A variety of caching issues found by running
all tests with statement caching turned on.
The cache system now has a more conservative approach where
any subclass of a SQL element will by default invalidate
the cache key unless it adds the flag inherit_cache=True
at the class level, or if it implements its own caching.
Add working caching to a few elements that were
omitted previously; fix some caching implementations
to suit lesser used edge cases such as json casts
and array slices.
Refine the way BaseCursorResult and CursorMetaData
interact with caching; to suit cases like Alembic
modifying table structures, don't cache the
cursor metadata if it were created against a
cursor.description using non-positional matching,
e.g. "select *". if a table re-ordered its columns
or added/removed, now that data is obsolete.
Additionally we have to adapt the cursor metadata
_keymap regardless of if we just processed
cursor.description, because if we ran against
a cached SQLCompiler we won't have the right
columns in _keymap.
Other refinements to how and when we do this
adaption as some weird cases
were exposed in the Postgresql dialect,
a text() construct that names just one column that
is not actually in the statement. Fixed that
also as it looks like a cut-and-paste artifact
that doesn't actually affect anything.
Various issues with re-use of compiled result maps
and cursor metadata in conjunction with tables being
changed, such as change in order of columns.
mappers can be cleared but the class remains, meaning
a mapper has to use itself as the cache key not the class.
lots of bound parameter / literal issues, due to Alembic
creating a straight subclass of bindparam that renders
inline directly. While we can update Alembic to not
do this, we have to assume other people might be doing
this, so bindparam() implements the inherit_cache=True
logic as well that was a bit involved.
turn on cache stats in logging.
Includes a fix to subqueryloader which moves all setup to
the create_row_processor() phase and elminates any storage
within the compiled context. This includes some changes
to create_row_processor() signature and a revising of the
technique used to determine if the loader can participate
in polymorphic queries, which is also applied to
selectinloading.
DML update.values() and ordered_values() now coerces the
keys as we have tests that pass an arbitrary class here
which only includes __clause_element__(), so the
key can't be cached unless it is coerced. this in turn
changed how composite attributes support bulk update
to use the standard approach of ClauseElement with
annotations that are parsed in the ORM context.
memory profiling successfully caught that the Session
from Query was getting passed into _statement_20()
so that was a big win for that test suite.
Apparently Compiler had .execute() and .scalar() methods
stuck on it, these date back to version 0.4 and there
was a single test in the PostgreSQL dialect tests
that exercised it for no apparent reason. Removed
these methods as well as the concept of a Compiler
holding onto a "bind".
Fixes: #5386
Change-Id: I990b43aab96b42665af1b2187ad6020bee778784
This reorganizes the BulkUD model in sqlalchemy.orm.persistence
to be based on the CompileState concept and to allow plain
update() / delete() to be passed to session.execute() where
the ORM synchronize session logic will take place.
Also gets "synchronize_session='fetch'" working with horizontal
sharding.
Adding a few more result.scalar_one() types of methods
as scalar_one() seems like what is normally desired.
Fixes: #5160
Change-Id: I8001ebdad089da34119eb459709731ba6c0ba975
The :paramref:`.Enum.create_constraint` and
:paramref:`.Boolean.create_constraint` parameters now default to False,
indicating when a so-called "non-native" version of these two datatypes is
created, a CHECK constraint will not be generated by default. These CHECK
constraints present schema-management maintenance complexities that should
be opted in to, rather than being turned on by default.
Fixes: #5367
Change-Id: I0a3fb608ce32143fa757546cc17ba2013e93272a
Ensure IN emits a warning when it coerces a FromClause
into a select(), however that it continues to allow the
scalar_subquery() coercion to be automatic, particularly
since it's not clear that "col IN (select)" is necessarily
"scalar" in the case of tuples.
Convert the "scalar_subquery()" warning emitted in other
cases to be a warning, rather than a deprecation warning.
I can't imagine taking this coercion out as it is intuitive
and is always going to happen; we just would like to note that
an implicit coercion is occurring.
