InnoDB inserts very slow and slowing down

Question

I have recently switched my project tables to InnoDB (thinking the relations would be a nice thing to have). I\'m using a PHP script to index about 500 products at a time. <

Answer 1

InnoDB provides more complex keys structure than MyIsam (FOREIGN KEYS) and regenerating keys is really slow in InnoDB. You should enclose all update/insert statements into one transactions (those are actually quite fast in InnoDB, once I had about 300 000 insert queries on InnoDb table with 2 indexes and it took around 30 minutes, once I enclosed every 10 000 inserts into BEGIN TRANSACTION and COMMIT it took less than 2 minutes).

I recommend to use:

BEGIN TRANSACTION;
SELECT ... FROM products;
UPDATE ...;
INSERT INTO ...;
INSERT INTO ...;
INSERT INTO ...;
COMMIT;

This will cause InnoDB to refresh indexes just once not few hundred times.

Let me know if it worked

Answer 2

I had a similar problem and it seems InnoDB has by default innodb_flush_log_at_trx_commit enabled which flushes every insert/update query on your hdd log file. The writing speed of your hard disk is a bottleneck for this process.

So try to modify your mysql config file

  `innodb_flush_log_at_trx_commit  = 0`

Restart mysql service.

I experienced about x100 speedup on inserts.