New merge table issue with underlying table

[Rob Brown]

I have inherited a database running on 5.0.96 with some merge tables that are showing errors when trying to upgrade to 5.1.67

Even when trying to drop the existing merge table and recreate it, I still get the same errors with the underlying tables, which appear to be fine...

mysql> repair table foo_20070101;
+------------------------+--------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+------------------------+--------+----------+----------+
| s123.r2_click_20070101 | repair | status | OK |
+------------------------+--------+----------+----------+
1 row in set (40.35 sec)

Hence, this table is healthy.


CREATE TABLE foo_20070131 LIKE foo_20070101;

ALTER TABLE foo_20070131 DROP PRIMARY KEY, ADD KEY (click_id);

ALTER TABLE foo_20070131 ENGINE=MERGE;

ALTER TABLE foo_20070131 UNION=(foo_20070101);

ERROR 1168 (HY000): Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist.

Is there anything more I can do to investigate the issue, or to try and "fix" the apparently-fine underlying table?

Thanks,
Rob