<feed xmlns='http://www.w3.org/2005/Atom'>
<title>delta/python-packages/sqlalchemy.git/lib/sqlalchemy/engine/create.py, branch review/mike_bayer/tutorial20</title>
<subtitle>github.com: zzzeek/sqlalchemy.git
</subtitle>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/'/>
<entry>
<title>improve engine logging docs</title>
<updated>2020-10-24T16:59:22+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-10-24T16:59:22+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=a1c51879aeb7811a23e454d2e90ad3bbae92b7a1'/>
<id>a1c51879aeb7811a23e454d2e90ad3bbae92b7a1</id>
<content type='text'>
the text here was a little confusing and didn't refer to major
configurational elements such as hide_parameters.

Change-Id: I4e2179e5a64c326d30b65a8871b924725c41b453
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
the text here was a little confusing and didn't refer to major
configurational elements such as hide_parameters.

Change-Id: I4e2179e5a64c326d30b65a8871b924725c41b453
</pre>
</div>
</content>
</entry>
<entry>
<title>Fix typo in :paramref:`_engine.create_engine.isolation_level` names</title>
<updated>2020-09-08T21:09:21+00:00</updated>
<author>
<name>Federico Caselli</name>
<email>cfederico87@gmail.com</email>
</author>
<published>2020-09-08T21:09:21+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=17f7faf3df8dc3d30e632c60a5d69d342876ad3d'/>
<id>17f7faf3df8dc3d30e632c60a5d69d342876ad3d</id>
<content type='text'>
Fixes: #5563
Change-Id: I29204fdf679d750c66ed17daf70bc8d7cb1b7f65
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fixes: #5563
Change-Id: I29204fdf679d750c66ed17daf70bc8d7cb1b7f65
</pre>
</div>
</content>
</entry>
<entry>
<title>make URL immutable</title>
<updated>2020-08-26T00:10:16+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-08-21T18:44:04+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=3668b3a30c4b9a9f4af13457f43bfc34c28cf448'/>
<id>3668b3a30c4b9a9f4af13457f43bfc34c28cf448</id>
<content type='text'>
it's not really correct that URL is mutable and doesn't do
any argument checking.   propose replacing it with an immutable
named tuple with rich copy-and-mutate methods.

At the moment this makes a hard change to the CreateEnginePlugin
docs that previously recommended url.query.pop().  I can't find
any plugins on github other than my own that are using this
feature, so see if we can just make a hard change on this one.

Fixes: #5526
Change-Id: I28a0a471d80792fa8c28f4fa573d6352966a4a79
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
it's not really correct that URL is mutable and doesn't do
any argument checking.   propose replacing it with an immutable
named tuple with rich copy-and-mutate methods.

At the moment this makes a hard change to the CreateEnginePlugin
docs that previously recommended url.query.pop().  I can't find
any plugins on github other than my own that are using this
feature, so see if we can just make a hard change on this one.

Fixes: #5526
Change-Id: I28a0a471d80792fa8c28f4fa573d6352966a4a79
</pre>
</div>
</content>
</entry>
<entry>
<title>Implement rudimentary asyncio support w/ asyncpg</title>
<updated>2020-08-13T22:41:53+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-07-04T16:21:36+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=5fb0138a3220161703e6ab1087319a669d14e7f4'/>
<id>5fb0138a3220161703e6ab1087319a669d14e7f4</id>
<content type='text'>
Using the approach introduced at
https://gist.github.com/zzzeek/6287e28054d3baddc07fa21a7227904e

We can now create asyncio endpoints that are then handled
in "implicit IO" form within the majority of the Core internals.
Then coroutines are re-exposed at the point at which we call
into asyncpg methods.

Patch includes:

* asyncpg dialect

* asyncio package

* engine, result, ORM session classes

* new test fixtures, tests

* some work with pep-484 and a short plugin for the
  pyannotate package, which seems to have so-so results

Change-Id: Idbcc0eff72c4cad572914acdd6f40ddb1aef1a7d
Fixes: #3414
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Using the approach introduced at
https://gist.github.com/zzzeek/6287e28054d3baddc07fa21a7227904e

We can now create asyncio endpoints that are then handled
in "implicit IO" form within the majority of the Core internals.
Then coroutines are re-exposed at the point at which we call
into asyncpg methods.

Patch includes:

* asyncpg dialect

* asyncio package

* engine, result, ORM session classes

* new test fixtures, tests

* some work with pep-484 and a short plugin for the
  pyannotate package, which seems to have so-so results

Change-Id: Idbcc0eff72c4cad572914acdd6f40ddb1aef1a7d
Fixes: #3414
</pre>
</div>
</content>
</entry>
<entry>
<title>Don't link on_connect to first_connect event handler</title>
<updated>2020-08-07T22:01:49+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-08-07T18:51:33+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=302e8dee82718df6c3a46de4c5283bdae51a650a'/>
<id>302e8dee82718df6c3a46de4c5283bdae51a650a</id>
<content type='text'>
Adjusted the dialect initialization process such that the
:meth:`_engine.Dialect.on_connect` is not called a second time on the first
connection.   The hook is called first, then the
:meth:`_engine.Dialect.initialize` is called if that connection is the
first for that dialect, then no more events are called.   This eliminates
the two calls to the "on_connect" function which can produce very difficult
debugging situations.

