caching of queries with isammerge tables forbiden using general way

SQL_SELECT_LIMIT as default will be applied only for SELECT statement if there was not explicit LIMIT clause
correct table list passed to class constructor of select_update


mysql-test/r/subselect.result:
  do not show limit if it is not explicit
mysql-test/r/union.result:
  test of LIMIT + ORDER
mysql-test/t/union.test:
  test of LIMIT + ORDER
sql/ha_isammrg.h:
  caching of queries with isammerge tables forbiden
sql/sql_cache.cc:
  removed check on isammerge
sql/sql_lex.cc:
  tag of explicit limit in statement
sql/sql_lex.h:
  tag of explicit limit in statement
sql/sql_parse.cc:
  blanks in empty line removed
  no limit by default (SQL_SELECT_LIMIT as default will be applied only for SELECT statement if there was not explicit LIMIT clause)
sql/sql_union.cc:
  reverted incorrect patch
sql/sql_update.cc:
  reverted incorrect patch
  correct table list passed to class constructor
sql/sql_yacc.yy:
  explicit LIMIT marked

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/ha_isammrg.h b/sql/ha_isammrg.h
index 05c1d862eb3..289277a9dac 100644
--- a/sql/ha_isammrg.h
+++ b/sql/ha_isammrg.h
@@ -68,4 +68,5 @@ class ha_isammrg: public handler
   int create(const char *name, TABLE *form, HA_CREATE_INFO *create_info);
   THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
 			     enum thr_lock_type lock_type);
+  uint8 table_cache_type() { return HA_CACHE_TBL_NOCACHE; }
 };