Marko Mäkelä added a comment - 2018-11-16 17:16 I think that this could occasionally fail in 10.2 as well. Starting with MariaDB 10.2 (and MySQL 5.7), temporary file creation for the merge sort in ALGORITHM=INPLACE is deferred until the main memory buffer runs out. I determined a tight limit for this in 10.2, but apparently that is too tight.

Thirunarayanan Balathandayuthapani added a comment - 2019-01-04 09:52 diff --git a/mysql-test/suite/innodb/t/alter_inplace_perfschema.test b/mysql-test/sui te/innodb/t/alter_inplace_perfschema.test index b832596..d5851e8 100644 --- a/mysql-test/suite/innodb/t/alter_inplace_perfschema.test +++ b/mysql-test/suite/innodb/t/alter_inplace_perfschema.test @@ -10,7 +10,7 @@ update performance_schema.setup_consumers set enabled='yes'; CREATE TABLE t1 (a serial, b varchar(255)) ENGINE=InnoDB; BEGIN; -let $n=247; +let $n=260; --disable_query_log while ($n) { dec $n; The limit could be too tight. we can increase the limit

Marko Mäkelä added a comment - 2019-01-04 15:39 Yes, increasing the limit should fix this. But can you please find out what exactly causes the occasional failures? Could it be because the size of the main-memory buffer is not always the same, and we could need more data to fill that buffer, to force the temporary file to be created?

Thirunarayanan Balathandayuthapani added a comment - 2019-01-07 12:03 Afaik, temporary file creation happens for the problematic test case scenario. May be some how, temporary file creation is not reflecting in performance schema query result.

Thirunarayanan Balathandayuthapani added a comment - 2019-01-08 12:59 diff --git a/mysql-test/suite/innodb/disabled.def b/mysql-test/suite/innodb/disabled.def index aea780e..35c941f 100644 --- a/mysql-test/suite/innodb/disabled.def +++ b/mysql-test/suite/innodb/disabled.def @@ -11,4 +11,3 @@ ##############################################################################   create-index-debug : MDEV-13680 InnoDB may crash when btr_page_alloc() fails -alter_inplace_perfschema : MDEV-17748 nnodb.alter_inplace_perfschema fails in buildbot with wrong result diff --git a/mysql-test/suite/innodb/r/alter_inplace_perfschema.result b/mysql-test/suite/innodb/r/alter_inplace_perfschema.result index 68e25664..83daa3d 100644 --- a/mysql-test/suite/innodb/r/alter_inplace_perfschema.result +++ b/mysql-test/suite/innodb/r/alter_inplace_perfschema.result @@ -8,6 +8,7 @@ SET DEBUG_SYNC = 'row_log_apply_before SIGNAL go WAIT_FOR gone'; ALTER TABLE t1 ADD INDEX(b), ALGORITHM=INPLACE; connection default; SET DEBUG_SYNC = 'now WAIT_FOR go'; +11 SELECT DISTINCT object_name FROM performance_schema.events_waits_history_long WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%'; object_name diff --git a/mysql-test/suite/innodb/t/alter_inplace_perfschema.test b/mysql-test/suite/innodb/t/alter_inplace_perfschema.test index b832596..e663735 100644 --- a/mysql-test/suite/innodb/t/alter_inplace_perfschema.test +++ b/mysql-test/suite/innodb/t/alter_inplace_perfschema.test @@ -18,12 +18,19 @@ INSERT INTO t1 SELECT NULL, REPEAT('b',255); } --enable_query_log COMMIT; +let $init_count = `select count_star from performance_schema.events_waits_summary_global_by_event_name WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%'`;   SET DEBUG_SYNC = 'row_log_apply_before SIGNAL go WAIT_FOR gone'; send ALTER TABLE t1 ADD INDEX(b), ALGORITHM=INPLACE;   connection default; SET DEBUG_SYNC = 'now WAIT_FOR go'; + +let $final_count = `select count_star from performance_schema.events_waits_summary_global_by_event_name WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%'`; + +let $diff = `SELECT $final_count - $init_count`; +echo $diff; + --replace_regex /.*[\\\/]tmp/tmp/ SELECT DISTINCT object_name FROM performance_schema.events_waits_history_long WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%'; The above patch can solve the issue.