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| -rw-r--r-- | doc/build/changelog/changelog_09.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/doc/build/changelog/changelog_09.rst b/doc/build/changelog/changelog_09.rst index 84110f0f3..78c7e0c9a 100644 --- a/doc/build/changelog/changelog_09.rst +++ b/doc/build/changelog/changelog_09.rst @@ -7,6 +7,21 @@ :version: 0.9.0 .. change:: + :tags: bug, orm + :tickets: 2778 + + A performance fix related to the usage of the :func:`.defer` option + when loading mapped entities. The function overhead of applying + a per-object deferred callable to an instance at load time was + significantly higher than that of just loading the data from the row + (note that ``defer()`` is meant to reduce DB/network overhead, not + necessarily function call count); the function call overhead is now + less than that of loading data from the column in all cases. There + is also a reduction in the number of "lazy callable" objects created + per load from N (total deferred values in the result) to 1 (total + number of deferred cols). Also in 0.8.3. + + .. change:: :tags: bug, sqlite :tickets: 2781 |