Here is an updated patch for this.
I have added some more documentation based on the discussions, including
some examples taken directly from the emails here.
One thing I have been struggling with a bit is the correct use of
LIKE_FALSE versus LIKE_ABORT in the MatchText() code. I have made some
small tweaks about this in this version that I think are more correct,
but it could use another look. Maybe also some more tests to verify
this one way or the other.
On 30.04.24 14:39, Daniel Verite wrote:
Peter Eisentraut wrote:
This patch adds support for using LIKE with nondeterministic
collations. So you can do things such as
col LIKE 'foo%' COLLATE case_insensitive
Nice!
The pattern is partitioned into substrings at wildcard characters
(so 'foo%bar' is partitioned into 'foo', '%', 'bar') and then then
whole predicate matches if a match can be found for each partition
under the applicable collation
Trying with a collation that ignores punctuation:
postgres=# CREATE COLLATION "ign_punct" (
provider = 'icu',
locale='und-u-ka-shifted',
deterministic = false
);
postgres=# SELECT '.foo.' like 'foo' COLLATE ign_punct;
?column?
----------
t
(1 row)
postgres=# SELECT '.foo.' like 'f_o' COLLATE ign_punct;
?column?
----------
t
(1 row)
postgres=# SELECT '.foo.' like '_oo' COLLATE ign_punct;
?column?
----------
f
(1 row)
The first two results look fine, but the next one is inconsistent.
From 34f5bb1e8f0ffbb39b1efc9777736f6b4d6c4caa Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Fri, 28 Jun 2024 06:55:45 +0200
Subject: [PATCH v2] Support LIKE with nondeterministic collations
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This allows for example using LIKE with case-insensitive collations.
There was previously no internal implementation of this, so it was met
with a not-supported error. This adds the internal implementation and
removes the error.
Unlike with deterministic collations, the LIKE matching cannot go
character by character but has to go substring by substring. For
example, if we are matching against LIKE 'foo%bar', we can't start by
looking for an 'f', then an 'o', but instead with have to find
something that matches 'foo'. This is because the collation could
consider substrings of different lengths to be equal. This is all
internal to MatchText() in like_match.c.
The changes in GenericMatchText() in like.c just pass through the
locale information to MatchText(), which was previously not needed.
This matches exactly Generic_Text_IC_like() below.
Note that ILIKE is not affected. It's unclear whether ILIKE makes
sense under nondeterministic collations.
This also updates match_pattern_prefix() in like_support.c to support
optimizing the case of an exact pattern with nondeterministic
collations. This was already alluded to in the previous code.
(includes documentation examples from Daniel Vérité)
Discussion:
https://www.postgresql.org/message-id/flat/700d2e86-bf75-4607-9cf2-f5b7802f6...@eisentraut.org
---
doc/src/sgml/charset.sgml | 2 +-
doc/src/sgml/func.sgml | 51 +++++++-
src/backend/utils/adt/like.c | 30 +++--
src/backend/utils/adt/like_match.c | 118 ++++++++++++++++++
src/backend/utils/adt/like_support.c | 29 ++---
.../regress/expected/collate.icu.utf8.out | 81 ++++++++++--
src/test/regress/sql/collate.icu.utf8.sql | 23 +++-
7 files changed, 292 insertions(+), 42 deletions(-)
diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml
index 834cb30c85a..533b3af9045 100644
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@@ -1197,7 +1197,7 @@ <title>Nondeterministic Collations</title>
to a performance penalty. Note, in particular, that B-tree cannot use
deduplication with indexes that use a nondeterministic collation. Also,
certain operations are not possible with nondeterministic collations,
- such as pattern matching operations. Therefore, they should be used
+ such as some pattern matching operations. Therefore, they should be used
only in cases where they are specifically wanted.
</para>
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2609269610b..833db120cb3 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -5374,9 +5374,10 @@ <title>Pattern Matching</title>
</caution>
<para>
- The pattern matching operators of all three kinds do not support
- nondeterministic collations. If required, apply a different collation to
- the expression to work around this limitation.
