GODRIVER-3156 Detect and discard closed idle connections. #1815
Conversation
| @@ -512,24 +513,53 @@ func (c *connection) close() error { | |||
| } | |||
|
|
|||
| func (c *connection) closed() bool { | |||
| return atomic.LoadInt64(&c.state) == connDisconnected | |||
| if atomic.LoadInt64(&c.state) == connDisconnected { | |||
There was a problem hiding this comment.
Suggest adding a comment to closed noting that the method checks both the client-side connection state as well as the server-side.
closed will return true if the connection has been closed client-side or by the server. If the connection has been closed by the server, this method will close the connection client-side to avoid returning a perished connection back to the pool.
There was a problem hiding this comment.
That's a great idea! This recommendation is also making me reconsider adding the logic to connection.closed, which previously would return quickly and do no system calls. It may be better to add a new method on connection or pool that is used in connectionPerished to prevent unintended side effects.
| // If the connection has been idle for less than 10 seconds, skip the liveness | ||
| // check. | ||
| idleStart, ok := c.idleStart.Load().(time.Time) | ||
| if !ok || idleStart.Add(10*time.Second).After(time.Now()) { |
There was a problem hiding this comment.
What is the significance of 10 seconds?
There was a problem hiding this comment.
My reference was the PyMongo driver, which checks connection liveness when it's idle for >1 second. I wanted to mitigate the risk that checking liveness too often would cause performance problems (since a liveness check takes at least 1ms), so I increased that threshold to 10s.
x/mongo/driver/topology/pool_test.go
Outdated
| Address: address.Address(addr.String()), | ||
| }, WithDialer(func(Dialer) Dialer { return d })) | ||
| err := p.ready() | ||
| noerr(t, err) |
There was a problem hiding this comment.
Suggest using the require package instead of noerr.
blink1073
added
priority-1-high
|
This looks relevant: |
API Change ReportNo changes found! |
GODRIVER-3156
Summary
connection.idleDeadlinetoconnection.idleStart, allowing us to calculate different idle deadlines for different purposes.Background & Motivation
Currently the Go driver never attempts to detect connections that were closed by the other side when checking out connections. As a result, it's possible to return a connection that's been closed by the other side where any read or write operations will immediately fail. Instead, we should check if the connection has been closed when checking out a connection.