Print Server Asynchronous Polling for Reliable Document Retrieval

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Solution Overview

Problem

In asynchronous communication systems, particularly in cloud services, delays in message reception can occur due to failures in third-party services, leading to issues where print requests are made before document input is confirmed, resulting in failed printing and increased costs from frequent service invocations in synchronized configurations, affecting print processing performance.

Innovation Solution

A print server system that utilizes a pub/sub messaging model with a named logical channel to enable asynchronous communication between document and print services, allowing for printing of input documents even when delays occur, by registering subscriptions to topics and using software containers for message transmission, thereby reducing direct communication dependencies and API invocations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If asynchronous communication is used between document and print services, then system flexibility and independence are improved, but message reception delays may occur due to third-party service failures

Engineering Contradiction:
Improveservice independenceVSAvoidmessage reception reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The print server proactively polls the document server at predetermined intervals to check for document availability and print requests, rather than passively waiting for asynchronous messages. This preliminary action ensures that printing operations can proceed without being blocked by message delivery delays, resolving the contradiction between using asynchronous communication for flexibility and maintaining reliable print execution.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If synchronized communication is used to ensure print requests are made only after document input is confirmed, then printing reliability is improved, but service invocation frequency increases leading to higher costs and reduced performance

Engineering Contradiction:
Improveprint execution reliabilityVSAvoidprint processing performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The print server performs periodic polling of the document server at predetermined time intervals to check for document availability and print requests. This periodic action reduces the frequency of service invocations compared to synchronized communication while ensuring that printing operations are not missed, thus improving print processing performance while maintaining acceptable reliability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The print server implements a feedback mechanism by continuously monitoring the document server's status through polling and adjusting its printing operations based on the current state. This feedback loop ensures that print requests are made at appropriate times without requiring frequent synchronous communication, thereby improving both productivity and cost-efficiency while maintaining print execution reliability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3594800B1Print server, control method, and program
Publication Date: 2022.08.31 CANON KK
  • EP3594800B1 patent drawingFigure 1
  • EP3594800B1 patent drawingFigure 2
  • EP3594800B1 patent drawingFigure 3

AI summary

A print server (101) includes a determination unit configured to receive a print request from a client, identify a document identification from the print request, and determine whether document information including the document identification is acquired, and an acquisition unit configured to acquire the document information by sending an inquiry to a document server (102) in response to a determination by the determination unit that the document information is not acquired.