Understanding the Report

A walk-through of every section the EasyGC analyzer produces.

Key indicators

Metric	What it means	Healthy range
GC Throughput	% of total time the application (not the collector) runs	≥ 95%
Avg Pause	Mean duration of stop-the-world collections	Depends on SLO; < 50 ms is comfortable
Max / P99 Pause	Worst and 99th-percentile pauses — the ones users feel	< 1 s
Young GC count	Number of minor collections	Normal to be frequent
Full GC count	Number of stop-the-world whole-heap collections	0 — any Full GC deserves investigation
Total Pause Time	Sum of all stop-the-world time in the log	Compare against SLA budgets
Allocation Rate	Average object allocation speed (MB/s)	Watch after code changes
Log Time Span	Wall-clock / uptime range the log covers	Longer = more reliable

JVM Memory

The maximum capacities observed in the log: total heap, young gen, old gen and metaspace. This tells you the effective -Xmx / -Xmn (or region) settings without touching the JVM.

TIP

Young/Old breakdown requires Java 8 style detailed logs. Unified logs (-Xlog:gc*) report whole-heap numbers; enable -Xlog:gc+heap* for region details.

Charts

• Heap Usage Around GC — the sawtooth of heap occupancy. The After GC line should oscillate in a stable band. If it climbs step by step, you are looking at retained objects that never get collected — a leak.
• GC Pause Times — every stop-the-world event over time, stacked by kind (young / full / CMS remark). Look for outliers and periodic spikes.
• GC Causes — what triggered each collection. Allocation Failure is healthy; System.gc(), Metaspace or Promotion failed are leads to follow.

Recommendations

Rules-based advice derived from your actual data, each with a severity:

• Critical — act now (memory leak, throughput below 50%).
• Warning — tune soon (Full GCs present, explicit GC calls, long max pause).
• Info — optimization opportunities (oversized heap, few events, humongous allocations).
• Good — patterns worth keeping (healthy throughput, ZGC sub-millisecond pauses).

GC Events

The full parsed event list: uptime, type, trigger cause, pause duration and heap sizes before/after every collection. Use it to correlate GC activity with your own application logs by timestamp.