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AppSync subscription stopped working after creating the 6th DynamoDB item


For some unknown reason, when there are 6+ items in a DynamoDB table, the createItem() subscription doesn't work, even when I was trying it in AWS AppSync console. No response at all after invoking createItem() through code, but the item gets created in DynamoDB though.

Is there a limit to the number of items in DynamoDB to subscriptions?

Edited by: PaulLTC on Jul 28, 2021 10:24 AM

Edited by: PaulLTC on Jul 28, 2021 10:25 AM

1 Answer

The solution to this is to create my own Custom query and subscription instead of the generated ones, and only include the ones I want in the payload.
The generated query and subscription have ~2.9k lines of code, and with hours of testing in AppSync console, I discovered that it probably exceeded the payload size (240KB over WebSockets and 120KB MQTT over WebSockets).

It is not too friendly that not even an error is thrown when the accumulated payload size is exceeded.

answered a year ago

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