Fixes: #5497
Change-Id: Icefc2e884e30ee7b4ac84b99dc54bf992a6085e3
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Adjusted the dialect initialization process such that the
:meth:`_engine.Dialect.on_connect` is not called a second time on the first
connection.   The hook is called first, then the
:meth:`_engine.Dialect.initialize` is called if that connection is the
first for that dialect, then no more events are called.   This eliminates
the two calls to the "on_connect" function which can produce very difficult
debugging situations.

Fixes: #5497
Change-Id: Icefc2e884e30ee7b4ac84b99dc54bf992a6085e3
</pre>
</div>
</content>
</entry>
<entry>
<title>Robustness for lambdas, lambda statements</title>
<updated>2020-08-05T20:42:26+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-08-05T20:42:26+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=cc57ea495f6460dd56daa6de57e40047ed999369'/>
<id>cc57ea495f6460dd56daa6de57e40047ed999369</id>
<content type='text'>
in order to accommodate relationship loaders
with lambda caching, a lot more is needed.  This is
a full refactor of the lambda system such that it
now has two levels of caching; the first level caches what
can be known from the __code__ element, then the next level
of caching is against the lambda itself and the contents
of __closure__.  This allows for the elements inside
the lambdas, like columns and entities, to change and
then be part of the cache key.  Lazy/selectinloads' use of
baked queries had to add distinct cache key elements,
which was attempted here but overall things needed to be
more robust than that.

This commit is broken out from the very long and sprawling
commit at Id6b5c03b1ce9ddb7b280f66792212a0ef0a1c541 .

Change-Id: I29a513c98917b1d503abfdd61e6b6e8800851aa8
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
in order to accommodate relationship loaders
with lambda caching, a lot more is needed.  This is
a full refactor of the lambda system such that it
now has two levels of caching; the first level caches what
can be known from the __code__ element, then the next level
of caching is against the lambda itself and the contents
of __closure__.  This allows for the elements inside
the lambdas, like columns and entities, to change and
then be part of the cache key.  Lazy/selectinloads' use of
baked queries had to add distinct cache key elements,
which was attempted here but overall things needed to be
more robust than that.

This commit is broken out from the very long and sprawling
commit at Id6b5c03b1ce9ddb7b280f66792212a0ef0a1c541 .

Change-Id: I29a513c98917b1d503abfdd61e6b6e8800851aa8
</pre>
</div>
</content>
</entry>
<entry>
<title>Add future=True to create_engine/Session; unify select()</title>
<updated>2020-07-08T15:05:11+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-06-26T20:15:19+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=91f376692d472a5bf0c4b4033816250ec1ce3ab6'/>
<id>91f376692d472a5bf0c4b4033816250ec1ce3ab6</id>
<content type='text'>
Several weeks of using the future_select() construct
has led to the proposal there be just one select() construct
again which features the new join() method, and otherwise accepts
both the 1.x and 2.x argument styles.   This would make
migration simpler and reduce confusion.

However, confusion may be increased by the fact that select().join()
is different  Current thinking is we may be better off
with a few hard behavioral changes to old and relatively unknown APIs
rather than trying to play both sides within two extremely similar
but subtly different APIs.  At the moment, the .join() thing seems
to be the only behavioral change that occurs without the user
taking any explicit steps.   Session.execute() will still
behave the old way as we are adding a future flag.

This change also adds the "future" flag to Session() and
session.execute(), so that interpretation of the incoming statement,
as well as that the new style result is returned, does not
occur for existing applications unless they add the use
of this flag.

The change in general is moving the "removed in 2.0" system
further along where we want the test suite to fully pass
even if the SQLALCHEMY_WARN_20 flag is set.

Get many tests to pass when SQLALCHEMY_WARN_20 is set; this
should be ongoing after this patch merges.

Improve the RemovedIn20 warning; these are all deprecated
"since" 1.4, so ensure that's what the messages read.
Make sure the inforamtion link is on all warnings.
Add deprecation warnings for parameters present and
add warnings to all FromClause.select() types of methods.

Fixes: #5379
Fixes: #5284
Change-Id: I765a0b912b3dcd0e995426427d8bb7997cbffd51
References: #5159
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several weeks of using the future_select() construct
has led to the proposal there be just one select() construct
again which features the new join() method, and otherwise accepts
both the 1.x and 2.x argument styles.   This would make
migration simpler and reduce confusion.

However, confusion may be increased by the fact that select().join()
is different  Current thinking is we may be better off
with a few hard behavioral changes to old and relatively unknown APIs
rather than trying to play both sides within two extremely similar
but subtly different APIs.  At the moment, the .join() thing seems
to be the only behavioral change that occurs without the user
taking any explicit steps.   Session.execute() will still
behave the old way as we are adding a future flag.

This change also adds the "future" flag to Session() and
session.execute(), so that interpretation of the incoming statement,
as well as that the new style result is returned, does not
occur for existing applications unless they add the use
of this flag.

