On Wed, 24 Oct 2012 08:23:49 +0200
Sönke Ludwig sludwig@rejectedsoftware.com wrote:

Am 10/24/2012 5:01 AM, schrieb Nick Sabalausky:

To avoid the cost of establishing a new connection to a MySQL DB
on potentially every page request, I tried making one connection to
the DB upon startup of my vibe.d app and then use that one
connection for each request. Worked fine until I tried making
concurrent page requests, at which point I (perhaps unsurprisingly)
got a message about the wrong fiber accessing a connection and then
it died with an InvalidMemoryOperationError. (But annoyingly, I
can't seem to reproduce it now.)

So I realize that's probably not a smart thing to do anyway, to
share a single connection across fibers. But how would I go about
reusing DB connections when possible? By using ConnectionPool,
maybe? But I'm not quite sure how to use that.

In my modified version of the mysql driver there is a trivial MysqlDB
class that uses a ConnectionPool. lockConnection() returns a RAII
struct that makes sure that a single connection is not used twice.

Usually I would also mirror the methods of the Connection class for
convenience, but since I don't really use it myself, I didn't put so
much time into it yet.


So, if I'm understanding this right, ConnectionPool.lockConnection
creates and opens a new connection when the current fiber doesn't
already have an open connection, and returns an existing open connection
when the current fiber does have one?