fix PcpMmvWriter race condition #133
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Fixes a race condition where metric updates can be lost if the happen while `PcpMmvWriter` is being reset. Previously, updates were dropped if the writer was not in a started state. If this happened while the the writer was executing `start()`, then it's possible the updated value would be lost if the old metric value had already been written. The issue is addressed here by blocking the metric update when the writer is in a `STARTING` state, until the writer has been fully started. If the writer is in a `STARTED` state, the update is applied immediately. If the writer is in a `STOPPED` state, the update is dropped immediately. Resolves performancecopilot#132
If the old code threw an exception starting, it would remaing in a stopped state. This replicates that behavior. If the start process fails, it reverts back to `STOPPED` and does not remain in a `STARTING` state.
tallpsmith
reviewed
Nov 18, 2024
Adds the config property `parfait.writer.wait` that can be used to adjust the amount of time an update metric operation will wait for the writer to start.
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Fixes a race condition where metric updates can be lost if the happen while
PcpMmvWriteris being reset. Previously, updates were dropped if the writer was not in a started state. If this happened while the the writer was executingstart(), then it's possible the updated value would be lost if the old metric value had already been written.The issue is addressed here by blocking the metric update when the writer is in a
STARTINGstate, until the writer has been fully started. If the writer is in aSTARTEDstate, the update is applied immediately. If the writer is in aSTOPPEDstate, the update is dropped immediately.Resolves #132