Hi, Rucha! On Dec 29, Rucha Deodhar wrote:

On Wed, Dec 29, 2021 at 12:50 AM Sergei Golubchik <serg@mariadb.org> wrote:

...

Why did put your fix here in a common code path in select, and not in, say, select_insert::send_data() ?

Yes, the counter can be incremented in select_insert::send_data() too.

But after writing record to INSERT table, we go back to evaluate_join_records() where the counter is incremented unconditionally. And CREATE TABLE...SELECT was failing with wrong output because it also uses this code.

I could have incremented counter conditionally so that it doesn't increment twice like so:

increment counter in select_insert::send_data() after record is written if (thd->lex->sql_command == SQLCOM_INSERT_SELECT || thd->lex->sql_command == SQLCOM_CREATE_TABLE)

I'd think you wouldn't need this if(), as select_insert::send_data() is not used for other sql commands.

And increment counter in evalaute_join_records() after one nested loop iteration ends (end_send()) if (join->thd->lex->sql_command != SQLCOM_INSERT_SELECT && join->thd->lex->sql_command != SQLCOM_CREATE_TABLE)

I see. That's not good.

I had initially implemented it this way but it kinda looked hacky to me. So I did a more general solution.

Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org