我已经编写了PHP脚本来批量加载Stack Overflow数据转储发布的数据。我导入了数百万行，并不需要那么长时间。
这里有一些提示：
Don’t rely on autocommit. The overhead of starting and committing a transaction for every row is enormous. Use explicit transactions, and commit after every 1000 rows (or more).
Use prepared statements. Since you are basically doing the same inserts thousands of times, you can prepare each insert before you start looping, and then execute during the loop, passing values as parameters. I don’t know how to do this with CodeIgniter’s database library, you’ll have to figure it out.
Tune MySQL for import. Increase cache buffers and so on. See Speed of INSERT Statements for more information.
Use LOAD DATA INFILE. If possible. It’s literally 20x faster than using INSERT to load data row by row. I understand if you can’t because you need to get the last insert id and so on. But in most cases, even if you read the CSV file, rearrange it and write it out to multiple temp CSV files, the data load is still faster than using INSERT.
Do it offline. Don’t run long-running tasks during a web request. The time limit of a PHP request will terminate the job, if not today then next Tuesday when the job is 10% longer. Instead, make the web request queue the job, and then return control to the user. You should run the data import as a server process, and periodically allow the user to glimpse the rate of progress. For instance, a cheap way to do this is for your import script to output “.” to a temp file, and then the user can request to view the temp file and keep reloading in their browser. If you want to get fancy, do something with Ajax.
