express.eventloop.lag.mean

Mean event loop lag

Dimensions:None

Available on:

Prometheus (1)

Interface Metrics (1)

Prometheus

nodejs_eventloop_lag_mean_seconds

Mean event loop lag in seconds

Dimensions:None

Sources

nodejs_eventloop_lag_mean_secondsgithub.com

Technical Annotations (14)

Configuration Parameters (2)

thresholdrecommended: 100

Event loop delay threshold in ms for warning alerts

resolutionrecommended: 10

Resolution for monitorEventLoopDelay histogram in ms

CLI Commands (4)

function processInChunks(data, chunkSize = 1000) { let index = 0; function nextChunk() { const end = Math.min(index + chunkSize, data.length); for (; index < end; index++) { processData(data[index]); } if (index < data.length) { setImmediate(nextChunk); } } nextChunk(); }

remediation

clinic doctor -- node your-app.jsdiagnostic

const { monitorEventLoopDelay } = require('perf_hooks'); const h = monitorEventLoopDelay(); h.enable(); setInterval(() => { console.log(`Event Loop Lag: ${Math.round(h.mean / 1e6)} ms`); }, 1000);

monitoring

node --inspect app.jsdiagnostic

Technical References (8)

perf_hookscomponentmonitorEventLoopDelaycomponentsetImmediatecomponentsetTimeoutcomponentevent loopconceptclinic.jscomponentclinic doctorcomponentblocked-atcomponent

Related Insights (4)

Event loop blocking causes complete application unresponsivenesscritical

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Synchronous loops block event loop causing application unresponsivenesscritical

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Event loop lag detection requires monitoring toolinginfo

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Event loop lag exceeding 50ms indicates blocking operationswarning

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