+ <function>SIMILAR TO</function> and <acronym>POSIX</acronym>-style regular
+ expressions do not support nondeterministic collations. If required, use
+ <function>LIKE</function> or apply a different collation to the expression
+ to work around this limitation.
</para>
<sect2 id="functions-like">
@@ -5422,6 +5423,45 @@ <title><function>LIKE</function></title>
</programlisting>
</para>
+ <para>
+ <function>LIKE</function> pattern matching supports nondeterministic
+ collations (see <xref linkend="collation-nondeterministic"/>), such as
+ case-insensitive collations or collations that, say, ignore punctuation.
+ So with a case-insensitive collation, one could have:
+<programlisting>
+'AbC' LIKE 'abc' COLLATE case_insensitive
<lineannotation>true</lineannotation>
+'AbC' LIKE 'a%' COLLATE case_insensitive
<lineannotation>true</lineannotation>
+</programlisting>
+ With collations that ignore certain characters or in general that consider
+ strings of different lengths equal, the semantics can become a bit more
+ complicated. Consider these examples:
+<programlisting>
+'.foo.' LIKE 'foo' COLLATE ign_punct <lineannotation>true</lineannotation>
+'.foo.' LIKE 'f_o' COLLATE ign_punct <lineannotation>true</lineannotation>
+'.foo.' LIKE '_oo' COLLATE ign_punct <lineannotation>false</lineannotation>
+</programlisting>
+ The way the matching works is that the pattern is partitioned into
+ sequences of wildcards and non-wildcard strings. For example, the pattern
+ <literal>f_o</literal> is partitioned into <literal>f, _, o</literal>, the
+ pattern <literal>_oo</literal> is partitioned into <literal>_,
+ oo</literal>. The input string matches the pattern if it can be
+ partitioned in such a way that the wildcards match one character or any
+ number of characters respectively and the non-wildcard partitions are
+ equal under the applicable collation. So for example, <literal>'.foo.'
+ LIKE 'f_o' COLLATE ign_punct</literal> is true because one can partition
+ <literal>.foo.</literal> into <literal>.f, o, o.</literal>, and then
+ <literal>'.f' = 'f' COLLATE ign_punct</literal>, <literal>'o'</literal>
+ matches the <literal>_</literal> wildcard, and <literal>'o.' = 'o' COLLATE
+ ign_punct</literal>. But <literal>'.foo.' LIKE '_oo' COLLATE
+ ign_punct</literal> is false because <literal>.foo.</literal> cannot be
+ partitioned in a way that the first character is any character and the
+ rest of the string compares equal to <literal>oo</literal>. (Note that
+ the single-character wildcard always matches exactly one character,
+ independent of the collation. So in this example, the
+ <literal>_</literal> would match <literal>.</literal>, but then the rest
+ of the input string won't match the rest of the pattern.)
+ </para>
+
<para>
<function>LIKE</function> pattern matching always covers the entire
string. Therefore, if it's desired to match a sequence anywhere within
@@ -5463,8 +5503,9 @@ <title><function>LIKE</function></title>
<para>
The key word <token>ILIKE</token> can be used instead of
- <token>LIKE</token> to make the match case-insensitive according
- to the active locale. This is not in the <acronym>SQL</acronym> standard
but is a
+ <token>LIKE</token> to make the match case-insensitive according to the
+ active locale. (But this does not support nondeterministic collations.)
+ This is not in the <acronym>SQL</acronym> standard but is a
<productname>PostgreSQL</productname> extension.
</para>
diff --git a/src/backend/utils/adt/like.c b/src/backend/utils/adt/like.c
index 57ead66b5aa..bbbe6c09d18 100644
--- a/src/backend/utils/adt/like.c
+++ b/src/backend/utils/adt/like.c
@@ -149,22 +149,32 @@ SB_lower_char(unsigned char c, pg_locale_t locale, bool
locale_is_c)
static inline int
GenericMatchText(const char *s, int slen, const char *p, int plen, Oid
collation)
{
- if (collation && !lc_ctype_is_c(collation))
- {
- pg_locale_t locale = pg_newlocale_from_collation(collation);
+ pg_locale_t locale = 0;
+ bool locale_is_c = false;
- if (!pg_locale_deterministic(locale))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("nondeterministic collations
are not supported for LIKE")));
+ if (!OidIsValid(collation))
+ {
+ /*
+ * This typically means that the parser could not resolve a
conflict
+ * of implicit collations, so report it that way.
