upgrade from 4.1 to 5.5

[sam engr]

I have read so many articles stating upgrade 4.1 to 5.0 then 5.0 to 5.1 and then 5.1 to 5.5.

My existing setup:

OS: RHEL5.8
MySQL: 4.1.22
ENGINE=MYISAM

will the following upgrade method work fine? if not why?

1. Get one to two weeks query log on old mysql (4.1.22).
2. Dump databases structure only (--no-data ) of existing MySQL 4.1.22
3. Dump databases (--with-data ) of existing MySQL 4.1.22
4. Install mysql-5.5 on other machine
named mysqltest1
5. Change the decimal definitions in databases structure dump (taken at step 2) as it was a major issue pointed out in almost all forums.
6. Verifies the timestamp definitions in databases structure dump (taken at step 2).
7. Restored the database structre got from step 2, 5 and 7
8. Restore the databases without dropping & creating databases & tables.
9. Run mysql-upgrade on mysql-5.5 to get and fix the table incompatibilities.
10. Disable concurrent inserts by setting concurrent_insert=0 in my.cnf on mysqltest1
11. Install mysql-4.1.22 on another machine named mysqltest2
12. Restore dumps taken on step 3 on this mysqltest2.
13. Play query log I got on step 1 on both machines (mysqltest1 and mysqltest2) with mk-upgrade
------(mk-upgrade compares query execution on two hosts by executing queries in the given file (or STDIN if no file given) and examining the results, errors, warnings, etc.produced on each.)
14. Rewrite the queries in code (especially Join if required by step 13's output)
15. Run the new queries on mysqltest1 and log the queries by enabling query-logs(general).
16. If satisfied on step 15 then push this machine mysqltest1 a slave machine with existing mysql-4.1.22 master.
17. Enable query logs on the new slave machine mysqltest1
18. Monitor for a week and address if we get any errors
19. If all ok in step 18 then upgrade all of your slave machines to mysql5.5 ; upgrade half of the slave machines to mysql 5.5 if you can maintain one tree for mysql-4.1.22 and one tree for mysql-5.5
20. Monitor for a week or two and then upgrade your secondary master to mysql-5.5 and then note issues if you get any in log.
21. Promote this secondary master to primary master by redirecting app/web traffic to this mysql-5.5 box.
22. Monitor for a month or so and then if all ok then upgrade rest of slave to mysql-5.5 and then the old primary master and then sync the data with replication on these latest upgraded machines.
23. All done.

I would like to see some comments.

Cheers