MDEV-6513 deprecate engine_condition_pushdown value of the @@optimizer_switch

* ignore the OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN bit
* issue a deprecation warning on 'engine_condition_pushdown=on'
* remove unused remains of the old pre-5.5 engine_condition_pushdown variable

8 files changed, 16 insertions, 42 deletions

diff --git a/sql/handler.h b/sql/handler.h
index 703d1c615b3..4ba312963ac 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -197,17 +197,11 @@ enum enum_alter_inplace_result {
 #define HA_RECORD_MUST_BE_CLEAN_ON_WRITE (1ULL << 41)
 
 /*
-  Table condition pushdown must be performed regardless of
-  'engine_condition_pushdown' setting.
-
-  This flag is aimed at storage engines that come with "special" predicates
-  that can only be evaluated inside the storage engine.  
-  For example, when one does 
-    select * from sphinx_table where query='{fulltext_query}'
-  then the "query=..." condition must be always pushed down into storage
-  engine.
+  This storage engine supports condition pushdown
 */
-#define HA_MUST_USE_TABLE_CONDITION_PUSHDOWN (1ULL << 42)
+#define HA_CAN_TABLE_CONDITION_PUSHDOWN (1ULL << 42)
+/* old name for the same flag */
+#define HA_MUST_USE_TABLE_CONDITION_PUSHDOWN HA_CAN_TABLE_CONDITION_PUSHDOWN
 
 /**
   The handler supports read before write removal optimization
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 6f0cbc24e63..31d51123f8d 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -8807,18 +8807,6 @@ mysqld_get_one_option(int optid,
     }
     break;
 #endif /* defined(ENABLED_DEBUG_SYNC) */
-  case OPT_ENGINE_CONDITION_PUSHDOWN:
-    /*
-      The last of --engine-condition-pushdown and --optimizer_switch on
-      command line wins (see get_options().
-    */
-    if (global_system_variables.engine_condition_pushdown)
-      global_system_variables.optimizer_switch|=
-        OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN;
-    else
-      global_system_variables.optimizer_switch&=
-        ~OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN;
-    break;
   case OPT_LOG_ERROR:
     /*
       "No --log-error" == "write errors to stderr",
@@ -9199,10 +9187,6 @@ static int get_options(int *argc_ptr, char ***argv_ptr)
                                       &extra_connection_count);
 #endif
 
-  global_system_variables.engine_condition_pushdown=
-    MY_TEST(global_system_variables.optimizer_switch &
-            OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN);
-
   opt_readonly= read_only;
 
   /*
diff --git a/sql/mysqld.h b/sql/mysqld.h
index d1efc5180a6..d68831a0d4f 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -558,7 +558,6 @@ enum options_mysqld
   OPT_DEBUG_SYNC_TIMEOUT,
   OPT_DELAY_KEY_WRITE_ALL,
   OPT_DEPRECATED_OPTION,
-  OPT_ENGINE_CONDITION_PUSHDOWN,
   OPT_IGNORE_DB_DIRECTORY,
   OPT_ISAM_LOG,
   OPT_KEY_BUFFER_SIZE,
diff --git a/sql/records.cc b/sql/records.cc
index 1b230c41156..cbcdb365f40 100644
--- a/sql/records.cc
+++ b/sql/records.cc
@@ -287,8 +287,8 @@ bool init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
 				  thd->variables.read_buff_size);
   }
   /* Condition pushdown to storage engine */
-  if ((thd->variables.optimizer_switch &
-       OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN) && 
+  if ((table->file->ha_table_flags() &
+       HA_MUST_USE_TABLE_CONDITION_PUSHDOWN) &&
       select && select->cond && 
       (select->cond->used_tables() & table->map) &&
       !table->file->pushed_cond)
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 243cc4459a0..dfa6da5b7ce 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -602,7 +602,6 @@ typedef struct system_variables
   my_bool tx_read_only;
   my_bool low_priority_updates;
   my_bool query_cache_wlock_invalidate;
-  my_bool engine_condition_pushdown;
   my_bool keep_files_on_create;
 
   my_bool old_mode;
diff --git a/sql/sql_priv.h b/sql/sql_priv.h
index 5dc19181e9b..9578c2fe8df 100644
--- a/sql/sql_priv.h
+++ b/sql/sql_priv.h
@@ -199,7 +199,7 @@ template <class T> bool valid_buffer_range(T jump,
 #define OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION    (1ULL << 2)
 #define OPTIMIZER_SWITCH_INDEX_MERGE_INTERSECT     (1ULL << 3)
 #define OPTIMIZER_SWITCH_INDEX_MERGE_SORT_INTERSECT (1ULL << 4)
-#define OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN (1ULL << 5)
+#define deprecated_ENGINE_CONDITION_PUSHDOWN       (1ULL << 5)
 #define OPTIMIZER_SWITCH_INDEX_COND_PUSHDOWN       (1ULL << 6)
 #define OPTIMIZER_SWITCH_DERIVED_MERGE             (1ULL << 7)
 #define OPTIMIZER_SWITCH_DERIVED_WITH_KEYS         (1ULL << 8)
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 5e8c3b26ff3..f7d492ceb68 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -9569,10 +9569,8 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
           if (tab->table)
           {
             tab->table->file->pushed_cond= NULL;
-            if (((thd->variables.optimizer_switch &
-                               OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN) ||
-                 (tab->table->file->ha_table_flags() &
-                  HA_MUST_USE_TABLE_CONDITION_PUSHDOWN)) &&
+            if ((tab->table->file->ha_table_flags() &
+                  HA_MUST_USE_TABLE_CONDITION_PUSHDOWN) &&
                 !first_inner_tab)
             {
               COND *push_cond= 
@@ -23631,10 +23629,8 @@ void JOIN_TAB::save_explain_data(Explain_table_access *eta, table_map prefix_tab
       {
         const COND *pushed_cond= tab->table->file->pushed_cond;
 
-        if (((thd->variables.optimizer_switch &
-             OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN) ||
-             (tab->table->file->ha_table_flags() &
-              HA_MUST_USE_TABLE_CONDITION_PUSHDOWN)) &&
+        if ((tab->table->file->ha_table_flags() &
+              HA_MUST_USE_TABLE_CONDITION_PUSHDOWN) &&
             pushed_cond)
         {
           eta->push_extra(ET_USING_WHERE_WITH_PUSHED_CONDITION);
diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc
index b9304403ee5..722dabeb15a 100644
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@@ -2222,13 +2222,15 @@ export const char *optimizer_switch_names[]=
   "exists_to_in",
   "default", NullS
 };
-/** propagates changes to @@engine_condition_pushdown */
 static bool fix_optimizer_switch(sys_var *self, THD *thd,
                                  enum_var_type type)
 {
   SV *sv= (type == OPT_GLOBAL) ? &global_system_variables : &thd->variables;
-  sv->engine_condition_pushdown=
-    MY_TEST(sv->optimizer_switch & OPTIMIZER_SWITCH_ENGINE_CONDITION_PUSHDOWN);
+  if (sv->optimizer_switch & deprecated_ENGINE_CONDITION_PUSHDOWN)
+    push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
+                        ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT,
+                        ER(ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT),
+                        "engine_condition_pushdown=on");
   return false;
 }
 static Sys_var_flagset Sys_optimizer_switch(