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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis webpage documents various versions of the \u003ccode\u003eMaxPendingMessagesOption\u003c/code\u003e for the Google Cloud Pub/Sub C++ client library.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version documented is 2.37.0-rc, while the page also includes documentation for versions ranging from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eMaxPendingMessagesOption\u003c/code\u003e relates to managing the number of messages that can be in a pending state after being sent but not yet received, which impacts memory usage.\u003c/p\u003e\n"],["\u003cp\u003eThis option is configurable with \u003ccode\u003estd::size_t\u003c/code\u003e type, giving the user control over memory consumption.\u003c/p\u003e\n"]]],[],null,[]]
