diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 00ccbe1bb5f6a7f59256d8124d6aae27ab35bf0c..ebcadf617aa80af3520e856545c7e648586c210a 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -1078,10 +1078,13 @@ SELECT '52093.89'::money::numeric::float8; <para> Values of type <type>character</type> are physically padded with spaces to the specified width <replaceable>n</>, and are - stored and displayed that way. However, the padding spaces are - treated as semantically insignificant. Trailing spaces are - disregarded when comparing two values of type <type>character</type>, - and they will be removed when converting a <type>character</type> value + stored and displayed that way. However, trailing spaces are treated as + semantically insignificant and disregarded when comparing two values + of type <type>character</type>. In collations where whitespace + is significant, this behavior can produce unexpected results, + e.g. <command>SELECT 'a '::CHAR(2) collate "C" < 'a\n'::CHAR(2) + returns true. + Trailing spaces are removed when converting a <type>character</type> value to one of the other string types. Note that trailing spaces <emphasis>are</> semantically significant in <type>character varying</type> and <type>text</type> values, and diff --git a/src/backend/utils/adt/varchar.c b/src/backend/utils/adt/varchar.c index 284b5d13093a2bf2de0320aa60f465e95822f0af..502ca44e04a961a9e7ce256ed4cb39636b4a1831 100644 --- a/src/backend/utils/adt/varchar.c +++ b/src/backend/utils/adt/varchar.c @@ -846,18 +846,6 @@ bpcharcmp(PG_FUNCTION_ARGS) len2; int cmp; - /* - * Trimming trailing spaces off of both strings can cause a string - * with a character less than a space to compare greater than a - * space-extended string, e.g. this returns false: - * SELECT E'ab\n'::CHAR(10) < E'ab '::CHAR(10); - * even though '\n' is less than the space if CHAR(10) was - * space-extended. The correct solution would be to trim only - * the longer string to be the same length of the shorter, if - * possible, then do the comparison. However, changing this - * might break existing indexes, breaking binary upgrades. - * For details, see http://www.postgresql.org/message-id/CAK+WP1xdmyswEehMuetNztM4H199Z1w9KWRHVMKzyyFM+hV=zA@mail.gmail.com - */ len1 = bcTruelen(arg1); len2 = bcTruelen(arg2);