java.lang.OutOfMemoryError: Java heap space

[jagtejsodhi]

Hey folks,

I'm using GeoIP2 version 2.15.0.

I realize this issue has been brought up before in the following links, but I'm still unable to get it working.
#123
https://stackoverflow.com/questions/59557001/maxmind-databasereader-java-heap-space
https://stackoverflow.com/questions/14876836/file-inside-jar-is-not-visible-for-spring

I'm building a Java spring boot application. This is my code to setup the Database Reader. Note - I am only creating the Database Reader ONCE, not per call.

ResourceLoader resourceLoader = new DefaultResourceLoader();

Resource resource = resourceLoader.getResource("classpath:/GeoLite2-City.mmdb");

DatabaseReader reader = new DatabaseReader.Builder(resource.getInputStream())
                    .fileMode(Reader.FileMode.MEMORY)
                    .withCache(new CHMCache())
                    .build();

However, when setting up the Database Reader I get this error:

java.lang.OutOfMemoryError: Java heap space
	at java.util.Arrays.copyOf(Arrays.java:3236) ~[na:1.8.0_292]
	at java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:118) ~[na:1.8.0_292]
	at java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93) ~[na:1.8.0_292]
	at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:153) ~[na:1.8.0_292]
	at com.maxmind.db.BufferHolder.<init>(BufferHolder.java:52) ~[maxmind-db-2.0.0.jar!/:na]
	at com.maxmind.db.Reader.<init>(Reader.java:90) ~[maxmind-db-2.0.0.jar!/:na]
	at com.maxmind.geoip2.DatabaseReader.<init>(DatabaseReader.java:89) ~[geoip2-2.15.0.jar!/:2.15.0]
	at com.maxmind.geoip2.DatabaseReader.<init>(DatabaseReader.java:62) ~[geoip2-2.15.0.jar!/:2.15.0]
	at com.maxmind.geoip2.DatabaseReader$Builder.build(DatabaseReader.java:216) ~[geoip2-2.15.0.jar!/:2.15.0]

Note: This only happens when I package the app as a WAR file and deploy to AWS, but works fine on my local machine.

Because I'm accessing the .mmdb file in the WAR, I can't use resource.getFile() because a FileNotFoundException gets thrown. And when passing an InputStream into the DatabaseReader Builder (resource.getInputStream()), the Out of Memory Error gets thrown.

Been stuck on this for several days now, I must be missing something. Thanks in advance!

[oschwald]

As mentioned in the Stack Overflow discussion, you would probably be best off moving the file out of the WAR file and then memory mapping it. That said, have you tried increasing -Xmx? What is your current maximum heap size?

[jagtejsodhi]

Yep, increasing -Xmx worked, but was hoping there was another way to solve the issue without increasing heap size.

With the way our deployment works, we deploy the WAR file directly so moving it out of the WAR file adds a layer of complexity that we don't want to take on just yet (but might have to.) For now, I'll go with the -Xmx increase, and come back to memory mapping later.

Thanks for the help.

[jagtejsodhi]

Hey @oschwald, I had some extra time so came back to this to try the approach you recommended (moving the file out of the WAR file and then memory mapping it.)

I looked up some resources on how to access a file outside the WAR, but only found information on how to read property files outside the WAR.

Do you have any more explanation or an example of how to do this? I'm super new to Spring Boot so sorry if this is an obvious question.

[oschwald]

You should be able to just create a File with the file system path, similar to this example. Perhaps the question is how to find the file on the file system. I don't know the details of how you are deploying, but a relative path should work.

[jagtejsodhi]

Yup, that was it. For anyone else reading this who is using Spring Boot to deploy a WAR to AWS EB:

First, do not package the DB file with the WAR. After building the WAR, create a Zip file that contains the WAR and the .mmdb DB file. Deploy this Zip file to AWS EB. You can do so by running this on command line:

zip -r server_release.zip your_war_file_name.war GeoLite2-City.mmdb

In your code, when loading the DB file:

FileSystemResource resource = new FileSystemResource("./GeoLite2-City.mmdb");

if (resource.exists()) {
  DatabaseReader reader = new DatabaseReader.Builder(resource.getFile())
  .fileMode(Reader.FileMode.MEMORY_MAPPED)
  .withCache(new CHMCache())
  .build();
} else {
    // handle case where DB file not found
}

My EC2 instance seems to fine now (not using too much memory or running out). Hope this helps someone else.

Thanks @oschwald for the help.