The change in general is moving the "removed in 2.0" system
further along where we want the test suite to fully pass
even if the SQLALCHEMY_WARN_20 flag is set.

Get many tests to pass when SQLALCHEMY_WARN_20 is set; this
should be ongoing after this patch merges.

Improve the RemovedIn20 warning; these are all deprecated
"since" 1.4, so ensure that's what the messages read.
Make sure the inforamtion link is on all warnings.
Add deprecation warnings for parameters present and
add warnings to all FromClause.select() types of methods.

Fixes: #5379
Fixes: #5284
Change-Id: I765a0b912b3dcd0e995426427d8bb7997cbffd51
References: #5159
</pre>
</div>
</content>
</entry>
<entry>
<title>introduce deferred lambdas</title>
<updated>2020-07-04T03:39:51+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2019-12-16T22:06:43+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=3dc9a4a2392d033f9d1bd79dd6b6ecea6281a61c'/>
<id>3dc9a4a2392d033f9d1bd79dd6b6ecea6281a61c</id>
<content type='text'>
The coercions system allows us to add in lambdas as arguments
to Core and ORM elements without changing them at all.   By allowing
the lambda to produce a deterministic cache key where we can also
cheat and yank out literal parameters means we can move towards
having 90% of "baked" functionality in a clearer way right in
Core / ORM.

As a second step, we can have whole statements inside the lambda,
and can then add generation with __add__(), so then we have
100% of "baked" functionality with full support of ad-hoc
literal values.

Adds some more short_selects tests for the moment for comparison.

Other tweaks inside cache key generation as we're trying to
approach a certain level of performance such that we can
remove the use of "baked" from the loader strategies.

As we have not yet closed #4639, however the caching feature
has been fully integrated as of
b0cfa7379cf8513a821a3dbe3028c4965d9f85bd, we will also
add complete caching documentation here and close that issue
as well.

Closes: #4639
Fixes: #5380
Change-Id: If91f61527236fd4d7ae3cad1f24c38be921c90ba
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The coercions system allows us to add in lambdas as arguments
to Core and ORM elements without changing them at all.   By allowing
the lambda to produce a deterministic cache key where we can also
cheat and yank out literal parameters means we can move towards
having 90% of "baked" functionality in a clearer way right in
Core / ORM.

As a second step, we can have whole statements inside the lambda,
and can then add generation with __add__(), so then we have
100% of "baked" functionality with full support of ad-hoc
literal values.

Adds some more short_selects tests for the moment for comparison.

Other tweaks inside cache key generation as we're trying to
approach a certain level of performance such that we can
remove the use of "baked" from the loader strategies.

As we have not yet closed #4639, however the caching feature
has been fully integrated as of
b0cfa7379cf8513a821a3dbe3028c4965d9f85bd, we will also
add complete caching documentation here and close that issue
as well.

Closes: #4639
Fixes: #5380
Change-Id: If91f61527236fd4d7ae3cad1f24c38be921c90ba
</pre>
</div>
</content>
</entry>
<entry>
<title>Fix a wide variety of typos and broken links</title>
<updated>2020-06-25T23:42:28+00:00</updated>
<author>
<name>aplatkouski</name>
<email>5857672+aplatkouski@users.noreply.github.com</email>
</author>
<published>2020-06-22T15:34:39+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=2a1a9f5f5a9723f757439657d2bdf224baed8748'/>
<id>2a1a9f5f5a9723f757439657d2bdf224baed8748</id>
<content type='text'>
Note the PR has a few remaining doc linking issues
listed in the comment that must be addressed separately.

Signed-off-by: aplatkouski &lt;5857672+aplatkouski@users.noreply.github.com&gt;
Closes: #5371
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5371
Pull-request-sha: 7e7d233cf3a0c66980c27db0fcdb3c7d93bc2510

Change-Id: I9c36e8d8804483950db4b42c38ee456e384c59e3
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Note the PR has a few remaining doc linking issues
listed in the comment that must be addressed separately.

Signed-off-by: aplatkouski &lt;5857672+aplatkouski@users.noreply.github.com&gt;
Closes: #5371
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5371
Pull-request-sha: 7e7d233cf3a0c66980c27db0fcdb3c7d93bc2510

Change-Id: I9c36e8d8804483950db4b42c38ee456e384c59e3
</pre>
</div>
</content>
</entry>
<entry>
<title>Turn on caching everywhere, add logging</title>
<updated>2020-06-10T19:29:01+00:00</updated>
<author>
<name>Mike Bayer</name>
<email>mike_mp@zzzcomputing.com</email>
</author>
<published>2020-06-07T00:40:43+00:00</published>
<link rel='alternate' type='text/html' href='http://git.baserock.org/cgit/delta/python-packages/sqlalchemy.git/commit/?id=b0cfa7379cf8513a821a3dbe3028c4965d9f85bd'/>
<id>b0cfa7379cf8513a821a3dbe3028c4965d9f85bd</id>
<content type='text'>
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
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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
</pre>
</div>
</content>
</entry>
</feed>