+ */
+ ereport(ERROR,
+ (errcode(ERRCODE_INDETERMINATE_COLLATION),
+ errmsg("could not determine which collation to
use for LIKE"),
+ errhint("Use the COLLATE clause to set the
collation explicitly.")));
}
+ if (lc_ctype_is_c(collation))
+ locale_is_c = true;
+ else
+ locale = pg_newlocale_from_collation(collation);
+
if (pg_database_encoding_max_length() == 1)
- return SB_MatchText(s, slen, p, plen, 0, true);
+ return SB_MatchText(s, slen, p, plen, locale, locale_is_c);
else if (GetDatabaseEncoding() == PG_UTF8)
- return UTF8_MatchText(s, slen, p, plen, 0, true);
+ return UTF8_MatchText(s, slen, p, plen, locale, locale_is_c);
else
- return MB_MatchText(s, slen, p, plen, 0, true);
+ return MB_MatchText(s, slen, p, plen, locale, locale_is_c);
}
static inline int
diff --git a/src/backend/utils/adt/like_match.c
b/src/backend/utils/adt/like_match.c
index f2990edff7e..0751b329b8e 100644
--- a/src/backend/utils/adt/like_match.c
+++ b/src/backend/utils/adt/like_match.c
@@ -198,6 +198,124 @@ MatchText(const char *t, int tlen, const char *p, int
plen,
NextByte(p, plen);
continue;
}
+ else if (locale && !locale->deterministic)
+ {
+ /*
+ * For nondeterministic locales, we find the next
substring of the
+ * pattern that does not contain wildcards and try to
find a
+ * matching substring in the text. Crucially, we
cannot do this
+ * character by character, as in the normal case, but
must do it
+ * substring by substring, partitioned by the wildcard
characters.
+ */
+ const char *p1;
+ size_t p1len;
+ const char *t1;
+ size_t t1len;
+ bool found_escape;
+ const char *subpat;
+ size_t subpatlen;
+ char *buf = NULL;
+
+ /*
+ * Determine next substring of pattern without
wildcards. p is
+ * the start of the subpattern, p1 is one past the last
byte. Also
+ * track if we found an escape character.
+ */
+ p1 = p;
+ p1len = plen;
+ found_escape = false;
+ while (p1len > 0)
+ {
+ if (*p1 == '\\')
+ {
+ found_escape = true;
+ NextByte(p1, p1len);
+ }
+ else if (*p1 == '_' || *p1 == '%')
+ break;
+ NextByte(p1, p1len);
+ }
+
+ /*
+ * If we found an escape character, then make an
unescaped copy of
+ * the subpattern.
+ */
+ if (found_escape)
+ {
+ char *b;
+
+ b = buf = palloc(p1 - p);
+ for (const char *c = p; c < p1; c++)
+ {
+ if (*c == '\\')
+ ;
+ else
+ *(b++) = *c;
+ }
+
+ subpat = buf;
+ subpatlen = b - buf;
+ }
+ else
+ {
+ subpat = p;
+ subpatlen = p1 - p;
+ }
+
+ /*
+ * Now build a substring of the text and try to match
it against
+ * the subpattern. t is the start of the text, t1 is
one past the
+ * last byte. We start with a zero-length string.
+ */
+ t1 = t;
+ t1len = tlen;
+ for (;;)
+ {
+ int cmp;
+
+ cmp = pg_strncoll(subpat, subpatlen, t, (t1 -
t), locale);
+
+ /*
+ * If we found a match, we have to test if the
rest of pattern
+ * can match against the rest of the string.
