Title: Waiting for PostgreSQL 13 – ALTER TABLE … ALTER COLUMN … DROP EXPRESSION
On 14th of January 2020, Peter Eisentraut committed patch:
ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION Add an ALTER TABLE subcommand for dropping the generated property from a column, per SQL standard. Discussion: https://www.postgresql.org/message-id/flat/-946e-0453-d841-%402ndquadrant.com
Continue reading Waiting for PostgreSQL 13 – ALTER TABLE … ALTER COLUMN … DROP EXPRESSION
On 30th of March 2019, Peter Eisentraut committed patch:
Generated columns This is an SQL-standard feature that allows creating columns that are computed from expressions rather than assigned, similar to a view or materialized view but on a column basis. This implements one kind of generated column: stored (computed on write). Another kind, virtual (computed on read), is planned for the future, and some room is left for it. Discussion: https://www.postgresql.org/message-id/flat/-4019-bdb1-699e-@2ndquadrant.com
Continue reading Waiting for PostgreSQL 12 – Generated columns
On 28th of March 2018, Andrew Dunstan committed patch:
Fast ALTER TABLE ADD COLUMN with a non-NULL default Currently adding a column to a table with a non-NULL default results in a rewrite of the table. For large tables this can be both expensive and disruptive. This patch removes the need for the rewrite as long as the default value is not volatile. The default expression is evaluated at the time of the ALTER TABLE and the result stored in a new column (attmissingval) in pg_attribute, and a new column (atthasmissing) is set to true. Any existing row when fetched will be supplied with the attmissingval. New rows will have the supplied value or the default and so will never need the attmissingval. Any time the table is rewritten all the atthasmissing and attmissingval settings for the attributes are cleared, as they are no longer needed. The most visible code change from this is in heap_attisnull, which acquires a third TupleDesc argument, allowing it to detect a missing value if there is one. In many cases where it is known that there will not be any (e.g. catalog relations) NULL can be passed for this argument. Andrew Dunstan, heavily modified from an original patch from Serge Rielau. Reviewed by Tom Lane, Andres Freund, Tomas Vondra and David Rowley. Discussion: https://postgr.es/m/-7002-4c27-59f5-@2ndQuadrant.com
Continue reading Waiting for PostgreSQL 11 – Fast ALTER TABLE ADD COLUMN with a non-NULL default
On 4th of December Peter Eisentraut committed patch by Pavel Stehule (with Peters tweaks) which adds default values for function arguments:
Default values for function arguments Pavel Stehule, with some tweaks by Peter Eisentraut
Continue reading Waiting for 8.4 – Default values for function arguments + integer in any base