Support for weak binding views to allow dropping of underlying objects BABEL_4_7_STABLE#3966
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jsudrik merged 3 commits intobabelfish-for-postgresql:BABEL_4_7_STABLEfrom Jul 15, 2025
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…s.This commit introduces support for both strong and weak view binding in Babelfish, aligning more closely with SQL Server's default behavior while maintaining flexibility. (babelfish-for-postgresql#3806) Description Currently, Babelfish only supports strong binding for views, which prevents dropping or altering referenced objects when views depend on them. This behavior differs from SQL Server, which by default allows dropping underlying tables or views unless WITH SCHEMABINDING is explicitly specified. With this change, Babelfish now supports configurable view binding modes: Strong binding (default): Prevents dropping referenced objects if views depend on them Weak binding: Allows dropping of referenced objects This feature aligns Babelfish more closely with SQL Server's behavior, providing greater flexibility Key aspects include: A new GUC parameter babelfishpg_tsql.weak_view_binding to control the default binding behavior (default is false) Support for explicit WITH SCHEMABINDING to create strongly bound views regardless of the GUC setting Ability to create weakly bound views by default when the GUC is enabled Proper handling of ALTER VIEW operations in both binding modes In SQL Server, views are weakly bound by default, allowing underlying objects to be dropped or altered. With our implementation, users can now choose between SQL Server's default behavior (weak binding) or the previously enforced behavior (strong binding). Important Limitation : This implementation currently only addresses DROP operations on tables, views, functions, procedures as well as ALTER operations on views when these objects are bound by dependent views. ALTER TABLE/ ALTER FUNCTION operations (such as dropping columns or changing data types) are still restricted when dependent views exist, regardless of binding mode. This differs from SQL Server's behavior, where weak binding also allows ALTER operations on referenced objects. When the same underlying object is recreated, its broken child view will get repaired only if it follows postgresql restrictions for CREATE OR REPLACE VIEW. [The new query must generate the same columns that were generated by the existing view query (that is, the same column names in the same order and with the same data types), but it may add additional columns to the end of the list] https://www.postgresql.org/docs/current/sql-createview.html#:~:text=The%20new%20query,be%20completely%20different. Issues Resolved BABEL-1660 Signed-off-by: Rahul Parande <rparande@amazon.com>
…e transaction snapshot Signed-off-by: Rahul Parande <rparande@amazon.com>
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Cherrypick from review and merged code in other branch.
Approved.
jsudrik
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babelfish-for-postgresql:BABEL_4_7_STABLE
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cherry-picked from PR: #3806 and #3963
Issues Resolved
BABEL-1660
Test Scenarios Covered
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Major version upgrade tests -
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