Bug #30269 Query cache eats memory

Although the query cache doesn't support retrieval of statements containing
column level access control, it was still possible to cache such statements
thus wasting memory.

This patch extends the access control check on the target tables to avoid
caching a statement with column level restrictions. 


mysql-test/r/query_cache.result:
  Added test
mysql-test/t/query_cache.test:
  Added test
sql/sql_cache.cc:
  The function check_table_access leaves the artifact
  grant.want_privileges= 1, if a statement refers to tables with column level
  privileges. To avoid the statement from being stored into the query cache,
  it is enough to check this flag and set 'safe_to_cache_query' to zero.
sql/sql_cache.h:
  - Removed 'static' attribute or class methods
  - Added THD parameter to process_and_count_tables

1 files changed, 24 insertions, 0 deletions

diff --git a/mysql-test/r/query_cache.result b/mysql-test/r/query_cache.result
index f1f99012910..ecf7df2d2ae 100644
--- a/mysql-test/r/query_cache.result
+++ b/mysql-test/r/query_cache.result
@@ -1502,6 +1502,30 @@ a	(select count(*) from t2)
 3	0
 4	0
 drop table t1,t2;
+DROP DATABASE IF EXISTS bug30269;
+CREATE DATABASE bug30269;
+USE bug30269;
+CREATE TABLE test1 (id int, name varchar(23));
+CREATE VIEW view1 AS SELECT id FROM test1;
+INSERT INTO test1 VALUES (5, 'testit');
+GRANT SELECT (id) ON TABLE bug30269.test1 TO 'bug30269'@'localhost';
+GRANT SELECT ON TABLE bug30269.view1 TO 'bug30269'@'localhost';
+set global query_cache_size= 81920;
+USE bug30269;
+show status like 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	0
+SELECT id FROM test1 WHERE id>2;
+id
+5
+SELECT id FROM view1 WHERE id>2;
+id
+5
+show status like 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	0
+DROP DATABASE bug30269;
+DROP USER 'bug30269'@'localhost';
 set GLOBAL query_cache_type=default;
 set GLOBAL query_cache_limit=default;
 set GLOBAL query_cache_min_res_unit=default;