Kettle JVM memory setting - the effect is not obvious

1、 View local JVM Memory size

     JVM The initial allocated memory is -Xms Appoint , The default is physical memory 1/64;JVM The maximum allocated memory is -Xmx finger set , The default is physical memory 1/4. The default free heap memory is less than 40% when ,JVM It's going to pile up until -Xmx The maximum limit of ; The free heap memory is larger than 70% when ,JVM It will reduce the pile until -Xms The minimum limit of . So the server is generally set up -Xms、 -Xmx Equal to avoid at every time GC Then adjust the size of the heap . You can use JVM Provided -Xmn -Xms -Xmx And other options to set heap memory , In general, we should -Xms and -Xmx The options are set to the same , and -Xmn by 1/4 Of -Xmx value , It is recommended that the maximum value of heap be set to the maximum value of available memory 80%. 

   

    Local computer configuration

2、 Set according to local size kettle Corresponding memory

      kettle When setting memory, you need to set the corresponding memory according to the size of local memory .

      My current host is 8GB Of memory ,JVM At most, you can use 2GB（8GB Of 1/4）.

      stay kettle Set up JVM Memory time , Generally speaking, online reference is that the maximum stack memory does not exceed the total memory 3/8 Some also say yes   Half , In short, there must be a degree .

      modify spoon.bat：

if "%PENTAHO_DI_JAVA_OPTIONS%"=="" set PENTAHO_DI_JAVA_OPTIONS="-Xms7680m" "-Xmx7680m" "-XX:MaxPermSize=3840m"

3、 Compare the efficiency improvement ratio after modification

At present excel The speed of the output ~~~15 strip / second ---》

After the change ---- A little bit faster Ignore it  

 

2019-6-24 Add ~~~~

excel The output really hasn't changed much , however ~~~~

Now reading data from the database is really ten times faster ...