[MariaDB developers] Re: 64ac6ed3e35: MDEV-31742 incorrect examined rows in case of stored function usage

21 Jul 2023

      Hi, Sanja,

Hmm, what author do you have in mind, Timour?
I suggest to remove this now and not leave dead code around.

On Jul 21, Oleksandr Byelkin wrote:
...
I also thought about removing it, but then decided to let the author to fix
it, here is an urgent fix because as the previous bug showed, our client
hit this problem.
There is also "cuted_fields+=       backup->cuted_fields;" which is very
suspicious.
On Fri, Jul 21, 2023 at 11:41 AM Sergei Golubchik  wrote:
...
On Jul 21, Oleksandr Byelkin wrote:
...
revision-id: 64ac6ed3e35 (mariadb-10.4.30-31-g64ac6ed3e35)
parent(s): 55a27bac80c
author: Oleksandr Byelkin
committer: Oleksandr Byelkin
timestamp: 2023-07-19 16:14:39 +0200
message:
MDEV-31742 incorrect examined rows in case of stored function usage
The counter is global so we do not need add backup to it
if we do not zero it after taking the backup.
may be backup->examined_row_count should be simply removed?
Sub_statement_state::examined_row_count, I mean.
Not saved, not restored?
There's also
void THD::add_slow_query_state(Sub_statement_state *backup)
  {
    affected_rows+=                backup->affected_rows;
    bytes_sent_old=                backup->bytes_sent_old;
    m_examined_row_count+=         backup->examined_row_count;
it's not even using inc_examined_row_count().
Also examined_row_count is mentioned in comments in sql_class.cc,
if you'll be removing it from Sub_statement_state, don't forget to fix
comments to match.
...
cuted_fields+=       backup->cuted_fields;
   DBUG_VOID_RETURN;
 }
Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org