Bug#55222 - RB://517 - Approved by Sunny

InnoDB does not attempt to handle lower_case_table_names == 2 when looking
up foreign table names and referenced table name.  It turned that server
variable into a boolean and ignored the possibility of it being '2'.  

The setting lower_case_table_names == 2 means that it should be stored and
displayed in mixed case as given, but compared internally in lower case.
Normally the server deals with this since it stores table names.  But
InnoDB stores referential constraints for the server, so it needs to keep
track of both lower case and given names.

This solution creates two table name pointers for each foreign and referenced
table name.  One to display the name, and one to look it up.  Both pointers
point to the same allocated string unless this setting is 2.  So the overhead
added is not too much.

Two functions are created in dict0mem.c to populate the ..._lookup versions
of these pointers.  Both dict_mem_foreign_table_name_lookup_set() and
dict_mem_referenced_table_name_lookup_set() are called 5 times each.

1 files changed, 55 insertions, 0 deletions

diff --git a/storage/innobase/dict/dict0mem.c b/storage/innobase/dict/dict0mem.c
index bbb8f810f44..32b02e3180f 100644
--- a/storage/innobase/dict/dict0mem.c
+++ b/storage/innobase/dict/dict0mem.c
@@ -33,6 +33,7 @@ Created 1/8/1996 Heikki Tuuri
 #include "data0type.h"
 #include "mach0data.h"
 #include "dict0dict.h"
+#include "srv0srv.h" /* srv_lower_case_table_names */
 #ifndef UNIV_HOTBACKUP
 # include "lock0lock.h"
 #endif /* !UNIV_HOTBACKUP */
@@ -288,6 +289,60 @@ dict_mem_foreign_create(void)
 }
 
 /**********************************************************************//**
+Sets the foreign_table_name_lookup pointer based on the value of
+srv_lower_case_table_names.  If that is 0 or 1, foreign_table_name_lookup
+will point to foreign_table_name.  If 2, then another string is allocated
+of the heap and set to lower case. */
+UNIV_INLINE
+void
+dict_mem_foreign_table_name_lookup_set(
+/*===================================*/
+	dict_foreign_t*	foreign,	/*!< in/out: foreign struct */
+	ibool		do_alloc)	/*!< in: is an alloc needed */
+{
+	if (srv_lower_case_table_names == 2) {
+		if (do_alloc) {
+			foreign->foreign_table_name_lookup = mem_heap_alloc(
+				foreign->heap,
+				strlen(foreign->foreign_table_name) + 1);
+		}
+		strcpy(foreign->foreign_table_name_lookup,
+		       foreign->foreign_table_name);
+		innobase_casedn_str(foreign->foreign_table_name_lookup);
+	} else {
+		foreign->foreign_table_name_lookup
+			= foreign->foreign_table_name;
+	}
+}
+
+/**********************************************************************//**
+Sets the referenced_table_name_lookup pointer based on the value of
+srv_lower_case_table_names.  If that is 0 or 1,
+referenced_table_name_lookup will point to referenced_table_name.  If 2,
+then another string is allocated of the heap and set to lower case. */
+UNIV_INLINE
+void
+dict_mem_referenced_table_name_lookup_set(
+/*======================================*/
+	dict_foreign_t*	foreign,	/*!< in/out: foreign struct */
+	ibool		do_alloc)	/*!< in: is an alloc needed */
+{
+	if (srv_lower_case_table_names == 2) {
+		if (do_alloc) {
+			foreign->referenced_table_name_lookup = mem_heap_alloc(
+				foreign->heap,
+				strlen(foreign->referenced_table_name) + 1);
+		}
+		strcpy(foreign->referenced_table_name_lookup,
+		       foreign->referenced_table_name);
+		innobase_casedn_str(foreign->referenced_table_name_lookup);
+	} else {
+		foreign->referenced_table_name_lookup
+			= foreign->referenced_table_name;
+	}
+}
+
+/**********************************************************************//**
 Adds a field definition to an index. NOTE: does not take a copy
 of the column name if the field is a column. The memory occupied
 by the column name may be released only after publishing the index. */