[SOLR-13446] Improve default heap size and related handling

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 8.0
• Component/s: scripts and tools
• Assignee: Unassigned
• Reporter: Shawn Heisey
• Created: 03/May/19 20:03
• Updated: 08/Jun/19 15:00

Description

Solr's scripts have a default max heap setting of 512MB. I think it's fair to say that for a production install, this is ridiculously small. Nearly everyone who runs a Solr server will need to increase this value.

I think it would be useful to issue a warning in the log when the heap size is below a certain value. Text like "Detected max heap size is XXXX. It might be necessary to increase the heap size for proper operation. See https://lucene.apache.org/solr/path/to/ref/guide/location for details."

For people who are running very small servers, there should be a config option to turn off that logging when somebody knows that the default heap size is perfectly fine for their setup.

At the same time, we also need to improve the default heap size. I'm going to ask everyone to bikeshed about what the new default should be. Initial thought is a 2GB default, to be made smaller automatically if detected system memory is low. If the admin has explicitly set the heap size, then none of this will take place.