MySQL 5.7 Release Notes
The CSV storage engine supports the
CHECK TABLE and
REPAIR TABLE statements to verify
and, if possible, repair a damaged CSV table.
When running the CHECK TABLE
statement, the CSV file is checked for validity
by looking for the correct field separators, escaped fields
(matching or missing quotation marks), the correct number of
fields compared to the table definition and the existence of a
corresponding CSV metafile. The first invalid
row discovered reports an error. Checking a valid table produces
output like that shown below:
mysql> CHECK TABLE csvtest;
+--------------+-------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------+-------+----------+----------+
| test.csvtest | check | status | OK |
+--------------+-------+----------+----------+A check on a corrupted table returns a fault such as
mysql> CHECK TABLE csvtest;
+--------------+-------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------+-------+----------+----------+
| test.csvtest | check | error | Corrupt |
+--------------+-------+----------+----------+
To repair a table, use REPAIR
TABLE, which copies as many valid rows from the existing
CSV data as possible, and then replaces the
existing CSV file with the recovered rows. Any
rows beyond the corrupted data are lost.
mysql> REPAIR TABLE csvtest;
+--------------+--------+----------+----------+
| Table | Op | Msg_type | Msg_text |
+--------------+--------+----------+----------+
| test.csvtest | repair | status | OK |
+--------------+--------+----------+----------+
Warning
During repair, only the rows from the CSV
file up to the first damaged row are copied to the new table.
All other rows from the first damaged row to the end of the
table are removed, even valid rows.