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changes.mady.by.user Joseph (Pepe) Kelly

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Date

Authors

Joseph (Pepe) Kelly, Marcello Fabbri (Unlicensed)

Status

Done.

Summary

Some exported placements show an unknown ESR status (?) on TIS instead of correctly displaying their exported status (✔)

Impact

Inaccurate information regarding some placement’s ESR status

...

  • : 15:33 BST - Slack notification regarding a high volume of messages in the Dead Letter Queue

  • : 15:58 BST - Poor interaction between the InboundDataWriterService and TCS identified as the culprit for messages being discarded when info hadn’t successfully been recorded into TIS

  • : Fix put in place to increase resilience of the InboundDataWriterService when interacting with TCS

  • : Affected data amended in order to display accurate ESR export status

Root Cause(s)

  • TCS didn’t have the data to show the tick to say the placement was updated.

  • The Inbound Data Writer service updates to TCS failed, which is responsible for updating the PlacementEsrEvent table where this data’s stored.

  • The message was not requeued (therefore re-processing was not attempted), and the updates where not applied.

  • TCS was momentarily unavailable* right when the Inbound Data Writer service sent the REST call and didn’t accommodate that call. It didn’t update anything.

  • The Inbound Data Writer service, treated TCS’s unavailability like a problem with the message which aren’t requeued.

  • *why was TCS unavaliable?unavailable? Could be a number of reasons every day different. For example, on April 6, 2021 there was a live defect between 2 and 2:30 pm which affected the stage and prod environment, and some RuntimeExceptions where thrown on Stage and affected the ESR-TIS interaction, i.e.:
    "z-exception-type": "java.lang.RuntimeException",
    "x-exception-message": "Throwing exception so that this message is not requeued",
    "eventSourceTimestamp": "2021-04-06T13:10:00.178Z",

Action Items

Action Items

Owner

Status

Fix current Placements whose status is currently inaccurate

Edward Barclay ongoing

https://hee-tis.atlassian.net/browse/TIS21-1650

Make the Inbound Data Writer service more resilient so it requeues the messages when TCS doesn’t respond

Marcello Fabbri (Unlicensed)

donehttps://hee-tis.atlassian.net/browse/TIS21-1651

Check elsewhere in the ESR interface for places where requeuing would be appropriate

Marcello Fabbri (Unlicensed)

ongoinghttps://hee-tis.atlassian.net/browse/TIS21-1746

...

Lessons Learned

  • Consider more carefully when it’s appropriate to requeue a message (re-attempt processing it) and when it’s ok not to requeue a message.