MVCC read from index on CHAR or VARCHAR wrongly omits rows

origin/10.6 af418bb9ef7e422282dc976640409a6af8fcd58c 2021-04-19T14:04:02+10:00

Scenario:

1. Start the server, create one table and fill it with 100 rows.

2. Session 1 runs in a loop some update like

     UPDATE table100_innodb_int_autoinc SET `col_varchar_255_ucs2_key` = CONVERT( 'degsotrsfannidwyvkuvlkeslrryhpkeevqmbksdrzadzpyisznignsytihyjixyalxfxpnafjwzgnkbbayklurufrsajtzohanbuvcfyykvtmesobixwipkoihhqykvoejckythjnjshxgohmecmklxryubdexjgxehdiqqui' USING ASCII )

    Session 2 runs in a loop

    CHECK TABLE table100_innodb_int_autoinc EXTENDED

After short time the CHECK TABLE harvests a

test.table100_innodb_int_autoinc check Warning InnoDB: Index 'col_varchar_255_ucs2_key' contains 98 entries, should be 100.

sdp:/data/Results/1618846463/TBR-36/dev/shm/vardir/1618846463/4/1/rr