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0247935c7b
In general, datatype I/O functions are supposed to be immutable or at worst stable. Some contrib I/O functions were, through oversight, not marked with any volatility property at all, which made them VOLATILE. Since (most of) these functions actually behave immutably, the erroneous marking isn't terribly harmful; but it can be user-visible in certain circumstances, as per a recent bug report from Joe Van Dyk in which a cast to text was disallowed in an expression index definition. To fix, just adjust the declarations in the extension SQL scripts. If we were being very fussy about this, we'd bump the extension version numbers, but that seems like more trouble (for both developers and users) than the problem is worth. A fly in the ointment is that chkpass_in actually is volatile, because of its use of random() to generate a fresh salt when presented with a not-yet-encrypted password. This is bad because of the general assumption that I/O functions aren't volatile: the consequence is that records or arrays containing chkpass elements may have input behavior a bit different from a bare chkpass column. But there seems no way to fix this without breaking existing usage patterns for chkpass, and the consequences of the inconsistency don't seem bad enough to justify that. So for the moment, just document it in a comment. Since we're not bumping version numbers, there seems no harm in back-patching these fixes; at least future installations will get the functions marked correctly.
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 "gmake all" and "gmake
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.