bk commit into 5.0 tree (kroki:1.2241) BUG#19111

[kroki]

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ChangeSet@stripped, 2006-10-10 13:44:04+04:00, kroki@stripped +3 -0
  Bug#19111: TRIGGERs selecting from a VIEW on the firing base table fail.
  
  In a trigger or a function used in a statement it is possible to do
  SELECT from a table being modified by the statement.  However,
  encapsulation of such SELECT into a view and selecting from a view
  instead of direct SELECT was not possible.
  
  This happened because tables used by views (which in their turn
  were used from functions/triggers) were not excluded from checks
  in unique_table() routine as it happens for the rest of tables
  added to the statement table list for prelocking.
  
  With this fix we ignore all such tables in unique_table(), thus
  providing consistency: inside a trigger or a functions SELECT from
  a view may be used where plain SELECT is allowed.  Modification of
  the same table from function or trigger is still disallowed.  Also,
  this patch doesn't affect the case where SELECT from the table being
  modified is done outside of function of trigger, such SELECTs are
  still disallowed (this limitation and visibility problem when function
  select from a table being modified are subjects of bug 21326).  See
  also bug 22427.

  mysql-test/r/view.result@stripped, 2006-10-10 13:44:01+04:00, kroki@stripped +16 -1
    Add result for bug#19111: TRIGGERs selecting from a VIEW on the
    firing base table fail.

  mysql-test/t/view.test@stripped, 2006-10-10 13:44:02+04:00, kroki@stripped +38 -1
    Add test case for bug#19111: TRIGGERs selecting from a VIEW on the
    firing base table fail.

  sql/sql_base.cc@stripped, 2006-10-10 13:44:02+04:00, kroki@stripped +8 -3
    In unique_table() do not check tables that are used in a stored
    function or a trigger ('prelocking_placeholder' is set).  If such
    function or a trigger will attempt to modify a table, the error will
    be given, however select is allowed there.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	kroki
# Host:	moonlight.intranet
# Root:	/home/tomash/src/mysql_ab/mysql-5.0-bug19111

--- 1.344/sql/sql_base.cc	2006-10-10 13:44:11 +04:00
+++ 1.345/sql/sql_base.cc	2006-10-10 13:44:11 +04:00
@@ -805,6 +805,10 @@ TABLE_LIST *find_table_in_list(TABLE_LIS
     Also SELECT::exclude_from_table_unique_test used to exclude from check
     tables of main SELECT of multi-delete and multi-update
 
+    We also skip tables with TABLE_LIST::prelocking_placeholder set,
+    because we want to allow SELECTs from them, and their modification
+    will rise the error anyway.
+
     TODO: when we will have table/view change detection we can do this check
           only once for PS/SP
 
@@ -851,12 +855,13 @@ TABLE_LIST* unique_table(THD *thd, TABLE
     if (((! (res= find_table_in_global_list(table_list, d_name, t_name))) &&
          (! (res= mysql_lock_have_duplicate(thd, table, table_list)))) ||
         ((!res->table || res->table != table->table) &&
-         res->select_lex && !res->select_lex->exclude_from_table_unique_test))
+         res->select_lex && !res->select_lex->exclude_from_table_unique_test &&
+         !res->prelocking_placeholder))
       break;
     /*
-      If we found entry of this table or or table of SELECT which already
+      If we found entry of this table or table of SELECT which already
       processed in derived table or top select of multi-update/multi-delete
-      (exclude_from_table_unique_test).
+      (exclude_from_table_unique_test) or prelocking placeholder.
     */
     table_list= res->next_global;
     DBUG_PRINT("info",

--- 1.162/mysql-test/r/view.result	2006-10-10 13:44:11 +04:00
+++ 1.163/mysql-test/r/view.result	2006-10-10 13:44:11 +04:00
@@ -2735,4 +2735,19 @@ m	e
 4	a
 1	b
 DROP VIEW v1;
-DROP TABLE IF EXISTS t1,t2;
+DROP TABLE t1,t2;
+DROP FUNCTION IF EXISTS f1;
+DROP VIEW IF EXISTS v1;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (i INT);
+INSERT INTO t1 VALUES (1);
+CREATE VIEW v1 AS SELECT MAX(i) FROM t1;
+CREATE TRIGGER t1_bi BEFORE INSERT ON t1 FOR EACH ROW
+SET NEW.i = (SELECT * FROM v1) + 1;
+INSERT INTO t1 VALUES (1);
+CREATE FUNCTION f1() RETURNS INT RETURN (SELECT * FROM v1);
+UPDATE t1 SET i= f1();
+DROP FUNCTION f1;
+DROP VIEW v1;
+DROP TABLE t1;
+End of 5.0 tests.

--- 1.147/mysql-test/t/view.test	2006-10-10 13:44:11 +04:00
+++ 1.148/mysql-test/t/view.test	2006-10-10 13:44:11 +04:00
@@ -2595,4 +2595,41 @@ CREATE TABLE t2 SELECT * FROM v1;
 SELECT * FROM t2;
 
 DROP VIEW v1;
-DROP TABLE IF EXISTS t1,t2;
+DROP TABLE t1,t2;
+
+
+#
+# Bug#19111: TRIGGERs selecting from a VIEW on the firing base table
+# fail
+#
+# Allow to select from a view on a table being modified in a trigger
+# and stored function, since plain select is allowed there.
+#
+--disable_warnings
+DROP FUNCTION IF EXISTS f1;
+DROP VIEW IF EXISTS v1;
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (i INT);
+INSERT INTO t1 VALUES (1);
+
+CREATE VIEW v1 AS SELECT MAX(i) FROM t1;
+
+# Plain 'SET NEW.i = (SELECT MAX(i) FROM t1) + 1' works, so select
+# from a view should work too.
+CREATE TRIGGER t1_bi BEFORE INSERT ON t1 FOR EACH ROW
+  SET NEW.i = (SELECT * FROM v1) + 1;
+INSERT INTO t1 VALUES (1);
+
+# Plain 'RETURN (SELECT MAX(i) FROM t1)' works in INSERT, so select
+# from a view should work too.
+CREATE FUNCTION f1() RETURNS INT RETURN (SELECT * FROM v1);
+UPDATE t1 SET i= f1();
+
+DROP FUNCTION f1;
+DROP VIEW v1;
+DROP TABLE t1;
+
+
+--echo End of 5.0 tests.