Hi!
>>>>> "Peter" == Peter Zaitsev <[EMAIL PROTECTED]> writes:
Peter> Hello mysql,
Peter> It seems like mysql sometimes tries to hard to repair the table with
Peter> myisam tables with fixed row format.
Peter> I've had a chance to several times found data in one of the tables
Peter> completely destroyed - the data looked like random.
mysql> select * from g01layers_stat_cities limit 10;
Peter>
+------------+------+----------------+------------+----------------+------------+------------+
Peter> | id | type | begin | counter | last | last_hit
| page_group |
Peter>
+------------+------+----------------+------------+----------------+------------+------------+
Peter> | 539167267 | 84 | 20231203141129 | 1920234272 | 20320611141829 | 1713399154
| 111 |
Peter> | 1650553888 | 108 | 20241103100405 | 1684091184 | 20311128204214 | 1936291423
| 39 |
Peter> | 1124731427 | 82 | 20061110120717 | 1111577632 | 20241029051540 | 1684091184
| 118 |
Peter> | 1985967218 | 105 | 19750527085147 | 1684611104 | 20311125200848 | 691024168
| 32 |
Peter> | 1734964078 | 110 | 20110715200141 | 1310741583 | 19870304184629 | 1869903201
| 95 |
Peter> | 1701995374 | 109 | 19930820102541 | 1663049738 | 20311125210119 | 1767862885
| 100 |
Peter> | 678719081 | 49 | 20320408165928 | 1734964078 | 19870323012758 | 1095124292
| 85 |
Peter> | 807870548 | 39 | 20141028110448 | 1280658976 | 19870113150012 | 544437280
| 116 |
Peter> | 1953719661 | 97 | 19960219154325 | 170666292 | 20340728025216 | 1948280176
| 105 |
Peter> | 1953393017 | 40 | 20320408165931 | 1734964078 | 19870323012758 | 1095124292
| 85 |
Peter>
+------------+------+----------------+------------+----------------+------------+------------+
Peter> 10 rows in set (0.00 sec)
Peter> It did't look like a possible bug in mysql so I checked other thing. I
Peter> took a table and completely replaced the data file with over file
Peter> which is not connected with mysql in any way, really it was a
Peter> mysqldump output for one of the databases.... and mysql was easily
Peter> able to repair the same way as it repairs a bit damaged tables - some
Peter> of duplicate key records there removed but it looked quite normal.
Peter> Of couse I had a trash in a file afterwards.
Peter> I don't have good solution for this yet, but it's not quite nice
Peter> behavior :)
In a fixed format file, all rows are stored after each other; No row
markers, no checksums...
This is very fast an efficient and pretty secure. The bad thing with
this is that if you somehow get bad data in the table, then MySQL has
no way of knowing if the data is a correct row or not.
Regards,
Monty
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