Fixes: #5369
Change-Id: I748f01f40bc85c64e2776f9b88ef35641fa8fb5c
This patch contains a variety of ORM and expression layer
tweaks to support ORM constructs in select() statements,
without the 1.3.x requiremnt in Query that a full
_compile_context() + new select() is needed in order to
get a working statement object.
Includes such tweaks as the ability to implement
aliased class of an aliased class,
as we are looking to fully support ACs against subqueries,
as well as the ability to access anonymously-labeled
ColumnProperty expressions within subqueries by
naming the ".key" of the label after the property
key. Some tuning to query.join() as well
as ORMJoin internals to allow things to work more
smoothly.
Change-Id: Id810f485c5f7ed971529489b84694e02a3356d6d
Added support for "CREATE SEQUENCE" and full :class:`.Sequence` support for
Microsoft SQL Server. This removes the deprecated feature of using
:class:`.Sequence` objects to manipulate IDENTITY characteristics which
should now be performed using ``mssql_identity_start`` and
``mssql_identity_increment`` as documented at :ref:`mssql_identity`. The
change includes a new parameter :paramref:`.Sequence.data_type` to
accommodate SQL Server's choice of datatype, which for that backend
includes INTEGER and BIGINT. The default starting value for SQL Server's
version of :class:`.Sequence` has been set at 1; this default is now
emitted within the CREATE SEQUENCE DDL for all backends.
Fixes: #4235Fixes: #4633
Change-Id: I6aa55c441e8146c2f002e2e201a7f645e667b916
This commit includes that we've removed the "_orm_query"
attribute from compile state as well as query context.
The attribute created reference cycles and also added
method call overhead. As part of this change,
the interface for ORMExecuteState changes a bit, as well
as the interface for the horizontal sharding extension
which now deprecates the "query_chooser" callable
in favor of "execute_chooser", which receives the contextual
object. This will also work more nicely when we implement
the new execution path for bulk updates and deletes.
Pre-merge execution options for statement, connection,
arguments all up front in Connection. that way they
can be passed to the before_execute / after_execute events,
and the ExecutionContext doesn't have to merge as second
time. Core execute is pretty close to 1.3 now.
baked wasn't using the new one()/first()/one_or_none() methods,
fixed that.
Convert non-buffered cursor strategy to be a stateless
singleton. inline all the paths by which the strategy
gets chosen, oracle and SQL Server dialects make use of the
already-invoked post_exec() hook to establish the alternate
strategies, and this is actually much nicer than it was before.
Add caching to mapper instance processor for getters.
Identified a reference cycle per query that was showing
up as a lot of gc cleanup, fixed that.
After all that, performance not budging much. Even
test_baked_query now runs with significantly fewer function
calls than 1.3, still 40% slower.
Basically something about the new patterns just makes
this slower and while I've walked a whole bunch of them
back, it hardly makes a dent. that said, the performance
issues are relatively small, in the 20-40% time increase
range, and the new caching feature
does provide for regular ORM and Core queries that
are cached, and they are faster than non-cached.
Change-Id: I7b0b0d8ca550c05f79e82f75cd8eff0bbfade053
Added :meth:`.Select.with_hint` output to the generic SQL string that is
produced when calling ``str()`` on a statement. Previously, this clause
would be omitted under the assumption that it was dialect specific.
The hint text is presented within brackets to indicate the rendering
of such hints varies among backends.
Fixes: #5353
References: #4667
Change-Id: I01d97d6baa993e495519036ec7ecd5ae62856c16
This patch replaces the ORM execution flow with a
single pathway through Session.execute() for all queries,
including Core and ORM.
Currently included is full support for ORM Query,
Query.from_statement(), select(), as well as the
baked query and horizontal shard systems. Initial
changes have also been made to the dogpile caching
example, which like baked query makes use of a
new ORM-specific execution hook that replaces the
use of both QueryEvents.before_compile() as well
as Query._execute_and_instances() as the central
ORM interception hooks.
select() and Query() constructs alike can be passed to
Session.execute() where they will return ORM
results in a Results object. This API is currently
used internally by Query. Full support for
Session.execute()->results to behave in a fully
2.0 fashion will be in later changesets.
bulk update/delete with ORM support will also
be delivered via the update() and delete()
constructs, however these have not yet been adapted
to the new system and may follow in a subsequent
update.
