Thursday, September 26, 2013

Upgrading / Migrating a MySQL 5.0 Database to MySQL 5.5 [InnoDB]

This post is an ultra, no, make that uber paranoid method of upgrading/migrating a relatively large (20+ GB on file) InnoDB database from MySQL version 5.0 to MySQL 5.5. Some might consider it overkill, but as it relates to a database of this size and maturity, I'd prefer not to take any unnecessary risks.

This assumes that the old server is running mysql 5.0 on CentOS 5.x and that the MySQL 5.5 is installed on a new server running CentOS 6, using the remi repositories. This is covered here.

Phase 1 - Prepare Data on the Old Server

1. Execute Database Check to ensure tables are clean
From terminal:
mysqlcheck –c mydbname –u root –p
<enter password when prompted>


2. Re-index tables before the dump
From mysql: (single line!)
select concat(‘ALTER TABLE`’, table_schema,’`.`’, table_name,’` Engine=InnoDB;’) from information_schema.tables where table_schema =‘mydbname’ into outfile ’/tmp/InnoBatch.sql’;

From shell:
mysql -u root –p --verbose < /tmp/InnoBatch.sql

3. Export the database as a dump file
 From shell:
mysqldump  -u root –p –e –c --verbose --default-character-set=utf8 --skip-set-charset --max-allowed-packet = 100M --single-transaction --databases mydbname –r /root/Desktop/mydbdump.sql

4. Copy to new DB server
scp –r /root/Desktop/mydbdump.sql root@new.db.srv.ip:/root/Desktop/


Phase 2 - Import to New Server

1. Create empty database shell for import

From mysql:
create database mdbname character set utf8 collate utf8_unicode_ci\

2. Issue Grant permissions to new DB (I hope you have this documented, else you might need to dump/restore the mysql.user table to new DB)

3. Import SQL file.(but first set a really high session value for max_allowed_packet to handle the large data import)
 set global max_allowed_packet = 1000000000;
source /root/Desktop/mydbdump.sql

4. Check mysql for transaction warnings
from mysql:
show warnings\G

5. Run upgrade script
From shell:
mysql_upgrade –u root –p --force

6. Rebuild InnoDB tables, which would force the InnoDB tables to upgrade
(source: http://www.mysqlperformanceblog.com/2010/05/14/mysql_upgrade-and-innodb-tables/ )

From mysql: (single line!)
select concat(‘ALTER TABLE`’, table_schema,’`.`’, table_name,’` Engine=InnoDB;’) from information_schema.tables where table_schema =‘mydbname’ into outfile ’/tmp/InnoBatch.sql’;
From shell:
mysql -u root –p --verbose < /tmp/InnoBatch.sql

7. Execute Database Check to ensure newly imported/upgraded tables are clean
From shell:
mysqlcheck –c mydbname –u root –p

Phase 3 - Compare old and new database
Checking data consistency to ensure all the data was transferred via an accurate record count.
http://dev.mysql.com/doc/refman/5.0/en/innodb-restrictions.html

1. On Old db server, generate query to perform record count on each table
from mysql: (single line!)
select concat(‘ SELECT “’,table_name, ‘” as table_name, count(*) as exact_row_count from ‘,table_schema, ‘.’ table_name, ‘ UNION’) from information_schema.tables where table_schema =‘mydbname’ into outfile ’/tmp/TableAnalysisQuery.sql’;

From shell:
nano /tmp/TableAnalysisQuery.sql
remove the LAST Union from the end of last line in the file.

2. Run the query to get table row count for all tables
From shell:
mysql –u root –p < /tmp/TableAnalysisQuery.sql > /root/Desktop/TableAnalysisResults-$(hostname).txt


3. On New db server, generate query to perform record count on each table
from mysql: (single line!)
select concat(‘ SELECT “’,table_name, ‘” as table_name, count(*) as exact_row_count from ‘,table_schema, ‘.’ table_name, ‘ UNION’) from information_schema.tables where table_schema =‘mydbname’ into outfile ’/tmp/TableAnalysisQuery.sql’;

From shell:
nano /tmp/TableAnalysisQuery.sql
remove the LAST Union from the end of last line in the file.

4. Run the query to get table row count for all tables
From shell:
mysql –u root –p < /tmp/TableAnalysisQuery.sql > /root/Desktop/TableAnalysisResults-$(hostname).txt

5. Copy both text files to a third machine for comparison

On OLD db server, from shell:
scp –r /root/Desktop/TableAnalysisResults-myolddb.mydomain.com.txt root@third.machine.ip:/root/Desktop

On NEW db server, from shell:
scp –r /root/Desktop/TableAnalysisResults-mynewdb.mydomain.com.txt root@third.machine.ip:/root/Desktop

ON third server
from shell:
diff –a /root/Desktop/TableAnalysisResults-myolddb.mydomain.com.txt /root/Desktop/TableAnalysisResults-mynewdb.mydomain.com.txt
No output from the previous command means that the data is consistent (as it relates to number of rows on each table) on both servers and the new database can be made active/ brought in production

<EOF>

That's it!
-noveck

No comments:

Post a Comment