After a publisher flushes a batch of messages the batch is (obviously) not received immediately by the service. While the batch remains pending it potentially consumes memory resources in the client (and/or the service).
Some applications may have constraints on the number of bytes and/or messages they can tolerate in this pending state, and may prefer to block or reject messages.
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 page provides a detailed list of versions for \u003ccode\u003eMaxPendingBytesOption\u003c/code\u003e, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eMaxPendingBytesOption\u003c/code\u003e is used to manage the maximum size of pending messages, which are messages sent but not yet received, and this is important to limit the client memory consumption.\u003c/p\u003e\n"],["\u003cp\u003eThis resource is specifically part of the Google Cloud Pub/Sub C++ client library, as indicated by the file paths.\u003c/p\u003e\n"],["\u003cp\u003eThe Alias for this type is \u003ccode\u003estd::size_t\u003c/code\u003e, which is a type alias for the maximum size of pending messages.\u003c/p\u003e\n"]]],[],null,[]]
