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Add 'FOR NO KEY UPDATE' / 'FOR KEY SHARE' support for Postgresql

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Adds ``key_share=True`` for with_for_update().

Co-authored-by: Mike Bayer <mike_mp@zzzcomputing.com>
Change-Id: I74e0c3fcbc023e1dc98a1fa0c7db67b4c3693a31
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/279
This commit is contained in:
Sergey Skopin
2016-05-31 10:02:08 -04:00
committed by Mike Bayer
parent a90b0101aa
commit 3ebd1b30eb
8 changed files with 141 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files
doc/build/changelog/changelog_11.rst
Vendored
+10
View File
@@ -97,6 +97,16 @@
objects present in the constraints collection. Pull request courtesy
Alex Grönholm.
.. change::
:tags: feature, postgresql
:pullreq: github:297
Added new parameter
:paramref:`.GenerativeSelect.with_for_update.key_share`, which
will render the ``FOR NO KEY UPDATE`` version of ``FOR UPDATE``
and ``FOR KEY SHARE`` instead of ``FOR SHARE``
on the Postgresql backend. Pull request courtesy Sergey Skopin.
.. change::
:tags: feature, postgresql, oracle
:pullreq: bitbucket:86
doc/build/changelog/migration_11.rst
Vendored
+17 -5
View File
@@ -2121,13 +2121,25 @@ should be calling upon ``sqlalchemy.dialects.postgresql``.
Engine URLs of the form ``postgres://`` will still continue to function,
however.
Support for SKIP LOCKED
-----------------------
Support for FOR UPDATE SKIP LOCKED / FOR NO KEY UPDATE / FOR KEY SHARE
-----------------------------------------------------------------------
The new parameter :paramref:`.GenerativeSelect.with_for_update.skip_locked`
in both Core and ORM will generate the "SKIP LOCKED" suffix for a
"SELECT...FOR UPDATE" or "SELECT.. FOR SHARE" query.
The new parameters :paramref:`.GenerativeSelect.with_for_update.skip_locked`
and :paramref:`.GenerativeSelect.with_for_update.key_share`
in both Core and ORM apply a modification to a "SELECT...FOR UPDATE"
or "SELECT...FOR SHARE" query on the Postgresql backend:
* SELECT FOR NO KEY UPDATE::
stmt = select([table]).with_for_update(key_share=True)
* SELECT FOR UPDATE SKIP LOCKED::
stmt = select([table]).with_for_update(skip_locked=True)
* SELECT FOR KEY SHARE::
stmt = select([table]).with_for_update(read=True, key_share=True)
Dialect Improvements and Changes - MySQL
=============================================
lib/sqlalchemy/dialects/postgresql/base.py
+6 -1
View File
@@ -1170,7 +1170,12 @@ class PGCompiler(compiler.SQLCompiler):
def for_update_clause(self, select, **kw):
if select._for_update_arg.read:
tmp = " FOR SHARE"
if select._for_update_arg.key_share:
tmp = " FOR KEY SHARE"
else:
tmp = " FOR SHARE"
elif select._for_update_arg.key_share:
tmp = " FOR NO KEY UPDATE"
else:
tmp = " FOR UPDATE"
lib/sqlalchemy/orm/query.py
+3 -2
View File
@@ -1398,7 +1398,7 @@ class Query(object):
@_generative()
def with_for_update(self, read=False, nowait=False, of=None,
skip_locked=False):
skip_locked=False, key_share=False):
"""return a new :class:`.Query` with the specified options for the
``FOR UPDATE`` clause.
@@ -1427,7 +1427,8 @@ class Query(object):
"""
self._for_update_arg = LockmodeArg(read=read, nowait=nowait, of=of,
skip_locked=skip_locked)
skip_locked=skip_locked,
key_share=key_share)
@_generative()
def params(self, *args, **kwargs):
lib/sqlalchemy/sql/selectable.py
+12 -5
View File
@@ -1673,7 +1673,7 @@ class ForUpdateArg(ClauseElement):
@classmethod
def parse_legacy_select(self, arg):
"""Parse the for_update arugment of :func:`.select`.
"""Parse the for_update argument of :func:`.select`.
:param mode: Defines the lockmode to use.
@@ -1723,7 +1723,9 @@ class ForUpdateArg(ClauseElement):
if self.of is not None:
self.of = [clone(col, **kw) for col in self.of]
def __init__(self, nowait=False, read=False, of=None, skip_locked=False):
def __init__(
self, nowait=False, read=False, of=None,
skip_locked=False, key_share=False):
"""Represents arguments specified to :meth:`.Select.for_update`.
.. versionadded:: 0.9.0
@@ -1733,6 +1735,7 @@ class ForUpdateArg(ClauseElement):
self.nowait = nowait
self.read = read
self.skip_locked = skip_locked
self.key_share = key_share
if of is not None:
self.of = [_interpret_as_column_or_from(elem)
for elem in util.to_list(of)]
@@ -1876,7 +1879,7 @@ class GenerativeSelect(SelectBase):
@_generative
def with_for_update(self, nowait=False, read=False, of=None,
skip_locked=False):
skip_locked=False, key_share=False):
"""Specify a ``FOR UPDATE`` clause for this :class:`.GenerativeSelect`.
