Hi, Rucha! what happens in this bug? Why does the server need to open_table() after my_ok()? On Oct 21, Rucha Deodhar wrote:

revision-id: 8c745467560 (mariadb-10.5.4-226-g8c745467560) parent(s): 308f8350c7b author: Rucha Deodhar <rucha.deodhar@mariadb.com> committer: Rucha Deodhar <rucha.deodhar@mariadb.com> timestamp: 2020-10-20 11:53:22 +0530 message:

MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)

Analysis: Assertion failure happens because we don't ignore kill query even if 'OK' is already sent. Fix: Check if we already sent 'OK'. If sent, ignore kill query.

diff --git a/mysql-test/main/alter_table.result b/mysql-test/main/alter_table.result index 197e52b35ca..204bfa5249c 100644 --- a/mysql-test/main/alter_table.result +++ b/mysql-test/main/alter_table.result @@ -3322,5 +3322,23 @@ Note 1176 Key 'x' doesn't exist in table 't1' unlock tables; drop table t1; # +# MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in +# Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK) +# +set @max_session_mem_used_save= @@max_session_mem_used; +CREATE TABLE t1 (a INT); +SELECT * FROM t1; +a +ALTER TABLE x MODIFY xx INT; +ERROR 42S02: Table 'test.x' doesn't exist +SET SESSION max_session_mem_used= 8192; +LOCK TABLE t1 WRITE; +ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT; +Warnings: +Note 1054 Unknown column 'b' in 't1' +set SESSION max_session_mem_used = @max_session_mem_used_save; +UNLOCK TABLES; +DROP TABLE t1; +# # End of 10.5 tests # diff --git a/mysql-test/main/alter_table.test b/mysql-test/main/alter_table.test index 6fe61a3222a..d09c4378339 100644 --- a/mysql-test/main/alter_table.test +++ b/mysql-test/main/alter_table.test @@ -2529,6 +2529,27 @@ alter table t1 rename key if exists x to xx; unlock tables; drop table t1;

+--echo # +--echo # MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in +--echo # Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK) +--echo # + +set @max_session_mem_used_save= @@max_session_mem_used; + +CREATE TABLE t1 (a INT); +SELECT * FROM t1; + +--error ER_NO_SUCH_TABLE +ALTER TABLE x MODIFY xx INT; + +SET SESSION max_session_mem_used= 8192; +LOCK TABLE t1 WRITE; +ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT; + +set SESSION max_session_mem_used = @max_session_mem_used_save; +UNLOCK TABLES; +DROP TABLE t1; + --echo # --echo # End of 10.5 tests --echo # diff --git a/sql/sql_base.cc b/sql/sql_base.cc index e6d0ab13e75..e8d39917ba6 100644 --- a/sql/sql_base.cc +++ b/sql/sql_base.cc @@ -1682,7 +1682,9 @@ bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx)

if (!(flags & MYSQL_OPEN_IGNORE_KILLED) && thd->killed) { - thd->send_kill_message(); + /* If we already sent 'ok', we can ignore any kill query statements */ + if (! thd->get_stmt_da()->is_set()) + thd->send_kill_message(); DBUG_RETURN(TRUE); }

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