Performance is also beginning to lag as of this
commit and some previous ones. It is hoped that
a few central functions such as the coercions
functions can be rewritten in C to re-gain
performance. Additionally, query caching
is now available and some subsequent patches
will attempt to cache more of the per-execution
work from the ORM layer, e.g. column getters
and adapters.
This patch also contains initial "turn on" of the
caching system enginewide via the query_cache_size
parameter to create_engine(). Still defaulting at
zero for "no caching". The caching system still
needs adjustments in order to gain adequate performance.
Change-Id: I047a7ebb26aa85dc01f6789fac2bff561dcd555d
Convert Query to do virtually all compile state computation
in the _compile_context() phase, and organize it all
such that a plain select() construct may also be used as the
source of information in order to generate ORM query state.
This makes it such that Query is not needed except for
its additional methods like from_self() which are all to
be deprecated.
The construction of ORM state will occur beyond the
caching boundary when the new execution model is integrated.
future select() gains a working join() and filter_by() method.
as we continue to rebase and merge each commit in the steps,
callcounts continue to bump around. will have to look at
the final result when it's all in.
References: #5159
References: #4705
References: #4639
References: #4871
References: #5010
Change-Id: I19e05b3424b07114cce6c439b05198ac47f7ac10
Start trying to convert fundamental objects to
C as we now rely on a fairly small core of things,
and 1.4 is having problems with complexity added being
slower than the performance gains we are trying to build in.
immutabledict here does seem to bench as twice as fast as the
Python one, see below. However, it does not appear to be
used prominently enough to make any dent in the performance
tests.
at the very least it may provide us some more lift-and-copy
code for more C extensions.
import timeit
from sqlalchemy.util._collections import not_immutabledict, immutabledict
def run(dict_cls):
for i in range(1000000):
d1 = dict_cls({"x": 5, "y": 4})
d2 = d1.union({"x": 17, "new key": "some other value"}, None)
assert list(d2) == ["x", "y", "new key"]
print(
timeit.timeit(
"run(d)", "from __main__ import run, not_immutabledict as d", number=1
)
)
print(
timeit.timeit(
"run(d)", "from __main__ import run, immutabledict as d", number=1
)
)
output:
python: 1.8799766399897635
C code: 0.8880784640205093
Change-Id: I29e7104dc21dcc7cdf895bf274003af2e219bf6d
The type coerce element did not correctly apply grouping rules when using
in an expression
Fixes: #5344
Change-Id: Id67b0e60ac54f8992f931aaed62731672f60c96c
A few small mistakes led to huge callcounts. Additionally,
the warn-on-get behavior which is attempting to warn for
deprecated access in SQLAlchemy 2.0 is very expensive; it's not clear
if its feasible to have this warning or to somehow alter how it
works.
Fixes: #5340
Change-Id: I73bdd2d7b6f1b25cc0222accabd585cf761a5af4
Disabled the "unicode returns" check that runs on dialect startup when
running under Python 3, which for many years has occurred in order to test
the current DBAPI's behavior for whether or not it returns Python Unicode
or Py2K strings for the VARCHAR and NVARCHAR datatypes. The check still
occurs by default under Python 2, however the mechanism to test the
behavior will be removed in SQLAlchemy 2.0 when Python 2 support is also
removed.
This logic was very effective when it was needed, however now that Python 3
is standard, all DBAPIs are expected to return Python 3 strings for
character datatypes. In the unlikely case that a third party DBAPI does
not support this, the conversion logic within :class:`.String` is still
available and the third party dialect may specify this in its upfront
dialect flags by setting the dialect level flag ``returns_unicode_strings``
to one of :attr:`.String.RETURNS_CONDITIONAL` or
:attr:`.String.RETURNS_BYTES`, both of which will enable Unicode conversion
even under Python 3.
