Overview:

The default setting of JVM should be: -Xmx1024m -XX:MaxPermSize=256m

If the server doesn't have enough memory, this setting should work too: -Xmx512m -XX:MaxPermSize=128m

Troubleshooting:

1. Out of Memory: Perm Gem Space

Solution: set the right XX:PermSize

2. Out of Memory: Heap Space

Possible causes:

a. Max Memory settings is too high. The server doesn't have enough memory for Java to use.

Solution: reduce the settings for -Xmx

b. Max Memory settings is too low. JVM runs out of memory.

Increase the settings for -Xmx

c. Big items in document. JVM trys to load these items into memory (e.g 100M+ item) and runs out of memory.

Solutions: remove these items with large size.

Query (MySQL):

select id, name, char_length(description) from document where char_length(description)

delete from evententry where document in (...);

delete from version where documentId in (...);

delete from document where id in (...);