Postgresql change column type update#

Select * from pg_stat_statements where query like '%optionB%' After no rows need changes, we can switch the columnsДЄLTER /*optionB*/ TABLE PRU DROP COLUMN A ДЄLTER /*optionB*/ TABLE PRU DROP COLUMN A1_CHANGED ДЄLTER /*optionB*/ TABLE PRU RENAME A1 TO A SELECT COUNT(1) FROM PRU WHERE A1_CHANGED is null SELECT COUNT(1) FROM PRU WHERE A1_CHANGED=true

Postgresql change column type update#

UPDATE /*optionB*/ PRU SET A1=A::INTEGER, A1_CHANGED=true WHERE id IN (SELECT id FROM PRU WHERE A1_CHANGED is null limit 100000) This sentence must be repeated multiple times until all rows were updated Update sentence with limit number or fows to update in single transaction Trigger to take care of ongoing changes from the applicationsД®LSEIF (NEW.a is null and OLD.a is not null) THENД®LSEIF (NEW.a is not null and OLD.a is null) THEN ALTER TABLE roads ALTER COLUMN geom TYPE geometry(MULTILINESTRING, 4326) USING STSetSRID(geom. The advantages of doing in this way is that the customer has more control about the process, it can be executed during multiples hours/days.ДЄLTER TABLE PRU ADD COLUMN A1 INTEGER, ADD COLUMN A1_CHANGED BOOLEAN Updates the SRID of all features in a geometry column. This method is the easiest one, but could generate high contention due to required exclusive lock for the table that could generate errors in applications, most of them will require stop applications to perform this type of long running operations.ДЄnother approach to change the datatype of the column could be to add some extra columns, migrate the data to those columns and finally drop old column and rename new one. Select * from pg_stat_statements where query like '%optionA%'

We could review stats from this command with following command: Generate rows until 2M, repeating this sentence:ДЄLTER /*optionA*/ TABLE PRU ALTER COLUMN A TYPE INTEGER USING A::INTEGER SELECT * FROM pg_stat_statements_reset() Supose table PRU with bigserial id column and column A, with integer data saved as Text that you want to change to Integer type: See the original author and article here.Дue to performance and locking reasons, change datatype column can be a long-running operation.