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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 provides documentation for the \u003ccode\u003eMaxPendingBytesOption\u003c/code\u003e within the Google Cloud Pub/Sub C++ client library, across multiple versions.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentation is for version 2.37.0-rc, with links to documentation for all versions from 2.11.0 up to 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eMaxPendingBytesOption\u003c/code\u003e controls the maximum size, in bytes, of pending messages before they are sent by the publisher.\u003c/p\u003e\n"],["\u003cp\u003eThis option helps applications manage memory usage by allowing them to set limits on the number of bytes used by messages waiting to be sent.\u003c/p\u003e\n"]]],[],null,[]]
