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This article mainly introduces the relevant knowledge of how to use the jstat command, the content is detailed and easy to understand, the operation is simple and fast, and has a certain reference value. I believe you will gain something after reading this jstat command article. Let's take a look at it.

Usage of jstat: jstat [generalOption, outputOptions vmid, [interva,count]

Parameters:

GeneralOption: generally use-gcutil to view GC

Vmid: virtual machine process number, that is, the currently running java process number

Interval: interval in seconds or milliseconds

Count: the number of times to print, or countless times by default

1. Query the overall usage of GC jstat-gcutil 23484 1000 5

The results show that:

S0: percentage of space used in Survivor space 0 in the Cenozoic era

S1: percentage of space used in Survivor space 1 in the Cenozoic era

E: percentage of space used by the new generation

O: percentage of space used in the old days

M: metadata area usage ratio

CCS: compress usage ratio

YGC: the number of times Yang GC has occurred since the application was started

YGCT: the time taken by Yang GC from the start of the application to the current [in seconds]

FGC: the number of times Full GC has occurred since the application was started

FGCT: the time taken by Full GC from the start of the application to the current

GCT: total time spent on garbage collection from the start of the application to the current [in seconds]

2. Overall garbage collection statistics jstat-gc 18528 1000 5

S0C: the size of the first survival area

S1C: the size of the second survival area

S0U: the usage size of the first survival area

S1U: the size of the second survival area used

EC: the size of Eden Park

EU: usage size of Eden Park

OC: old age size

OU: size used in the old days

MC: method area size

MU: method area use size

CCSC: compress class space size

CCSU: compressed class space usage size

YGC: the number of garbage collection of the younger generation

YGCT: the time consumed by the younger generation of garbage collection

FGC: the number of garbage collection in the old days

FGCT: time spent on garbage collection in the old days

GCT: total time spent on garbage collection

3. New generation garbage collection statistics jstat-gcnew 18528 1000 5

S0C: size of the first survival area

S1C: the size of the second survival area

S0U: the usage size of the first survival area

S1U: the size of the second survival area used

TT: the number of times an object has survived in the new generation

MTT: the maximum number of times an object has survived in the new generation

DSS: expected survival area size

EC: the size of Eden Park

EU: usage size of Eden Park

YGC: the number of garbage collection of the younger generation

YGCT: the time consumed by the younger generation of garbage collection

4. Heap memory Statistics jstat-gccapacity 18528 1000 5 / / overall Statistics jstat-gcnewcapacity 18528 1000 5 / / Cenozoic Statistics jstat-gcoldcapacity 18528 1000 5 / / Old Age Statistics

NGCMN: minimum capacity of Cenozoic era

NGCMX: maximum capacity of Cenozoic era

NGC: current Cenozoic capacity

S0C: size of the first survival area

S1C: the size of the second survival area

EC: the size of Eden Park

OGCMN: minimum capacity in the old days

OGCMX: maximum capacity in the old days

OGC: current old age size

OC: current old age size

MCMN: minimum metadata capacity

MCMX: maximum metadata capacity

MC: current metadata space size

CCSMN: minimum compressed class space size

CCSMX: maximum compressed class space size

CCSC: current compressed class space size

YGC: the number of gc of the younger generation

FGC: the number of GC in the old era

This is the end of the article on "how to use the jstat command". Thank you for reading! I believe you all have a certain understanding of the knowledge of "how to use jstat commands". If you want to learn more, you are welcome to follow the industry information channel.

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