CODEWITHSUNDEEP
javagarbage-collection
Zack
Zack

Reputation: 69

Unknown line in loggc output

I have enabled logging of Garbage Collection for my web application using the -Xloggc:/path/to/file option. All the documentation/tutorials online explain what lines like these mean:

[GC 4044799K->4039197K(9122624K), 0.2320070 secs]
[GC 7108933K->5064363K(9122624K), 1.2854980 secs]
[Full GC 4832238K->1823552K(9122624K), 8.7740310 secs]

But about 7% of the entries look like the ones below and my question is what does it mean?:

[GC 6536892K(9122624K), 1.6101470 secs]
[GC 5299301K(9122624K), 0.2458250 secs]

And as far as I can find there is no documentation on what this means (I even went to page 2 of Google's results). There is no arrow, so I assume this means that it tried to garbage collect and couldn't. I have no concrete confirmation of this; it is just my assumption.

Edit: I added in real values, but the numbers are really all over the place.

Upvotes: 2

Views: 64

Answers (1)

JQian
JQian

Reputation: 226

I suspect you are using CMS GC, and this means, Capacity of tenured generation space is 9122624K and CMS GC is triggered when space size is 6536892K. 

[GC 6536892K(9122624K), 1.6101470 secs]

The explanation from Hotspot can be found at this link

Upvotes: 1

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