bloom-filter: default value for components_memory_reclaim_threshold is too strict #18607
Labels
area/memory footprint
backport/5.2
Issues that should be backported to 5.2 branch once they'll be fixed
backport/5.4
Issues that should be backported to 5.4 branch once they'll be fixed
backport/6.0
status/regression
Milestone
components_memory_reclaim_threshold
controls when we start evicting bloom filters from memory. It defaults to 0.1, which comes down to 10% of the shard's memory. It looks like this is too strict and causes unnecessary bloom filter eviction in otherwise healthy clusters. One cluster which was impacted by this, had a BF/memory ratio of 0.6. The eviction mechanism was introduced to avert OOM disasters, not to enforce lean bloom filters and so the default should be adjusted accordingly and increased to as high as 0.8 or even maybe 0.9. The idea is that by default it should only kick in when OOM is iminent, it should not intervene on clusters which have high BF memory consumption but are otherwise fine.The text was updated successfully, but these errors were encountered: