```sql CREATE TABLE [MyTable] ( [ID] INTEGER PRIMARY KEY NOT NULL, [Foo] INTEGER, [Bar] INTEGER); -- Insert 50000 identical rows INSERT INTO [MyTable] ([Foo], [Bar]) SELECT 123, 456 FROM generate_series(1, 50000, 1); -- All rows are: [Foo]==123, [Bar]==456 -- Drop the [Foo] column ALTER TABLE [MyTable] DROP COLUMN [Foo]; -- All rows should be: [Bar]==456 -- However, mysteriously, some rows now have [Bar]==123 : SELECT COUNT(*) FROM [MyTable] WHERE [Bar]=123 -- (Prints 17226 for me) ```