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Mike Bayer
8d5ed4c39e
This patch adds new warnings for all elements that
don't indicate their caching behavior, including user-defined
ClauseElement subclasses and third party dialects.
it additionally adds new documentation to discuss an apparent
performance degradation in 1.4 when caching is disabled as a
result in the significant expense incurred by ORM
lazy loaders, which in 1.3 used BakedQuery so were actually
cached.
As a result of adding the warnings, a fair degree of
lesser used SQL expression objects identified that they did not
define caching behavior so would have been producing
``[no key]``, including PostgreSQL constructs ``hstore``
and ``array``. These have been amended to use inherit
cache where appropriate. "on conflict" constructs in
PostgreSQL, MySQL, SQLite still explicitly don't generate
a cache key at this time.
The change also adds a test for all constructs via
assert_compile() to assert they will not generate cache
warnings.
Fixes: #7394
Change-Id: I85958affbb99bfad0f5efa21bc8f2a95e7e46981
(cherry picked from commit 22deafe152)