Removed tc_purge() and purge_tables() argument

It was mistakenly used by tdc_start_shutdown() to make sure TABLE_SHARE
gets evicted from table definition cache when it becomes unused. However
same effect is achieved by resetting tdc_size and tc_size.

Part of MDEV-17882 - Cleanup refresh version

sql/backup.cc

@@ -204,7 +204,7 @@ static bool backup_flush(THD *thd)
     Free unused tables and table shares so that mariabackup knows what
     is safe to copy
   */
-  tc_purge(false);
+  tc_purge();
   tdc_purge(true);
 
   DBUG_RETURN(0);

sql/sql_base.cc

@@ -311,13 +311,9 @@ OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild)
 
 /**
    Close all tables that are not in use in table definition cache
-
-   @param purge_flag  Argument for tc_purge. true if we should force all
-                      shares to be deleted. false if it's enough to just
-                      evict those that are not in use.
 */
 
-void purge_tables(bool purge_flag)
+void purge_tables()
 {
   /*
     Force close of all open tables.
@@ -331,7 +327,7 @@ void purge_tables(bool purge_flag)
     Get rid of all unused TABLE and TABLE_SHARE instances. By doing
     this we automatically close all tables which were marked as "old".
   */
-  tc_purge(purge_flag);
+  tc_purge();
   /* Free table shares which were not freed implicitly by loop above. */
   tdc_purge(true);
 }
@@ -360,7 +356,7 @@ bool close_cached_tables(THD *thd, TABLE_LIST *tables,
   if (!tables)
   {
     /* Free tables that are not used */
-    purge_tables(false);
+    purge_tables();
     if (!wait_for_refresh)
       DBUG_RETURN(false);
   }
@@ -561,7 +557,7 @@ bool flush_tables(THD *thd, flush_tables_type flag)
   flush_tables_error_handler error_handler;
   DBUG_ENTER("flush_tables");
 
-  purge_tables(false);  /* Flush unused tables and shares */
+  purge_tables();  /* Flush unused tables and shares */
 
   /*
     Loop over all shares and collect shares that have open tables

sql/sql_base.h

@@ -299,7 +299,7 @@ void close_log_table(THD *thd, Open_tables_backup *backup);
 
 bool close_cached_tables(THD *thd, TABLE_LIST *tables,
                          bool wait_for_refresh, ulong timeout);
-void purge_tables(bool purge_flag);
+void purge_tables();
 bool flush_tables(THD *thd, flush_tables_type flag);
 bool close_cached_connection_tables(THD *thd, LEX_CSTRING *connect_string);
 void close_all_tables_for_name(THD *thd, TABLE_SHARE *share,

sql/table_cache.cc

@@ -323,12 +323,12 @@ static my_bool tc_purge_callback(TDC_element *element, tc_purge_arg *arg)
 }
 
 
-void tc_purge(bool mark_flushed)
+void tc_purge()
 {
   tc_purge_arg argument;
   TABLE *table;
 
-  argument.mark_flushed= mark_flushed;
+  argument.mark_flushed= false;
   tdc_iterate(0, (my_hash_walk_action) tc_purge_callback, &argument);
   while ((table= argument.purge_tables.pop_front()))
     intern_close_table(table);
@@ -655,7 +655,7 @@ void tdc_start_shutdown(void)
     tdc_size= 0;
     tc_size= 0;
     /* Free all cached but unused TABLEs and TABLE_SHAREs. */
-    purge_tables(true);
+    purge_tables();
   }
   DBUG_VOID_RETURN;
 }

sql/table_cache.h

@@ -91,7 +91,7 @@ extern int tdc_iterate(THD *thd, my_hash_walk_action action, void *argument,
                        bool no_dups= false);
 
 extern uint tc_records(void);
-extern void tc_purge(bool mark_flushed= false);
+extern void tc_purge();
 extern void tc_add_table(THD *thd, TABLE *table);
 extern void tc_release_table(TABLE *table);
 extern TABLE *tc_acquire_table(THD *thd, TDC_element *element);