Add range_minus_multi and multirange_minus_multi functions The existing range_minus function raises an exception when the range is "split", because then the result can't be represented by a single range. For example '[0,10)'::int4range - '[4,5)' would be '[0,4)' and '[5,10)'.
This commit adds new set-returning functions so that callers can get results even in the case of splits. There is no risk of an exception for multiranges, but a set-returning function lets us handle them the same way we handle ranges. Both functions return zero results if the subtraction would give an empty range/multirange. The main use-case for these functions is to implement UPDATE/DELETE FOR PORTION OF, which must compute the application-time of "temporal leftovers": the part of history in an updated/deleted row that was not changed. To preserve the untouched history, we will implicitly insert one record for each result returned by range/multirange_minus_multi. Using a set-returning function will also let us support user-defined types for application-time update/delete in the future. Author: Paul A. Jungwirth <[email protected]> Reviewed-by: Peter Eisentraut <[email protected]> Reviewed-by: Chao Li <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/ec498c3d-5f2b-48ec-b989-5561c8aa2024%40illuminatedcomputing.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/5eed8ce50ce9df1067b95593dde9f4fc526dfc72 Modified Files -------------- doc/src/sgml/func/func-range.sgml | 42 +++++++ src/backend/utils/adt/multirangetypes.c | 71 +++++++++++ src/backend/utils/adt/rangetypes.c | 167 ++++++++++++++++++++++++++ src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.dat | 8 ++ src/include/utils/rangetypes.h | 2 + src/test/regress/expected/multirangetypes.out | 116 ++++++++++++++++++ src/test/regress/expected/rangetypes.out | 54 +++++++++ src/test/regress/sql/multirangetypes.sql | 22 ++++ src/test/regress/sql/rangetypes.sql | 10 ++ 10 files changed, 493 insertions(+), 1 deletion(-)
