public async Task SequentialCreatesOnlyUseOneChannel()
{
//SpannerClients if created sequentially should only use a single channel.
//This is to faciliate good session pool hits (which is per channel). If we always
//round robin'd clients, then we would get hard cache misses until we populated all
//of the caches per channel.
//Since channels are lazily created, this also saves resources for scenarios like rich clients
//that may only need a single session for multiple sequential workloads.
//Our default setting for # channels = 4 needs to work well for all scenarios.
var firstReturnedClient = new Mock <SpannerClient>();
var mockClientFactory = SetupMockClientFactory(firstReturnedClient);
var testPool = new ClientPool(mockClientFactory);
var expectedClient = firstReturnedClient.Object;
Assert.Same(expectedClient, await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder));
testPool.ReleaseClient(expectedClient, s_defaultConnectionStringBuilder);
Assert.Same(expectedClient, await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder));
testPool.ReleaseClient(expectedClient, s_defaultConnectionStringBuilder);
Assert.Same(expectedClient, await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder));
testPool.ReleaseClient(expectedClient, s_defaultConnectionStringBuilder);
var s = new StringBuilder();
Assert.Equal(0, testPool.GetPoolInfo(s));
Logger.DefaultLogger.Info(() => s.ToString());
Assert.Equal(1, mockClientFactory.Invocations);
}
private static async Task <SpannerClient> GetSpannerClientAsync(ClientPool pool)
{
//immediately yield to increase contention for stress testing.
await Task.Yield();
return(await pool.AcquireClientAsync(s_defaultConnectionStringBuilder));
}
public async Task RoundRobin()
{
var mockClientFactory = SetupMockClientFactory();
var testPool = new ClientPool(mockClientFactory);
var clientList = new List <SpannerClient>();
for (var i = 0; i < SpannerOptions.Instance.MaximumGrpcChannels; i++)
{
var newClient = await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder);
Assert.DoesNotContain(newClient, clientList);
clientList.Add(newClient);
}
//now we wrap around.
var firstReusedClient = await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder);
Assert.Same(clientList[0], firstReusedClient);
testPool.ReleaseClient(firstReusedClient, s_defaultConnectionStringBuilder);
foreach (var client in clientList)
{
testPool.ReleaseClient(client, s_defaultConnectionStringBuilder);
}
var s = new StringBuilder();
Assert.Equal(0, testPool.GetPoolInfo(s));
Logger.DefaultLogger.Info(() => s.ToString());
//now that everything got released, lets ensure the client order is preserved so
//that we again get the first client.
Assert.Same(firstReusedClient, await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder));
testPool.ReleaseClient(firstReusedClient, s_defaultConnectionStringBuilder);
Assert.Equal(SpannerOptions.Instance.MaximumGrpcChannels, mockClientFactory.Invocations);
}
public async Task ClientsCreatedOnDemandAsync()
{
//SpannerClients should not be precreated, but be created lazily.
var mockClientFactory = SetupMockClientFactory();
var testPool = new ClientPool(mockClientFactory);
var clientAcquired = await testPool.AcquireClientAsync(s_defaultConnectionStringBuilder);
testPool.ReleaseClient(clientAcquired, s_defaultConnectionStringBuilder);
Assert.Equal(1, mockClientFactory.Invocations);
var s = new StringBuilder();
Assert.Equal(0, testPool.GetPoolInfo(s));
Logger.DefaultLogger.Info(() => s.ToString());
}
