519fc1bd9e
This adds support for infinity to the interval data type, using the same input/output representation as the other date/time data types that support infinity. This allows various arithmetic operations on infinite dates, timestamps and intervals. The new values are represented by setting all fields of the interval to INT32/64_MIN for -infinity, and INT32/64_MAX for +infinity. This ensures that they compare as less/greater than all other interval values, without the need for any special-case comparison code. Note that, since those 2 values were formerly accepted as legal finite intervals, pg_upgrade and dump/restore from an old database will turn them from finite to infinite intervals. That seems OK, since those exact values should be extremely rare in practice, and they are outside the documented range supported by the interval type, which gives us a certain amount of leeway. Bump catalog version. Joseph Koshakow, Jian He, and Ashutosh Bapat, reviewed by me. Discussion: https://postgr.es/m/CAAvxfHea4%2BsPybKK7agDYOMo9N-Z3J6ZXf3BOM79pFsFNcRjwA%40mail.gmail.com
The PostgreSQL contrib tree
---------------------------
This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree. This does not preclude their
usefulness.
User documentation for each module appears in the main SGML
documentation.
When building from the source distribution, these modules are not
built automatically, unless you build the "world" target. You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.
Some directories supply new user-defined functions, operators, or
types. To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command. In a fresh database,
you can simply do
CREATE EXTENSION module_name;
See the PostgreSQL documentation for more information about this
procedure.