Creating a shallow copy of the config object for every connection created by the pool

[andrecardoso]

This prevents changing one connection's config object when other connections changes their config object (by changing its user, for example).

I had a problem with this because I'm using the connection's config.database property to know when to switch users.

[dougwilson]

this.config.connectionConfig is a typed object; this extend destroys that typing. Please fix this.

[dougwilson]

OK, I see what you mean. Because of https://github.com/felixge/node-mysql/blob/v2.2.0/lib/protocol/sequences/ChangeUser.js#L29-L32 .changeUser is basically incompatible with the pool. This solution is not a good one, as if you change user on a pooled connection and return it, now pool.getConnection may return a connection with a different context than the rest. Calling .changeUser on a pooled connection needs to also remove it from the pool.

[andrecardoso]

Should I have a pool for each user/database?

[dougwilson]

Yes, if you are changing the user a lot. Each time you call .changeUser it is a lot of protocol overhead; so the call is not cheap. You also don't have to then worry about what user a connection will be when you get one from the pool, as they'll always be the same user.

[andrecardoso]

Nice. Thanks!