Email searching is slow or not working with Dovecot Solr

Symptoms

Email searching slow

Email searching returns a server error

• Server Error (Internal Server Error)
• Server error (OK)

Dovecot Solr failed notifications

The service “cpanel-dovecot-solr” appears to be down.

Dovecot Solr memory errors

# Native memory allocation (mmap) failed to map 49164288 
bytes for committing reserved memory.

OpenJDK 64-Bit Server VM warning: 
INFO: os::commit_memory(0x00000001e3a00000, 1050148864, 0) 
failed; error='Cannot allocate memory' (errno=12)

Cause

Dovecot Solr is exceeding its memory limit when searching for emails. Exceeding the memory causes the service to fail when executing queries. If the database becomes too large, it can also cause searches to fail because the service crashes during a query. Searches on large databases or large email accounts can also become very slow.

Resolution

Increase the memory limit.

• Edit the configuration file at the path /etc/sysconfig/cpanel-dovecot-solr
• Change the default value from SOLR_MEMORY="512m" to SOLR_MEMORY="1024m" or higher if needed.

• Restart the service 

  /usr/local/cpanel/scripts/restartsrv_cpanel_dovecot_solr