How to enable GC logs in Java8

Step-by-step guide

• Add the following lines to the integrator.sh file under $JVM_MEM_OPTS \ as below.

$JVM_MEM_OPTS \    -XX:+HeapDumpOnOutOfMemoryError \    -XX:HeapDumpPath="$CARBON_HOME/repository/logs/heap-dump.hprof" \    -XX:+PrintGC \    -XX:+PrintGCDetails \    -XX:+PrintGCDateStamps \    -Xloggc:"$PRODUCT_HOME/logs/gc.log" \ $JAVA_OPTS \

• It will print the GC logs into gc.log file inside <product_location>/logs/ directory.

If you have encountered an issue of 'Too many open files', you can monitor the open file counts from the following commands.

TID: [-1] [] [202X-0X-XX 10:30:03,426] WARN {org.apache.synapse.transport.passthru.PassThroughHttpSSLListener} - System may be unstable: HTTPS ListeningIOReactor encountered a checked exception : Too many open files {org.apache.synapse.transport.passthru.PassThroughHttpSSLListener} java.io.IOException: Too many open files at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:424 

Monitor the open file count and the details for specific processes via the below command.

lsof -a -d ^mem -d ^cwd -d ^rtd -d ^txt -d ^DEL -p > out_with_wso2_pid.txt 

Monitor the open file count and the details from all processes running in the VM via the below command.

lsof -a -d ^mem -d ^cwd -d ^rtd -d ^txt -d ^DEL > out_for_all.txt

How to check Master, Slave database differences

If you observed Master, Slave database difference, please execute the following SQL statements and check the results.

SELECT CONCAT(ROUND(SUM(data_length) / (1024*1024*1024),2),'GB') Data_Size, CONCAT(ROUND(SUM(index_length)/ (1024*1024*1024),2),'GB') Index_Size, CONCAT(ROUND((sum(data_length)+sum(index_length))/(1024*1024*1024),2),'GB') Total_Size  FROM information_schema.TABLES  WHERE TABLE_SCHEMA NOT IN ('information_schema', 'performance_schema', 'sys')  GROUP BY NULL; 

SELECT table_schema, table_name, CONCAT(ROUND((data_free / 1024 / 1024),2),'MB') data_free  FROM information_schema.tables  WHERE table_schema NOT IN ('mysql', 'information_schema', 'performance_schema', 'sys')    AND ENGINE LIKE 'InnoDB' AND data_free > 100 * 1024 *  1024;