1berry/MariaDB-server
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Improve a comment.

Browse Source
This commit is contained in:
konstantin@mysql.com 2005-07-15 13:21:08 +04:00
parent 0f6e1380dc
commit 68fb78ca33
1 changed files with 12 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
sql/sql_class.h
View File

@ -1162,12 +1162,22 @@ public:
This is to track items changed during execution of a prepared
statement/stored procedure. It's created by
register_item_tree_change() in memory root of THD, and freed in
rollback_item_tree_changes(). For conventional execution it's always 0.
rollback_item_tree_changes(). For conventional execution it's always
empty.
*/
Item_change_list change_list;
/*
Current prepared Query_arena if there one, or 0
A permanent memory area of the statement. For conventional
execution, the parsed tree and execution runtime reside in the same
memory root. In this case current_arena points to THD. In case of
a prepared statement or a stored procedure statement, thd->mem_root
conventionally points to runtime memory, and thd->current_arena
points to the memory of the PS/SP, where the parsed tree of the
statement resides. Whenever you need to perform a permanent
transformation of a parsed tree, you should allocate new memory in
current_arena, to allow correct re-execution of PS/SP.
Note: in the parser, current_arena == thd, even for PS/SP.
*/
Query_arena *current_arena;
/*