On 5/24/2022 10:33 PM, Paul Russell wrote:
Thanks for the link. We’ll see what the patch provides for additional info. We are aware of the need to reindex for solr 9. We will reindex to a separate instance. Are there performance benefits to using the core upgrade utility when going from 7.7.x to 8.11?
In general, things do get at least marginally faster with a major version upgrade. I do not recall seeing mentions of any significant performance regressions in core functionality. We have heard about some of the more exotic features of Solr going slower when someone upgrades.
One of the significant ancillary changes from 7 to 8 is switching garbage collection from CMS to G1GC. This change does require slightly more memory, but it should be off-heap memory, so I don't think the GC change would directly cause a heap-related OOME unless you were already on the verge of that. But if the heap is what caused the OOME ... upgrades to Solr will usually require at least slightly more heap ... because that is the primary tradeoff in most search engines -- using memory to increase performance.
It will be very important to see what resource was depleted when OOME is thrown, which is where the patch to the bin/solr script will be helpful. What happens when the patch is installed is that java is configured to crash when an OOME happens, and it will create a crash log which shows the first line from the OOME exception, describing what resource was depleted.
Thanks, Shawn
