<div dir="ltr">Dear Experts, <div><br></div><div>We have an application running on jre <span style="color:black;font-family:Calibri,sans-serif;font-size:11pt">1.8u261 with the below jvm arguments:</span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"> -Xms8g
-Xmx8g -XX:MetaspaceSize=2g -XX:MaxMetaspaceSize=2g -XX:+UseG1GC -XX:ParallelGCThreads=2
-XX:ConcGCThreads=1 -XX:+PrintFlagsFinal</span><span style="color:black;font-family:Calibri,sans-serif;font-size:11pt"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">From the jfrs, we could see Humongous allocation failures are happening in the G1New and aswell G1Old spaces:</span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><table border="0" cellpadding="0" cellspacing="0" width="1017" style="border-collapse:collapse;width:763pt">
<colgroup><col width="57" style="width:43pt">
<col width="64" span="15" style="width:48pt">
</colgroup><tbody><tr height="19" style="height:14.5pt">
<td height="19" width="57" style="height:14.5pt;width:43pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">GC ID</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Cause</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Collector Name</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Longest Pause</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Sum of Pauses</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Final References</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Weak References</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Soft References</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Phantom References</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Duration</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Start Time</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">End Time</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Used Heap Before GC</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Used Heap After GC</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Used Heap Delta</td>
<td width="64" style="width:48pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">Duration in seconds</td>
</tr>
<tr height="19" style="height:14.5pt">
<td height="19" class="gmail-xl63" align="right" style="height:14.5pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7,156</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1 Humongous Allocation</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1New</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">164.046 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">164.046 ms</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">128</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">164.046 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:53:52.858 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:53:53.022 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.73 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.33 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">-407 MiB</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0.164046</td>
</tr>
<tr height="19" style="height:14.5pt">
<td height="19" class="gmail-xl63" align="right" style="height:14.5pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7,157</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1 Humongous Allocation</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1Old</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">182.956 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">197.682 ms</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3</td>
<td class="gmail-xl63" align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">72,074</td>
<td class="gmail-xl63" align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3,638</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">24</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.831 s</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:53:52.858 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:53:55.689 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.73 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.58 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">-1.14 GiB</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.831</td>
</tr>
<tr height="19" style="height:14.5pt">
<td height="19" class="gmail-xl63" align="right" style="height:14.5pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7,178</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1 Humongous Allocation</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1New</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">88.197 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">88.197 ms</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">4</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">4</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">88.197 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:54:05.838 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:54:05.926 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.74 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.49 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">-258 MiB</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">0.088197</td>
</tr>
<tr height="19" style="height:14.5pt">
<td height="19" class="gmail-xl63" align="right" style="height:14.5pt;padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7,179</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1 Humongous Allocation</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">G1Old</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">183.655 ms</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">197.983 ms</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">1</td>
<td class="gmail-xl63" align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">71,947</td>
<td class="gmail-xl63" align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3,640</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">24</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.558 s</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:54:05.838 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">7/22/24, 3:54:08.396 AM</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">3.74 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.66 GiB</td>
<td style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">-1.08 GiB</td>
<td align="right" style="padding-top:1px;padding-right:1px;padding-left:1px;color:black;font-size:11pt;vertical-align:bottom;border:none">2.558</td>
</tr>
</tbody></table></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">But the java tuning document mentions that humongous allocation happens in the old generation. How do we interpret this above data? Under which circumstances do we see this kind of behaviour (humongous allocation failure in g1new space), </span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">ref: </span><a href="https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/g1_gc_tuning.html" style="font-family:Calibri,sans-serif;font-size:11pt;color:blue">https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/g1_gc_tuning.html</a></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">Could you please throw some light.</span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">Thanks in advance</span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif">Ravi</span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div><div><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif"><br></span></div></div>