Otherwise we
+ * have to continue here try matching with a
longer substring.
+ * (This is similar to the recursion for the
'%' wildcard
+ * above.)
+ *
+ * Note that we can't just wind forward p and t
and continue
+ * with the main loop. This would fail for
example with
+ *
+ * U&'\0061\0308bc' LIKE U&'\00E4_c' COLLATE
ignore_accents
+ *
+ * You'd find that t=\0061 matches p=\00E4, but
then the rest
+ * won't match; but t=\0061\0308 also matches
p=\00E4, and
+ * then the rest will match.
+ */
+ if (cmp == 0)
+ {
+ int matched =
MatchText(t1, t1len, p1, p1len, locale, locale_is_c);
+
+ if (matched == LIKE_TRUE)
+ {
+ if (buf)
+ pfree(buf);
+ return matched;
+ }
+ }
+
+ /*
+ * Didn't match. If we used up the whole text,
then the match
+ * fails. Otherwise, try again with a longer
substring.
+ */
+ if (t1len == 0)
+ return LIKE_FALSE;
+ else
+ NextChar(t1, t1len);
+ }
+ if (buf)
+ pfree(buf);
+ continue;
+ }
else if (GETCHAR(*p) != GETCHAR(*t))
{
/* non-wildcard pattern char fails to match text char */
diff --git a/src/backend/utils/adt/like_support.c
b/src/backend/utils/adt/like_support.c
index 2635050861f..3c691a5cc95 100644
--- a/src/backend/utils/adt/like_support.c
+++ b/src/backend/utils/adt/like_support.c
@@ -272,22 +272,6 @@ match_pattern_prefix(Node *leftop,
return NIL;
patt = (Const *) rightop;
- /*
- * Not supported if the expression collation is nondeterministic. The
- * optimized equality or prefix tests use bytewise comparisons, which is
- * not consistent with nondeterministic collations. The actual
- * pattern-matching implementation functions will later error out that
- * pattern-matching is not supported with nondeterministic collations.
(We
- * could also error out here, but by doing it later we get more precise
- * error messages.) (It should be possible to support at least
- * Pattern_Prefix_Exact, but no point as long as the actual
- * pattern-matching implementations don't support it.)
- *
- * expr_coll is not set for a non-collation-aware data type such as
bytea.
- */
- if (expr_coll && !get_collation_isdeterministic(expr_coll))
- return NIL;
-
/*
* Try to extract a fixed prefix from the pattern.
*/
@@ -404,6 +388,8 @@ match_pattern_prefix(Node *leftop,
{
if (!op_in_opfamily(eqopr, opfamily))
return NIL;
+ if (indexcollation != expr_coll)
+ return NIL;
expr = make_opclause(eqopr, BOOLOID, false,
(Expr *) leftop, (Expr
*) prefix,
InvalidOid,
indexcollation);
@@ -411,6 +397,17 @@ match_pattern_prefix(Node *leftop,
return result;
}
+ /*
+ * Anything other than Pattern_Prefix_Exact is not supported if the
+ * expression collation is nondeterministic. The optimized equality or
+ * prefix tests use bytewise comparisons, which is not consistent with
+ * nondeterministic collations.
+ *
+ * expr_coll is not set for a non-collation-aware data type such as
bytea.
+ */
+ if (expr_coll && !get_collation_isdeterministic(expr_coll))
+ return NIL;
+
/*
* Otherwise, we have a nonempty required prefix of the values. Some
* opclasses support prefix checks directly, otherwise we'll try to
diff --git a/src/test/regress/expected/collate.icu.utf8.out
b/src/test/regress/expected/collate.icu.utf8.out
index 7d59fb44316..8bfdf33c2fa 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1272,6 +1272,30 @@ CREATE COLLATION ctest_det (provider = icu, locale = '',
deterministic = true);
NOTICE: using standard form "und" for ICU locale ""
CREATE COLLATION ctest_nondet (provider = icu, locale = '', deterministic =
false);
NOTICE: using standard form "und" for ICU locale ""
+SELECT 'abc' LIKE 'abc' COLLATE ctest_det;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT 'abc' LIKE 'a\bc' COLLATE ctest_det;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT 'abc' LIKE 'abc' COLLATE ctest_nondet;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT 'abc' LIKE 'a\bc' COLLATE ctest_nondet;
+ ?column?
