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authorAlexander Barkov <bar@mariadb.com>2018-06-27 12:53:49 +0400
committerAlexander Barkov <bar@mariadb.com>2018-06-27 12:54:05 +0400
commit56145be2951e0085848187bf6df8a0269e53fc7a (patch)
tree582b1092ea07e717be7a89566fe5abca5833a746 /sql/sp_head.h
parent1d6bc0f01f58cacc1d31975eb5579a197f451a41 (diff)
downloadmariadb-git-56145be2951e0085848187bf6df8a0269e53fc7a.tar.gz
MDEV-16584 SP with a cursor inside a loop wastes THD memory aggressively
Problem: push_cursor() created sp_cursor instances on THD::main_mem_root, which is freed only after the SP instructions loop. Changes: - Moving sp_cursor declaration from sp_rcontext.h to sql_class.h - Deriving sp_instr_cpush from sp_cursor. So now sp_cursor is created only once (at the SP parse time) and then reused on all loop iterations - Adding a new method reset() into sp_cursor (and its parent classes) to reset an sp_cursor instance before reuse. - Moving former sp_cursor members m_fetch_count, m_row_count, m_found into a separate class sp_cursor_statistics. This helps to reuse the code in sp_cursor constructors, and in sp_cursor::reset() - Adding a helper method sp_rcontext::pop_cursor(). - Adding "THD*" parameter to so_rcontext::pop_cursors() and pop_all_cursors() - Removing "new" and "delete" from sp_rcontext::push_cursor() and sp_rconext::pop_cursor(). - Fixing sp_cursor not to derive from Sql_alloc, as it's now allocated only as a part of sp_instr_cpush (and not allocated separately). - Moving lex_keeper->disable_query_cache() from sp_cursor::sp_cursor() to sp_instr_cpush::execute(). - Adding tests
Diffstat (limited to 'sql/sp_head.h')
-rw-r--r--sql/sp_head.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/sql/sp_head.h b/sql/sp_head.h
index dcea4191cde..580859b8831 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -1757,7 +1757,8 @@ private:
/** This is DECLARE CURSOR */
-class sp_instr_cpush : public sp_instr
+class sp_instr_cpush : public sp_instr,
+ public sp_cursor
{
sp_instr_cpush(const sp_instr_cpush &); /**< Prevent use of these */
void operator=(sp_instr_cpush &);