the event
  hook, where it will then take effect as the actual
  options used.  Previously, changing the dict would
  be silently ignored which seems counter-intuitive
  and not very useful.
* A lot of DefaultDialect/DefaultExecutionContext
  methods and attributes, including underscored ones, move
  to interfaces.  This is not fully ideal as it means
  the Dialect/ExecutionContext interfaces aren't publicly
  subclassable directly, but their current purpose
  is more of documentation for dialect authors who should
  (and certainly are) still be subclassing the DefaultXYZ
  versions in all cases

Overall, Result was the most extremely difficult class
hierarchy to type here as this hierarchy passes through
largely amorphous "row" datatypes throughout, which
can in fact by all kinds of different things, like
raw DBAPI rows, or Row objects, or "scalar"/Any, but
at the same time these types have meaning so I tried still
maintaining some level of semantic markings for these,
it highlights how complex Result is now, as it's trying
to be extremely efficient and inlined while also being
very open-ended and extensible.

Change-Id: I98b75c0c09eab5355fc7a33ba41dd9874274f12a

Re-implement c version immutabledict / processors / resultproxy / utils with cython.
Performance is in general in par or better than the c version
Added a collection module that has cython version of OrderedSet and IdentitySet

Added a new test/perf file to compare the implementations.
Run ``python test/perf/compiled_extensions.py all`` to execute the comparison test.

See results here: https://docs.google.com/document/d/1nOcDGojHRtXEkuy4vNXcW_XOJd9gqKhSeALGG3kYr6A/edit?usp=sharing

Fixes: #7256
Change-Id: I2930ef1894b5048210384728118e586e813f6a76
Signed-off-by: Federico Caselli <cfederico87@gmail.com>