To guarantee messages are received by the service in the same order that the application gives them to a publisher, the client library needs to wait until a batch of messages is successfully delivered before sending the next batch, otherwise batches may arrive out of order as there is no guarantee the same channel or network path is used for each batch.
For applications that do not care about message ordering, this can limit the throughput. Therefore, the behavior is disabled by default.
See Also
the documentation for the Publisher class for details.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with links to documentation for versions back to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eThe content focuses on \u003ccode\u003eMessageOrderingOption\u003c/code\u003e in the \u003ccode\u003egoogle::cloud::pubsub\u003c/code\u003e namespace, outlining its role in guaranteeing message order.\u003c/p\u003e\n"],["\u003cp\u003eMessage ordering ensures messages are received in the same order they are sent, requiring the client library to wait for successful delivery of batches.\u003c/p\u003e\n"],["\u003cp\u003eMessage ordering is disabled by default because it can limit throughput for applications that don't need it.\u003c/p\u003e\n"],["\u003cp\u003eDetailed information about message ordering can be found in the \u003ccode\u003ePublisher\u003c/code\u003e class documentation.\u003c/p\u003e\n"]]],[],null,[]]
