[FEATURE REQ]: Evaluate improvements for `CosmosDiagnostics`.

[jeet1995]

Tasks

• [ ] From incidents and customer concerns, the stringified representation of CosmosDiagnostics occupies space which breaches size / character limits in whatever log analytics service the customer may choose to use, causing diagnostic strings to be truncated - an example of such limits specific to Azure Monitor - https://learn.microsoft.com/en-us/azure/azure-monitor/service-limits#logs-ingestion-api. Evaluate ways to reduce the size / characters taken up by a stringified representation of CosmosDiagnostics instance without losing the information it wishes to convey.

• [ ] As a part of the above issue, evaluate if there is a way to rejig the diagnostic string to display errors first as opposed to successes.

• [ ] The diagnostic string captures configurations set at the client-level or through operation-specific Cosmos*RequestOptions instances. With, dynamic request options - see #40061, operation-specific Cosmos*RequestOptions instances can be overridden. It could help to understand the source of these settings in the diagnostics.

• [ ] Expose CosmosDiagnostics for handleChanges and handleLatestVersionChanges overloads exposed for ChangeFeedProcessor. For handleLatestVersionChanges, both ALL_VERSIONS_AND_DELETES and INCREMENTAL change feed modes should emit CosmosDiagnostics. Validate the correctness of the diagnostics emitted by the queryChangeFeed() API.

[github-actions[bot]]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @kushagraThapar @pjohari-ms @TheovanKraay.

[Vrinda2311]

@jeet1995 @kushagraThapar Found below issues in CosmosDiagnostics.

1. CosmosDiagnostics does not accurately represent the actual consistencyCfg in use, especially when overridden by dynamic request options. It only displays the client level consistency configuration.
2. Similarly, CosmosDiagnostics does not accurately represent the actual e2ePolicyCfg in use, especially when overridden by dynamic request options. It only displays the client level e2ePolicy.
3. Query/readMany operations do not honor excluded regions. Same is not even reflected in the diagnostics.

[tvaron3]

One suggestion for the showing the options in the diagnostics is only showing the effective options, so which one were actually executed in the request regardless of client, dynamic, or request level.