MDEV-24176 Preparations

1. moved fix_vcol_exprs() call to open_table() mysql_alter_table() doesn't do lock_tables() so it cannot win from fix_vcol_exprs() from there. Tests affected: main.default_session 2. Vanilla cleanups and comments.

Author: midenok

sql/field.h

@@ -616,6 +616,10 @@ class Virtual_column_info: public Sql_alloc
  {
  in_partitioning_expr= TRUE;
  }
+ bool fix_expr(THD *thd);
+ bool fix_session_expr(THD *thd);
+ bool fix_session_expr_for_read(THD *thd, Field *field);
+ bool fix_and_check_expr(THD *thd, TABLE *table);
  inline bool is_equal(const Virtual_column_info* vcol) const;
  inline void print(String*);
 };

sql/item.cc

@@ -6376,8 +6376,9 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
  }
 #endif
  fixed= 1;
- if (field->vcol_info)
- fix_session_vcol_expr_for_read(thd, field, field->vcol_info);
+ if (field->vcol_info &&
+ field->vcol_info->fix_session_expr_for_read(thd, field))
+ goto error;
  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
  !outer_fixed && !thd->lex->in_sum_func &&
  select &&
@@ -9503,7 +9504,8 @@ bool Item_default_value::fix_fields(THD *thd, Item **items)
  Even if DEFAULT() do not read tables fields, the default value
  expression can do it.
  */
- fix_session_vcol_expr_for_read(thd, def_field, def_field->default_value);
+ if (def_field->default_value->fix_session_expr_for_read(thd, def_field))
+ goto error;
  if (should_mark_column(thd->column_usage))
  def_field->default_value->expr->update_used_tables();
  def_field->move_field(newptr+1, def_field->maybe_null() ? newptr : 0, 1);

sql/item.h

@@ -2924,6 +2924,12 @@ class Item_ident :public Item_result_field
  const char *db_name;
  const char *table_name;
  LEX_CSTRING field_name;
+ /*
+ NOTE: came from TABLE::alias_name_used and this is only a hint! It works
+ only in need_correct_ident() condition. On other cases it is FALSE even if
+ table_name is alias! It cannot be TRUE in these cases, lots of spaghetti
+ logic depends on that.
+ */
  bool alias_name_used; /* true if item was resolved against alias */
  /* 
  Cached value of index for this field in table->field array, used by prep. 

sql/sql_base.cc

@@ -2040,6 +2040,9 @@ bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx)
  table_list->updatable= 1; // It is not derived table nor non-updatable VIEW
  table_list->table= table;
 
+ if (table->vcol_fix_exprs(thd))
+ goto err_lock;
+
 #ifdef WITH_PARTITION_STORAGE_ENGINE
  if (unlikely(table->part_info))
  {
@@ -5290,52 +5293,44 @@ static void mark_real_tables_as_free_for_reuse(TABLE_LIST *table_list)
  }
 }
 
-int TABLE::fix_vcol_exprs(THD *thd)
+bool TABLE::vcol_fix_exprs(THD *thd)
 {
+ if (pos_in_table_list->placeholder() || !s->vcols_need_refixing ||
+ pos_in_table_list->lock_type < TL_WRITE_ALLOW_WRITE)
+ return false;
+
+ DBUG_ASSERT(pos_in_table_list != thd->lex->first_not_own_table());
+
+ bool result= true;
+ Security_context *save_security_ctx= thd->security_ctx;
+ Query_arena *stmt_backup= thd->stmt_arena;
+ if (thd->stmt_arena->is_conventional())
+ thd->stmt_arena= expr_arena;
+
+ if (pos_in_table_list->security_ctx)
+ thd->security_ctx= pos_in_table_list->security_ctx;
+
+
  for (Field **vf= vfield; vf && *vf; vf++)
- if (fix_session_vcol_expr(thd, (*vf)->vcol_info))
- return 1;
+ if ((*vf)->vcol_info->fix_session_expr(thd))
+ goto end;
 
  for (Field **df= default_field; df && *df; df++)
  if ((*df)->default_value &&
- fix_session_vcol_expr(thd, (*df)->default_value))
- return 1;
+ (*df)->default_value->fix_session_expr(thd))
+ goto end;
 
  for (Virtual_column_info **cc= check_constraints; cc && *cc; cc++)
- if (fix_session_vcol_expr(thd, (*cc)))
- return 1;
-
- return 0;
-}
-
-
-static bool fix_all_session_vcol_exprs(THD *thd, TABLE_LIST *tables)
-{
- Security_context *save_security_ctx= thd->security_ctx;
- TABLE_LIST *first_not_own= thd->lex->first_not_own_table();
- DBUG_ENTER("fix_session_vcol_expr");
+ if ((*cc)->fix_session_expr(thd))
+ goto end;
 
- int error= 0;
- for (TABLE_LIST *table= tables; table && table != first_not_own && !error;
- table= table->next_global)
- {
- TABLE *t= table->table;
- if (!table->placeholder() && t->s->vcols_need_refixing &&
- table->lock_type >= TL_WRITE_ALLOW_WRITE)
- {
- Query_arena *stmt_backup= thd->stmt_arena;
- if (thd->stmt_arena->is_conventional())
- thd->stmt_arena= t->expr_arena;
- if (table->security_ctx)
- thd->security_ctx= table->security_ctx;
+ result= false;
 
- error= t->fix_vcol_exprs(thd);
+end:
+ thd->security_ctx= save_security_ctx;
+ thd->stmt_arena= stmt_backup;
 
- thd->security_ctx= save_security_ctx;
- thd->stmt_arena= stmt_backup;
- }
- }
- DBUG_RETURN(error);
+ return result;
 }
 
 
@@ -5500,9 +5495,7 @@ bool lock_tables(THD *thd, TABLE_LIST *tables, uint count,
  }
  }
 
- bool res= fix_all_session_vcol_exprs(thd, tables);
- if (!res)
- res= thd->decide_logging_format(tables);
+ const bool res= thd->decide_logging_format(tables);
 
  DBUG_RETURN(res);
 }

sql/sql_partition.cc

@@ -5548,7 +5548,6 @@ that are reorganised.
  my_error(ER_ROW_IS_REFERENCED, MYF(0));
  goto err;
  }
- tab_part_info->num_parts-= num_parts_dropped;
  }
  else if (alter_info->partition_flags & ALTER_PARTITION_REBUILD)
  {
@@ -6214,8 +6213,6 @@ static bool mysql_drop_partitions(ALTER_PARTITION_PARAM_TYPE *lpt)
  char path[FN_REFLEN+1];
  partition_info *part_info= lpt->table->part_info;
  List_iterator<partition_element> part_it(part_info->partitions);
- uint i= 0;
- uint remove_count= 0;
  int error;
  DBUG_ENTER("mysql_drop_partitions");
 
@@ -6230,16 +6227,6 @@ static bool mysql_drop_partitions(ALTER_PARTITION_PARAM_TYPE *lpt)
  lpt->table->file->print_error(error, MYF(0));
  DBUG_RETURN(TRUE);
  }
- do
- {
- partition_element *part_elem= part_it++;
- if (part_elem->part_state == PART_IS_DROPPED)
- {
- part_it.remove();
- remove_count++;
- }
- } while (++i < part_info->num_parts);
- part_info->num_parts-= remove_count;
  DBUG_RETURN(FALSE);
 }