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authorunknown <timour@mysql.com>2005-09-20 14:00:39 +0300
committerunknown <timour@mysql.com>2005-09-20 14:00:39 +0300
commit5f81fbb323d33c1060e364d8f9fda7bc1d378d2e (patch)
treed031eaf7feabd68d99d14853fcc0997336db1054 /sql
parent8607842ea0009e813f827676a501379b282c2362 (diff)
downloadmariadb-git-5f81fbb323d33c1060e364d8f9fda7bc1d378d2e.tar.gz
Fix for BUG#13127.
The problem was in the way table references are pre-filtered when resolving a qualified field. When resolving qualified table references we search recursively in the operands of the join. If there is natural/using join with a merge view, the first call to find_field_in_table_ref makes a recursive call to itself with the view as the new table reference to search for the column. However the view has both nested_join and join_columns != NULL so it skipped the test whether the view name matches the field qualifier. As a result the field was found in the view since the view already has a field with the same name. Thus the field was incorrectly resolved as the view field. mysql-test/r/select.result: Test for BUG#13127. mysql-test/t/select.test: Test for BUG#13127. sql/sql_base.cc: The patch contains two independent changes: - When searching for qualified fields, include merge views and information schema tables used with SHOW (both using TABLE_LIST::field_translation to represent result fields) in the test that compares the qualifying table with the name of the table reference being searched. This change fixes the bug. - Do not search the materialized list of columns of a NATURAL/USING join if 'table_list' is a stored table or merge view. Instead search directly in the table or view as if it is not under a natural join. This is a performance improvement since if 'table_list' is a stored table, then the search can utilize the name hash for table names.
Diffstat (limited to 'sql')
-rw-r--r--sql/sql_base.cc94
1 files changed, 63 insertions, 31 deletions
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index fb23093731a..d10c0d279d0 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -2948,6 +2948,18 @@ find_field_in_table(THD *thd, TABLE *table, const char *name, uint length,
belongs - differs from 'table_list' only for
NATURAL_USING joins.
+ DESCRIPTION
+ Find a field in a table reference depending on the type of table
+ reference. There are three types of table references with respect
+ to the representation of their result columns:
+ - an array of Field_translator objects for MERGE views and some
+ information_schema tables,
+ - an array of Field objects (and possibly a name hash) for stored
+ tables,
+ - a list of Natural_join_column objects for NATURAL/USING joins.
+ This procedure detects the type of the table reference 'table_list'
+ and calls the corresponding search routine.
+
RETURN
0 field is not found
view_ref_found found value in VIEW (real result is in *ref)
@@ -2971,16 +2983,30 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
/*
Check that the table and database that qualify the current field name
- are the same as the table we are going to search for the field.
- This is done differently for NATURAL/USING joins or nested joins that
- are operands of NATURAL/USING joins because there we can't simply
- compare the qualifying table and database names with the ones of
- 'table_list' because each field in such a join may originate from a
- different table.
+ are the same as the table reference we are going to search for the field.
+
+ We exclude from the test below NATURAL/USING joins and any nested join
+ that is an operand of NATURAL/USING join, because each column in such
+ joins may potentially originate from a different table. However, base
+ tables and views that are under some NATURAL/USING join are searched
+ as usual base tables/views.
+
+ We include explicitly table references with a 'field_translation' table,
+ because if there are views over natural joins we don't want to search
+ inside the view, but we want to search directly in the view columns
+ which are represented as a 'field_translation'.
+
TODO: Ensure that table_name, db_name and tables->db always points to
something !
*/
- if (!(table_list->nested_join && table_list->join_columns) &&
+ if (/* Exclude natural joins and nested joins underlying natural joins. */
+ (!(table_list->nested_join && table_list->join_columns) ||
+ /* Include merge views and information schema tables. */
+ table_list->field_translation) &&
+ /*
+ Test if the field qualifiers match the table reference we plan
+ to search.
+ */
table_name && table_name[0] &&
(my_strcasecmp(table_alias_charset, table_list->alias, table_name) ||
(db_name && db_name[0] && table_list->db && table_list->db[0] &&
@@ -2988,25 +3014,48 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
DBUG_RETURN(0);
*actual_table= NULL;
+
if (table_list->field_translation)
{
+ /* 'table_list' is a view or an information schema table. */
if ((fld= find_field_in_view(thd, table_list, name, item_name, length,
ref, check_grants_view,
register_tree_change)))
*actual_table= table_list;
}
- else if (table_list->nested_join && table_list->join_columns)
+ else if (!(table_list->nested_join && table_list->join_columns))
{
/*
- If this is a NATURAL/USING join, or an operand of such join which is a
- join itself, and the field name is qualified, then search for the field
- in the operands of the join.
+ 'table_list' is a stored table. It is so because the only type of nested
+ join passed to this procedure is a NATURAL/USING join or an operand of a
+ NATURAL/USING join.
+ */
+ if ((fld= find_field_in_table(thd, table_list->table, name, length,
+ check_grants_table, allow_rowid,
+ cached_field_index_ptr)))
+ *actual_table= table_list;
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+ /* check for views with temporary table algorithm */
+ if (check_grants_view && table_list->view &&
+ fld && fld != WRONG_GRANT &&
+ check_grant_column(thd, &table_list->grant,
+ table_list->view_db.str,
+ table_list->view_name.str,
+ name, length))
+ fld= WRONG_GRANT;
+#endif
+ }
+ else
+ {
+ /*
+ 'table_list' is a NATURAL/USING join, or an operand of such join that
+ is a nested join itself.
+
+ If the field name we search for is qualified, then search for the field
+ in the table references used by NATURAL/USING the join.
*/
if (table_name && table_name[0])
{
- /*
- Qualified field; Search for it in the tables used by the natural join.
- */
List_iterator<TABLE_LIST> it(table_list->nested_join->join_list);
TABLE_LIST *table;
while ((table= it++))
@@ -3032,23 +3081,6 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
check_grants_table || check_grants_view,
register_tree_change, actual_table);
}
- else
- {
- if ((fld= find_field_in_table(thd, table_list->table, name, length,
- check_grants_table, allow_rowid,
- cached_field_index_ptr)))
- *actual_table= table_list;
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
- /* check for views with temporary table algorithm */
- if (check_grants_view && table_list->view &&
- fld && fld != WRONG_GRANT &&
- check_grant_column(thd, &table_list->grant,
- table_list->view_db.str,
- table_list->view_name.str,
- name, length))
- fld= WRONG_GRANT;
-#endif
- }
DBUG_RETURN(fld);
}
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