spanner: client.Close cancels existing existing createSession calls
When client.Close is called, the invocation blocks until any CreateSession
requests that are currently inflight finish. This CL changes that behavior by
making a client.Close call immediately cancel inflight CreateSession requests.
This generally results in faster Close calls: if CreateSession is hanging it
is dramatically faster.
Change-Id: I25933e8032b95b10e2a298ad85bec262de9dac22
Reviewed-on: https://code-review.googlesource.com/c/36690
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Eno Compton <enocom@google.com>
diff --git a/spanner/session.go b/spanner/session.go
index 4c33dad..f26d6aa 100644
--- a/spanner/session.go
+++ b/spanner/session.go
@@ -760,7 +760,8 @@
// done is used to signal that health checker should be closed.
done chan struct{}
// once is used for closing channel done only once.
- once sync.Once
+ once sync.Once
+ maintainerCancel func()
}
// newHealthChecker initializes new instance of healthChecker.
@@ -769,12 +770,13 @@
workers = 1
}
hc := &healthChecker{
- interval: interval,
- workers: workers,
- pool: pool,
- sampleInterval: sampleInterval,
- ready: make(chan struct{}),
- done: make(chan struct{}),
+ interval: interval,
+ workers: workers,
+ pool: pool,
+ sampleInterval: sampleInterval,
+ ready: make(chan struct{}),
+ done: make(chan struct{}),
+ maintainerCancel: func() {},
}
hc.waitWorkers.Add(1)
go hc.maintainer()
@@ -787,6 +789,9 @@
// close closes the healthChecker and waits for all healthcheck workers to exit.
func (hc *healthChecker) close() {
+ hc.mu.Lock()
+ hc.maintainerCancel()
+ hc.mu.Unlock()
hc.once.Do(func() { close(hc.done) })
hc.waitWorkers.Wait()
}
@@ -984,9 +989,9 @@
}
sessionsToKeep := maxUint64(hc.pool.MinOpened,
minUint64(currSessionsOpened, hc.pool.MaxIdle+maxSessionsInUse))
- hc.mu.Unlock()
-
ctx, cancel := context.WithTimeout(context.Background(), hc.sampleInterval)
+ hc.maintainerCancel = cancel
+ hc.mu.Unlock()
// Replenish or Shrink pool if needed.
// Note: we don't need to worry about pending create session requests, we only need to sample the current sessions in use.
