Hi! I’m using InfluxDB to store real-time data from various energy monitors. I’ve had out of memory problems and would like to know if I’ve missed something obvious.
My hardware is 2Gb t2.medium AWS instance, with 8 databases. Each database is written to via HTTP at 10s intervals in a batch. Each batch contains about 10 readings. Based on the “hardware recommendations” this too little memory, but quite low requirements.
Generally the posting of data is fine. Memory problems occurs on compaction (solved via config file " max-concurrent-compactions = 1") and continuous queries (unsolved). My schema is generally:
use iotalcibne
Using database iotalcibne
show measurements
name: measurements
name
----
hourly
iotawatt
select * from iotawatt limit 10
time PF Volts Watts ct device units
---- -- ----- ----- -- ------ -----
2018-12-15T08:10:00Z 255.01 Lights1 ilcibne Watts
2018-12-15T08:10:00Z 269.43 Voltage ilcibne Volts
2018-12-15T08:10:00Z 0.748 Lights1PF ilcibne PF
2018-12-15T08:10:00Z 0.11 Power1Kitchen ilcibne Watts
2018-12-15T08:10:00Z 0.23 Power4SouthOffice ilcibne Watts
2018-12-15T08:10:00Z 0.24 Power5OpenPlan ilcibne Watts
2018-12-15T08:10:00Z 0.22 Power2Rack ilcibne Watts
2018-12-15T08:10:00Z 1012.44 TotalCircuits ilcibne Watts
2018-12-15T08:10:00Z 1011.41 TotalLights ilcibne Watts
2018-12-15T08:10:00Z 756.4 Lights2 ilcibne Watts
I think this is ‘good’ for memory usage: there are limited numbers of distinct tag values under “ct”. However, I have 8 databases with different names, each like this. The series count is 120
My question (finally!): from a memory-use / performance point of view, would I be better off have one single database? (This would have an additional tag-name “input-device” which would identify which of the 8 units posted the data.)
My “SHOW STATS” is attached: stats.txt (898.0 KB)