+----------
+ t
+(1 row)
+
CREATE TABLE test6 (a int, b text);
-- same string in different normal forms
INSERT INTO test6 VALUES (1, U&'\00E4bc');
@@ -1296,6 +1320,19 @@ SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_nondet;
2 | äbc
(2 rows)
+SELECT * FROM test6 WHERE b LIKE 'äbc' COLLATE ctest_det;
+ a | b
+---+-----
+ 1 | äbc
+(1 row)
+
+SELECT * FROM test6 WHERE b LIKE 'äbc' COLLATE ctest_nondet;
+ a | b
+---+-----
+ 1 | äbc
+ 2 | äbc
+(2 rows)
+
-- same with arrays
CREATE TABLE test6a (a int, b text[]);
INSERT INTO test6a VALUES (1, ARRAY[U&'\00E4bc']);
@@ -1512,7 +1549,12 @@ SELECT x FROM test3ci WHERE x <> 'abc';
(2 rows)
SELECT x FROM test3ci WHERE x LIKE 'a%';
-ERROR: nondeterministic collations are not supported for LIKE
+ x
+-----
+ abc
+ ABC
+(2 rows)
+
SELECT x FROM test3ci WHERE x ILIKE 'a%';
ERROR: nondeterministic collations are not supported for ILIKE
SELECT x FROM test3ci WHERE x SIMILAR TO 'a%';
@@ -1630,7 +1672,12 @@ SELECT x FROM test3bpci WHERE x <> 'abc';
(2 rows)
SELECT x FROM test3bpci WHERE x LIKE 'a%';
-ERROR: nondeterministic collations are not supported for LIKE
+ x
+-----
+ abc
+ ABC
+(2 rows)
+
SELECT x FROM test3bpci WHERE x ILIKE 'a%';
ERROR: nondeterministic collations are not supported for ILIKE
SELECT x FROM test3bpci WHERE x SIMILAR TO 'a%';
@@ -1727,7 +1774,7 @@ SELECT string_to_array('ABCDEFGHI'::char(9) COLLATE
case_insensitive, NULL, 'b')
-- This tests the issue described in match_pattern_prefix(). In the
-- absence of that check, the case_insensitive tests below would
-- return no rows where they should logically return one.
-CREATE TABLE test4c (x text COLLATE "C");
+CREATE TABLE test4c (x text COLLATE case_insensitive);
INSERT INTO test4c VALUES ('abc');
CREATE INDEX ON test4c (x);
SET enable_seqscan = off;
@@ -1741,10 +1788,18 @@ SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE
case_sensitive; -- ok, no rows
---
(0 rows)
-SELECT x FROM test4c WHERE x LIKE 'ABC' COLLATE case_insensitive; -- error
-ERROR: nondeterministic collations are not supported for LIKE
-SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE case_insensitive; -- error
-ERROR: nondeterministic collations are not supported for LIKE
+SELECT x FROM test4c WHERE x LIKE 'ABC' COLLATE case_insensitive; -- ok
+ x
+-----
+ abc
+(1 row)
+
+SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE case_insensitive; -- ok
+ x
+-----
+ abc
+(1 row)
+
RESET enable_seqscan;
-- Unicode special case: different variants of Greek lower case sigma.
-- A naive implementation like citext that just does lower(x) =
@@ -1838,6 +1893,18 @@ SELECT * FROM test4 WHERE b = 'Cote' COLLATE
case_insensitive;
1 | cote
(1 row)
+-- This is a tricky one. A naive implementation would first test
+-- \00E4 matches \0061, which is true under ignore_accents, but then
+-- the rest of the string won't match anymore. Therefore, the
+-- algorithm has to test whether the rest of the string matches, and
+-- if not try matching \00E4 against a longer substring like
+-- \0061\0308, which will then work out.
