The maximum number of outstanding bytes per streaming pull.
The Cloud Pub/Sub C++ client library uses streaming pull requests to receive messages from the service. The service will stop delivering messages if this many bytes or more worth of messages have not been acknowledged nor rejected.
If a negative or 0 value is supplied, the number of bytes will be unlimited.
Example
namespace pubsub = ::google::cloud::pubsub;
using ::google::cloud::future;
using ::google::cloud::Options;
using ::google::cloud::StatusOr;
auto sample = [](std::string project_id, std::string subscription_id) {
// Change the flow control watermarks, by default the client library uses
// 0 and 1,000 for the message count watermarks, and 0 and 10MiB for the
// size watermarks. Recall that the library stops requesting messages if
// any of the high watermarks are reached, and the library resumes
// requesting messages when *both* low watermarks are reached.
auto constexpr kMiB = 1024 * 1024L;
auto subscriber = pubsub::Subscriber(pubsub::MakeSubscriberConnection(
pubsub::Subscription(std::move(project_id), std::move(subscription_id)),
Options{}
.set<pubsub::MaxOutstandingMessagesOption>(1000)
.set<pubsub::MaxOutstandingBytesOption>(8 * kMiB)));
auto session = subscriber.Subscribe(
[](pubsub::Message const& m, pubsub::AckHandler h) {
std::move(h).ack();
std::cout << "Received message " << m << "\n";
PleaseIgnoreThisSimplifiesTestingTheSamples();
});
return std::make_pair(subscriber, std::move(session));
};
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-14 UTC."],[[["This webpage details the `MaxOutstandingBytesOption` within the Google Cloud Pub/Sub C++ client library, which controls the maximum number of unacknowledged or unrejected bytes allowed during streaming pull operations."],["The page provides a version history of the `MaxOutstandingBytesOption` struct, ranging from version 2.11.0 up to the latest release candidate version 2.37.0-rc."],["Setting `MaxOutstandingBytesOption` to a negative or zero value will result in no limit to the number of bytes received, enabling unlimited message reception."],["The `MaxOutstandingBytesOption` struct is an alias of `std::int64_t`, which means you are able to use an integer to set the maximum value of the bytes received."],["The content demonstrates how to configure the `MaxOutstandingBytesOption` using a code sample, showing how to adjust flow control watermarks to manage the delivery of messages."]]],[]]
