Question

When performing the default mysqldump on a innodb database, does it perform table locking and pending “INSERTS” are queued? I have transactional database, and out of 100K+ records, I found maybe 2-3 dozen duplicate records (all fields are the same such as timestamp except for the primary keys).

I suspect the user on the front end application clicked “Save” on the GUI while a database backup is in progress, and then clicks it a few more times until he receives a response. That’s my theory.

Please share your thoughts.

Answer 1

I believe mysqldump locks by default. Since you are using innodb, use --single-transaction to prevent locking (see this question). Or use something like the innodb hot backup tool.