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.
Thousands of students and teachers across Wales will benefit from cutting-edge data analytics technology to improve student engagement, retention and performance as a result of a funding boost to be announced today by the Higher Education Funding Council for Wales (HEFCW) and Jisc.
The training impulse (TRIMP), the heart rate stress score (HRSS) and the running stress score (rTSS) are all measures of training load but are just one piece of the puzzle. Empower yourself to train smart with exercise science articles from Thomas Solomo