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Unexpected pagination behavior #1329
Description
Describe the bug
I am surprised that the following code does no pagination:
let mut output = ec2_client.describe_instances().into_paginator().send();
// Only ever makes 1 request; no MaxResults parameter is present on the request.I had to explicitly set max results via .page_size(i32) on the paginator. The pagination docs seem to say that it's sufficient to call .into_paginator(). I'm not sure if this is a difference between the EC2 & S3 SDK or if the documentation is just misleading for all SDKs.
Regression Issue
- Select this option if this issue appears to be a regression.
Expected Behavior
I would expect some default page size to be set by .into_paginator() otherwise many users will be surprised (as we were) that they're not making paginated requests.
Current Behavior
No pagination if you only call .into_paginator() (with .page_size).
Reproduction Steps
I confirmed this by turning on tracing debug logging and observing the before and after requests being maide by the SDK once I added .page_size.
Possible Solution
This is either a bug (my expectation) or it's a documentation issue.
Additional Information/Context
No response
Version
├── aws-config v1.8.1
│ ├── aws-credential-types v1.2.3
│ │ ├── aws-smithy-async v1.2.5
│ │ ├── aws-smithy-runtime-api v1.8.1
│ │ │ ├── aws-smithy-async v1.2.5 (*)
│ │ │ ├── aws-smithy-types v1.3.2
│ │ ├── aws-smithy-types v1.3.2 (*)
│ ├── aws-runtime v1.5.8
│ │ ├── aws-credential-types v1.2.3 (*)
│ │ ├── aws-sigv4 v1.3.3
│ │ │ ├── aws-credential-types v1.2.3 (*)
│ │ │ ├── aws-smithy-http v0.62.1
│ │ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ │ ├── aws-smithy-types v1.3.2 (*)
│ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-smithy-async v1.2.5 (*)
│ │ ├── aws-smithy-http v0.62.1 (*)
│ │ ├── aws-smithy-runtime v1.8.3
│ │ │ ├── aws-smithy-async v1.2.5 (*)
│ │ │ ├── aws-smithy-http v0.62.1 (*)
│ │ │ ├── aws-smithy-http-client v1.0.6
│ │ │ │ ├── aws-smithy-async v1.2.5 (*)
│ │ │ │ ├── aws-smithy-protocol-test v0.63.4
│ │ │ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ │ ├── aws-smithy-types v1.3.2 (*)
│ │ │ │ │ │ ├── aws-lc-rs v1.13.1
│ │ │ │ │ │ │ ├── aws-lc-sys v0.29.0
│ │ │ │ │ │ │ ├── aws-lc-rs v1.13.1 (*)
│ │ │ ├── aws-smithy-observability v0.1.3
│ │ │ │ └── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-types v1.3.7
│ │ │ ├── aws-credential-types v1.2.3 (*)
│ │ │ ├── aws-smithy-async v1.2.5 (*)
│ │ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ │ ├── aws-smithy-types v1.3.2 (*)
│ ├── aws-sdk-sso v1.74.0
│ │ ├── aws-credential-types v1.2.3 (*)
│ │ ├── aws-runtime v1.5.8 (*)
│ │ ├── aws-smithy-async v1.2.5 (*)
│ │ ├── aws-smithy-http v0.62.1 (*)
│ │ ├── aws-smithy-json v0.61.4
│ │ │ └── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-smithy-runtime v1.8.3 (*)
│ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-types v1.3.7 (*)
│ ├── aws-sdk-ssooidc v1.75.0
│ │ ├── aws-credential-types v1.2.3 (*)
│ │ ├── aws-runtime v1.5.8 (*)
│ │ ├── aws-smithy-async v1.2.5 (*)
│ │ ├── aws-smithy-http v0.62.1 (*)
│ │ ├── aws-smithy-json v0.61.4 (*)
│ │ ├── aws-smithy-runtime v1.8.3 (*)
│ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-types v1.3.7 (*)
│ ├── aws-sdk-sts v1.76.0
│ │ ├── aws-credential-types v1.2.3 (*)
│ │ ├── aws-runtime v1.5.8 (*)
│ │ ├── aws-smithy-async v1.2.5 (*)
│ │ ├── aws-smithy-http v0.62.1 (*)
│ │ ├── aws-smithy-json v0.61.4 (*)
│ │ ├── aws-smithy-query v0.60.7
│ │ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-smithy-runtime v1.8.3 (*)
│ │ ├── aws-smithy-runtime-api v1.8.1 (*)
│ │ ├── aws-smithy-types v1.3.2 (*)
│ │ ├── aws-smithy-xml v0.60.10
│ │ ├── aws-types v1.3.7 (*)
│ ├── aws-smithy-async v1.2.5 (*)
│ ├── aws-smithy-http v0.62.1 (*)
│ ├── aws-smithy-json v0.61.4 (*)
│ ├── aws-smithy-runtime v1.8.3 (*)
│ ├── aws-smithy-runtime-api v1.8.1 (*)
│ ├── aws-smithy-types v1.3.2 (*)
│ ├── aws-types v1.3.7 (*)
├── aws-sdk-ec2 v1.144.0
│ ├── aws-credential-types v1.2.3 (*)
│ ├── aws-runtime v1.5.8 (*)
│ ├── aws-smithy-async v1.2.5 (*)
│ ├── aws-smithy-http v0.62.1 (*)
│ ├── aws-smithy-json v0.61.4 (*)
│ ├── aws-smithy-query v0.60.7 (*)
│ ├── aws-smithy-runtime v1.8.3 (*)
│ ├── aws-smithy-runtime-api v1.8.1 (*)
│ ├── aws-smithy-types v1.3.2 (*)
│ ├── aws-smithy-xml v0.60.10 (*)
│ ├── aws-types v1.3.7 (*)
├── aws-smithy-runtime v1.8.3 (*)
├── aws-smithy-types v1.3.2 (*)
Environment details (OS name and version, etc.)
MacOS
Logs
No response
Activity
ysaito1001 commentedon Jul 30, 2025
Thank you for bringing this up. I believe what you've described is true; If you we not set a page size by
page_size, theMaxResultswon't make it into a request (code), in which case it relies on the service’s default behavior to return whatever amount of data, and paginates withNextToken.S3 should have the same issue since paginators are code-generated from the common logic of paginator within codegen.
Will call it out in the paginator's documentation.