We had several cases of OOM errors and I had thought it was related to
indexing or searching, but then noticed even when ES was idle (no
indexing or searching), an OOM would occur after 30-40 minutes of
I am using 8g min/max heap size, all other settings on default. Index
size is 125gb in 200m docs per day.
When I change the max_merged_segment to 2g (from default of 5g), the
OOM errors do not occur. We have the default setting of 10 segments,
though each newly created index has between 60-70 segments after a 24-
hour period, and auto-merge reduces that to about 50 segments after 48-
hours. We create a index every 24 hours and rarely write to a
Is it possible that merging is causing the OOM?