My question is whether it is safe to perform multiple dumps at the same time in mysql, i.e. running:
mysql -u root -p database1 < database1.sql
mysql -u root -p database2 < database2.sql
on the same host and database server of course;
The databases will be empty when the process starts; (just created from cmd)
These are huge dumps if it matters, one file is 10G and the other 100G.
In general terms is safe as long as the databases are "independent". With this I mean each database has references only to itself.
For MySQL in particular VIEWs to missing tables are a problem.
Let me illustrate with an example:
create schema database1;
create table database1.mytable (id int);
create schema database2;
create view database2.myview as select * from database1.mytable;
We take separate dumps: database1.sql and database2.sql
If you try to restore them on a different server, we must pay attention to the restore order, let's say we are starting with empty schemas database1 and database2
This will work:
mysql -u root database1 < database1.sql
mysql -u root database2 < database2.sql
But this will fail:
mysql -u root -p database2 < database2.sql
mysql -u root -p database1 < database1.sql
Because the database2.myview references a table that does not exist.
TLDR: if you are running database restores in parallel and there are references between them you could get into trouble.