As part of this change, disabling testing of the doctest tutorials under
Python 2.
Fixes: #5315
Change-Id: I1260e894611409d3b7fe1a92bd90c52043bbcf19
This method might be used more significantly in the
ORM refactor, so further refine it.
* all get_children() methods now work entirely based on iterators.
Basically only select() was sensitive to this anymore and it now
chains the iterators together
* remove all kinds of flags like column_collections, schema_visitor
that apparently aren't used anymore.
* remove the "depthfirst" visitors as these don't seem to be
used either.
* make sure select() yields its columns first as these will be used
to determine the current mapper.
Change-Id: I05273a2d5306a57c2d1b0979050748cf3ac964bf
Added a "schema" parameter to the :func:`_expression.table` construct,
allowing ad-hoc table expressions to also include a schema name.
Pull request courtesy Dylan Modesitt.
Fixes: #5309Closes: #5310
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5310
Pull-request-sha: ce85681050
Change-Id: I32015d593e1ee1121c7426fbffdcc565d025fad1
A warning is emitted when making use of the :attr:`.MetaData.sorted_tables`
attribute as well as the :func:`_schema.sort_tables` function, and the
given tables cannot be correctly sorted due to a cyclic dependency between
foreign key constraints. In this case, the functions will no longer sort
the involved tables by foreign key, and a warning will be emitted. Other
tables that are not part of the cycle will still be returned in dependency
order. Previously, the sorted_table routines would return a collection that
would unconditionally omit all foreign keys when a cycle was detected, and
no warning was emitted.
Fixes: #5316
Change-Id: I14f72ccf39cb568bc77e8da16d0685718b2b9960
This is based off of
I8091919d45421e3f53029b8660427f844fee0228 and includes
all documentation-only changes as a separate merge,
once the parent is merged.
Change-Id: I711adea23df0f9f0b1fe7c76210bd2de6d31842d
Fixed issue where an :class:`.Index` that is deferred in being associated
with a table, such as as when it contains a :class:`.Column` that is not
associated with any :class:`.Table` yet, would fail to attach correctly if
it also contained a non table-oriented expession.
Fixes: #5298
Change-Id: I0111c400f6bd4a9f31bf00a9957816c7a3fac783
As progress is made on the _future.Result, including breaking
it out such that DBAPI behaviors are local to specific
implementations, it becomes apparent that the Result object
is a functional superset of ResultProxy and that basic
operations like fetchone(), fetchall(), and fetchmany()
behave pretty much exactly the same way on the new object.
Reorganize things so that ResultProxy is now referred to
as LegacyCursorResult, which subclasses CursorResult
that represents the DBAPI-cursor version of Result,
making use of a multiple inheritance pattern so that
the functionality of Result is also available in non-DBAPI
contexts, as will be necessary for some ORM
patterns.
Additionally propose the composition system for Result
that will form the basis for ORM-alternative result
systems such as horizontal sharding and dogpile cache.
As ORM results will soon be coming directly from
instances of Result, these extensions will instead
build their own ResultFetchStrategies that perform
the special steps to create composed or cached
result sets.
Also considering at the moment not emitting deprecation
warnings for fetchXYZ() methods; the immediate issue
is Keystone tests are calling upon it, but as the
implementations here are proving to be not in any
kind of conflict with how Result works, there's
not too much issue leaving them around and deprecating
at some later point.
References: #5087
References: #4395Fixes: #4959
Change-Id: I8091919d45421e3f53029b8660427f844fee0228
Deprecate usage of ``DISTINCT ON`` in dialect other than PostgreSQL.
Previously this was silently ignored.
Deprecate old usage of string distinct in MySQL dialect
Fixes: #4002
Change-Id: I38fc64aef75e77748083c11d388ec831f161c9c9
Implemented the SQLAlchemy 2 :func:`.future.create_engine` function which
is used for forwards compatibility with SQLAlchemy 2. This engine
features always-transactional behavior with autobegin.
