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74f26a1934
bpchar equality ignores trailing spaces, so equal values in a column with no length specifier can have different images. Similarly, oidvector equality intentionally pays no attention to the array lower bound field. We nevertheless allowed nbtree deduplication to be used with indexes built with bpchar_ops, bpchar_pattern_ops, or oidvector_ops. A posting list split could therefore place a TID in an index tuple whose key was equal to, but not bytewise identical to, the corresponding table value. This allowed index-only scans to return subtly wrong results. To fix, drop support function 4 from the affected opclasses (we can't change catalog contents on branches 14 through 18, so we just disable deduplication by adding hard-coding to the relevant support functions). Deliberately leave the oidvector opclass alone on branches 14 through 18, though. Disallowing oidvector deduplication on these branches would make pg_amcheck report that pg_proc_proname_args_nsp_index has a corrupt metapage, needlessly alarming users. System catalog oidvector values always have a lower bound of 0, so the issue can't cause harm there; a user can only hit it by indexing an oidvector column that stores the output of a function like trim_array(). It seems very unlikely that any user would ever do that. Users should REINDEX any B-Tree index on a bpchar column. Author: Shihao Zhong <zhong950419@gmail.com> Co-authored-by: Peter Geoghegan <pg@bowt.ie> Reported-by: Ke <kehan5800@gmail.com> Reported-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Bug: #19749 Discussion: https://postgr.es/m/19749-d46adf7c7d910b07@postgresql.org Discussion: https://postgr.es/m/CAGRkXqQQ311Lg=62x5UdZtPuRFgpT6XpPMw4X9E3tgbTu162Mw@mail.gmail.com Backpatch-through: 14
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.