postgres/contrib/hstore
Andrew Gierth d5890f49da Fix hstore hash function for empty hstores upgraded from 8.4.
Hstore data generated on pg 8.4 and pg_upgraded to current versions
remains in its original on-disk format unless modified. The same goes
for values generated by the addon hstore-new module on pre-9.0
versions. (The hstoreUpgrade function converts old values on the fly
when read in, but the on-disk value is not modified by this.)

Since old-format empty hstores (and hstore-new hstores) have
representations compatible with the new format, hstoreUpgrade thought
it could get away without modifying such values; but this breaks
hstore_hash (and the new hstore_hash_extended) which assumes
bit-perfect matching between semantically identical hstore values.
Only one bit actually differs (the "new version" flag in the count
field) but that of course is enough to break the hash.

Fix by making hstoreUpgrade unconditionally convert all old values to
new format.

Backpatch all the way, even though this changes a hash value in some
cases, because in those cases the hash value is already failing - for
example, a hash join between old- and new-format empty hstores will be
failing to match, or a hash index on an hstore column containing an
old-format empty value will be failing to find the value since it will
be searching for a hash derived from a new-format datum. (There are no
known field reports of this happening, probably because hashing of
hstores has only been useful in limited circumstances and there
probably isn't much upgraded data being used this way.)

Per concerns arising from discussion of commit eb6f29141b. Original
bug is my fault.

Discussion: https://postgr.es/m/60b1fd3b-7332-40f0-7e7f-f2f04f777747%402ndquadrant.com
2018-11-24 09:59:49 +00:00
..
data Add GIN support for pg_trgm. From Guillaume Smet <guillaume.smet@gmail.com> 2007-03-14 14:21:53 +00:00
expected Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00
sql Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00
.gitignore Support "make check" in contrib 2011-04-25 22:27:11 +03:00
Makefile Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00
hstore--1.0--1.1.sql Fix typo in update scripts for some contrib modules. 2013-07-19 04:13:01 +09:00
hstore--1.1--1.2.sql Fix whitespace issues found by git diff --check, add gitattributes 2013-11-10 14:48:29 -05:00
hstore--1.2--1.3.sql Introduce jsonb, a structured format for storing json. 2014-03-23 16:40:19 -04:00
hstore--1.3--1.4.sql Update extensions with GIN/GIST support for parallel query. 2016-06-14 13:34:37 -04:00
hstore--1.4--1.5.sql Distinguish selectivity of < from <= and > from >=. 2017-09-13 11:12:39 -04:00
hstore--1.4.sql Update extensions with GIN/GIST support for parallel query. 2016-06-14 13:34:37 -04:00
hstore--1.5--1.6.sql Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00
hstore--unpackaged--1.0.sql Fix typos in some error messages thrown by extension scripts when fed to psql. 2014-08-25 18:30:37 +02:00
hstore.control Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00
hstore.h Make DatumGetFoo/PG_GETARG_FOO/PG_RETURN_FOO macro names more consistent. 2017-09-18 15:21:23 -04:00
hstore_compat.c Fix hstore hash function for empty hstores upgraded from 8.4. 2018-11-24 09:59:49 +00:00
hstore_gin.c Make DatumGetFoo/PG_GETARG_FOO/PG_RETURN_FOO macro names more consistent. 2017-09-18 15:21:23 -04:00
hstore_gist.c Change TRUE/FALSE to true/false 2017-11-08 11:37:28 -05:00
hstore_io.c Fix assorted compiler warnings seen in the buildfarm. 2018-05-02 15:52:54 -04:00
hstore_op.c Add a 64-bit hash function for type hstore. 2018-11-23 13:37:34 -05:00