The application processes transactions successfully. For the affected transactions, the database is updated correctly (status becomes ACQUIRED), the outbox event is generated and delivered successfully, and the expected application log is visible in AWS CloudWatch. However, for a subset of Funding Order IDs (FOIDs), the same log event is not searchable in Splunk. This suggests the application generated the log successfully and CloudWatch collected it, but the event is either not reaching Splunk consistently or is not being indexed/searchable. During our investigation, we attempted to reproduce the issue in a performance environment before deploying a fix. We increased the logging buffer size from 1 MB to 8 MB because we suspected that high TPS might be contributing to log forwarding delays or dropped events. We then executed load tests in the 500–600 TPS range. Surprisingly, we observed approximately 1,000 records in the outbox database table, while the corresponding Splunk search returned more than 100,000 events. This is the opposite of what we expected—we were anticipating fewer events in Splunk if logs were being dropped. We are now validating whether we are comparing distinct FOIDs versus total log events, and we have modified the load test to generate unique FOIDs to eliminate duplicates. We are also testing with gradually increasing TPS (25, 50, 75, 100, etc.) to determine whether there is a threshold where database counts and Splunk counts begin to diverge. At the infrastructure level, we recently made changes related to Splunk Deployment Server configuration, endpoint/CIDR updates, and Terraform-managed infrastructure, although we have not established any direct correlation between those changes and the observed behavior. Given these observations, how would you approach isolating the root cause? Would you first investigate duplicate ingestion (multiple forwarders or monitor stanzas), forwarder buffering, inputs.conf/outputs.conf, deployment server bundle consistency, HEC/Universal Forwarder behavior, indexing/parsing, or query methodology? Are there specific Splunk internal logs, metrics, or diagnostics you would recommend reviewing to determine whether the issue is due to ingestion, indexing, duplicate forwarding, or simply how the events are being counted? Any guidance or similar experiences would be greatly appreciated. This is a production observability issue, and we’re trying to narrow the exact failure point before concluding the RCA.
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