E.g.::
@@ -1917,12 +1920,16 @@ class GenerativeSelect(SelectBase):
.. versionadded:: 1.1.0
.. versionadded:: 0.9.0
:param key_share: boolean, will render ``FOR NO KEY UPDATE``,
or if combined with ``read=True`` will render ``FOR KEY SHARE``,
on the Postgresql dialect.
.. versionadded:: 1.1.0
"""
self._for_update_arg = ForUpdateArg(nowait=nowait, read=read, of=of,
skip_locked=skip_locked)
skip_locked=skip_locked,
key_share=key_share)
@_generative
def apply_labels(self):
test/dialect/postgresql/test_compiler.py
+53 -1
View File
@@ -1,7 +1,7 @@
# coding: utf-8
from sqlalchemy.testing.assertions import AssertsCompiledSQL, is_, \
assert_raises
assert_raises, assert_raises_message
from sqlalchemy.testing import engines, fixtures
from sqlalchemy import testing
from sqlalchemy import Sequence, Table, Column, Integer, update, String,\
@@ -667,6 +667,58 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR SHARE OF mytable SKIP LOCKED")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(key_share=True, nowait=True,
of=[table1.c.myid, table1.c.name]),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR NO KEY UPDATE OF mytable NOWAIT")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(key_share=True, skip_locked=True,
of=[table1.c.myid, table1.c.name]),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR NO KEY UPDATE OF mytable SKIP LOCKED")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(key_share=True,
of=[table1.c.myid, table1.c.name]),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR NO KEY UPDATE OF mytable")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(key_share=True),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR NO KEY UPDATE")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(read=True, key_share=True),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR KEY SHARE")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(read=True, key_share=True, of=table1),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR KEY SHARE OF mytable")
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(read=True, key_share=True, skip_locked=True),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = %(myid_1)s "
"FOR KEY SHARE SKIP LOCKED")
ta = table1.alias()
self.assert_compile(
ta.select(ta.c.myid == 7).
test/dialect/test_oracle.py
+15 -1
View File
@@ -341,6 +341,20 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
"FROM mytable WHERE mytable.myid = :myid_1 FOR UPDATE OF "
"mytable.myid, mytable.name SKIP LOCKED")
# key_share has no effect
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(key_share=True),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = :myid_1 FOR UPDATE")
# read has no effect
self.assert_compile(
table1.select(table1.c.myid == 7).
with_for_update(read=True, key_share=True),
"SELECT mytable.myid, mytable.name, mytable.description "
"FROM mytable WHERE mytable.myid = :myid_1 FOR UPDATE")
ta = table1.alias()
self.assert_compile(
ta.select(ta.c.myid == 7).
@@ -925,7 +939,7 @@ drop synonym %(test_schema)s.local_table;
oracle_resolve_synonyms=True)
self.assert_compile(parent.select(),
"SELECT %(test_schema)s_pt.id, "
"%(test_schema)s_pt.data FROM %(test_schema)s_pt"
"%(test_schema)s_pt.data FROM %(test_schema)s_pt"
% {"test_schema": testing.config.test_schema})
select([parent]).execute().fetchall()
test/orm/test_lockmode.py
+25 -2
View File
@@ -53,17 +53,18 @@ class LegacyLockModeTest(_fixtures.FixtureTest):
sess.query(User.id).with_lockmode, 'unknown_mode'
)
class ForUpdateTest(_fixtures.FixtureTest):
@classmethod
def setup_mappers(cls):
User, users = cls.classes.User, cls.tables.users
mapper(User, users)
def _assert(self, read=False, nowait=False, of=None,
def _assert(self, read=False, nowait=False, of=None, key_share=None,
assert_q_of=None, assert_sel_of=None):
User = self.classes.User
s = Session()
q = s.query(User).with_for_update(read=read, nowait=nowait, of=of)
q = s.query(User).with_for_update(read=read, nowait=nowait, of=of, key_share=key_share)
sel = q._compile_context().statement
assert q._for_update_arg.read is read
@@ -72,9 +73,15 @@ class ForUpdateTest(_fixtures.FixtureTest):
assert q._for_update_arg.nowait is nowait
assert sel._for_update_arg.nowait is nowait
assert q._for_update_arg.key_share is key_share
assert sel._for_update_arg.key_share is key_share
eq_(q._for_update_arg.of, assert_q_of)
eq_(sel._for_update_arg.of, assert_sel_of)
def test_key_share(self):
self._assert(key_share=True)
def test_read(self):
self._assert(read=True)
@@ -172,6 +179,22 @@ class CompileTest(_fixtures.FixtureTest, AssertsCompiledSQL):
dialect="postgresql"
)
def test_postgres_for_no_key_update(self):
User = self.classes.User
sess = Session()
self.assert_compile(sess.query(User.id).with_for_update(key_share=True),
"SELECT users.id AS users_id FROM users FOR NO KEY UPDATE",
dialect="postgresql"
)
def test_postgres_for_no_key_nowait_update(self):
User = self.classes.User
sess = Session()
self.assert_compile(sess.query(User.id).with_for_update(key_share=True, nowait=True),
"SELECT users.id AS users_id FROM users FOR NO KEY UPDATE NOWAIT",
dialect="postgresql"
)
def test_postgres_update_of_list(self):
User = self.classes.User
sess = Session()