+SELECT U&'\0061\0308bc' LIKE U&'\00E4_c' COLLATE ignore_accents;
+ ?column?
+----------
+ t
+(1 row)
+
-- foreign keys (should use collation of primary key)
-- PK is case-sensitive, FK is case-insensitive
CREATE TABLE test10pk (x text COLLATE case_sensitive PRIMARY KEY);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql
b/src/test/regress/sql/collate.icu.utf8.sql
index 80f28a97d78..481a995c998 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -514,6 +514,12 @@ CREATE COLLATION testcoll_rulesx (provider = icu, locale =
'', rules = '!!wrong!
CREATE COLLATION ctest_det (provider = icu, locale = '', deterministic = true);
CREATE COLLATION ctest_nondet (provider = icu, locale = '', deterministic =
false);
+SELECT 'abc' LIKE 'abc' COLLATE ctest_det;
+SELECT 'abc' LIKE 'a\bc' COLLATE ctest_det;
+
+SELECT 'abc' LIKE 'abc' COLLATE ctest_nondet;
+SELECT 'abc' LIKE 'a\bc' COLLATE ctest_nondet;
+
CREATE TABLE test6 (a int, b text);
-- same string in different normal forms
INSERT INTO test6 VALUES (1, U&'\00E4bc');
@@ -522,6 +528,9 @@ CREATE TABLE test6 (a int, b text);
SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_det;
SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_nondet;
+SELECT * FROM test6 WHERE b LIKE 'äbc' COLLATE ctest_det;
+SELECT * FROM test6 WHERE b LIKE 'äbc' COLLATE ctest_nondet;
+
-- same with arrays
CREATE TABLE test6a (a int, b text[]);
INSERT INTO test6a VALUES (1, ARRAY[U&'\00E4bc']);
@@ -637,14 +646,14 @@ CREATE UNIQUE INDEX ON test3bpci (x); -- error
-- This tests the issue described in match_pattern_prefix(). In the
-- absence of that check, the case_insensitive tests below would
-- return no rows where they should logically return one.
-CREATE TABLE test4c (x text COLLATE "C");
+CREATE TABLE test4c (x text COLLATE case_insensitive);
INSERT INTO test4c VALUES ('abc');
CREATE INDEX ON test4c (x);
SET enable_seqscan = off;
SELECT x FROM test4c WHERE x LIKE 'ABC' COLLATE case_sensitive; -- ok, no rows
SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE case_sensitive; -- ok, no
rows
-SELECT x FROM test4c WHERE x LIKE 'ABC' COLLATE case_insensitive; -- error
-SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE case_insensitive; -- error
+SELECT x FROM test4c WHERE x LIKE 'ABC' COLLATE case_insensitive; -- ok
+SELECT x FROM test4c WHERE x LIKE 'ABC%' COLLATE case_insensitive; -- ok
RESET enable_seqscan;
-- Unicode special case: different variants of Greek lower case sigma.
@@ -687,6 +696,14 @@ CREATE TABLE test4 (a int, b text);
SELECT * FROM test4 WHERE b = 'Cote' COLLATE ignore_accents; -- still
case-sensitive
SELECT * FROM test4 WHERE b = 'Cote' COLLATE case_insensitive;
+-- This is a tricky one. A naive implementation would first test
+-- \00E4 matches \0061, which is true under ignore_accents, but then
+-- the rest of the string won't match anymore. Therefore, the
+-- algorithm has to test whether the rest of the string matches, and
+-- if not try matching \00E4 against a longer substring like
+-- \0061\0308, which will then work out.
+SELECT U&'\0061\0308bc' LIKE U&'\00E4_c' COLLATE ignore_accents;
+
-- foreign keys (should use collation of primary key)
-- PK is case-sensitive, FK is case-insensitive
base-commit: 3e53492aa7084bceaa92757c90e067d79768797e
--
2.45.2