Allow execution options per statement execution. This includes
that the before_execute() and after_execute() events now accept
an additional dictionary with these options, empty if not
passed; a legacy event decorator is added for backwards compatibility
which now also emits a deprecation warning.
Add some basic tests for execution, transactions, and
the new result object. Build out on a new testing fixture
that swaps in the future engine completely to start with.
Change-Id: I70e7338bb3f0ce22d2f702537d94bb249bd9fb0a
Fixes: #4644
towards the goal of reducing verbosity and repetition
in test fixtures as well as that we are moving to
connection only for execution, move the insert_data()
classmethod to accept a connection and adjust all
fixtures to use it.
Change-Id: I3bf534acca0d5f4cda1d4da8ae91f1155b829b09
In I27cac9bd265c86ff2a3381ff9f844f60ef991cfc we modernized
the default tests and converted the "a in b" CTE tests to combinations,
however apparently the existing tests were not testing all
combinations and had repeats instead. The combinations
decorator has made this much easier to spot, so use
the correct combinations that were originally intended.
Change-Id: Icd904887bff00c31525497d0b1508fabaf052dc9
Use modern execution patterns, goal is so that these same tests
can work for the future engine
break sequence tests into test_sequences suite
sequence tests that are testing implicit execution patterns
at least move into their own suite that will go into test_deprecations
eventually.
Change-Id: I27cac9bd265c86ff2a3381ff9f844f60ef991cfc
The recipe given out on the ML for improving ABC
fails in 1.4 due to find_tables() missing out on subqueries,
which is due to the refactor of Alias into multiple sub-types.
Change-Id: Idd2803b26a84b28db28e0b8c328b8f24550577e4
- Remove deprecated method ``get_primary_keys` in the :class:`.Dialect` and
:class:`.Inspector` classes.
- Remove deprecated event ``dbapi_error`` and the method ``ConnectionEvents.dbapi_error`.
- Remove support for deprecated engine URLs of the form ``postgres://``.
- Remove deprecated dialect ``mysql+gaerdbms``.
- Remove deprecated parameter ``quoting`` from :class:`.mysql.ENUM`
and :class:`.mysql.SET` in the ``mysql`` dialect.
- Remove deprecated function ``comparable_property``. and function
``comparable_using`` in the declarative extension.
- Remove deprecated function ``compile_mappers``.
- Remove deprecated method ``collection.linker``.
- Remove deprecated method ``Session.prune`` and parameter ``Session.weak_identity_map``.
This change also removes the class ``StrongInstanceDict``.
- Remove deprecated parameter ``mapper.order_by``.
- Remove deprecated parameter ``Session._enable_transaction_accounting`.
- Remove deprecated parameter ``Session.is_modified.passive``.
- Remove deprecated class ``Binary``. Please use :class:`.LargeBinary`.
- Remove deprecated methods ``Compiled.compile``, ``ClauseElement.__and__`` and
``ClauseElement.__or__`` and attribute ``Over.func``.
- Remove deprecated ``FromClause.count`` method.
- Remove deprecated parameter ``Table.useexisting``.
- Remove deprecated parameters ``text.bindparams`` and ``text.typemap``.
- Remove boolean support for the ``passive`` parameter in ``get_history``.
- Remove deprecated ``adapt_operator`` in ``UserDefinedType.Comparator``.
Fixes: #4643
Change-Id: Idcd390c77bf7b0e9957907716993bdaa3f1a1763
Ensure length parameter added to Enum in
Iea05dc8cd9e33959bb968b394fb10a7dd068c873 is correctly propagated
to new enum objects adapted from this one.
Fixes: #5183
`
Change-Id: I7f20d926f73ec8260938963df87e29894c7e55e2
The `Enum` type now supports the parameter `Enum.length`
to specify the length of the VARCHAR column to create when using
non native enums by setting `Enum.native_enum` to `False`
Fixes: #5183
Change-Id: Iea05dc8cd9e33959bb968b394fb10a7dd068c873
Mike Bayer