Tian Jiang created IOTDB-385:
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Summary: Bloom Filter for time ranges
Key: IOTDB-385
URL: https://issues.apache.org/jira/browse/IOTDB-385
Project: Apache IoTDB
Issue Type: Improvement
Reporter: Tian Jiang
Situation:
Device1 generates data at 1 pm, 5 pm, and 8 pm, Device2 generates data at 1 pm,
7 pm, and 8 pm. The query is "SELECT * FROM Device1, Device2 WHERE 13:00:00 <
time < 18:00:00".
It is clear that Device2 is not satisfied, but we still need to query it since
we currently only record startTime and endTIme for each device.
Solution:
For each device, assuming its startTime is t_s, then each timestamp _t_d >=
t_s_ can be cast to a time range id using: _id = ceiling((t_d - t_s) /
interval_length)_, where the interval_length is 1 hour for the above example.
Having this id, a bloom filter (maybe other filters) can be built to tell if we
truly have data satisfying the time condition.
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