Hi, Rucha! Note test failures in buildbot, don't forget to update all result files before pushing. On Dec 28, Rucha Deodhar wrote:

revision-id: 4774601a3cd (mariadb-10.2.40-192-g4774601a3cd) parent(s): 42fea34d4a9 author: Rucha Deodhar committer: Rucha Deodhar timestamp: 2021-12-27 16:48:04 +0530 message:

MDEV-26698: Incorrect row number upon INSERT .. SELECT from the same table: rows are counted twice

Analysis: When the table we are trying to insert into and the SELECT table are same for INSERT ... SELECT, rows from the SELECT table are copied into internal temporary table and then to the INSERT table. We only want to count the rows when we start inserting into the table. Fix: Reset the counter to 1 before starting to copy from internal temporary table to select table and then increment the counter.

diff --git a/sql/sql_select.cc b/sql/sql_select.cc index a331f4f3dbc..7a50f3d74ac 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -3832,6 +3832,8 @@ mysql_select(THD *thd, } }

+ thd->get_stmt_da()->reset_current_row_for_warning();

What is this for? It wasn't needed before.

if ((err= join->optimize())) { goto err; // 1 @@ -19124,10 +19126,10 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,

if (found) { + unlock_row= false; enum enum_nested_loop_state rc; /* A match from join_tab is found for the current partial join. */ rc= (*join_tab->next_select)(join, join_tab+1, 0); - join->thd->get_stmt_da()->inc_current_row_for_warning();

By moving this down you skip few returns, incl NESTED_LOOP_OK and NESTED_LOOP_NO_MORE_ROWS. Are you sure it's fine? Won't the counter be off, if the query execution continues after, say, NESTED_LOOP_OK?

if (rc != NESTED_LOOP_OK && rc != NESTED_LOOP_NO_MORE_ROWS) DBUG_RETURN(rc); if (return_tab < join->return_tab) @@ -26945,6 +26943,12 @@ AGGR_OP::end_send() table->reginfo.lock_type= TL_UNLOCK;

bool in_first_read= true; + + /* + Reset the counter before copying rows from internal temporary table to + INSERT table.

this code is also used for group by. Please, add a test for insert ... select ... group by Why did put your fix here in a common code path in select, and not in, say, select_insert::send_data() ?

+ */ + join_tab->join->thd->get_stmt_da()->reset_current_row_for_warning(); while (rc == NESTED_LOOP_OK) { int error; @@ -26968,6 +26972,8 @@ AGGR_OP::end_send() else { rc= evaluate_join_record(join, join_tab, 0); + /* Increment the counter after copying rows. */ + join_tab->join->thd->get_stmt_da()->inc_current_row_for_warning(); } }

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